Split isolated input post for electrical measurement tools

Abstract

A device for performing electrical measurements according to the present disclosure includes a first input post that is electrically conductive, a second input post that is electrically conductive, and an electrically insulating sleeve at least partially surrounding the first and second input posts. The sleeve includes a first rib extending longitudinally of the sleeve and a second rib extending longitudinally of the sleeve. The first rib and the second rib are configured to separate the first and second input posts.

Description

[Technical field]

[0001] The present disclosure relates generally to electrical measurement tools, and more particularly to electrical measurement tools that enable a circuit breaker device to become non-conductive or an alarm device to generate an alarm in response to test leads being connected to input posts that are inconsistent with a selected mode of operation to reduce the risk of damage to the electrical measurement tool. [Background technology]

[0002] Electrical measurement tools such as digital multimeters have been used to measure a variety of different electrical properties, such as current, voltage, and resistance. A typical digital multimeter includes different input terminals to which electrical test leads may be connected to electrically connect the digital multimeter to an electrical circuit having an electrical property to be measured. Specifically, a typical digital multimeter includes four input terminals, including a first input terminal internally coupled to an electrical circuit arranged to measure relatively large currents, a second input terminal internally coupled to an electrical circuit arranged to measure moderate and relatively small currents, a third input terminal internally coupled to a common potential, and a fourth input terminal internally coupled to an electrical circuit arranged to measure voltage and other electrical properties.

[0003] In addition, a typical digital multimeter includes a knob that can be rotated by a user to select several different operating modes of the digital multimeter, e.g., operating modes for different types of current and voltage measurements. If a user connects test leads to the input terminals for measuring current with the knob rotated to a position corresponding to the operating mode for measuring voltage, a large current may flow through the digital multimeter. The large current may damage the device being tested and may blow the digital multimeter's internal fuse. If the power supply voltage exceeds the fuse rating of the digital multimeter's internal fuse, arcing, damage to the multimeter, and injury to the user may occur. Summary of the Invention

[0004] The present disclosure teaches a device including one or more split input terminals used for current measurement that can reduce the risk of damage to the device. A controller coupled to the split input terminals receives signals indicative of the mode in which the device is operating and signals indicative of whether a test lead is inserted into the split input terminal and whether the input posts of the split input terminal are electrically coupled to each other. The controller can cause a circuit interruption device to be non-conductive to protect internal components of the device, such as fuses. Additionally or alternatively, the controller can cause an alert device to generate an alert for a user of the device, so that the user can take corrective action before damage to the device or injury to the user occurs. [Brief description of the drawings]

[0005] [Figure 1] FIG. 2 is a front plan view of the exterior of a device according to an embodiment described herein. [Figure 2A] 2 is a perspective view of an electrically insulating sleeve of a split input terminal included in the device shown in FIG. 1. [Figure 2B] 2 is a perspective view of an electrically insulating sleeve of a split input terminal included in the device shown in FIG. 1. [Figure 2C] 2 is a perspective view of a pair of input posts of a split input terminal included in the device shown in FIG. 1. [Figure 2D] FIG. 2D is a perspective view of a partially assembled split input terminal in which a pair of input posts shown in FIG. 2C are inserted into the electrically insulating sleeve shown in FIGS. 2A and 2B. [Figure 2E] 2 is a perspective view of a pair of electrical connectors of a split input terminal included in the device shown in FIG. 1. [Figure 2F] 2 is a perspective view of a pair of electrical connectors of a split input terminal included in the device shown in FIG. 1. [Figure 2G]FIG. 2C is a perspective view of a type of screw used to attach a pair of electrical connectors shown in FIGS. 2E and 2F to a pair of input posts included in a partially assembled split input terminal shown in FIG. 2D, according to an embodiment described herein. [Figure 3A] 2 is a cross-sectional view of a portion of the case of the device shown in FIG. 1. [Figure 3B] 3B is an enlarged perspective view of a portion of the case shown in FIG. 3A. FIG. [Figure 3C] FIG. 3B is a cross-sectional view of a portion of the case of the device shown in FIG. 3A with two partially assembled split input terminals inserted into the case. [Figure 3D] 3D is an enlarged perspective view of a portion of the case shown in FIG. 3C. FIG. [Figure 3E] FIG. 2 is a front view of a portion of a printed circuit board. [Figure 3F] FIG. 3C is a cross-sectional view of a portion of a partially assembled device including a portion of the case shown in FIG. 3C with the portion of the printed circuit board shown in FIG. 3E positioned on top and two split input terminals coupled to the printed circuit board. [Figure 3G] FIG. 3F is an enlarged perspective view of a portion of the device shown in FIG. 3F. [Figure 3H] FIG. 3H is a cross-sectional view of a portion of the device shown in FIG. 3F taken along line 3H according to an embodiment described herein. [Figure 4] FIG. 1 is a simplified block diagram of a device according to embodiments described herein. [Diagram 5] FIG. 2 is a logic flow diagram of a device according to embodiments described herein. [Figure 6A] FIG. 1 is a diagram illustrating the use of a device according to embodiments described herein. [Figure 6B] FIG. 1 is a diagram illustrating the use of a device according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] An electrical measurement tool may be damaged if used to measure an electrical property with test leads connected to input terminals of the electrical measurement tool that are inappropriate based on the selected mode of operation. For example, if a digital multimeter is operated in a voltage measurement mode and used to measure voltage with test leads connected to input terminals of the digital multimeter that are intended to measure current, the internal fuse of the digital multimeter may be damaged.

[0007] In accordance with the present disclosure, damage to the electrical measurement tool can be prevented. The present disclosure teaches a split input terminal that allows the electrical measurement tool to determine whether a test lead is connected to the input terminal while the electrical measurement tool is operating in a selected mode of operation. If the electrical measurement tool determines that a test lead is connected to the input terminal while the electrical measurement tool is operating in a selected mode of operation, the electrical measurement tool renders a circuit breaker device non-conductive to prevent current flow through components that may be damaged by improper operation of the electrical measurement tool. Additionally or alternatively, if the electrical measurement tool determines that a test lead is connected to the input terminal while the electrical measurement tool is operating in a selected mode of operation, the electrical measurement tool generates a warning on a warning device so that an operator of the electrical measurement tool may take corrective action (e.g., connect a test lead to a different input terminal or change the operating mode of the electrical measurement tool) before the electrical measurement tool is used in a manner that may damage the electrical measurement tool.

[0008] 1 is a diagram of an exterior view of a system or device 100 according to embodiments described herein. In one or more implementations, the device 100 is a digital multimeter. For example, the device may resemble in many relevant respects a Model 17B+ Digital Multimeter available from Fluke Calibration, as modified by the present disclosure.

[0009] The device 100 includes a case 102 that encloses various components of the device 100. A rotatable knob 104 is provided at a front portion of the case 102. The rotatable knob 104 can be rotated such that a tip of the knob is located at one of a number of positions 106a-106j at the front portion of the case 102.

[0010] More specifically, while the rotary knob 104 is rotated to position 106a, the device 100 is turned off and battery power is not supplied to the various electrical components of the device 100. While the rotary knob 104 is rotated to position 106b, the device 100 operates in a mode in which a relatively large alternating current (AC) voltage is measurable by the measurement circuitry. While the rotary knob 104 is rotated to position 106c, the device 100 operates in a mode in which a relatively large direct current (DC) voltage is measurable by the measurement circuitry. While the rotary knob 104 is rotated to position 106d, the device 100 operates in a mode in which a relatively small DC voltage is measurable by the measurement circuitry. While the rotary knob 104 is rotated to position 106e, the device 100 operates in a mode in which a resistance is measurable by the measurement circuitry, continuity can be checked by the measurement circuitry, or a diode junction is measurable by the measurement circuitry. While the rotatable knob 104 is rotated to position 106f, the device 100 operates in a mode in which a capacitance can be measured by the measurement circuit. While the rotatable knob 104 is rotated to position 106g, the device 100 operates in a mode in which a relatively large AC or DC current can be measured by the measurement circuit. While the rotatable knob 104 is rotated to position 106h, the device 100 operates in a mode in which a medium AC or DC current can be measured by the measurement circuit. While the rotatable knob 104 is rotated to position 106i, the device 100 operates in a mode in which a relatively small AC or DC current can be measured by the measurement circuit. While the rotatable knob 104 is rotated to position 106j, the device 100 operates in a mode in which a temperature can be measured by the measurement circuit.

[0011] The case 102 has four recessed portions 110-116 in which four input terminals 118-124 are respectively disposed. The input terminal 118 is a split input terminal including an electrically insulating sleeve surrounding two input posts spaced apart and electrically insulated from each other, at least one of the input posts of the split input terminal 118 being electrically coupled to a portion of a measurement circuit arranged to measure a relatively large AC or DC current. When a conductive connector of an electrical test lead is inserted into the insulating sleeve of the split input terminal 118, the conductive connector electrically couples the input posts of the split input terminal 118 to each other. The input terminal 120 is also a split input terminal having a configuration similar to that of the input terminal 118, at least one of the input posts of the split input terminal 120 being electrically coupled to a portion of a measurement circuit arranged to measure a medium and a relatively small AC or DC current. The input terminal 122 is a conventional input terminal including an electrically insulating sleeve and a single input post electrically coupled to a common or reference potential. Input terminal 124 is also a conventional input terminal and includes an electrically insulating sleeve and a single input post that is electrically coupled to various portions of a measurement circuit arranged, among other things, to measure voltages of different magnitudes.

[0012] In addition, device 100 includes an indicator 126 that is used to generate warnings to a user of device 100. For example, indicator 126 includes a red light-emitting diode (LED) that flashes when a user inserts a test least into split input terminal 118 or split input terminal 120 while rotatable knob 104 is rotated to a position that sets an operational mode other than an operational mode for current measurement. Device 100 also includes buttons 128a-128e that are used by a user to provide inputs to control the operation of device 100. In addition, device 100 includes a display device 130 that displays the results of electrical measurements, operational status information, and warnings. In one or more implementations, display device 130 includes a liquid crystal device (LCD) display screen.

[0013] 2A and 2B are perspective views of an electrical insulating sleeve 200 included in a split input terminal according to an embodiment described herein. For example, an electrical insulating sleeve 200 is included in each of the split input terminals 118 and 120 of the device 100 shown in FIG. 1. The electrical insulating sleeve 200 includes a generally cylindrical body portion 200a and a flange portion 200b extending radially from the body portion 200a. A rib 200c extends longitudinally of the electrical insulating sleeve 200 inside the body portion 200a and protrudes outwardly from the flange portion 200b. Similarly, a rib 200d extends longitudinally of the electrical insulating sleeve 200 inside the body portion 200a and protrudes outwardly from the flange portion 200b. The ribs 200c and 200d divide an inner compartment of the body portion 200a into distinct portions 200e and 200f spaced apart from each other by the ribs 200c and 200d. Thus, when the input posts are disposed in portions 200e and 200f, the input posts are spaced apart from one another and, therefore, the input posts are not electrically coupled to one another unless a test lead is inserted into insulating sleeve 200, which allows a controller of device 100 to determine when a test lead has been inserted into a split input terminal that includes the input posts, as described in more detail below.

[0014] 2A and 2B, rib 200c includes two side surfaces 200c1 and 200c2, and rib 200d includes two side surfaces 200d1 and 200d2. In one or more embodiments, side surfaces 200c1 and 200c2 of rib 200c are substantially perpendicular to the inner surface of cylindrical body portion 200a, and side surfaces 200d1 and 200d2 of rib 200d are substantially perpendicular to the inner surface of cylindrical body portion 200a. In one or more embodiments, side surfaces 200c1 and 200c2 of rib 200c form an angle of less than 90 degrees with the inner surface of cylindrical body portion 200a, and side surfaces 200d1 and 200d2 of rib 200d form an angle of less than 90 degrees with the inner surface of cylindrical body portion 200a. Side surfaces 200c1 and 200c2 of rib 200c and side surfaces 200d1 and 200d2 of rib 200d retain the input post of the split input terminal within insulating sleeve 200 during assembly of device 100.

[0015] 2C is a perspective view of a pair of input posts 210 and 212 of a split input terminal according to embodiments described herein. For example, a pair of input posts 210 and 212 are included in each of the split input terminals 118 and 120 of the device 100 shown in FIG. 1. The input post 210 includes a base portion 210a with an aperture 210b formed adjacent a threaded portion formed in the base portion 210a, and a curved terminal portion 210c extending from the base portion 210a. Similarly, the input post 212 includes a base portion 212a with an aperture 212b formed adjacent a threaded portion formed in the base portion 212a, and a curved terminal portion 212c extending from the base portion 212a.

[0016] Figure 2D is a perspective view of a partially assembled split input terminal with a pair of input posts 210 and 212, shown in Figure 2C, inserted into the electrically insulating sleeve 200 shown in Figures 2A and 2B. More specifically, input post 210 is inserted into portion 200e of the inner compartment of body portion 200a, and input post 212 is inserted into portion 200f of the inner compartment of body portion 200a. As seen in Figure 2D, ribs 200c and 200d of electrically insulating sleeve 200 keep input posts 210 and 212 spaced apart and electrically isolated from each other. After input post 210 and input post 212 are inserted into insulating sleeve 200, input post 210 contacts side surface 200c2 of rib 200c and side surface 200d2 of rib 200d, and input post 212 contacts side surface 200c1 of rib 200c and side surface 200d1 of rib 200d.

[0017] 2E and 2F are perspective views of a pair of electrical connectors 214 and 216 of a split input terminal according to embodiments described herein. For example, each of the split input terminals 118 and 120 of the device 100 shown in FIG. 1 includes a pair of electrical connectors 214 and 216. The electrical connector 214 includes a connection portion 214a for electrically connecting the split input terminal to a component of the device 100, a contact portion 214b for electrically connecting the electrical connector 214 to an input post of the split input terminal, an aperture 214c formed in the contact portion 214b, a retention portion 214d extending from the contact portion 214b, and a retention portion 214e extending from the contact portion 214b. In one or more implementations, the contact portion 214b is flat, and the retention portions 214d and 214e are perpendicular to the contact portion 214b. Similarly, the electrical connector 216 includes a connection portion 216a for electrically connecting the split input terminal to a component of the device 100, a contact portion 216b for electrically connecting the electrical connector 216 to an input post of the split input terminal, an aperture 216c formed in the contact portion 216b, a retention portion 216d extending from the contact portion 216b, and a retention portion 216e extending from the contact portion 216b. In one or more implementations, the contact portion 216b is flat and the retention portions 216d and 216e are perpendicular to the contact portion 216b.

[0018] 2G is a perspective view of a type of screw 218 used to attach a pair of electrical connectors 214 and 216 to a pair of input posts 210 and 212 included in the partially assembled split input terminal shown in FIG. 2D according to an embodiment described herein. The screw 218 includes a base portion 218a and a threaded portion 218b extending from the base portion 218a. The threaded portion 218b has a diameter smaller than the diameter of the apertures 210b and 212b of the pair of input posts 210 and 212 and smaller than the diameter of the apertures 214c and 216c of the pair of electrical connectors 214 and 216. The threaded portion 218b includes threads that mate with threads included in the threaded portions of the input posts 210 and 212.

[0019] 3A is a cross-sectional view of a portion of the case 102 of the device 100 shown in FIG. 1. FIG. 3B is an enlarged perspective view of the portion of the case 102 shown in FIG. 3A. As shown in FIG. 3B, the recessed portion 110 of the case 102 includes a generally cylindrical side wall 110a. The end of the recessed portion 110 of the case 102 includes an aperture 110b and a separation portion 110c that extends across the aperture case and divides the aperture 110b into two portions. The structure of the recessed portion 112 is similar to that of the recessed portion 110.

[0020] FIG. 3C is a cross-sectional view of a portion of the case 102 of the device 100 shown in FIG. 3A with two partially assembled split input terminals inserted into the case 102. FIG. 3D is an enlarged perspective view of the portion of the case 102 shown in FIG. 3C. More specifically, FIGS. 3C and 3D show the portion of the case 102 of the device 100 shown in FIG. 3A after two partially assembled split input terminals (each similar to the partially assembled split terminal shown in FIG. 2D) have been inserted into the recessed portions 110 and 112 from the front side of the case 102. As shown in FIGS. 3C and 3D, when the input terminals 210 and 212 are inserted into the recessed portions 110, the split portion 110c is disposed between the base portion 210a of the input post 210 and the base portion 212a of the input post 212.

[0021] 3E is a front view of a portion of a printed circuit board 220 according to embodiments described herein. The printed circuit board 220 has apertures 220a-d formed therein, each corresponding to a recessed portion of the case 102. More specifically, aperture 220a corresponds to recessed portion 116 of the case 102, aperture 220b corresponds to recessed portion 114 of the case 102, aperture 220c corresponds to recessed portion 112 of the case 102, and aperture 220d corresponds to recessed portion 110 of the case 102. The printed circuit board 220 has electrical conductors 222a-f formed thereon, each of which is coupled to a conductive trace that is coupled to an electrical component of the device 100.

[0022] 3F is a cross-sectional view of a portion of a partially assembled device 100 including a portion of the case 102 shown in FIG. 3C with a portion of the printed circuit board 220 shown in FIG. 3E disposed thereon and two split input terminals 118 and 120 coupled to the printed circuit board 220. More specifically, each of the electrical connectors of the split input terminals 118 and 120 is soldered to an electrical conductor formed on the printed circuit board 220. For example, the electrical connector 214 of the split input terminal 118 is soldered to the electrical conductor 222a and the electrical connector 216 of the split input terminal 118 is soldered to the electrical conductor 222b. As shown in FIG. 3F, the recessed portions 118-124 of the case 102 are disposed in any one of the apertures 220a-220d formed in the printed circuit board 220.

[0023] FIG. 3G is an enlarged perspective view of a portion of the device 100 shown in FIG. 3F. The electrical connector 214 is coupled to the input post 210 using a screw 218, and the electrical connector 216 is coupled to the input post 212 using a screw 218. As shown in FIG. 3G, the retaining portion 214d of the electrical connector 214 is disposed on a side surface of the electrical connector 214 between the electrical connectors 214 and 216. Similarly, the retaining portion 216d of the electrical connector 216 is disposed on a side surface of the electrical connector 216 between the electrical connectors 214 and 216. The retaining portion 214d of the electrical connector 214 and the retaining portion 216d of the electrical connector 216 are offset from each other across the separation portion 110c so as not to contact each other. Also, the retaining portion 214e of the electrical connector 214 and the retaining portion 216e of the electrical connector 216 are provided on the side wall 110a of the recessed portion 110 of the case 102. Retaining portions 214d and 214e of electrical connector 214 prevent electrical connector 214 from rotating while screw 218 is turned (e.g., with a screwdriver) to attach electrical connector 214 to input post 210. Similarly, retaining portions 216d and 216e of electrical connector 216 prevent electrical connector 216 from rotating while screw 218 is turned to attach electrical connector 216 to input post 212.

[0024] Figure 3H is a cross-sectional view of a portion of device 100 taken along line 3H of Figure 3F, according to an embodiment described herein. As shown in Figure 3H, the input posts of each of split input terminals 118 and 120 are held apart from one another by ribs (e.g., rib 200c) of electrically insulating sleeve 200 and by separate portions (e.g., separate portion 110c) of recessed portions 110 and 112 of case 102.

[0025] Figure 4 is a simplified block diagram of device 100 according to an embodiment described herein. Figure 4 shows split input terminal 118 and a conventional common input terminal 122. For simplicity of explanation, Figure 4 does not show split input terminal 120. However, split input terminal 120 is connected in a manner similar to the manner in which split input terminal 118 is connected, as described below.

[0026] 4, the input post 210 of the split input terminal 118 is electrically coupled (e.g., with a wire and solder) to a first terminal of a pull-up resistor 224, which has a second terminal electrically coupled to a power supply terminal V+ that is coupled to a logic high voltage output from a power supply (e.g., a battery). In addition, the input post 210 of the split input terminal 118 is electrically coupled to a detection circuit 226, which is electrically coupled to a controller 228. In one or more embodiments, the controller 228 includes a processor and a memory that stores instructions that, when executed by the processor, cause the controller 228 to perform the functions of the controller 228 described herein. In one or more implementations, the detection circuit 226 outputs a signal having a logic high voltage while an electrical test lead is not inserted into the split input terminal 118 and outputs a signal having a logic low voltage while an electrical test lead is inserted into the split input terminal 118.

[0027] The other input post 212 of the split input terminal 118 is electrically coupled to a first terminal of a circuit breaker device 230 having a control terminal electrically coupled to a controller 228. The circuit breaker device 230 also has a second terminal electrically coupled to a first terminal of a fuse 232. The controller 228 provides a control signal to the circuit breaker device 230 that controls whether the circuit breaker device 230 is in a conductive state in which the first and second terminals of the circuit breaker device 230 are electrically coupled to one another, or in a non-conductive state in which the first and second terminals of the circuit breaker device 230 are not electrically coupled to one another. For example, when the control signal provided by the controller 228 to the circuit breaker device 230 has a logical low value, the circuit breaker device 230 is in a non-conductive state, and when the control signal provided by the controller 228 to the circuit breaker device 230 has a logical high value, the circuit breaker device 230 is in a conductive state. Examples of the circuit breaker device 230 include a relay, a contactor, and a reed switch. When the circuit breaker device 230 is in a non-conducting state, the input post 212 of the split input terminal 118 is not electrically coupled to the fuse 232, which prevents the fuse 232 from being damaged (e.g., blown) when a large voltage at open circuit (VOC) is present between the split input terminal 118 and the common terminal 122. A second terminal of the fuse 232 is electrically coupled to a first terminal of a shunt resistor 234. A second terminal of the shunt resistor 234 is electrically coupled to the common input terminal 122.

[0028] Additionally, a mode selection circuit 236 and an alarm circuit 238 are electrically coupled to the controller 228. In one or more implementations, the mode selection circuit 236 includes an encoder mechanically coupled to the rotatable knob 104, generates one or more signals indicative of an operational mode corresponding to a current position of the rotatable knob 104, and provides one or more signals indicative of the operational mode to the controller 228. The operational mode corresponds to a particular operational mode selected using the rotatable knob 104. The controller 228 uses the one or more signals indicative of the operational mode provided by the mode selection circuit 236 and the signal provided by the detection circuit 226 to determine whether to place the circuit breaker device 230 in a conducting or non-conducting state and whether to generate an alert to the alarm circuit 238 or the display device 130.

[0029] In one or more embodiments, when the tip of the rotatable knob 104 is positioned at position 106a, which corresponds to the VAC mode of operation, the mode selection circuit 236 provides one or more signals to the measurement circuit 118 indicative of a code of "0001". When the tip of the rotatable knob 104 is positioned at position 106b, which corresponds to the VDC mode of operation, the mode selection circuit 236 provides one or more signals to the measurement circuit 118 indicative of a code of "0010". When the tip of the rotatable knob 104 is positioned at position 106c, which corresponds to the mV DC mode of operation, the mode selection circuit 236 provides one or more signals to the measurement circuit 118 indicative of a code of "0011". When the tip of the rotatable knob 104 is positioned at position 106d, which corresponds to the mV DC mode of operation, the mode selection circuit 236 provides one or more signals to the measurement circuit 118 indicative of a code of "0100". When the tip of the rotary knob 104 is positioned at position 106e, which corresponds to the Ω mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “0101” to the measurement circuit 118. When the tip of the rotary knob 104 is positioned at position 106f, which corresponds to the capacitance mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “0110” to the measurement circuit 118. When the tip of the rotary knob 104 is positioned at position 106g, which corresponds to the A AC or DC mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “0111” to the measurement circuit 118. When the tip of the rotary knob 104 is positioned at position 106h, which corresponds to the mA AC or DC mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “1000” to the measurement circuit 118. When the tip of the rotatable knob 104 is positioned at position 106i, which corresponds to the μA mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “1001” to the measurement circuit 118. When the tip of the rotatable knob 104 is positioned at position 106j, which corresponds to the °C mode of operation, the mode selection circuit 236 provides one or more signals indicative of a code of “1010” to the measurement circuit 118.

[0030] In one or more implementations, the alarm circuit 238 includes a sound emitting device (e.g., a buzzer) that emits a sound when the controller 228 applies current to the sound emitting device. In one or more implementations, the alarm circuit 238 includes a speaker, and the controller 228 causes the speaker to emit a sound that warns that damage to the device 100 may occur if the device 100 is operated in the current operating mode because a test is inserted into a particular terminal (e.g., split input terminal 118 or 120). Additionally or alternatively, the alarm circuit 238 may include a light emitting device (e.g., an LED) that emits light when the controller 228 applies current to the light emitting device. In one or more implementations, a switch is electrically coupled between the alarm circuit 238 and a terminal coupled to the voltage provided by the battery, and the controller 228 provides a control signal that causes the switch to be in a conducting or non-conducting state depending on the voltage level of the control signal. For example, when the control signal provided by the controller 228 has a logical low voltage, the switch is in a non-conductive state, thereby preventing the voltage provided by the battery from being supplied to the alarm circuit 228 and no alarm or warning is generated by the alarm circuit 238, and when the control signal provided by the controller 228 has a logical high voltage, the switch is in a conductive state, thereby allowing the voltage provided by the battery to be supplied to the alarm circuit 228 and an alarm or warning is generated by the alarm circuit 238.

[0031] [Table 1]

[0032] Table 1 above illustrates an example of a logic table that may be stored by the controller 228 and used to determine whether to place the circuit breaker device 230 in a conducting or non-conducting state and whether to cause the alarm circuit 238 to generate an alarm or warning (e.g., emit an alarm sound and / or turn on a warning light) to alert a user that damage to the device 100 may occur if the device 100 is operated in its current configuration.

[0033] 5 is a logic flow diagram illustrating a logic flow 300 of the device 100 according to embodiments described herein. In one or more implementations, the logic flow 300 corresponds to the logic flow of the controller 228. The logic flow 300 begins at 302.

[0034] At 302, a determination is made whether a current measurement mode of operation has been selected. For example, the current measurement mode of operation includes three modes of operation corresponding to A, mA, or μA measurement, and the modes of operation not for current measurement include modes of operation corresponding to V ac, V dc, mV dc, capacitance, Ω, or °C. The controller 228 determines whether a current measurement mode of operation has been selected based on one or more signals provided by the mode selection circuit 236. If at 302, it is determined that the current measurement mode of operation has been selected, the logic flow 300 proceeds to 304. If at 302, it is determined that the current measurement mode of operation has not been selected, the logic flow 300 proceeds to 306.

[0035] At 304, the circuit breaker device is controlled to be in a conducting state or the warning device is controlled to stop generating a warning. For example, the controller 228 provides a control signal to the circuit breaker device 230 having a logic low voltage that causes the circuit breaker device 230 to be in a conducting state. Additionally or alternatively, the controller 228 provides a control signal to the alarm circuit 238 having a logic low voltage that causes the alarm circuit 238 to stop generating an alarm or warning. Additionally or alternatively, the controller 228 provides a control signal to the display device 130 that causes the display device 130 to stop generating a warning (e.g., stop displaying the warning message). The logic flow 300 then returns to 302.

[0036] At 306, a determination is made as to whether an electrical test lead is connected to the split input terminal. For example, the controller 228 determines whether a test lead is connected to the split input terminal 118 by determining whether the signal provided by the detection circuit 226 has a logic high voltage or a logic low voltage. If at 306, it is determined that a test lead is connected (e.g., the signal provided by the detection circuit 226 has a logic low voltage), the logic flow 300 proceeds to 308. If at 306, it is determined that a test lead is not connected (e.g., the signal provided by the detection circuit 226 has a logic high voltage), the logic flow 300 proceeds to 310.

[0037] At 308, the circuit breaker device is controlled to be in a non-conducting state or the warning device is controlled to generate a warning. For example, the controller 228 provides a control signal to the circuit breaker device 230 having a logic high voltage that causes the circuit breaker device 230 to be in a non-conducting state. Additionally or alternatively, the controller 228 provides a control signal to the alarm circuit 238 having a logic high voltage that causes the alarm circuit 238 to generate an alarm or warning. Additionally or alternatively, the controller 228 provides a control signal to the display device 130 that causes the display device 130 to generate a warning by displaying a warning message (e.g., "WARNING! Damage may occur if the test leads are not removed from the A or mA μA input terminals or the operating mode is not changed"). The logic flow 300 then returns to 302.

[0038] At 310, the circuit breaker device is controlled to be in a conducting state or the warning device is controlled to stop generating a warning. For example, the controller 228 provides a control signal having a logic low voltage to the circuit breaker device 230, which causes the circuit breaker device 230 to be in a conducting state. Additionally or alternatively, the controller 228 provides a control signal to the alarm circuit 238 having a logic low voltage that causes the alarm circuit 238 to stop generating an alarm or warning. Additionally or alternatively, the controller 228 provides a control signal to the display device 130 that causes the display device 130 to stop generating a warning (e.g., stop displaying the warning message). The logic flow 300 then returns to 302.

[0039] 6A and 6B are diagrams for illustrating the use of the device 100 according to the embodiments described herein. FIG. 6A shows an example in which the device 100 is used to measure a current flowing through a circuit 402. The circuit 402 includes a voltage source 404, a switch 406, a node 408, a node 410, and a resistor 412 electrically coupled in series. A user connects a first connector of a test lead 414 to the common terminal 122 and a second connector of the test lead 414 to the node 410. A user also connects a first connector of a test lead 416 to the split input terminal 118 and a second connector of the test lead 416 to the node 408. In addition, a user rotates the rotary knob 104 so that the tip is in a position 106f corresponding to a current measurement operation mode (e.g., A). A user closes the switch 406 of the circuit 402, and the current flowing from the node 408 to the node 410 is measured by the measurement circuit, and the result of the current measurement is displayed by the display device 130.

[0040] 6A illustrates correct operation of the device 100. In other words, the user has rotated the rotatable knob 104 to a position corresponding to a current measurement mode of operation suitable for connecting a test lead to the split input terminal 118. Thus, the device 100 does not render the circuit breaker device 130 non-conductive and does not generate a warning via the display device 130 or the alarm circuit 238. However, if the user subsequently rotates the rotatable knob 104 to a position not corresponding to a current measurement mode of operation (e.g., V AC) while the test lead 416 is connected to the split input terminal 118 (or split input terminal 120), the device 100 renders the circuit breaker device 130 non-conductive and generates a warning via the display device 130 or the alarm circuit 238 until the user either disconnects the test lead 416 from the split input terminal 118 (or split input terminal 120) or rotates the rotatable knob 104 to a position corresponding to a current measurement mode of operation.

[0041] 6B illustrates an example in which device 100 is used to measure a voltage between two terminals of a voltage source 418. A user connects a first connector of test lead 414 to common terminal 122 and a second connector of test lead 414 to one of the terminals of voltage source 418. The user also connects a first connector of test lead 416 to input terminal 124 and a second connector of test lead 416 to the other terminal of voltage source 418. In addition, the user rotates rotatable knob 104 to position 106a that does not correspond to a current measurement mode of operation (e.g., V AC).

[0042] 6B illustrates correct operation of the device 100. In other words, the user has rotated the rotatable knob 104 to a position that does not correspond to a current measurement mode of operation suitable for connecting a test lead to the input terminal 124. Thus, the device 100 does not place the circuit breaker device 130 in a non-conductive state and does not generate a warning via the display device 130 or the alarm circuit 238. However, if the user subsequently disconnects the first connector of the test lead 416 from the input terminal 124 and then connects the first connector of the test lead 416 to the split input terminal 118 or 120 while the rotatable knob 104 is in the position shown in FIG. 6B, this will cause the circuit breaker device 130 to be placed in a non-conductive state or generate a warning via the display device 130 or the alarm circuit 238 until the user disconnects the test lead 416 from the split input terminal 118 (or the split input terminal 120) or rotates the rotatable knob 104 to a position that corresponds to a current measurement mode of operation.

[0043] The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, as necessary, using concepts from various patents, applications, and publications to provide still further embodiments. Although the mode selection circuit 236 described above outputs a code indicating a position of the rotatable knob 104 that corresponds to an operational mode of the device 100, the mode selector 104 may be implemented using different types of selection mechanisms. For example, the mode selector 104 can include a touch screen that outputs different codes that each correspond to a different operational mode of the device 100 based on a selection made using the touch screen.

[0044] A device for performing electrical measurements according to the present disclosure may be summarized as including a first input post that is electrically conductive, a second input post that is electrically conductive, and an electrically insulating sleeve at least partially surrounding the first and second input posts. The sleeve may include a first rib extending longitudinally of the sleeve and a second rib extending longitudinally of the sleeve. The first rib and the second rib may be configured to separate the first and second input posts.

[0045] The device may be a digital multimeter, and the first input post, the second input post, and the sleeve may be included in an input terminal for measuring current.

[0046] The device may further include a case. The case may include a portion extending across an aperture formed in the case. The first input post and the second input post may extend through an aperture formed in the case, and the portion of the case extending across the aperture formed in the case is disposed between the first input post and the second input post.

[0047] The first input post may contact a first surface of the first rib and a first surface of the second rib, and the second input post may contact a second surface of the first rib and a second surface of the second rib.

[0048] The device may further include a circuit board, a first electrical connector electrically coupled to the first input post and the first electrical conductor on the circuit board, and a second electrical connector electrically coupled to the second input post and the second electrical conductor on the circuit board. The first electrical connector may be coupled to the first input post and the second electrical connector may be coupled to the second input post by a screw. The first electrical connector may be coupled to the first electrical conductor and the second electrical connector may be coupled to the second electrical conductor by a solder.

[0049] The device may further include a case including a recessed portion within which the first input post, the second input post, and the sleeve are at least partially disposed, and a circuit board including an aperture within which the recessed portion of the case may be disposed.

[0050] The device may further include a first electrical connector electrically coupled to the first input post, a second electrical connector electrically coupled to the second input post, and a case including a recessed portion within which the first input post, the second input post, and the sleeve are at least partially disposed. The first electrical connector and the second electrical connector may each include a contact portion, a first retention portion extending from the contact portion, and a second retention portion extending from the contact portion. The contact portion and the first retention portion of the first electrical connector may be disposed on the first input post, and the second retention portion of the first electrical connector may be disposed on a sidewall of the recessed portion of the case. The contact portion and the first retention portion of the second electrical connector may be disposed on the second input post, and the second retention portion of the second electrical connector may be disposed on a sidewall of the recessed portion of the case.

[0051] The device may further include a mode selection circuit that outputs at least one signal indicative of at least one mode in which the device operates, a detection circuit that outputs at least one signal indicative of whether the first input post is electrically coupled to the second input post, and a controller that outputs at least one control signal based on the at least one signal output by the mode selection circuit and the at least one signal output by the detection circuit. The device may further include a circuit breaker device that receives the at least one control signal output by the controller. The at least one control signal can place the circuit breaker device in a non-conductive state while the at least one signal output by the mode selection circuit indicates a first mode in which the device operates and the at least one signal output by the detection circuit indicates that the first input post is electrically coupled to the second input post. The at least one control signal can place the circuit breaker device in a conductive state while the at least one signal output by the mode selection circuit indicates a second mode in which the device operates and the at least one signal output by the detection circuit indicates that the first input post is electrically coupled to the second input post. The device may further include a warning device that receives the at least one control signal output by the controller. The at least one control signal can cause the warning device to generate a warning while the at least one signal output by the mode selection circuit indicates a first mode in which the device operates and the at least one signal output by the detection circuit indicates that the first input post is electrically coupled to the second input post. The at least one control signal can cause the warning device to stop generating a warning while the at least one signal output by the mode selection circuit indicates a second mode in which the device operates and the at least one signal output by the detection circuit indicates that the first input post is electrically coupled to the second input post.

[0052] A system for performing electrical measurements according to the present disclosure may be summarized as including a split input terminal including a first input post, a second input post, and an electrically insulating sleeve at least partially surrounding the first and second input posts, the sleeve including a pair of ribs extending longitudinally of the sleeve to separate the first and second input posts, and a controller coupled to the split input terminal and configured to control a circuit breaker device or an alarm device based on a device operation mode associated with a status of electrical connectivity between the first and second input posts.

[0053] The controller can control the circuit breaker device to a non-conducting state or control the warning device to generate a warning while the device operational mode is in a first mode and the status of the electrical connectivity is a status where the first input post is electrically coupled to the second input post. The controller can control the circuit breaker device to a conducting state or control the warning device to cease generating a warning while the device operational mode is in a second mode and the status of the electrical connectivity is a status where the first input post is electrically coupled to the second input post. The controller can control the circuit breaker device to a conducting state or control the warning device to cease generating a warning while the status of the electrical connectivity is a status where the first input post is not electrically coupled to the second input post.

[0054] The system may further include a mode selection circuit that outputs at least one signal to the controller indicative of a device operating mode, and a detection circuit that outputs at least one signal to the controller indicative of a status of the electrical connection between the first input post and the second input post.

[0055] The warning device may be at least one of a light emitting device that emits light, a sound emitting device that emits sound, and a display device that displays a message.

[0056] A method of operating a digital multimeter device to reduce a risk of damaging the digital multimeter device according to the present disclosure may be summarized as including receiving at least one signal indicative of a mode in which the digital multimeter device is operating, receiving at least one signal indicative of whether a first input post of the split input terminal is electrically coupled to a second input post of the split input terminal, and causing a circuit breaker device to become non-conductive or an alarm device to generate an alarm based on the at least one signal indicative of a mode in which the digital multimeter device is operating and the at least one signal indicative of whether the first input post is electrically coupled to the second input post.

[0057] Placing the circuit breaker device in a non-conductive state or causing the warning device to generate a warning may include causing the circuit breaker device to be in a non-conductive state or causing the warning device to generate a warning while the at least one signal indicative of a mode in which the digital multimeter is operating indicates a first mode and the at least one signal indicative of whether the first input post is electrically coupled to the second input post indicates that the first input post is electrically coupled to the second input post, and the method may further include ceasing causing the circuit breaker device to be in a conductive state or causing the warning device to generate a warning while the at least one signal indicative of a mode in which the digital multimeter device is operating indicates a second mode, different from the first mode, and the at least one signal indicative of whether the first input post is electrically coupled to the second input post indicates that the first input post is electrically coupled to the second input post.

[0058] The method may further include placing the circuit breaker device in a conductive state or causing the warning device to cease generating the warning while the at least one signal indicating whether the first input post is electrically coupled to the second input post indicates that the first input post is not electrically coupled to the second input post.

[0059] Placing the circuit breaker device in a non-conducting state or causing the warning device to generate a warning may include placing the circuit breaker device in a non-conducting state and causing the warning device to generate a warning.

[0060] The step of causing the warning device to generate a warning may include at least one of causing a light emitting device to emit light, causing a sound emitting device to emit a sound, or causing a display device to display a message.

[0061] These and other changes can be made to the embodiments in light of the above Detailed Description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but rather to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure herein.

Claims

1. A device (100) for performing electrical measurements, said device (100) comprising: a first input post (210) that is conductive; a second input post (212) that is conductive; an electrically insulating sleeve (200) at least partially surrounding said first input post (210) and said second input post (212); The sleeve (200) has a first rib (200c) extending in a longitudinal direction of the sleeve (200) and a second rib (200d) extending in the longitudinal direction of the sleeve (200); The device (100), wherein the first rib (200c) and the second rib (200d) are configured to separate the first input post (210) and the second input post (212).

2. the device (100) being a digital multimeter; The device (100) of claim 1, wherein the first input post (210), the second input post (212), and the sleeve (200) are included in an input terminal (118) for measuring current.

3. The device further includes a case (102), the case (102) includes a portion (110c) extending across an aperture (110b) formed in the case (102); 2. The device (100) of claim 1, wherein the first input post (210) and the second input post (212) extend through the aperture (110b) formed in the case (102), and a portion (110c) of the case (102) that extends across the aperture (110b) formed in the case (102) is disposed between the first input post (210) and the second input post (212).

4. the first input post (210) is in contact with a first surface (200c1) of the first rib (200c) and a first surface (200d1) of the second rib (200d); 2. The device (100) of claim 1, wherein the second input post (212) is in contact with a second surface (200c2) of the first rib (200c) and a second surface (200d2) of the second rib (200d).

5. A circuit board (220); a first electrical connector (214) electrically coupled to the first input post (210) and to a first electrical conductor (222a) on the circuit board (220); a second electrical connector (216) electrically coupled to the second input post (212) and to a second electrical conductor (222b) on the circuit board (220); The first electrical connector (214) is coupled to the first input post (210) and the second electrical connector (216) is coupled to the second input post (212) by a screw (218); 2. The device (100) of claim 1, wherein the first electrical connector (214) is coupled to the first electrical conductor (222a) and the second electrical connector (216) is coupled to the second electrical conductor (222b) by solder.

6. a case (102) including a recessed portion (110) into which the first input post (210), the second input post (212), and the sleeve (200) are at least partially disposed; The device (100) of claim 1, further comprising: a circuit board (220) including an aperture within which the recessed portion (110) of the case (102) is disposed.

7. a first electrical connector (214) electrically coupled to the first input post (210); a second electrical connector (216) electrically coupled to the second input post (212); a case (102) including a recessed portion (110) into which the first input post (210), the second input post (212), and the sleeve (200) are at least partially disposed; The first electrical connector (214) and the second electrical connector (216) each have a contact portion (214b, 216b), a first retention portion (214d, 216d) extending from the contact portion (214b, 216b), and a second retention portion (214e, 216e) extending from the contact portion (214b, 216b); the contact portion (214b) and the first retaining portion (214d) of the first electrical connector (214) are disposed on the first input post (210), and the second retaining portion (214e) of the first electrical connector (214) is disposed on a side wall (110a) of the recessed portion (110) of the case (102); 2. The device (100) of claim 1, wherein the contact portion and the first retaining portion (216d) of the second electrical connector (216) are disposed on the second input post (212), and the second retaining portion (216e) of the second electrical connector (216) is disposed on the side wall (110a) of the recessed portion (110) of the case (102).

8. a mode selection circuit (236) that outputs at least one signal indicative of at least one mode in which the device (100) is to operate; a detection circuit (226) that outputs at least one signal indicative of whether the first input post (210) is electrically coupled to the second input post (212); 2. The device (100) of claim 1, further comprising: a controller (228) that outputs at least one control signal based on the at least one signal output by the mode selection circuit (236) and the at least one signal output by the detection circuit (226).

9. a circuit breaker device (230) that receives the at least one control signal output by the controller (228); the at least one control signal causes the circuit breaker device (230) to be non-conductive while the at least one signal output by the mode selection circuit (236) indicates a first mode in which the device (100) is operating and the at least one signal output by the detection circuit (226) indicates that the first input post (210) is electrically coupled to the second input post (212); 9. The device (100) of claim 8, wherein the at least one control signal causes the circuit breaker device (230) to be conductive while the at least one signal output by the mode selection circuit (236) indicates a second mode in which the device (100) is operating and the at least one signal output by the detection circuit (226) indicates that the first input post (210) is electrically coupled to the second input post (212).

10. a warning device (130, 238) receiving the at least one control signal output by the controller (228); the at least one control signal causes the warning device (130, 238) to generate a warning while the at least one signal output by the mode selection circuit (236) indicates a first mode in which the device (100) is operating and the at least one signal output by the detection circuit (226) indicates that the first input post (210) is electrically coupled to the second input post (212); 9. The device (100) of claim 8, wherein the at least one control signal causes the warning device (130, 238) to stop generating the warning while the at least one signal output by the mode selection circuit (236) indicates a second mode in which the device (100) is operating and the at least one signal output by the detection circuit (226) indicates that the first input post (210) is electrically coupled to the second input post (212).

11. 1. A system for performing electrical measurements, the system comprising: a split input terminal (118) including a first input post (210), a second input post (212), and an electrically insulating sleeve (200) at least partially surrounding the first input post (210) and the second input post (212), the sleeve (200) including a pair of ribs (200c, 200d) extending longitudinally of the sleeve (200) to separate the first input post (210) and the second input post (212); a controller (228) coupled to the split input terminal (118) and configured to control a circuit breaker device (230) or an alarm device (130, 238) based on a device operation mode associated with a status of electrical connectivity between the first input post (210) and the second input post (212).

12. the controller (228) controls the circuit breaker device (230) to be non-conductive or controls the warning device (130, 238) to generate a warning while the device operating mode is in a first mode and the electrical connectivity status is a status in which the first input post (210) is electrically coupled to the second input post (212); 12. The system of claim 11, wherein the controller (228) controls the circuit breaker device (230) to be conductive or controls the warning device (130, 238) to stop generating the warning while the device operating mode is in a second mode and the electrical connectivity status is a status in which the first input post (210) is electrically coupled to the second input post (212).

13. 13. The system of claim 12, wherein the controller (228) controls the circuit breaker device (230) to be conductive or controls the warning device (130, 238) to stop generating the warning while the electrical connectivity status is a status in which the first input post (210) is not electrically coupled to the second input post (212).

14. a mode selection circuit (236) that outputs at least one signal to the controller (228) indicative of the device operating mode; 12. The system of claim 11, further comprising: a detection circuit (226) that outputs at least one signal to the controller (228) indicative of a status of electrical connectivity between the first input post (210) and the second input post (212).

15. 12. The system of claim 11, wherein the warning device (130, 238) is at least one of a light emitting device (100) that emits light, a sound emitting device (100) that emits sound, or a display device (130) that displays a message.

16. A method of operating a digital multimeter device (100) to reduce a risk of damaging the digital multimeter device (100), comprising: receiving at least one signal indicative of a mode in which the digital multimeter device (100) is operating; receiving at least one signal indicating whether a first input post (210) of a split input terminal (118) is electrically coupled to a second input post (212) of said split input terminal (118); and placing a circuit breaker device (230) in a non-conducting state or generating an alarm in an alarm device (130, 238) based on the at least one signal indicative of the mode in which the digital multimeter device (100) is operating and the at least one signal indicative of whether the first input post (210) is electrically coupled to the second input post (212).

17. placing the circuit breaker device (230) in a non-conducting state or causing the warning device (130, 238) to generate the warning comprises placing the circuit breaker device (230) in a non-conducting state or causing the warning device (130, 238) to generate the warning while the at least one signal indicative of a mode in which the digital multimeter device (100) is operating indicates a first mode and the at least one signal indicative of whether the first input post (210) is electrically coupled to the second input post (212) indicates that the first input post (210) is electrically coupled to the second input post (212); 17. The method of claim 16, further comprising: causing the circuit breaker device (230) to be conductive or causing the warning device (130, 238) to cease generating the warning while the at least one signal indicative of the mode in which the digital multimeter device (100) is operating indicates a second mode different from the first mode and the at least one signal indicative of whether the first input post (210) is electrically coupled to the second input post (212) indicates that the first input post (210) is electrically coupled to the second input post (212).

18. 18. The method of claim 17, further comprising placing the circuit breaker device in the conductive state or causing the warning device to cease generating the warning while the at least one signal indicating whether the first input post is electrically coupled to the second input post indicates that the first input post is not electrically coupled to the second input post.

19. 17. The method of claim 16, wherein causing the circuit breaker device (230) to be in a non-conducting state or causing the warning device (130, 238) to generate the warning comprises causing the circuit breaker device (230) to be in a non-conducting state and causing the warning device (130, 238) to generate the warning.

20. 17. The method of claim 16, wherein causing the warning device (130, 238) to generate the warning includes at least one of causing a light-emitting device (238) to emit light, causing a sound-producing device (238) to emit a sound, and causing a display device (130) to display a message.

Images