Voltage-stabilized power supply circuit for testing electronic level meter

Abstract

The utility model discloses a voltage-stabilized power supply circuit for testing an electronic level meter in the technical field of electronic level meter testing, which comprises a transformer, a middle shaft head of a secondary coil of the transformer is grounded, and two ends of the secondary coil of the transformer are connected with a rectification filter circuit. The rectification filter circuit is respectively connected with the positive voltage stabilizing circuit and the negative voltage stabilizing circuit, and the positive voltage stabilizing circuit and the negative voltage stabilizing circuit are connected with the filter output circuit. 220 V alternating current input from a power grid generates positive and negative direct current voltage through the transformer and the rectification filter circuit, the positive and negative direct current voltage is output to the positive voltage stabilizing circuit and the negative voltage stabilizing circuit, and the positive voltage stabilizing circuit and the negative voltage stabilizing circuit generate positive voltage output and negative voltage output respectively. The circuit is simple in structure, low in cost, convenient for follow-up maintenance and detection, and capable of providing long-time stable voltage for a test link of the electronic level meter.

Description

Technical Field

[0001] This utility model relates to a voltage regulator circuit for testing electronic levels. Background Technology

[0002] High-precision electronic levels are widely used in precision machining due to their high measurement accuracy. This high accuracy also places stringent requirements on the production and testing processes of high-precision electronic levels. A ±6V DC linear regulated power supply is used to power the testing phase of the high-precision electronic level. Electronic levels must undergo prolonged testing to prove their reliability, thus requiring a regulated power supply to provide a stable voltage over a long period. Furthermore, the testing process often involves simultaneously testing multiple instruments, necessitating a large current output from the regulated power supply to meet the power demands of the testing phase. Simultaneously, the stability of the regulated power supply's output voltage directly affects the accuracy and reliability of the electronic level's test results. In practical applications, switching power supplies are typically used as DC power sources. However, the output voltage of switching power supplies contains ripple signals of 10~100kHz and 50~200mV, which significantly interfere with the test results of high-precision electronic levels. Utility Model Content

[0003] The purpose of this invention is to provide a regulated power supply circuit for testing electronic levels. The circuit has a simple structure, low cost, and is convenient for subsequent maintenance and testing. It can provide a stable voltage for a long time during the testing process of electronic levels.

[0004] To achieve the above objectives, this utility model provides a regulated power supply circuit for testing an electronic level, including a transformer, with the intermediate shaft of the transformer's secondary coil grounded, and both ends of the transformer's secondary coil connected to a rectifier and filter circuit. The rectifier and filter circuit is connected to a positive voltage regulator circuit and a negative voltage regulator circuit, respectively, and the positive voltage regulator circuit and the negative voltage regulator circuit are connected to a filter output circuit.

[0005] Compared with the prior art, the beneficial effects of this utility model are that the 220 V AC power input from the power grid is transformed into positive and negative DC voltages through a transformer and rectifier filter circuit, and output to the positive voltage regulator circuit and the negative voltage regulator circuit. The positive voltage regulator circuit and the negative voltage regulator circuit respectively generate positive voltage output and negative voltage output. The output voltage is output as the power supply voltage after passing through the filter output circuit. The circuit structure is simple, the cost is low, and it is convenient for subsequent maintenance and testing. It can provide a stable voltage for a long time for the testing of electronic level instruments.

[0006] As a further improvement of this utility model, the rectifier filter circuit includes a rectifier bridge. The positive terminal of diode VD1 and the negative terminal of diode VD3 of the rectifier bridge are connected to one end of the secondary coil of the transformer. The positive terminal of diode VD2 and the negative terminal of diode VD4 of the rectifier bridge are connected to the other end of the secondary coil of the transformer. The negative terminals of diodes VD1 and VD2 are connected to the positive terminal of capacitor C11. The positive terminals of diodes VD3 and VD4 are connected to the negative terminal of capacitor C21. The negative terminal of capacitor C11 is connected to the positive terminal of capacitor C21.

[0007] In this way, the 220V AC power is transformed into positive and negative DC voltages through the transformer and rectifier bridge, and then output to the voltage regulator circuit after being filtered by the filter capacitors C11 and C21.

[0008] As a further improvement of this utility model, the positive voltage regulator circuit includes a three-terminal regulator U1. Pin 1 of the three-terminal regulator U1 is connected to the positive terminal of capacitor C11, the negative terminal of diode D11, and the collector of transistor Q11. The positive terminal of diode D11 is connected to pin 3 of the three-terminal regulator U1 and the base of transistor Q11. Pin 2 of the three-terminal regulator U1 is connected to one end of rheostat R11, one end of resistor R12, the positive terminal of capacitor C12, and the positive terminal of diode D12. Pin 3 of the three-terminal regulator U1 is connected to the other end of resistor R12, the negative terminal of diode D12, and one end of resistor R13. The other end of resistor R13 is connected to the emitter of transistor Q11.

[0009] Thus, the positive voltage regulator circuit generates a positive voltage output based on the adjustable three-terminal regulator U1. It uses a transient suppression diode D11 to suppress the surge current during power switching and protect the regulator. It also uses an NPN power transistor Q11 to improve the power supply's output capability.

[0010] As a further improvement of this utility model, the negative voltage regulator circuit includes a three-terminal regulator U2. Pin 1 of the three-terminal regulator U2 is connected to the negative terminal of capacitor C21, the positive terminal of diode D21, and the collector of transistor Q21. The negative terminal of diode D21 is connected to pin 3 of the three-terminal regulator U2 and the base of transistor Q21. Pin 2 of the three-terminal regulator U2 is connected to one end of rheostat R21, one end of resistor R22, the negative terminal of capacitor C22, and the negative terminal of diode D22. Pin 3 of the three-terminal regulator U2 is connected to the other end of resistor R22, the positive terminal of diode D22, and one end of resistor R23. The other end of resistor R23 is connected to the emitter of transistor Q21. The other end of rheostat R21 is connected to the other end of rheostat R11. The positive terminal of capacitor C22 is connected to the negative terminal of capacitor C12.

[0011] Thus, the negative voltage regulator circuit generates a negative voltage output based on the adjustable three-terminal regulator U2. It uses a transient suppression diode D21 to suppress the surge current during power switching and protect the regulator. It also uses a PNP power transistor Q21 to improve the power supply's output capability.

[0012] As a further improvement of this utility model, the filter output circuit includes capacitors C13 and C23. The positive terminal of capacitor C13 is connected to the emitter of transistor Q11 and one end of resistor R14. The negative terminal of capacitor C13 is connected to the positive terminal of capacitor C23. The negative terminal of capacitor C23 is connected to the emitter of transistor Q21 and one end of resistor R24. The other end of resistor R24 ​​is connected to the other end of resistor R14.

[0013] The voltage output from the positive and negative voltage regulator circuit is filtered by capacitors C13 and C23, ultimately resulting in a stable power supply voltage for testing. Attached Figure Description

[0014] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings:

[0016] like Figure 1 The circuit shown is a regulated power supply circuit for testing an electronic level, including a transformer. The intermediate shaft of the transformer's secondary coil is grounded. The two ends of the transformer's secondary coil are connected to a rectifier and filter circuit. The rectifier and filter circuit is connected to a positive voltage regulator circuit and a negative voltage regulator circuit, respectively. The positive voltage regulator circuit and the negative voltage regulator circuit are connected to a filter output circuit.

[0017] The rectifier filter circuit includes a rectifier bridge. The positive terminals of diodes VD1 and VD3 of the rectifier bridge are connected to one end of the secondary coil of the transformer. The positive terminals of diodes VD2 and VD4 of the rectifier bridge are connected to the other end of the secondary coil of the transformer. The negative terminals of diodes VD1 and VD2 are connected to the positive terminal of capacitor C11. The positive terminals of diodes VD3 and VD4 are connected to the negative terminal of capacitor C21. The negative terminal of capacitor C11 is connected to the positive terminal of capacitor C21.

[0018] The positive voltage regulator circuit includes a three-terminal regulator U1. Pin 1 of the three-terminal regulator U1 is connected to the positive terminal of capacitor C11, the negative terminal of diode D11, and the collector of transistor Q11. The positive terminal of diode D11 is connected to pin 3 of the three-terminal regulator U1 and the base of transistor Q11. Pin 2 of the three-terminal regulator U1 is connected to one end of rheostat R11, one end of resistor R12, the positive terminal of capacitor C12, and the positive terminal of diode D12. Pin 3 of the three-terminal regulator U1 is connected to the other end of resistor R12, the negative terminal of diode D12, and one end of resistor R13. The other end of resistor R13 is connected to the emitter of transistor Q11.

[0019] The negative voltage regulator circuit includes a three-terminal regulator U2. Pin 1 of the three-terminal regulator U2 is connected to the negative terminal of capacitor C21, the positive terminal of diode D21, and the collector of transistor Q21. The negative terminal of diode D21 is connected to pin 3 of the three-terminal regulator U2 and the base of transistor Q21. Pin 2 of the three-terminal regulator U2 is connected to one end of rheostat R21, one end of resistor R22, the negative terminal of capacitor C22, and the negative terminal of diode D22. Pin 3 of the three-terminal regulator U2 is connected to the other end of resistor R22, the positive terminal of diode D22, and one end of resistor R23. The other end of resistor R23 is connected to the emitter of transistor Q21. The other end of rheostat R21 is connected to the other end of rheostat R11. The positive terminal of capacitor C22 is connected to the negative terminal of capacitor C12.

[0020] The filter output circuit includes capacitors C13 and C23. The positive terminal of capacitor C13 is connected to the emitter of transistor Q11 and one end of resistor R14. The negative terminal of capacitor C13 is connected to the positive terminal of capacitor C23. The negative terminal of capacitor C23 is connected to the emitter of transistor Q21 and one end of resistor R24. The other end of resistor R24 ​​is connected to the other end of resistor R14.

[0021] In this invention, the adjustable three-terminal voltage regulator U1 with positive voltage output has an output voltage range of 1.25V to 37V, which can meet the power requirements of the electronic level. The output voltage is adjusted by a variable resistor R11 and a resistor D12. A 1.25V Zener diode D12 is connected between the output port and the ground port of the adjustable three-terminal voltage regulator U1, ensuring that the voltage between the output port and the ground port is 1.25V during normal operation. An NPN power transistor Q11 is used to increase the output current, which is the sum of the output current of the adjustable three-terminal voltage regulator U1 and the output current of the power transistor Q11.

[0022] The adjustable three-terminal regulator U2, with a negative voltage output, has an output voltage range of -37V to -1.2V, which meets the power requirements of the electronic level. The output voltage is adjusted using potentiometer R21 and resistor R22. A 1.25V Zener diode D22 connects the output port of the adjustable three-terminal regulator U2 to the ground port. During normal operation, the adjustable voltage between the output port and ground port of the adjustable three-terminal regulator U2 is -1.25V. A PNP power transistor Q21 is used to increase the output current, which is the sum of the output current of the adjustable three-terminal regulator U2 and the output current of the power transistor Q21.

[0023] During operation, the 220 V AC power input from the power grid is converted into positive and negative DC voltages through a 220 V to dual 9 V transformer and rectifier bridge. After being filtered by filter capacitors C11 and C21, the voltages are output to the positive and negative voltage regulation circuits.

[0024] The positive voltage regulator circuit is based on the adjustable three-terminal regulator U1 to generate a positive voltage output. It uses a transient suppression diode D11 to suppress the surge current during power switching and protect the regulator. It also uses an NPN power transistor Q11 to improve the power supply's output capability.

[0025] The negative voltage regulator circuit is based on the adjustable three-terminal regulator U2 to generate a negative voltage output. It uses a transient suppression diode D21 to suppress the surge current during power switching and protect the regulator. It also uses a PNP power transistor Q21 to improve the power supply's output capability.

[0026] The positive and negative voltages are filtered by capacitors C13 and C23 respectively before being output as the power supply voltage. The power supply circuit has a simple structure, low cost, and facilitates subsequent equipment maintenance and testing. The rated output voltage of the DC linear regulated power supply is ±6V, and the rated current is 1A.

[0027] This invention features excellent load regulation and high short-term and long-term stability of the output voltage, ensuring it does not interfere with high-precision electronic level testing and meets the requirements of the testing process. Furthermore, its simple circuit structure, low cost, and ease of subsequent equipment maintenance and testing facilitate easy application.

[0028] This utility model is not limited to the above embodiments. Based on the technical solutions disclosed herein, those skilled in the art can make some substitutions and modifications to some of the technical features without creative labor, and these substitutions and modifications are all within the protection scope of this utility model.

Claims

1. A regulated power supply circuit for testing electronic levels, characterized in that: It includes a transformer, the intermediate shaft of the transformer's secondary coil is grounded, the two ends of the transformer's secondary coil are connected to a rectifier and filter circuit, the rectifier and filter circuit is connected to a positive voltage regulator circuit and a negative voltage regulator circuit respectively, and the positive voltage regulator circuit and the negative voltage regulator circuit are connected to a filter output circuit.

2. The regulated power supply circuit for testing an electronic level according to claim 1, characterized in that: The rectifier filter circuit includes a rectifier bridge. The positive terminals of diodes VD1 and VD3 of the rectifier bridge are connected to one end of the secondary coil of the transformer. The positive terminals of diodes VD2 and VD4 of the rectifier bridge are connected to the other end of the secondary coil of the transformer. The negative terminals of diodes VD1 and VD2 are connected to the positive terminal of capacitor C11. The positive terminals of diodes VD3 and VD4 are connected to the negative terminal of capacitor C21. The negative terminal of capacitor C11 is connected to the positive terminal of capacitor C21.

3. The regulated power supply circuit for testing an electronic level according to claim 2, characterized in that: The positive voltage regulator circuit includes a three-terminal regulator U1. Pin 1 of the three-terminal regulator U1 is connected to the positive terminal of capacitor C11, the negative terminal of diode D11, and the collector of transistor Q11. The positive terminal of diode D11 is connected to pin 3 of the three-terminal regulator U1 and the base of transistor Q11. Pin 2 of the three-terminal regulator U1 is connected to one end of rheostat R11, one end of resistor R12, the positive terminal of capacitor C12, and the positive terminal of diode D12. Pin 3 of the three-terminal regulator U1 is connected to the other end of resistor R12, the negative terminal of diode D12, and one end of resistor R13. The other end of resistor R13 is connected to the emitter of transistor Q11.

4. The regulated power supply circuit for testing an electronic level according to claim 3, characterized in that: The negative voltage regulator circuit includes a three-terminal regulator U2. Pin 1 of the three-terminal regulator U2 is connected to the negative terminal of capacitor C21, the positive terminal of diode D21, and the collector of transistor Q21. The negative terminal of diode D21 is connected to pin 3 of the three-terminal regulator U2 and the base of transistor Q21. Pin 2 of the three-terminal regulator U2 is connected to one end of rheostat R21, one end of resistor R22, the negative terminal of capacitor C22, and the negative terminal of diode D22. Pin 3 of the three-terminal regulator U2 is connected to the other end of resistor R22, the positive terminal of diode D22, and one end of resistor R23. The other end of resistor R23 is connected to the emitter of transistor Q21. The other end of rheostat R21 is connected to the other end of rheostat R11. The positive terminal of capacitor C22 is connected to the negative terminal of capacitor C12.

5. The regulated power supply circuit for testing an electronic level according to claim 4, characterized in that: The filter output circuit includes capacitors C13 and C23. The positive terminal of capacitor C13 is connected to the emitter of transistor Q11 and one end of resistor R14. The negative terminal of capacitor C13 is connected to the positive terminal of capacitor C23. The negative terminal of capacitor C23 is connected to the emitter of transistor Q21 and one end of resistor R24. The other end of resistor R24 ​​is connected to the other end of resistor R14.

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