Key switch testing device

Abstract

The utility model discloses a key switch testing device, which comprises a key module used for testing, a constant current source connected with the key module, and a control module used for controlling the constant current source to be electrified. The control module stops supplying power to the constant current source when the key module is not closed to form a loop, so that the constant current source cannot supply power to the key module, and the technical effect that the constant current source, the key module and the control module do not generate power consumption when the key module is not closed is achieved; the problem that the power consumption of the test circuit is wasted because the voltage stabilizing diode in the constant current source still has static power consumption even if the test key is in an unclosed state in the test circuit in the prior art is solved, and the power consumption of the test circuit is reduced.

Description

Technical Field

[0001] This utility model relates to the field of test circuits, and in particular to a push-button switch test device. Background Technology

[0002] In the existing CCM (Camera Module) testing process, the on / off function of the buttons needs to be tested. The test circuit used in the existing testing method can be referenced. Figure 1 The switching state of a button is usually detected by detecting the current. Specifically, a simple constant current source is built using a Zener diode and a transistor. When the button is closed, the test circuit generates current and is detected by the control unit, which then enables the MCU (microcontroller unit) to execute the corresponding function.

[0003] However, this detection method has a drawback: the constant current source needs to continuously power the button to maintain its standby state, meaning the test circuit is in a constant-power state. Therefore, even when the constant current source is in a standby state where it does not need to be activated, the internal Zener diode still consumes power. This means that the Zener diode also generates static power consumption when the button is in the open state, resulting in wasted power consumption in the test circuit. Therefore, how to realize a button switch testing device and button detection system that can continuously test the switching function of the button while reducing the power consumption of the test circuit has become an urgent problem to be solved. Utility Model Content

[0004] Therefore, it is necessary to propose a button switch testing device that can continuously test the switching function of buttons while reducing the power consumption of the test circuit, in order to address the above problems.

[0005] This utility model provides a button switch testing device for performing button switch switching tests, including a button module, a constant current source, and a control module;

[0006] The first terminal of the control module is connected to the output terminal of the external test board, the second terminal of the control module is connected to the first terminal of the constant current source, and the third terminal of the control module is grounded, so that the control module powers the constant current source when the circuit forms a loop. The second terminal of the constant current source is connected to the output terminal of the external test board, and the third terminal of the constant current source is connected to the first terminal of the button module. The second terminal of the button module, the ground terminal of the constant current source, and the ground terminal of the external test board are all grounded, so as to form a circuit loop when the button module is closed.

[0007] Furthermore, the constant current source includes a first transistor and a Zener diode, with the base of the first transistor connected to the negative terminal of the Zener diode, and the positive terminal of the Zener diode grounded.

[0008] Furthermore, the constant current source also includes a first resistor, a second resistor, a first capacitor, and a second capacitor;

[0009] The first end of the first resistor and the first end of the second capacitor are connected to the emitter of the first transistor. The second end of the first resistor is used to connect to ground through the button module. The base of the first transistor is also connected to the first end of the second resistor and the first end of the first capacitor. The second end of the first capacitor is connected to the positive terminal of the Zener diode and grounded at the same time. The second end of the second resistor is connected to the third end of the control module. The second end of the second capacitor is connected to the button module and grounded.

[0010] The first resistor is used as a sampling resistor for the constant current source. It is used to sample the acquired test current and output it to the grounding terminal of the external test board through the second terminal of the first resistor and then ground it.

[0011] Furthermore, the push-button switch testing device also includes a filtering module;

[0012] The first end of the filtering module is connected to the output end of the external test board, the second end of the filtering module is connected to the constant current source, and the third end of the filtering module is connected to the control module, which is used to filter the current output from the external test board.

[0013] Furthermore, the filtering module includes a filtering inductor for performing filtering;

[0014] The first end of the filter inductor is connected to the output end of the external test board, and the second end of the filter inductor is connected to the collector of the first transistor and the first end of the control module.

[0015] Furthermore, the filtering module also includes a third capacitor, a fourth capacitor, and a fifth capacitor for synchronous filtering following the filtering inductor;

[0016] The first terminal of the third capacitor and the first terminal of the fourth capacitor are connected to the output terminal of the external test board and the first terminal of the filter inductor. The first terminal of the fifth capacitor is connected to the second terminal of the filter inductor. The second terminals of the third capacitor, the fourth capacitor, and the fifth capacitor are grounded.

[0017] Furthermore, the external test board has a power supply terminal;

[0018] The first terminal of the third capacitor, the first terminal of the fourth capacitor, the first terminal of the filter inductor, the collector of the first transistor, and the first terminal of the control module are all connected to the power supply terminal, thereby making the power supply terminal the output terminal of the external test board.

[0019] Furthermore, the control module includes a second transistor for controlling the conduction of the first transistor;

[0020] The emitter and base of the second transistor are both connected to the output terminal of the external test board. The collector of the second transistor is connected to the base of the first transistor. Thus, when the base of the second transistor receives the voltage output by the control module, it switches to the on state. The voltage output by the collector of the second transistor is applied to the base of the first transistor, thereby controlling the first transistor to conduct.

[0021] Furthermore, the control module also includes a third resistor, a fourth resistor, and a fifth resistor;

[0022] The first end of the third resistor is connected to the collector of the first transistor, the emitter of the second transistor, and the second end of the filter inductor. The second end of the third resistor is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the base of the second transistor and the first end of the fifth resistor. The second end of the fifth resistor is connected to the first end of the button module.

[0023] Furthermore, the capacitance of the first capacitor is 0.1μF, the capacitance of the second capacitor is 1nF, the capacitance of the third capacitor is 0.1μF, the capacitance of the fourth capacitor is 1nF, and the capacitance of the fifth capacitor is 1nF.

[0024] The aforementioned push-button switch testing device, by setting the control module to stop supplying power to the constant current source when the push-button module is not closed to form a circuit, thereby preventing the constant current source from powering the push-button module, achieves the technical effect that the constant current source, push-button module, and control module do not generate power when the push-button module is not closed. This solves the problem in the prior art where the Zener diode in the constant current source still has static power consumption even when the push-button is not closed, resulting in wasted power in the test circuit, and reduces the power consumption of the test circuit. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This refers to the button testing circuit in the CCM testing process of the background technology;

[0027] Figure 2 This is a frame structure diagram of a push-button switch testing device in one embodiment;

[0028] Figure 3 This is a circuit diagram of a push-button switch testing device in one embodiment;

[0029] The labels in the diagram are: 1-Button module, 2-Constant current source, 3-Control module, 4-Filter module. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] refer to Figure 2 This utility model provides a button switch testing device for performing button switch switching tests, including a button module 1, a constant current source 2, and a control module 3;

[0032] The first terminal of the control module 3 is connected to the output terminal of the external test board, the second terminal of the control module 3 is connected to the first terminal of the constant current source, and the third terminal of the control module 3 is grounded, so that the control module 3 powers the constant current source 2 when the circuit forms a loop. The second terminal of the constant current source is connected to the output terminal of the external test board, and the third terminal of the constant current source is connected to the first terminal of the button module 1, so that when the test circuit is turned on, the constant current source 2 outputs a constant voltage and applies it to the button module 1, so that a constant test current is generated in the button module 1. The second terminal of the button module 1, the ground terminal of the constant current source 2, and the ground terminal of the external test board are all grounded, so as to form a circuit loop when the button module 1 is closed.

[0033] As described in the above embodiments, the technical solution of this utility model is a button switch testing device for testing a button module 1, including a button module 1 for testing, a constant current source 2 connected to the button module 1, and a control module 3 for controlling the power-on of the constant current source 2. In this embodiment, the output terminal of the external test board is connected to the first terminal of the constant current source 2 and the first terminal of the control module 3, the second terminal of the constant current source 2 is connected to the first terminal of the button module 1, the second terminal of the button module 1 and the second terminal of the control module 3 are connected and grounded, and the first terminal of the constant current source is also connected to the second terminal of the control module 3.

[0034] The specific implementation process of this embodiment is as follows: When the button module 1 is closed, the circuit is turned on, and the control module 3 and the constant current source 2 form a loop. At this time, the output terminal of the external test board supplies power to the constant current source 2. The constant current source 2 is powered on and outputs voltage to the button module 1. The ground terminal of the button module 1 is grounded synchronously with the ground terminal of the external test board. At this time, the external test board can determine whether the ground terminal of the button module 1 is connected and forms a loop through its ground terminal. After confirming that a loop has been formed, the test of the button module 1 is started. It can be understood that when the button module 1 generates a test current, it can be determined that the loop has been successfully formed.

[0035] When button module 1 is not closed, the circuit is not connected, meaning that a loop cannot be formed through button module 1. Therefore, at this time, button module 1, constant current source 2, and control module 3 do not generate power consumption.

[0036] This embodiment, through the above structure, sets the control module to stop supplying power to the constant current source when the button module is not closed to form a circuit. This prevents the constant current source from powering on and outputting voltage to the button module, achieving the technical effect that the constant current source, button module, and control module do not generate power consumption when the button module is not closed. This solves the problem in the prior art where the Zener diode in the constant current source still has static power consumption even when the test button is not closed, resulting in wasted power consumption in the test circuit, and reduces the power consumption of the test circuit.

[0037] refer to Figure 3 In one embodiment, the constant current source 2 includes a first transistor Q1 and a Zener diode D1. The base b1 of the first transistor Q1 is connected to the negative terminal of the Zener diode D1, and the positive terminal of the Zener diode D1 is grounded.

[0038] As described in the above embodiment, when the circuit is turned on, the constant current source 2 obtains the voltage output from the control module 3 and powers on. The base b1 of the first transistor Q1 is provided with a base bias voltage VB through the Zener diode D1. The voltage VE obtained by the emitter e1 of the first transistor Q1 is (VB-0.7)V, thereby the button module 1 obtains the voltage output by the external test board. At this time, the first transistor Q1 is working in the amplification region. At the same time, the Zener diode D1 is used to provide a base bias voltage VB to the base b1 of the first transistor Q1. It can be understood that at this time, the base bias voltage VB is equivalent to the Zener diode D1's regulated voltage value, which is a fixed value. And since the base bias voltage VB is provided by the Zener diode D1, it will not change due to the voltage change provided by the control module 3.

[0039] When the circuit is not conducting, the control module 3 cannot supply power, and the base b1 of the first transistor Q1 cannot obtain voltage. At this time, the first transistor Q1 of the constant current source 2 is in a non-conducting state (not powered on), thus achieving the effect of not consuming power.

[0040] refer to Figure 3 In one embodiment, the constant current source 2 further includes a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2;

[0041] The first terminal of the first resistor R1 and the first terminal of the second capacitor C2 are connected to the emitter e1 of the first transistor Q1. The second terminal of the first resistor R1 is connected to the first terminal of the button module 1. The base b1 of the first transistor Q1 is also connected to the first terminal of the second resistor R2 and the first terminal of the first capacitor C1. The second terminal of the first capacitor C1 is connected to the positive terminal of the Zener diode D1 and grounded. The second terminal of the second resistor R2 is connected to the third terminal of the control module 3. The second terminal of the second capacitor C2 is connected to the second terminal of the button module 1 and grounded.

[0042] The first resistor R1 is used as the sampling resistor of the constant current source 2, so as to sample the acquired signal and feed it back to the external test board.

[0043] As described in the above embodiments, the constant current source 2 further includes a first resistor R1, a second resistor R2, a first capacitor C1, and a second capacitor C2. The first end of the first resistor R1 and the first end of the second capacitor C2 are connected to the emitter e1 of the first transistor Q1. The second end of the first resistor R1 is connected to the first end of the button module 1. The second end of the second capacitor C2 is connected to the second end of the button module 1 and grounded, so that the first resistor R1 is used as the sampling resistor of the constant current source 2, thereby sampling the acquired signal and feeding it back to the external test board. At the same time, the second capacitor C2 is used as the filter capacitor of the first resistor R1.

[0044] Similarly, the base b1 of the first transistor Q1 is also connected to the first end of the second resistor R2 and the first end of the first capacitor C1. The second end of the second resistor R2 is connected to the third end of the control module 3. The second end of the first capacitor C1 is connected to the positive terminal of the Zener diode D1 and grounded, so that the second resistor R2 acts as the current limiting resistor of the control module 3 and the first capacitor C1 acts as the filter capacitor of the Zener diode D1.

[0045] refer to Figure 2 and Figure 2 In one embodiment, the button switch testing device further includes a filtering module 4;

[0046] The first end of the filter module 4 is connected to the output end of the external test board, the second end of the filter module 4 is connected to the constant current source 2, and the third end of the filter module 4 is connected to the control module 3, which is used to filter the current output from the external test board.

[0047] As described in the above embodiments, the first end of the filter module 4 is connected to the output end of the external test board, the second end of the filter module 4 is connected to the constant current source 2, and the third end of the filter module 4 is connected to the control module 3. It can be understood that the filter module 4 is used to filter the current of the test circuit and output it to the constant current source 2.

[0048] refer to Figure 3 In one embodiment, the filtering module 4 includes a filtering inductor L1 for performing filtering;

[0049] The first end of the filter inductor L1 is connected to the output end of the external test board, and the second end of the filter inductor L1 is connected to the collector c1 of the first transistor Q1 and the first end of the control module 3.

[0050] As described in the above embodiment, the first end of the filter inductor L1 is connected to the output end of the external test board, and the second end of the filter inductor L1 is connected to the collector c1 of the first transistor Q1 and the first end of the control module 3, thereby achieving the effect of filtering the current output by the external test board and outputting it to the constant current source 2.

[0051] refer to Figure 3 In one embodiment, the filtering module 4 further includes a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5 for synchronous filtering following the filtering inductor L1.

[0052] The first terminal of the third capacitor C3, the first terminal of the fourth capacitor C4, and the first terminal of the filter inductor L1 are all connected to the output terminal of the external test board 1. The first terminal of the fifth capacitor C5 is connected to the second terminal of the filter inductor L1. The second terminals of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are grounded.

[0053] As described in the above embodiments, the filtering module 4 also includes a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5 for synchronous filtering following the filtering inductor L1. The first end of the third capacitor C3 and the first end of the fourth capacitor C4 are connected to the output end of the external test board 1 and the first end of the filtering inductor L1, respectively. The first end of the fifth capacitor C5 is connected to the second end of the filtering inductor L1. The second ends of the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are grounded, thereby realizing synchronous filtering following the filtering inductor L1.

[0054] refer to Figure 2 and Figure 2 In one embodiment, the external test board has a power supply terminal VCC;

[0055] The first terminal of the third capacitor C3, the first terminal of the fourth capacitor C4, the first terminal of the filter inductor L1, the collector C1 of the first transistor Q1, and the first terminal of the control module 3 are all connected to the power supply terminal VCC, so that the power supply terminal VCC serves as the output terminal of the external test board.

[0056] As described in the above embodiment, the first end of the external test board 1 is the power supply terminal of the external test board 1. Voltage is applied to the first end of the third capacitor C3, the first end of the fourth capacitor C4, the first end of the filter inductor L1, the collector c1 of the first transistor Q1, and the first end of the control module 3. The second end of the third capacitor C3, the second end of the fourth capacitor C4, and the second end of the fifth capacitor C5 are connected to the ground terminal, thereby forming a corresponding test circuit.

[0057] refer to Figure 3 In one embodiment, the control module 3 includes a second transistor Q2 for controlling the first transistor Q1 to conduct;

[0058] The emitter e2 and base b2 of the second transistor Q2 are both connected to the output terminal of the external test board. The collector c2 of the second transistor Q2 is connected to the base b1 of the first transistor Q1. It can be understood that when the circuit is not conducting, there is no current in the control module 3 and the overall circuit. When a predetermined voltage difference is formed between the base b2 and emitter e2 of the second transistor Q2 and it switches to the conducting state, the collector c2 of the second transistor Q2 outputs a voltage to the base b1 of the first transistor Q1, thereby controlling the first transistor Q1 to conduct.

[0059] As described in the above embodiment, the control module 3 includes a second transistor Q2. It can be understood that when the button module 1 is closed and the circuit is turned on, the base b2 of the second transistor Q2 receives a voltage. At this time, the second transistor Q2 is turned on, and the Zener diode D1 operates, causing a voltage to exist at the base b1 of the first transistor Q1. For example, if the Zener diode D1 operates at 2.4V, then the voltage obtained by the base b1 of the first transistor Q1 is 2.4V. Only when the base b1 of the first transistor Q1 has a voltage will the emitter e1 of the first transistor Q1 have a voltage. Therefore, the function of the Zener diode D1 is to stabilize the voltage at the base b1 of the first transistor Q1, thereby stabilizing the voltage at the emitter e1 of the first transistor Q1. When the voltage at the emitter e1 of the first transistor Q1 is stable, the current after the button module 1 is closed will stabilize, thus achieving the purpose of circuit testing.

[0060] refer to Figure 3 In one embodiment, the control module 3 further includes a third resistor R3, a fourth resistor R4, and a fifth resistor R5;

[0061] The first end of the third resistor R3 is connected to the collector c1 of the first transistor Q1, the emitter e2 of the second transistor Q1, and the second end of the filter inductor L1. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is connected to the base b2 of the second transistor Q2 and the first end of the fifth resistor R5. The second end of the fifth resistor R5 is connected to the first end of the button module 1.

[0062] As described in the above embodiment, the first end of the third resistor R3 is connected to the collector c1 of the first transistor Q1, the emitter e2 of the second transistor Q1, and the second end of the filter inductor L1. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4. Then, the second end of the fourth resistor R4 is connected to the base b2 of the second transistor Q2 and the first end of the fifth resistor R5. It can be seen that the fourth resistor R4 acts as a voltage divider resistor at the front end of the base of the second transistor Q2, while the first end of the fifth resistor R5 is connected to the base b2 of the second transistor Q2, thus making the fifth resistor R5 act as a voltage divider resistor for the second transistor Q2.

[0063] Understandably, when button module 1 is closed and the circuit is turned on, the base b2 of the second transistor Q2 receives voltage. Due to the voltage division of the third resistor R3, the fourth resistor R4 (i.e., as long as the sum of their resistances reaches the set threshold, the specific resistance can be formed by a single resistor or by multiple resistors superimposed; in this embodiment, the set threshold is met by superimposing two resistors, i.e., by the third resistor R3 and the fourth resistor R4); and the fifth resistor R5, the voltage at the emitter e2 of the second transistor Q2 is greater than the voltage at the base b2 of the second transistor Q2. Therefore, the second transistor Q2 is turned on, and the Zener diode D1 is activated.

[0064] In one embodiment, the capacitance of the first capacitor C1 is 0.1μF, the capacitance of the second capacitor C2 is 1nF, the capacitance of the third capacitor C3 is 0.1μF, the capacitance of the fourth capacitor C4 is 1nF, and the capacitance of the fifth capacitor C5 is 1nF.

[0065] As described in the above embodiment, the capacitance of the first capacitor C1 is 0.1μF, and the capacitance of the second capacitor C2 is 1nF. Thus, by combining the capacitances of the two capacitors, the filtering effect of the constant current source 2 is achieved. Similarly, the capacitance of the third capacitor C3 is 0.1μF, the capacitance of the fourth capacitor is 1nF, and the capacitance of the fifth capacitor is 1nF. Thus, by combining the capacitances of the three capacitors, the filtering effect of the corresponding filtering module 4 is achieved.

[0066] As can be seen from the above embodiments, the greatest beneficial effect of this utility model is that by setting a first transistor Q1 and a second transistor Q2, and when the button module 1 is closed and the circuit is conducting, the second transistor Q2 switches to the conducting state after obtaining a predetermined voltage through the base b2 of the second transistor Q2, thereby supplying power to the constant current source 2. At this time, the first transistor Q1 switches to the conducting state and is grounded through the button module 1, so that the external test board can identify whether a loop is formed between the button module 1, the constant current source 2 and the control module 3 through the ground terminal pin, and test the button module 1 by testing the current in the button module 1 after determining that a loop has been formed. This achieves the technical effect of stopping the power supply to the constant current source when the button module is not closed to form a loop, so that the constant current source cannot power the button module. This achieves the technical effect that the constant current source, the button module and the control module do not generate power when the button module is not closed. This solves the problem in the prior art that even when the test button is not closed, the Zener diode in the constant current source still has static power consumption, which leads to the waste of power in the test circuit, and reduces the power consumption of the test circuit.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A key switch testing device for performing a key switch switching test, characterized by, The key module, the constant current source and the control module are included. The first end of the control module is connected with the output end of the external test board, the second end of the control module is connected with the first end of the constant current source, the third end of the control module is grounded, so that the control module is powered on the constant current source when the circuit is formed, the second end of the constant current source is connected with the output end of the external test board, and the third end of the constant current source is connected with the first end of the key module.

2. The key switch testing device of claim 1, wherein The constant current source includes a first triode and a voltage stabilizing diode, the base of the first triode is connected with the negative electrode of the voltage stabilizing diode, and the positive electrode of the voltage stabilizing diode is grounded.

3. The key switch testing apparatus of claim 2, wherein The constant current source further includes a first resistor, a second resistor, a first capacitor and a second capacitor. The first end of the first resistor and the first end of the second capacitor are connected with the emitter of the first triode, the second end of the first resistor is grounded through the key module, the base of the first triode is further connected with the first end of the second resistor and the first end of the first capacitor, the second end of the first capacitor is connected with the positive electrode of the voltage stabilizing diode and grounded at the same time, the second end of the second resistor is connected with the third end of the control module, and the second end of the second capacitor is connected with the key module and grounded.

4. The key switch testing device of claim 3, wherein The filter module is further included. The first end of the filter module is connected with the output end of the external test board, the second end of the filter module is connected with the constant current source, and the third end of the filter module is connected with the control module, so as to filter the current output from the external test board.

5. The key switch testing device of claim 4, wherein, The filter module includes a filter inductor for filtering. The first end of the filter inductor is connected with the output end of the external test board, and the second end of the filter inductor is connected with the collector of the first triode and the first end of the control module.

6. The key switch testing device of claim 5, wherein, The filter module further includes a third capacitor, a fourth capacitor and a fifth capacitor for synchronous filtering following the filter inductor. The first end of the third capacitor and the first end of the fourth capacitor are connected with the output end of the external test board and the first end of the filter inductor, the first end of the fifth capacitor is connected with the second end of the filter inductor, and the second end of the third capacitor, the second end of the fourth capacitor and the second end of the fifth capacitor are grounded.

7. The key switch testing apparatus of claim 6, wherein The external test board has a power supply end. The first end of the third capacitor, the first end of the fourth capacitor, the first end of the filter inductor, the collector of the first triode and the first end of the control module are all connected with the power supply end.

8. The key switch testing apparatus of claim 5, wherein The control module includes a second triode for controlling the first triode to be turned on. The emitter of the second triode and the base of the second triode are both connected with the output end of the external test board, and the collector of the second triode is connected with the base of the first triode.

9. The key switch testing apparatus of claim 8, wherein The control module further includes a third resistor, a fourth resistor and a fifth resistor. The first end of the third resistor is connected with the collector of the first transistor, the emitter of the second transistor and the second end of the filter inductor, the second end of the third resistor is connected with the first end of the fourth resistor, the second end of the fourth resistor is connected with the base of the second transistor and the first end of the fifth resistor, and the second end of the fifth resistor is connected with the first end of the key module.

10. The key switch testing apparatus of claim 6, wherein The capacity of the first capacitor is 0.1 μF, the capacity of the second capacitor is 1 nF, the capacity of the third capacitor is 0.1 μF, the capacity of the fourth capacitor is 1 nF, and the capacity of the fifth capacitor is 1 nF.

Images