Delay circuit and electrical switching device
By combining control circuits and RC delay circuits, the delay circuit structure is simplified, solving the problems of circuit complexity and increased layout area caused by the increase of components in the prior art, and achieving a smaller PCB layout area.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DELIXI ELECTRIC
- Filing Date
- 2025-07-28
- Publication Date
- 2026-07-28
AI Technical Summary
Existing delay circuits require additional components such as resistors, diodes, and capacitors, resulting in complex circuitry and increased PCB layout area.
By combining a control circuit, an RC delay circuit, and an output circuit, the charging and discharging of the capacitor in the RC delay circuit is controlled by a control signal to achieve delay control, reducing the reliance on additional components.
The circuit structure of the delay circuit is simplified, and the PCB layout area is reduced.
Smart Images
Figure CN224571229U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of low-voltage electrical technology, and in particular to a time delay circuit and an electrical switching device. Background Technology
[0002] A delay circuit is an electronic circuit that can achieve the function of "signal or action delay". Its core function is to output a signal or trigger an action after receiving an input signal and waiting for a preset time interval.
[0003] Currently, delay circuits often use timer chips such as the 555 timer to adjust the delay time according to the input voltage. However, in addition to the timer chip, other components such as resistors, diodes, and capacitors are needed to control the pins of the timer chip, which makes the delay circuit complex and increases the required printed circuit board (PCB) layout area. Utility Model Content
[0004] This application provides a delay circuit and an electrical switching device, which has a simple circuit and reduces the PCB layout area.
[0005] In a first aspect, this application provides a delay circuit, which includes: a control circuit, an RC delay circuit, and an output circuit;
[0006] The input terminal of the control circuit is electrically connected to a first trigger signal, the output terminal of the control circuit is electrically connected to a first control terminal of the RC delay circuit, the input terminal of the RC delay circuit is electrically connected to an input voltage, the output terminal of the RC delay circuit and the second control terminal of the RC delay circuit are both electrically connected to the input terminal of the output circuit, the input terminal of the output circuit is also electrically connected to a second trigger signal, the level of the first trigger signal is opposite to the level of the second trigger signal, and the output terminal of the output circuit is used to output the output voltage;
[0007] The control circuit is used to generate a control signal according to the first trigger signal and transmit the control signal to the RC delay circuit.
[0008] The output circuit is used to control the third transistor in the output circuit to be cut off when the second trigger signal indicates that the delay circuit is working;
[0009] The RC delay circuit is used to charge the capacitor in the RC delay circuit with the input voltage according to the control signal until the voltage on the capacitor exceeds the preset voltage, thereby obtaining the delay signal and transmitting the delay signal to the output circuit.
[0010] The output circuit is used to control the turn-on of the cut-off third transistor according to the delay signal to obtain a first output voltage, so that the delay circuit completes the delay control, and the output voltage includes the first output voltage.
[0011] The delay circuit provided in the first aspect allows the control circuit to generate a control signal based on the first trigger signal and transmit the control signal to the RC delay circuit, enabling the RC delay circuit to acquire the control signal. When the second trigger signal indicates that the delay circuit is working, the output circuit can control the third transistor in the output circuit to be cut off. Thus, the RC delay circuit can charge the capacitor in the RC delay circuit using the input voltage according to the control signal until the voltage on the capacitor exceeds a preset voltage, obtaining a delay signal, and transmitting the delay signal to the output circuit, enabling the output circuit to acquire the delay signal. In this way, the output circuit can control the cut-off third transistor to be turned on according to the delay signal, obtaining the first output voltage, thus enabling the delay circuit to complete the delay control. Since the delay circuit is based on the RC delay circuit for delay control, compared to delay circuits in related technologies, the delay circuit of this application does not require additional components, simplifying the circuit. This reduces the PCB layout area of the delay circuit.
[0012] In one possible design, the output circuit is further configured to control the third transistor in the output circuit to turn on when the second trigger signal indicates that the delay circuit is not working, thereby obtaining a second output voltage, the output voltage including the second output voltage;
[0013] The RC delay circuit is also used to discharge the capacitor according to the second trigger signal.
[0014] In one possible design, the RC delay circuit includes: a first transistor, a first resistor, a capacitor, a first Zener diode, a second resistor, and a discharge circuit;
[0015] The emitter of the first transistor is electrically connected to the input voltage, the base of the first transistor is electrically connected to the output terminal of the control circuit, the collector of the first transistor is electrically connected to the first terminal of the first resistor, the second terminal of the first resistor is electrically connected to the upper plate of the capacitor, the negative terminal of the first Zener diode, and the first terminal of the discharge circuit, the positive terminal of the first Zener diode is electrically connected to the first terminal of the second resistor, the second terminal of the second resistor is electrically connected to the control terminal of the discharge circuit and the input terminal of the output circuit, and the second plate of the capacitor and the second terminal of the discharge circuit are both grounded.
[0016] The discharge circuit is configured to be turned on according to the second trigger signal to discharge the capacitor.
[0017] In one possible design, the RC delay circuit further includes: a second Zener diode;
[0018] The negative terminal of the second Zener diode is electrically connected between the second end of the first resistor and the upper plate of the capacitor, and the positive terminal of the second Zener diode is grounded.
[0019] In one possible design, the discharge circuit includes: a second transistor and a third resistor;
[0020] The collector of the second transistor is electrically connected to the second end of the first resistor, the base of the second transistor is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the input end of the output circuit, and the emitter of the second transistor is grounded.
[0021] In one possible design, the control circuit includes: a transistor and a fourth resistor;
[0022] The gate terminal of the transistor is electrically connected to the first trigger signal, the drain terminal of the transistor is electrically connected to the first terminal of the fourth resistor, the second terminal of the fourth resistor is electrically connected to the first control terminal of the RC delay circuit, and the source terminal of the transistor is grounded.
[0023] In one possible design, the control circuit further includes: a fifth resistor;
[0024] The first end of the fifth resistor is electrically connected to the first trigger signal, and the second end of the fifth resistor is electrically connected to the gate end of the transistor.
[0025] In one possible design, the output circuit includes: the third transistor and the diode;
[0026] The positive terminal of the diode is electrically connected to the second trigger signal, the negative terminal of the diode is electrically connected to the base of the third transistor, the collector of the third transistor is used to output the output voltage, and the emitter of the third transistor is grounded.
[0027] In a second aspect, this application provides an electrical switching device, the electrical switching device comprising: the delay circuit in the second aspect and various possible designs of the second aspect.
[0028] In one possible design, the electrical switching device is a contactor or a molded case circuit breaker.
[0029] The beneficial effects of the electrical switching device provided in the second aspect and the various possible designs of the second aspect can be seen in the beneficial effects of the first aspect and the various possible embodiments of the first aspect, and will not be repeated here.
[0030] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description
[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic diagram of a delay circuit provided in an embodiment of this application.
[0033] Explanation of reference numerals in the attached figures:
[0034] 100. Delay circuit; 110. RC delay circuit; 111. Discharge circuit; 120. Control circuit; 130. Output circuit. Detailed Implementation
[0035] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0036] The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0037] The terms "connected" and "connected" should be interpreted broadly. For example, in circuit structures, "connected" or "connected" can refer not only to physical connections but also to electrical or signal connections. This could be a direct connection (physical connection) or an indirect connection via at least one intermediate component, as long as the circuit is connected. It could also refer to the internal connection between two components. Similarly, a signal connection can refer to a connection via a circuit or a medium, such as radio waves. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.
[0038] In related technologies, in addition to the timer chip, delay circuits also require other components such as resistors, diodes, and capacitors to control the pins of the timer chip, which makes the delay circuit complex and increases the PCB layout area required for the delay circuit.
[0039] Therefore, this application provides a time delay circuit and an electrical switching device.
[0040] The electrical switching device can be a contactor or a molded case circuit breaker. For ease of explanation, the embodiments in this application are all illustrated using the application of a time delay circuit in a contactor as an example.
[0041] Reference Figure 1 , Figure 1 This is a schematic diagram of a delay circuit provided in an embodiment of this application. Figure 1 As shown, the delay circuit 100 may include: a control circuit 120, an RC delay circuit 110, and an output circuit 130.
[0042] The input terminal of control circuit 120 is electrically connected to the first trigger signal TRIG, and the output terminal of control circuit 120 is electrically connected to the first control terminal of RC delay circuit 110. The input terminal of RC delay circuit 110 is electrically connected to the input voltage VCC, and the output terminal of RC delay circuit 110 is connected to the first control terminal of RC delay circuit 110. Second control The control terminals are all electrically connected to the input terminals of the output circuit 130, and the output... circuit The input terminal of 130 is also electrically connected to the second trigger signal TRIG. The level of the first trigger signal TRIG is opposite to the level of the second trigger signal TRIG. The output terminal of the output circuit 130 is used to output the output voltage VOUT.
[0043] The control circuit 120, RC delay circuit 110 and output circuit 130 can be set separately or integrated. This application embodiment does not make specific limitations on this.
[0044] Wherein, when the first trigger signal TRIG is High electricity Normally, the second trigger signal TRIG is at a low level. When the first trigger signal TRIG is at a low level, the second trigger signal TRIG is at a high level.
[0045] That middle, A high-level first trigger signal TRIG indicates that the delay circuit 100 is working; correspondingly, a low-level second trigger signal TRIG indicates that the delay circuit 100 is not in operation. do. A low-level first trigger signal TRIG indicates that the delay circuit 100 is not working, and correspondingly, a high-level second trigger signal TRIG indicates that the delay circuit 100 is not working.
[0046] The control circuit 120 can generate a control signal based on the first trigger signal TRIG. Furthermore, the control circuit 120 can transmit the signal to the RC delay circuit 110. control The signal enables the RC delay circuit 110 to acquire the control signal.
[0047] When the second trigger signal TRIG indicates that the delay circuit 100 is working, the output circuit 130 can control the third transistor Q4 in the output circuit 130 to be turned off.
[0048] In this way, the RC delay circuit 110 can charge the capacitor C1 in the RC delay circuit 110 with the input voltage VCC according to the control signal until the voltage on the capacitor C1 exceeds the preset voltage, thus obtaining a delay signal. Furthermore, the RC delay circuit 110 can transmit the delay signal to the output circuit 130.
[0049] When the delay circuit 100 is applied to a molded case circuit breaker, the input voltage VCC remains constant, i.e., a constant voltage, and the duration of the delay signal is a constant preset duration; that is, the duration of the delay signal is fixed. When the delay circuit 100 is applied to a contactor, the input voltage VCC rises from a low voltage to the rated voltage or even exceeds the rated voltage, and the duration of the delay signal gradually increases from a short duration to the preset duration; that is, the duration of the delay signal is variable.
[0050] Thus, the output circuit 130 can control the cut-off third transistor Q4 to turn on according to the delay signal, thereby obtaining the first output voltage and enabling the delay circuit 100 to complete the delay control.
[0051] The output voltage VOUT may include the first output voltage.
[0052] Since the delay circuit 100 is based on an RC delay circuit for delay control, compared to delay circuits in related technologies, the delay circuit 100 of this application does not require additional components, thus simplifying the circuit. This reduces the cost of the delay circuit 100. PCB Layout area.
[0053] In some examples, when the second trigger signal TRIG indicates that the delay circuit 100 is not working, the output circuit 130 can control the third transistor Q4 in the output circuit 130 to turn on, thus... To the Two output voltages.
[0054] The RC delay circuit 110 can discharge capacitor C1 according to the second trigger signal TRIG.
[0055] The output voltage VOUT may include a second output voltage.
[0056] The delay circuit provided in this application can generate a control signal based on a first trigger signal and transmit the control signal to the RC delay circuit, enabling the RC delay circuit to acquire the control signal. When the second trigger signal indicates that the delay circuit is working, the output circuit can control the third transistor in the output circuit to be cut off. Thus, the RC delay circuit can charge the capacitor in the RC delay circuit using the input voltage according to the control signal until the voltage on the capacitor exceeds a preset voltage, obtaining a delay signal, and transmitting the delay signal to the output circuit, enabling the output circuit to acquire the delay signal. In this way, the output circuit can control the cut-off third transistor to be turned on according to the delay signal, obtaining a first output voltage, thus enabling the delay circuit to complete the delay control. Since the delay circuit is based on the RC delay circuit to achieve delay control, compared with the delay circuits in related technologies, the delay circuit of this application does not require additional components, simplifying the circuit. Therefore, the PCB layout area of the delay circuit can be reduced.
[0057] Based on the description of the above embodiments, an exemplary possible implementation of the RC delay circuit 110 is provided. Figure 1 As shown, the RC delay circuit 110 may include: a first transistor Q1, a first resistor R1, a capacitor C1, a first Zener diode ZD1, a second resistor R2, and a discharge circuit 111.
[0058] The emitter of the first transistor Q1 is electrically connected to the input voltage VCC. The base of the first transistor Q1 is electrically connected to the output terminal of the control circuit 120. The collector of the first transistor Q1 is electrically connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is electrically connected to the upper plate of the capacitor C1, the negative terminal of the first Zener diode ZD1, and the first terminal of the discharge circuit 111. The positive terminal of the first Zener diode ZD1 is electrically connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is electrically connected to the control terminal of the discharge circuit 111 and the input terminal of the output circuit 130. The second plate of the capacitor C1 and the second terminal of the discharge circuit 111 are both grounded.
[0059] In this circuit, the emitter of the first transistor Q1 is the input terminal of the RC delay circuit 110, the second terminal of the second resistor R2 is the output terminal of the RC delay circuit 110, the base of the first transistor Q1 is the first control terminal of the RC delay circuit 110, and the control terminal of the discharge circuit 111 is the second control terminal of the RC delay circuit 110.
[0060] Among them, the conduction current of the first Zener diode ZD1 Press as Preset voltage.
[0061] The discharge circuit 111 can be turned on according to the second trigger signal TRIG to discharge the capacitor C1.
[0062] Based on the description of the above embodiments, an exemplary alternative implementation of the RC delay circuit 110 is provided. Figure 1 As shown, the RC delay circuit 110 may also include a second Zener diode ZD2.
[0063] The negative terminal of the second Zener diode ZD2 is electrically connected between the second end of the first resistor R1 and the upper plate of the capacitor C1, and the positive terminal of the second Zener diode ZD2 is grounded.
[0064] The second Zener diode ZD2 enables the RC delay circuit 110 to control the duration of the delay signal according to the change of the input voltage VCC.
[0065] In applications where the contactor operates at a lower pull-in voltage to ensure stable engagement, specifically when the input voltage VCC is low (resulting in a weaker pull-in force), the delay signal duration needs to be extended. When the input voltage VCC is at or above its rated voltage, the delay signal duration must remain constant. Without a second Zener diode ZD2, the charging time of capacitor C1 is longer when the input voltage VCC is lower, and shorter when VCC is higher. With a second Zener diode ZD2, when the input voltage VCC exceeds its forward voltage, the charging time of capacitor C1 remains constant, thus maintaining a constant delay signal duration. When the input voltage VCC is lower than the forward voltage of the second Zener diode ZD2, the charging time of capacitor C1 is longer, extending the delay signal duration.
[0066] Based on the description of the above embodiments, an exemplary possible implementation of the discharge circuit 111 is provided. Figure 1 As shown, the discharge circuit 111 may include: a second transistor Q3 and a third resistor R3.
[0067] The collector of the second transistor Q3 is electrically connected to the second end of the first resistor R1, the base of the second transistor Q3 is electrically connected to the first end of the third resistor R3, the second end of the third resistor R3 is electrically connected to the input end of the output circuit 130, and the emitter of the second transistor Q3 is grounded.
[0068] In this circuit, the collector of the second transistor Q3 is the first terminal of the discharge circuit 111, the second terminal of the third resistor R3 is the control terminal of the discharge circuit 111, and the emitter of the second transistor Q3 is the second terminal of the discharge circuit 111.
[0069] Based on the description of the above embodiments, an exemplary possible implementation of the control circuit 120 is provided. For example... Figure 1 As shown, the control circuit 120 may include: transistor Q2 and fourth resistor R4.
[0070] The gate of transistor Q2 is electrically connected to the first trigger signal TRIG, the drain of transistor Q2 is electrically connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is electrically connected to the first control end of the RC delay circuit 110, and the source of transistor Q2 is grounded.
[0071] In this circuit, the gate terminal of transistor Q2 is the input terminal of control circuit 120, and the second terminal of the fourth resistor R4 is the output terminal of control circuit 120.
[0072] Based on the description of the above embodiments, another possible implementation of the control circuit 120 is exemplarily described. For example... Figure 1As shown, the control circuit 120 may also include a fifth resistor R5.
[0073] The first terminal of the fifth resistor R5 is electrically connected to the first trigger signal TRIG, and the second terminal of the fifth resistor R5 is electrically connected to the gate terminal of the transistor Q2.
[0074] Among them, the first end of the fifth resistor R5 is the input end of the control circuit 120, and the second end of the fourth resistor R4 is the output end of the control circuit 120.
[0075] Based on the description of the above embodiments, an exemplary possible implementation of the output circuit 130 is provided. Figure 1 As shown, the output circuit 130 may include: a third transistor Q4 and Two poles Pipe D1.
[0076] The positive terminal of diode D1 is electrically connected to the second trigger signal TRIG, the negative terminal of diode D1 is electrically connected to the base of the third transistor Q4, the collector of the third transistor Q4 is used to output the output voltage VOUT, and the emitter of the third transistor Q4 is grounded.
[0077] In this circuit, the positive terminal of diode D1 is the input terminal of output circuit 130, and the collector of the third transistor Q4 is the output terminal of output circuit 130.
[0078] The working principle of the delay circuit 100 is explained in detail below:
[0079] When the first trigger signal TRIG is high, that is, when the delay circuit 100 is working, i.e., when contact is made... Instrument At the initial state of trigger engagement, transistor Q2 is turned on, causing the first transistor Q1 to conduct. At this time, the second trigger signal TRIG is low, and the third transistor Q4 is turned off. Thus, the input voltage VCC charges capacitor C1 through the first resistor R1. As time increases, the voltage across capacitor C1 rises continuously. When the voltage across capacitor C1 exceeds the forward voltage of the first Zener diode ZD1, the current generated by the input voltage VCC through the first resistor R1 flows through the second resistor R2, turning on the previously off third transistor Q4. Therefore, the contactor's engagement state ends; that is, the delay circuit 100 completes the delay control of the contactor's engagement.
[0080] When the first trigger signal TRIG is low usually, In other words, when the delay circuit 100 is not working, i.e., when the contactor is in the released state, the second trigger signal TRIG is high, causing the third transistor Q4 to conduct. At this time, the second transistor Q3 conducts, causing the capacitor C1 to discharge.
[0081] Furthermore, when the input voltage VCC is lower than the forward voltage of the second Zener diode ZD2, the charging time of capacitor C1 is extended until the voltage across capacitor C1 reaches a constant value, thus extending the duration of the delay signal. Consequently, by extending the contactor's engagement time, the contactor's engagement speed is slowed down. Therefore, the contactor can achieve stable engagement control under under-voltage conditions.
[0082] When the input voltage VCC exceeds the forward voltage of the second Zener diode ZD2, the charging time of capacitor C1 remains constant, thus keeping the duration of the delay signal constant. Therefore, when the input voltage VCC reaches or exceeds the rated voltage, the contactor can maintain a constant engagement time.
[0083] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A delay circuit, characterized in that, The delay circuit includes: a control circuit, an RC delay circuit, and an output circuit; The input terminal of the control circuit is electrically connected to a first trigger signal, the output terminal of the control circuit is electrically connected to a first control terminal of the RC delay circuit, the input terminal of the RC delay circuit is electrically connected to an input voltage, the output terminal of the RC delay circuit and the second control terminal of the RC delay circuit are both electrically connected to the input terminal of the output circuit, the input terminal of the output circuit is also electrically connected to a second trigger signal, the level of the first trigger signal is opposite to the level of the second trigger signal, and the output terminal of the output circuit is used to output the output voltage; The control circuit is used to generate a control signal according to the first trigger signal and transmit the control signal to the RC delay circuit. The output circuit is used to control the third transistor in the output circuit to be cut off when the second trigger signal indicates that the delay circuit is working; The RC delay circuit is used to charge the capacitor in the RC delay circuit with the input voltage according to the control signal until the voltage on the capacitor exceeds the preset voltage, thereby obtaining a delay signal, and transmitting the delay signal to the output circuit. The output circuit is used to control the turn-on of the cut-off third transistor according to the delay signal to obtain a first output voltage, so that the delay circuit completes the delay control, and the output voltage includes the first output voltage.
2. The circuit according to claim 1, characterized in that, The output circuit is further configured to control the third transistor in the output circuit to turn on when the second trigger signal indicates that the delay circuit is not working, so as to obtain a second output voltage, the output voltage including the second output voltage; The RC delay circuit is also used to discharge the capacitor according to the second trigger signal.
3. The circuit according to claim 2, characterized in that, The RC delay circuit includes: a first transistor, a first resistor, a capacitor, a first Zener diode, a second resistor, and a discharge circuit; The emitter of the first transistor is electrically connected to the input voltage, the base of the first transistor is electrically connected to the output terminal of the control circuit, the collector of the first transistor is electrically connected to the first terminal of the first resistor, the second terminal of the first resistor is electrically connected to the upper plate of the capacitor, the negative terminal of the first Zener diode, and the first terminal of the discharge circuit, the positive terminal of the first Zener diode is electrically connected to the first terminal of the second resistor, the second terminal of the second resistor is electrically connected to the control terminal of the discharge circuit and the input terminal of the output circuit, and the second plate of the capacitor and the second terminal of the discharge circuit are both grounded. The discharge circuit is configured to be turned on according to the second trigger signal to discharge the capacitor.
4. The circuit according to claim 3, characterized in that, The RC delay circuit also includes: a second Zener diode; The negative terminal of the second Zener diode is electrically connected between the second end of the first resistor and the upper plate of the capacitor, and the positive terminal of the second Zener diode is grounded.
5. The circuit according to claim 3, characterized in that, The discharge circuit includes: a second transistor and a third resistor; The collector of the second transistor is electrically connected to the second end of the first resistor, the base of the second transistor is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the input end of the output circuit, and the emitter of the second transistor is grounded.
6. The circuit according to any one of claims 1-5, characterized in that, The control circuit includes: a transistor and a fourth resistor; The gate terminal of the transistor is electrically connected to the first trigger signal, the drain terminal of the transistor is electrically connected to the first terminal of the fourth resistor, the second terminal of the fourth resistor is electrically connected to the first control terminal of the RC delay circuit, and the source terminal of the transistor is grounded.
7. The circuit according to claim 6, characterized in that, The control circuit also includes: a fifth resistor; The first end of the fifth resistor is electrically connected to the first trigger signal, and the second end of the fifth resistor is electrically connected to the gate end of the transistor.
8. The circuit according to any one of claims 1-5, characterized in that, The output circuit includes: the third transistor and the diode; The positive terminal of the diode is electrically connected to the second trigger signal, the negative terminal of the diode is electrically connected to the base of the third transistor, the collector of the third transistor is used to output the output voltage, and the emitter of the third transistor is grounded.
9. An electrical switching device, characterized in that, include: The delay circuit as described in any one of claims 1-8.
10. The electrical switching device according to claim 9, characterized in that, The electrical switching device is a contactor or a molded case circuit breaker.