CN219936044U - Relay on-off detection circuit and household appliance - Google Patents
Relay on-off detection circuit and household appliance Download PDFInfo
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- CN219936044U CN219936044U CN202321423978.XU CN202321423978U CN219936044U CN 219936044 U CN219936044 U CN 219936044U CN 202321423978 U CN202321423978 U CN 202321423978U CN 219936044 U CN219936044 U CN 219936044U
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Abstract
The utility model provides a relay on-off detection circuit and a household appliance product, wherein the relay on-off detection circuit comprises a first current limiting unit, a first rectifying unit, a photoelectric coupler, a pull-up resistor and an instantaneous energy storage unit; the first end of the first current limiting unit is used for being connected with the voltage output end of the relay driving circuit, and the second end of the first current limiting unit is connected with the input end of the first rectifying unit; the output end of the first rectifying unit is connected with the first input end of the photoelectric coupler; the second input end of the photoelectric coupler is used for connecting a zero line; the first end of the pull-up resistor is used for being connected with a first low-voltage power supply, the second end of the pull-up resistor is respectively connected with the first output end of the photoelectric coupler and the first end of the instantaneous energy storage unit, and the second end of the pull-up resistor is also used for outputting an on-off power detection level; the second end of the instantaneous energy storage unit and the second output end of the photoelectric coupler are used for grounding. The utility model can determine the on-off condition of the relay by constructing a relay on-off detection circuit composed of pure hardware.
Description
Technical Field
The utility model relates to the field of electricity, in particular to a relay on-off detection circuit and a household appliance.
Background
The existing household appliances have a plurality of high-power loads, such as refrigerator compressors, air conditioner compressors, heating wires of washing machines with heating functions and the like, which are important components in the household appliances, and the relay is a key device for controlling whether the high-power loads are powered on or not, if the relay has adhesion failure, the high-power loads can work for a long time in an uncontrolled manner, the service life of the device can be reduced, and even potential safety hazards exist; if the relay breaks down, the load can not start working, and negative influence is brought to the user experience, so that the working state of the relay is required to be monitored.
Disclosure of Invention
The utility model provides a relay on-off detection circuit and a household appliance, which can determine the on-off condition of a relay by constructing the relay on-off detection circuit composed of pure hardware.
In order to solve the above technical problems, an embodiment of the present utility model provides a relay on/off detection circuit, including:
the first current limiting unit is used for connecting the voltage output end of the relay driving circuit, and the second end of the first current limiting unit is connected with the input end of the first rectifying unit;
the output end of the first rectifying unit is connected with the first input end of the photoelectric coupler;
the second input end of the photoelectric coupler is used for connecting a zero line, the first output end of the photoelectric coupler is used for being grounded, the second output end of the photoelectric coupler is connected with a first low-voltage power supply through a pull-up resistor, and the second output end of the photoelectric coupler is also used for outputting an on-off power detection level;
and the first end of the instantaneous energy storage unit is connected with the first output end of the photoelectric coupler, and the second end of the instantaneous energy storage unit is connected with the second output end of the photoelectric coupler.
As an improvement of the scheme, the relay on-off detection circuit further comprises a second rectifying unit;
and the input end of the second rectifying unit is connected with the second input end of the photoelectric coupler, and the output end of the second rectifying unit is connected with the first input end of the photoelectric coupler.
As an improvement of the scheme, the relay on-off detection circuit further comprises a second current limiting unit;
the first end of the second current limiting unit is respectively connected with the input end of the second rectifying unit and the second input end of the photoelectric coupler, and the second end is used for being connected with a zero line.
As an improvement of the scheme, the first current limiting unit is a first resistor, the second current limiting unit is a second resistor, the first rectifying unit is a first rectifying diode, the second rectifying unit is a second rectifying diode, and the instantaneous energy storage unit is an energy storage capacitor.
As an improvement of the scheme, the resistance value of the first resistor is 100 kiloohms, the resistance value of the second resistor is 100 kiloohms, the capacitance value of the energy storage capacitor is 2.2 microfarads, the resistance value of the pull-up resistor is 100 kiloohms, and the voltage of the first low-voltage power supply is 5 volts.
As an improvement of the above solution, the second output end of the photoelectric coupler is further configured to output an on-off detection level, including: the second output end of the photoelectric coupler is also used for outputting the on-off detection level to the signal input end of the microcontroller;
and the control end of the microcontroller is used for being connected with the controlled end of the relay driving circuit.
As an improvement of the scheme, the relay driving circuit comprises a third current limiting unit, a feedback resistor, a switching tube, a follow current unit and a relay;
the first end of the third current limiting unit is connected with the controlled end of the relay driving circuit, and the second end of the third current limiting unit is respectively connected with the control input end of the switching tube and the first end of the feedback resistor;
the signal output end of the switching tube is respectively connected with the first end of the relay and the input end of the follow current unit, and the grounding end of the switching tube is used for grounding;
the output end of the follow current unit is connected with a second low-voltage power supply and the second end of the relay respectively;
the second end of the feedback resistor is used for being grounded;
the third end of the relay is used for being connected with a live wire, and the fourth end of the relay is used for being connected with a voltage output end of the relay driving circuit;
the voltage output end of the relay driving circuit is also used for connecting a load.
As an improvement of the above scheme, the third current limiting unit is a fourth resistor, the freewheel unit is a freewheel diode, the switching tube is an NPN triode, the control input end of the switching tube is a base, the signal output end of the switching tube is a collector, and the grounding end of the switching tube is an emitter;
the relay driving circuit further comprises an RC protection unit, wherein the RC protection unit comprises a protection resistor and a protection capacitor which are connected in series; one end of the RC protection unit is used for being connected with a live wire, and the other end of the RC protection unit is used for being connected with the voltage output end.
As an improvement of the scheme, the resistance value of the fourth resistor is 4.7 kilo-ohms, the resistance value of the feedback resistor is 10 kilo-ohms, and the voltage of the second low-voltage power supply is 12 volts.
The embodiment of the utility model also provides a household appliance, which comprises the relay on-off detection circuit according to any embodiment.
Compared with the prior art, the embodiment of the utility model has the beneficial effects that the embodiment of the utility model provides a relay on-off detection circuit and a household appliance, wherein the relay on-off detection circuit comprises: the device comprises a first current limiting unit, a first rectifying unit, a photoelectric coupler, a pull-up resistor and an instantaneous energy storage unit, wherein a first end of the first current limiting unit is used for being connected with a voltage output end of a relay driving circuit, and a second end of the first current limiting unit is connected with an input end of the first rectifying unit; the output end of the first rectifying unit is connected with the first input end of the photoelectric coupler; the second input end of the photoelectric coupler is used for connecting a zero line; the first end of the pull-up resistor is used for being connected with a first low-voltage power supply, the second end of the pull-up resistor is respectively connected with the first output end of the photoelectric coupler and the first end of the instantaneous energy storage unit, and the second end of the pull-up resistor is also used for outputting an on-off power detection level; the second end of the instantaneous energy storage unit and the second output end of the photoelectric coupler are used for grounding. The relay on-off detection circuit of the embodiment is composed of a first current limiting unit, a first rectifying unit, a photoelectric coupler, a pull-up resistor and each hardware module of the instantaneous energy storage unit, and the working state of the relay can be determined by the level output by the relay on-off detection circuit, so that the relay on-off detection circuit is suitable for various household electrical appliances.
Drawings
Fig. 1 is a schematic structural diagram of a relay on-off detection circuit according to a preferred embodiment of the present utility model;
fig. 2 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model;
fig. 3 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model;
fig. 4 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model;
fig. 5 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model;
FIG. 6 is a schematic diagram of the flow of MCU related signals according to the preferred embodiment of the present utility model;
FIG. 7 is a schematic diagram of a judging logic of an MCU according to a preferred embodiment of the present utility model;
fig. 8 is a schematic structural diagram of a relay driving circuit according to a preferred embodiment of the present utility model;
fig. 9 is a schematic structural diagram of a relay driving circuit according to a preferred embodiment of the present utility model;
FIG. 10 is a schematic diagram of a load interface provided by a preferred embodiment of the present utility model;
fig. 11 is a schematic structural diagram of an NPN transistor according to a preferred embodiment of the present utility model;
wherein; 11. a first current limiting unit; 12. a first rectifying unit; 13. an instantaneous energy storage unit; 14. a second rectifying unit; 15. a second current limiting unit; 16. a third current limiting unit; 17. a freewheel unit; 18. a switching tube IC1 and a photoelectric coupler; k1, a relay; r1, a first resistor; r2, a second resistor; r3, pull-up resistor; r4, a third resistor; r5, a feedback resistor; d1, a first rectifying diode; d2, a second rectifying diode; d3, a freewheel diode; n1, NPN triode; c1, an energy storage capacitor; RC1, RC protection unit; r6, a protection resistor; c2, protecting the capacitor; l: a firing line; n, zero line.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1, a preferred embodiment of the present utility model provides a relay on-off detection circuit, which includes a first current limiting unit 11, a first rectifying unit 12, a photocoupler IC1, a pull-up resistor R3 and an instantaneous energy storage unit 13;
the first current limiting unit 11 has a first end for connecting with a voltage output end of the relay driving circuit, and a second end connected with an input end of the first rectifying unit 12;
the output end of the first rectifying unit 12 is connected with the first input end of the photoelectric coupler IC 1;
the second input end of the photoelectric coupler IC1 is used for being connected with a zero line N;
the second input end of the photoelectric coupler IC1 is used for being connected with a zero line N, the first output end of the photoelectric coupler IC1 is used for being grounded, the second output end of the photoelectric coupler IC1 is connected with a first low-voltage power supply through a pull-up resistor R3, and the second output end of the photoelectric coupler IC1 is also used for outputting a power-on/off detection level;
the first end of the instantaneous energy storage unit 13 is connected with the first output end of the photoelectric coupler IC1, and the second end of the instantaneous energy storage unit is connected with the second output end of the photoelectric coupler IC 1.
Specifically, the main function of the relay on-off detection circuit is to detect the on-off state of the relay K1, and the relay on-off detection circuit mainly comprises a first current limiting unit 11, a first rectifying unit 12, a photoelectric coupler IC1, a pull-up resistor R3 and an instantaneous energy storage unit 13. The first end of the first current limiting unit 11 is used as an input end of a relay on-off detection circuit and is used for being connected with a voltage output end of a relay driving circuit, and is actually connected with a voltage input end LOAD1 of a LOAD, and is used for receiving a level signal output by the relay driving circuit, the second output end of the photoelectric coupler IC1 is used as an output end of the relay on-off detection circuit and is used for being connected with a signal input end detection end of a microcontroller (Microcontroller Unit, MCU), and the microcontroller can determine the running state of the relay K1 according to the received on-off detection level.
The working principle of the circuit is as follows: when the switch of the relay K1 is turned off, there is no voltage between the voltage input terminal LOAD1 of the LOAD and the zero line NN, the photocoupler IC1 is not turned on, and the second output terminal of the photocoupler IC1 is at a high level. When the relay K1 is closed, the LOAD1 conducts 220V alternating current with the zero line NN, the voltage output by the voltage output end of the relay driving circuit is commercial power voltage, the voltage is input into the first rectifying unit 12 for rectification after being limited by the first current limiting unit 11, the forward voltage passes through, the reverse voltage is cut off, the photoelectric coupler IC1 is conducted in the positive half period of the alternating current, the 3 pin and the 4 pin of the photoelectric coupler IC1 are approximately short-circuited, which is equivalent to the grounding of the first low voltage source (+ 5V), at the moment, the detection pin is in a low level, the photoelectric coupler IC1 is not conducted in the negative half period of the alternating current point, at the moment, the detection pin is still in a low level due to the charging reason of the photoelectric coupler IC1, and in summary, when the input end of the photoelectric coupler IC1 has alternating current, the detection pin outputs a low level; when the input end of the photoelectric coupler IC1 has no alternating current, the detection pin outputs high level.
In the prior art, the detection mode of judging whether the relay K1 is stuck or disconnected by taking the PWM signal as the detection signal is complex, the MCU software resource is occupied, the code quantity is large, and more BUG is easy to appear.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model, where the relay on/off detection circuit further includes a second rectifying unit 14; the input end of the second rectifying unit 14 is connected with the second input end of the photoelectric coupler IC1, and the output end of the second rectifying unit is connected with the first input end of the photoelectric coupler IC 1.
It can be understood that the second rectifying unit 14 is connected in parallel to the input end of the photo-coupler IC1, and is used for protecting the photo-coupler IC1 from reverse breakdown during reverse voltage, so as to improve the reliability of the current detection of the relay K1.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a relay on/off detection circuit according to a preferred embodiment of the present utility model, where the relay on/off detection circuit further includes a second current limiting unit 15; the first end of the second current limiting unit 15 is connected to the input end of the second rectifying unit 14 and the second input end of the photocoupler IC1, respectively, and the second end is used for connecting the zero line N.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a relay on-off detection circuit according to a preferred embodiment of the present utility model, where the first current limiting unit 11 is a first resistor R1, the second current limiting unit 15 is a second resistor R2, the first rectifying unit 12 is a first rectifying diode D1, the second rectifying unit 14 is a second rectifying diode D2, and the instantaneous energy storage unit 13 is an energy storage capacitor C1.
Illustratively, the energy storage capacitor C1 charges according to the formula:where U is the voltage (5V) of the first low voltage power supply, uc is the voltage across the capacitor, t is the charging time, τ is the time constant, where τ=r3·c1, the frequency of the alternating current is 50Hz, the negative half-axis period is only 0.01s, i.e. t=0.01 s, bringing u=5v, r3=100deg.kΩ, c1=2.2uf to a Uc value of about 0.22V, and determining that the voltage is low in the case of 5V for the MCU power supply, so the detection pin is still low when the optocoupler IC1 is not conducting.
It should be noted that the above description of the specific structures of the first current limiting unit 11, the second current limiting unit 15, the first rectifying unit 12, the second rectifying unit 14 and the transient energy storage unit 13 is only for example, and may be specifically designed according to practical situations.
Referring to fig. 5, fig. 5 is a schematic structural diagram of a relay on-off detection circuit according to a preferred embodiment of the present utility model, wherein the resistance of the first resistor R1 is 100 kiloohms, the resistance of the second resistor R2 is 100 kiloohms, the capacitance of the storage capacitor C1 is 2.2 microfarads, the resistance of the pull-up resistor R3 is 100 kiloohms, and the voltage of the first low voltage power supply is 5 v.
It should be noted that, specific values of the first resistor R1, the second resistor R2, the pull-up resistor R3, the voltage of the energy storage capacitor C1, and the first low-voltage power supply are not limited to the specific settings, and the device may be selected according to practical situations.
In a preferred embodiment, the second output terminal of the photo coupler IC1 is further configured to output an on-off detection level, including: the second output end of the photoelectric coupler IC1 is also used for outputting a power on-off detection level to the signal input end of the microcontroller; and the control end of the microcontroller is used for being connected with the controlled end of the relay driving circuit.
Specifically, referring to the schematic flow diagram of the MCU related signals shown in fig. 6, the working principle of the microcontroller is as follows: the microcontroller is used for controlling the relay driving circuit, and the control end of the microcontroller sends a control signal to the controlled end of the relay driving circuit to control the on-off of the relay K1. The MCU receives a detection signal (on-off detection level) of an on-off detection circuit (relay on-off detection circuit), when the on-off detection level is low, the relay K1 is judged to be closed, and when the on-off detection level is high, the relay K1 is judged to be opened.
The whole system consists of three parts: the relay driving circuit, the MCU and the on-off detection circuit. The specific working principle is shown in fig. 6, the whole system takes an MCU as a control circuit, when a load needs to be connected to a power supply for working, the MCU sends a start signal to a relay driving circuit, then the MCU reads the input level of an on-off detection circuit, judges whether the relay K1 has an off fault according to preset judgment logic, when the load needs to be disconnected from the power supply and does not work, the MCU sends a closing signal to the relay driving circuit, then the MCU reads the input level of the detection circuit, and judges whether the relay K1 has an adhesion fault according to the preset judgment logic in software. The specific judgment logic is as shown in fig. 7, after the circuit board is electrified, judging whether the load is required to work in the running process of the system, when the load is required to work, the MCU sends a closed relay K1 signal, then the MCU detects an on-off signal (on-off detection level), and if the detected signal is high level, the MCU sends a relay K1 open-circuit fault signal; if the detection signal is low level, the state of the relay K1 is normal, an instruction of closing the load is waited, when the instruction of closing the load is received, the MCU sends a signal of disconnecting the relay K1, then the MCU detects the on-off signal, if the signal is low level, an adhesion fault signal of the relay K1 is sent to the MCU, if the signal is high level, the state of the relay K1 is normal, and the system continues to work normally.
Referring to fig. 8, fig. 8 is a schematic structural diagram of a relay driving circuit according to a preferred embodiment of the present utility model, the relay driving circuit includes a third current limiting unit 16, a feedback resistor R5, a switching tube 18, a freewheel unit 17 and a relay K1;
the first end of the third current limiting unit 16 is connected with the controlled end of the relay driving circuit, and the second end of the third current limiting unit is respectively connected with the control input end of the switch tube 18 and the first end of the feedback resistor R5;
the signal output end of the switch tube 18 is respectively connected with the first end of the relay K1 and the input end of the follow current unit 17, and the grounding end is used for grounding;
the output end of the follow current unit 17 is respectively connected with a second low-voltage power supply and the second end of the relay K1;
the second end of the feedback resistor R5 is used for being grounded;
the third end of the relay K1 is used for being connected with a live wire L, and the fourth end of the relay K1 is used for being connected with a voltage output end of the relay driving circuit;
the voltage output end of the relay driving circuit is also used for connecting a load.
Referring to fig. 9, fig. 9 is a schematic structural diagram of a relay driving circuit according to a preferred embodiment of the present utility model, in a preferred embodiment, the third current limiting unit 16 is a third resistor R4, the freewheel unit 17 is a freewheel diode D3, the switch tube 18 is an NPN triode N1, a control input end of the switch tube 18 is a base, a signal output end of the switch tube 18 is a collector, and a ground end of the switch tube 18 is an emitter;
the relay driving circuit further comprises an RC protection unit RC1, wherein the RC protection unit RC1 comprises a protection resistor R6 and a protection capacitor C2 which are connected in series; one end of the RC protection unit RC1 is used for being connected with a live wire L, and the other end of the RC protection unit RC1 is used for being connected with the voltage output end.
In a preferred embodiment, referring to fig. 9, the third resistor R4 has a resistance of 4.7 kilo-ohms, the feedback resistor R5 has a resistance of 10 kilo-ohms, and the second low voltage power supply has a voltage of 12 v.
Specifically, the MCU controls the on-off of a load power supply by sending high and low level to control the suction of the relay K1, so that the purpose of controlling the work of the strong electric load by the MCU is achieved. SIGNAL is the controlled end of the relay driving circuit, which is used to connect the control end (any IO port) of MCU, MCU outputs high level or low level; the resistance value of the third resistor R4 is 4.7K, which is used for limiting the current of the base terminal of the NPN triode N1; the resistance value of a feedback resistor R5 of the base electrode and the emitter electrode of the NPN triode N1 is 10K; d1 is a freewheeling diode D3; whether the RC protection unit RC1 is used or not is selected according to the type of the load, the RC protection unit RC1 is needed when the load is an inductive load, the protection capacitor C2 has the effect of controlling discharge when the contact of the electromagnetic relay K1 is disconnected, the protection resistor R6 has the effect of limiting current when the load is connected next time, and the RC protection unit RC1 is not needed when the load is a resistive load; +12V is a direct current 12V power supply on the circuit board as a second low voltage power supply; one end of a switching part of the relay K1 is connected with a live wire L of the mains supply, the other end of the switching part is connected with a LOAD voltage input end LOAD1, and the other interface of the LOAD is connected with a zero line N, as can be seen in fig. 10. Preferably, the zero line N is a mains supply zero line N, and the structure of the NPN transistor N1 can be seen in fig. 11.
The working principle of the relay driving circuit is that when the SIGNAL pin outputs high level, the NPN triode N1 is conducted, the coil of the relay K1 is electrified, the normally open contact of the relay K1 is closed, and the load is electrified to work; when the SIGNAL pin outputs a low level, the NPN triode N1 is cut off, the coil of the relay K1 is powered off, the normally open contact of the relay K1 is disconnected, and the load is powered off to stop working.
The embodiment of the utility model also provides a household appliance, which comprises the relay on-off detection circuit according to any embodiment. Further, the home appliance further comprises a home appliance body.
The home appliance may be a refrigerator, an air conditioner, a washing machine, or the like, and is not limited thereto. The load may be a refrigerator compressor, an air conditioner compressor, a heating wire of a washing machine with a heating function, etc., and is not limited herein.
Compared with the prior art, the embodiment of the utility model has the beneficial effects that the embodiment of the utility model provides a relay on-off detection circuit and a household appliance, wherein the relay on-off detection circuit comprises: the device comprises a first current limiting unit 11, a first rectifying unit 12, a photoelectric coupler IC1, a pull-up resistor R3 and an instantaneous energy storage unit 13, wherein a first end of the first current limiting unit 11 is used for being connected with a voltage output end of a relay driving circuit, and a second end of the first current limiting unit is connected with an input end of the first rectifying unit; the output end of the first rectifying unit 12 is connected with the first input end of the photoelectric coupler IC 1; the second input end of the photoelectric coupler IC1 is used for connecting a zero line N; the first end of the pull-up resistor R3 is used for being connected with a first low-voltage power supply, the second end of the pull-up resistor R3 is respectively connected with the first output end of the photoelectric coupler IC1 and the first end of the instantaneous energy storage unit 13, and the second end of the pull-up resistor R3 is also used for outputting an on-off detection level; a second terminal of the transient energy storage unit 13 and a second output terminal of the optocoupler IC1 are used for grounding. The relay on-off detection circuit of the embodiment is composed of a first current limiting unit 11, a first rectifying unit 12, a photoelectric coupler IC1, a pull-up resistor R3 and an instantaneous energy storage unit 13, and the working state of the relay K1 can be determined by the level output by the relay on-off detection circuit, so that the relay on-off detection circuit is suitable for various household electrical appliances.
While the foregoing is directed to the preferred embodiments of the present utility model, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the utility model, such changes and modifications are also intended to be within the scope of the utility model.
Claims (10)
1. A relay on-off detection circuit, comprising:
the first current limiting unit is used for connecting the voltage output end of the relay driving circuit, and the second end of the first current limiting unit is connected with the input end of the first rectifying unit;
the output end of the first rectifying unit is connected with the first input end of the photoelectric coupler;
the second input end of the photoelectric coupler is used for connecting a zero line, the first output end of the photoelectric coupler is used for being grounded, the second output end of the photoelectric coupler is connected with a first low-voltage power supply through a pull-up resistor, and the second output end of the photoelectric coupler is also used for outputting an on-off power detection level;
and the first end of the instantaneous energy storage unit is connected with the first output end of the photoelectric coupler, and the second end of the instantaneous energy storage unit is connected with the second output end of the photoelectric coupler.
2. The relay on-off detection circuit of claim 1, further comprising:
and the input end of the second rectifying unit is connected with the second input end of the photoelectric coupler, and the output end of the second rectifying unit is connected with the first input end of the photoelectric coupler.
3. The relay on-off detection circuit according to claim 2, further comprising:
and the first end of the second current limiting unit is respectively connected with the input end of the second rectifying unit and the second input end of the photoelectric coupler, and the second end of the second current limiting unit is used for being connected with a zero line.
4. The relay on-off detection circuit of claim 3, wherein the first current limiting unit is a first resistor, the second current limiting unit is a second resistor, the first rectifying unit is a first rectifying diode, the second rectifying unit is a second rectifying diode, and the instantaneous energy storage unit is an energy storage capacitor.
5. The relay on/off detection circuit according to claim 4, wherein the resistance of the first resistor is 100 kilo ohms, the resistance of the second resistor is 100 kilo ohms, the capacitance of the energy storage capacitor is 2.2 microfarads, the resistance of the pull-up resistor is 100 kilo ohms, and the voltage of the first low-voltage power supply is 5 v.
6. The relay on-off detection circuit according to any one of claims 1 to 5, wherein the second output terminal of the photo coupler is further configured to output an on-off detection level, comprising: the second output end of the photoelectric coupler is also used for outputting the on-off detection level to the signal input end of the microcontroller;
and the control end of the microcontroller is used for being connected with the controlled end of the relay driving circuit.
7. The relay on-off detection circuit according to claim 6, wherein the relay driving circuit includes a third current limiting unit, a feedback resistor, a switching tube, a freewheel unit, and a relay;
the first end of the third current limiting unit is connected with the controlled end of the relay driving circuit, and the second end of the third current limiting unit is respectively connected with the control input end of the switching tube and the first end of the feedback resistor;
the signal output end of the switching tube is respectively connected with the first end of the relay and the input end of the follow current unit, and the grounding end of the switching tube is used for grounding;
the output end of the follow current unit is connected with a second low-voltage power supply and the second end of the relay respectively;
the second end of the feedback resistor is used for being grounded;
the third end of the relay is used for being connected with a live wire, and the fourth end of the relay is used for being connected with a voltage output end of the relay driving circuit;
the voltage output end of the relay driving circuit is also used for connecting a load.
8. The relay on-off detection circuit according to claim 7, wherein the third current limiting unit is a fourth resistor, the freewheel unit is a freewheel diode, the switching tube is an NPN triode, a control input end of the switching tube is a base, a signal output end of the switching tube is a collector, and a ground end of the switching tube is an emitter;
the relay driving circuit further comprises an RC protection unit, wherein the RC protection unit comprises a protection resistor and a protection capacitor which are connected in series; one end of the RC protection unit is used for being connected with a live wire, and the other end of the RC protection unit is used for being connected with the voltage output end.
9. The relay on-off detection circuit according to claim 8, wherein a resistance value of the fourth resistor is 4.7 kilo-ohms, a resistance value of the feedback resistor is 10 kilo-ohms, and a voltage of the second low-voltage power supply is 12 v.
10. An electric home appliance comprising the relay on-off detection circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321423978.XU CN219936044U (en) | 2023-06-06 | 2023-06-06 | Relay on-off detection circuit and household appliance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202321423978.XU CN219936044U (en) | 2023-06-06 | 2023-06-06 | Relay on-off detection circuit and household appliance |
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| Publication Number | Publication Date |
|---|---|
| CN219936044U true CN219936044U (en) | 2023-10-31 |
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| CN202321423978.XU Active CN219936044U (en) | 2023-06-06 | 2023-06-06 | Relay on-off detection circuit and household appliance |
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| CN (1) | CN219936044U (en) |
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