CN210724184U - Teaching experiment equipment overload protection circuit - Google Patents
Teaching experiment equipment overload protection circuit Download PDFInfo
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- CN210724184U CN210724184U CN201922239594.2U CN201922239594U CN210724184U CN 210724184 U CN210724184 U CN 210724184U CN 201922239594 U CN201922239594 U CN 201922239594U CN 210724184 U CN210724184 U CN 210724184U
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 230000001755 vocal effect Effects 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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Abstract
An overload protection circuit for teaching experiment equipment comprises a resistor R1, wherein one end of the resistor R1 is connected with a pin of a rectifier bridge 1 and a common contact of a relay K1, a normally closed contact of K1 is connected with the anode of electric equipment, and the cathode of the electric equipment is connected with the AC1N end of an alternating current power supply; the other end of a resistor R1 is connected with an AC1L end and a pin of a rectifier bridge 3, a pin of a rectifier bridge 2 is connected with an anode of an optocoupler diode of a photocoupler U1, a cathode of the optocoupler diode is connected with a pin of a rectifier bridge 4, a collector of an optocoupler triode of a U1 is connected with one end of a switch button S1 and an anode of a one-way thyristor Q1, the other end of S1 is connected with a direct-current power supply VCC end, a gate of Q1 is connected with an emitter of the optocoupler triode of U1, a cathode of Q1 is connected with one ends of resistors R2, R3, a coil of a relay K1 and a cathode of a diode D1, the other end of a resistor R2 is connected with one end of a buzzer LS1, the other end of an LS1 is connected with; the utility model has the advantages of simple circuit, low cost and the like.
Description
Technical Field
The utility model belongs to the technical field of circuit protection, concretely relates to teaching experiment equipment overload protection circuit.
Background
The electrical and electronic experimental equipment is used as an important tool for practice and teaching, and has been widely applied to colleges and universities such as colleges and universities, vocational schools, vocational technical schools and the like. However, due to reasons such as equipment aging and irregular personnel operation, the equipment slowly shows partial defects in the use process, for example, when students operate experiments, overload, short circuit and other conditions of the equipment sometimes occur due to misoperation, and if no protective measures are taken, the mathematical equipment is damaged quickly and needs to be maintained or replaced. At present, electrical and electronic experimental equipment used in schools is basically provided with short circuit and overload protection circuits, but the method is usually realized through fuses, and although the method has the advantages of simple circuits, convenience in installation and the like, the fuses need to be frequently replaced when overload accidents occur, and the replacement cost is high. In addition, the method is lack of a corresponding overload reminding circuit, and the overload accident cannot be timely known when the overload accident occurs, so that the delay of the overhaul time is caused.
Disclosure of Invention
In order to overcome the shortcoming of the prior art, the utility model aims to provide a teaching experiment equipment overload protection circuit carries out overload protection through audible and visual alarm's mode when test equipment transships, has advantages such as with low costs, security performance height.
In order to achieve the above purpose, the utility model discloses the technical scheme who takes does:
an overload protection circuit for teaching experiment equipment comprises a resistor R1, wherein one end of the resistor R1 is connected with a 1 st pin of a rectifier bridge BR1 and a common contact end of a relay K1, a normally closed contact end of the relay K1 is connected with a positive end of electric equipment, and a negative end of the electric equipment is connected with an N end of an alternating current power supply AC 1;
the other end of the resistor R1 is connected with the L end of an alternating current power supply AC1 and the 3 rd pin of a rectifier bridge BR1, the 2 nd pin of the rectifier bridge BR1 is connected with the anode end of an optocoupler diode of a photocoupler U1, the cathode end of the optocoupler diode is connected with the 4 th pin of a rectifier bridge BR1, the collector end of an optocoupler triode of the photocoupler U1 is connected with one end of a switch button S1 and the anode end of a unidirectional thyristor Q1, the other end of the switch button S1 is connected with a direct current power supply VCC end, the gate end of the unidirectional thyristor Q1 is connected with the emitter end of the optocoupler triode of the photocoupler U1, the cathode end of the unidirectional thyristor Q1 is connected with one end of a resistor R2, one end of a relay K1 coil and the cathode end of a diode D1, the other end of the resistor R2 is connected with one end of a buzzer LS1, the other end of the buzzer LS1 is connected with the cathode end of a red light emitting diode L1, the anode, the anode terminal of the red light emitting diode L1 is connected to the other terminal of the resistor R3.
The direct-current power supply VCC is 6V, the buzzer LS1 is an active buzzer, and the working voltage is 3.3V.
The relay K1 is a 5-pin relay, the product model is SRD-05VDC-SL-C, and the power supply voltage is 5V.
The model of the photoelectric coupler U1 is PC817, the model of the one-way controllable silicon Q1 is 2N1595, and the model of the diode D1 is IN 4005.
The resistor R1 is a high-precision sampling resistor with the resistance of 1.4V/maximum current of the electric equipment.
The resistors R2 and R3 are respectively 200 omega and 300 omega.
The utility model has the advantages that:
1. realize overload detection through sampling resistance R1, when the emergence overload accident, can be timely cut off the power supply input through relay K1, compare the traditional working method of changing the fuse, detect with low costs, work efficiency is high.
2. Overload reminding is carried out in the mode of sound-light alarm of the active buzzer LS1 and the red light-emitting diode L1, so that a user can be quickly reminded of timely carrying out accident handling during overload, and damage to electric equipment caused by overload accidents is avoided.
3. The circuit has the advantages of simple circuit structure, high reliability, low cost, reusability and the like.
Drawings
Fig. 1 is a schematic circuit diagram of the present invention.
Fig. 2 is a schematic current flow diagram of the electric device in normal operation.
Fig. 3 is a schematic view of the instantaneous current flow when the unidirectional thyristor is triggered when the electrical equipment is in overload accident.
Fig. 4 is a schematic view of the instantaneous current flow when the unidirectional thyristor is not turned off after being triggered when an overload accident occurs to the electric equipment.
Detailed Description
The present invention will be further explained with reference to the drawings and examples.
Referring to fig. 1, the overload protection circuit for teaching experiment equipment comprises a resistor R1, wherein one end of the resistor R1 is connected with a 1 st pin of a rectifier bridge BR1 and a common contact end of a relay K1, a normally closed contact end of the relay K1 is connected with a positive terminal of electric equipment, and a negative terminal of the electric equipment is connected with an N terminal of an alternating current power supply AC 1;
the other end of the resistor R1 is connected with the L end of an alternating current power supply AC1 and the 3 rd pin of a rectifier bridge BR1, the 2 nd pin of the rectifier bridge BR1 is connected with the anode end of an optocoupler diode of a photocoupler U1, the cathode end of the optocoupler diode is connected with the 4 th pin of a rectifier bridge BR1, the collector end of an optocoupler triode of the photocoupler U1 is connected with one end of a switch button S1 and the anode end of a unidirectional thyristor Q1, the other end of the switch button S1 is connected with a direct current power supply VCC end, the gate end of the unidirectional thyristor Q1 is connected with the emitter end of the optocoupler triode of the photocoupler U1, the cathode end of the unidirectional thyristor Q1 is connected with one end of a resistor R2, one end of a relay K1 coil and the cathode end of a diode D1, the other end of the resistor R2 is connected with one end of a buzzer LS1, the other end of the buzzer LS1 is connected with the cathode end of a red light emitting diode L1, the anode, the anode terminal of the red light emitting diode L1 is connected to the other terminal of the resistor R3.
The direct-current power supply VCC is 6V, the buzzer LS1 is an active buzzer, and the working voltage is 3.3V.
The relay K1 is a 5-pin relay, the product model is SRD-05VDC-SL-C, and the power supply voltage is 5V.
The model of the photoelectric coupler U1 is PC817, the model of the one-way controllable silicon Q1 is 2N1595, and the model of the diode D1 is IN 4005.
The resistor R1 is a high-precision sampling resistor with the resistance of 1.4V/maximum current of the electric equipment.
The resistors R2 and R3 are respectively 200 omega and 300 omega.
The utility model discloses a theory of operation does:
as shown in fig. 1 and 2, when the AC power supply AC1 is turned on, the switch button S1 is pressed, and the electric device normally operates, the resistor R1 samples current, at this time, voltage across both ends of the resistor R1 is less than 1.4V (voltage across both ends of an optocoupler diode of the optocoupler U1 after rectification by the rectifier bridge is less than 1.2V), because minimum on voltage of the optocoupler U1 is 1.2V, the optocoupler diode of the optocoupler U1 is not conductive at this time, so that the optocoupler triode stops being conductive, no current passes through a coil of the relay K1, the switch is maintained at a normally closed contact end, at this time, current flows from an L end of the AC power supply AC1 through the resistor R1, the normally closed contact of the relay K1 and the N end of the AC power supply AC1 after the electric device flows into the normally closed contact, so as to provide power input.
As shown in fig. 1 and 3, when an overload accident occurs due to an excessive input current, the voltage across the resistor R1 is greater than 1.4V, the voltage across the optocoupler diode of the optocoupler U1 is greater than 1.2V, and at this time, the optocoupler diode of the optocoupler U1 is turned on, so that the optocoupler triode of the optocoupler U1 is also turned on, at this time, the current flows through the optocoupler triode from the dc power VCC terminal and then flows into the gate terminal of the triac Q1 (the gate terminal voltage is about 4.8V after voltage division by the optocoupler triode), at this time, the triac Q1 is turned on, the current flows through the triac Q1 from the dc power VCC terminal and then branches into three paths, one path of current flows through the resistor R2 and the buzzer LS1 and then flows into the GND terminal, one path of current flows through the resistor R3 and the red light emitting diode L1 and then flows into the GND terminal, another path of current flows through the coil of the relay K1 and, the relay coil is electrified, so that the normally open contact is electrified, the normally closed contact is deenergized, and the switch is attracted to the normally open contact end. The input of the AC power source AC1 is cut off, and the electric equipment stops operating. Meanwhile, as the current flows through the buzzer LS1 and the red light emitting diode L1, the buzzer LS1 buzzes, the red light emitting diode L1 emits light, and the overload accident is reminded to the user in a sound-light alarm mode, so that the user can timely process the accident.
As shown in fig. 1 and 4, after the power supply of the AC power supply AC1 stops the power supply input, no voltage is output at the two ends of the resistor R1, the optocoupler diode of the optocoupler U1 is turned off, the optocoupler triode is turned off, and the triac Q1 is turned off, so that the one-way thyristor Q1 continues to be kept in the on state, and thus the relay K1 continues to be attracted, the red light emitting diode L1 continues to emit light, the buzzer LS1 continues to sound, when the AC power supply AC1 is turned off, the switch button S1 is pressed, the one-way thyristor Q1 stops being turned on, the coil of the relay K1 is de-energized, the normally open contact of the relay is de-energized, so that the relay switch returns to the normally closed contact end, and meanwhile, since no current flows through the buzzer LS1 and the red light emitting diode L1, the buzzer LS 85. After the overload fault is eliminated, the AC1 is connected, and the next overload protection can be performed after the switch button S1 is pressed. The utility model has the advantages of low cost, convenient operation, repeated utilization, etc.
Claims (6)
1. The utility model provides a teaching experiment equipment overload protection circuit which characterized in that: the power supply comprises a resistor R1, wherein one end of the resistor R1 is connected with a 1 st pin of a rectifier bridge BR1 and a common contact end of a relay K1, a normally closed contact end of the relay K1 is connected with a positive end of electric equipment, and a negative end of the electric equipment is connected with an N end of an alternating current power supply AC 1;
the other end of the resistor R1 is connected with the L end of an alternating current power supply AC1 and the 3 rd pin of a rectifier bridge BR1, the 2 nd pin of the rectifier bridge BR1 is connected with the anode end of an optocoupler diode of a photocoupler U1, the cathode end of the optocoupler diode is connected with the 4 th pin of a rectifier bridge BR1, the collector end of an optocoupler triode of the photocoupler U1 is connected with one end of a switch button S1 and the anode end of a unidirectional thyristor Q1, the other end of the switch button S1 is connected with a direct current power supply VCC end, the gate end of the unidirectional thyristor Q1 is connected with the emitter end of the optocoupler triode of the photocoupler U1, the cathode end of the unidirectional thyristor Q1 is connected with one end of a resistor R2, one end of a relay K1 coil and the cathode end of a diode D1, the other end of the resistor R2 is connected with one end of a buzzer LS1, the other end of the buzzer LS1 is connected with the cathode end of a red light emitting diode L1, the anode, the anode terminal of the red light emitting diode L1 is connected to the other terminal of the resistor R3.
2. The overload protection circuit for teaching experiment equipment as claimed in claim 1, wherein: the direct-current power supply VCC is 6V, the buzzer LS1 is an active buzzer, and the working voltage is 3.3V.
3. The overload protection circuit for teaching experiment equipment as claimed in claim 1, wherein: the relay K1 is a 5-pin relay, the product model is SRD-05VDC-SL-C, and the power supply voltage is 5V.
4. The overload protection circuit for teaching experiment equipment as claimed in claim 1, wherein: the model of the photoelectric coupler U1 is PC817, the model of the one-way controllable silicon Q1 is 2N1595, and the model of the diode D1 is IN 4005.
5. The overload protection circuit for teaching experiment equipment as claimed in claim 1, wherein: the resistor R1 is a high-precision sampling resistor with the resistance of 1.4V/maximum current of the electric equipment.
6. The overload protection circuit for teaching experiment equipment as claimed in claim 1, wherein: the resistors R2 and R3 are respectively 200 omega and 300 omega.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922239594.2U CN210724184U (en) | 2019-12-14 | 2019-12-14 | Teaching experiment equipment overload protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922239594.2U CN210724184U (en) | 2019-12-14 | 2019-12-14 | Teaching experiment equipment overload protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN210724184U true CN210724184U (en) | 2020-06-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201922239594.2U Expired - Fee Related CN210724184U (en) | 2019-12-14 | 2019-12-14 | Teaching experiment equipment overload protection circuit |
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| CN (1) | CN210724184U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112769094A (en) * | 2020-12-28 | 2021-05-07 | 苏州工业园区天和仪器有限公司 | Alternating current overload detection protection circuit |
-
2019
- 2019-12-14 CN CN201922239594.2U patent/CN210724184U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112769094A (en) * | 2020-12-28 | 2021-05-07 | 苏州工业园区天和仪器有限公司 | Alternating current overload detection protection circuit |
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Granted publication date: 20200609 |
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| CF01 | Termination of patent right due to non-payment of annual fee |