CN206292294U - A kind of transistor over-current detection circuit - Google Patents
A kind of transistor over-current detection circuit Download PDFInfo
- Publication number
- CN206292294U CN206292294U CN201621446077.2U CN201621446077U CN206292294U CN 206292294 U CN206292294 U CN 206292294U CN 201621446077 U CN201621446077 U CN 201621446077U CN 206292294 U CN206292294 U CN 206292294U
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- CN
- China
- Prior art keywords
- transistor
- current detection
- detection circuit
- transformer
- supply line
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Abstract
The utility model discloses a kind of transistor over-current detection circuit, it is related to the over-current detection technical field element such as including single phase poaer supply line (L, N), breaker (QF), fuse (FU), contactor (KM), auxiliary reclay (KA), current transformer (TA), step-down transformer (T), rectifier bridge (UR1), rectifier bridge (UR2), transistor (VT1), transistor (VT2), three terminal regulator 7812, resistance, electric capacity, light emitting diode.The utility model transistor over-current detection circuit simple structure, cost are relatively low；Circuit can automatically cut off power supply when user power utilization overcurrent or supply line are short-circuited failure.
Description
Technical field
The utility model is related to over-current detection technical field, more particularly to a kind of transistor over-current detection circuit.
Background technology
Overcurrent protection is exactly a kind of protected mode for acting protection device when electric current exceedes predetermined maximum, when
Flow through when exceeding certain numerical value adjusted in advance by the electric current in protection original paper, protection device starts, and uses time limit safety action
Selectivity, make circuit breaker trip or provide alarm signal.When there is phase fault in power network, electric current can increase suddenly,
Voltage declines suddenly, overcurrent protection be exactly by the requirement of route choosing, the action current of setting current relay, work as circuit
When middle fault current reaches the working value of electric current relay, electric current relay action has choosing by the requirement of protection device selectivity
The disengagement failure circuit of selecting property.
Utility model content
The utility model when user power utilization overcurrent or supply line are short-circuited failure in order to automatically cut off confession
A kind of circuit, there is provided transistor over-current detection circuit.
To achieve the above object, the technical solution adopted in the utility model is：
A kind of transistor over-current detection circuit, including single phase poaer supply line (L, N), the single phase poaer supply line (L, N) are led to successively
The main contacts of breaker (QF), fuse (FU), contactor (KM) is crossed for load supplying, the coil of contactor (KM) with it is middle after
It is connected in parallel between single phase poaer supply line (L, N) after the normally-closed contact series connection of electrical equipment (KA)；Single phase poaer supply line (L, N) two ends are connected with change
Depressor (T) primary side, transformer (T) secondary is filtered, with three-terminal voltage-stabilizing by rectifier bridge (UR2) rectification by filter capacitor (C2)
The input of device 7812 is connected, and the earth terminal of three terminal regulator 7812 is connected to the ground, the output end output of three terminal regulator 7812
12V direct currents；Current transformer (TA) primary side is serially connected on single phase poaer supply line (L), and current transformer (TA) secondary is through over commutation
Bridge (UR1) rectification, is filtered by filter capacitor (C1), and resistance (R1) is connected in parallel on filter capacitor (C1) two ends, transistor (VT1)
Base stage is connected with resistance (R1), and the emitter stage of transistor (VT1) is connected with the base stage of transistor (VT2), the collection of transistor (VT1)
Electrode is connected with the colelctor electrode of transistor (VT2), coil one end and transistor (VT2) current collection of auxiliary reclay (KA)
Extremely it is connected, the other end is electrically connected with 12V direct currents.
Further, the transformer (T) is step-down transformer.
Further, the turn ratio of transformer (T) primary and secondary side is 18:1.
Further, there is resistance (R2) that the coil of auxiliary reclay (KA) is connected in parallel on after being connected with light emitting diode (VD1)
Two ends.
Further, the normally opened contact of auxiliary reclay (KA) is connected in parallel on transistor (VT2) after being connected with button (SB)
Colelctor electrode and emitter stage between.
Further, resistance (R3) is connected in parallel on the output end of three terminal regulator 7812 after being connected with light emitting diode (VD3)
Between ground.
Further, diode (VD2) is connected between the output end and input of the three terminal regulator 7812.
Further, the output end of the three terminal regulator 7812 is parallel with output filter capacitor (C3).
The beneficial effects of the utility model：A kind of transistor over-current detection circuit, over-current detection circuit is by transistor, contact
The elements such as device, auxiliary reclay, current transformer, step-down transformer, voltage-stablizer, rectifier bridge, filter capacitor are constituted, circuit structure
Simply, cost is relatively low；The circuit can automatically cut off power supply when user power utilization overcurrent or supply line are short-circuited failure
Power supply.
Brief description of the drawings
Fig. 1 is the utility model over-current detection circuit schematic diagram.
Specific embodiment
In order that technological means, creation characteristic, reached purpose and effect that the utility model is realized are easy to understand, under
Face combines and is specifically illustrating, and the utility model is expanded on further.
During specific implementation, with reference to Fig. 1, a kind of transistor over-current detection circuit, including single phase poaer supply line (L, N), breaker
(QF), fuse (FU), contactor (KM), auxiliary reclay (KA), current transformer (TA), step-down transformer (T), rectifier bridge
(UR1), rectifier bridge (UR2), transistor (VT1), transistor (VT2), three terminal regulator 7812.Single phase poaer supply line (L, N) is successively
Main contacts by breaker (QF), fuse (FU), contactor (KM) is load supplying.The coil of contactor (KM) and centre
It is connected in parallel between single phase poaer supply line (L, N) after the normally-closed contact series connection of relay (KA).Single phase poaer supply line (L, N) two ends are connected with
Transformer (T) primary side, transformer (T) secondary is filtered by rectifier bridge (UR2) rectification by filter capacitor (C2), steady with three ends
The input of depressor 7812 is connected, and the earth terminal of three terminal regulator 7812 is connected to the ground, and the output end of three terminal regulator 7812 is defeated
Go out 12V direct currents.Transformer (T) is step-down transformer, and the turn ratio of step-down transformer primary and secondary side is 18: 1.Current Mutual Inductance
Device (TA) primary side is serially connected on single phase poaer supply line (L), current transformer (TA) secondary by rectifier bridge (UR1) rectification, by filter
Ripple electric capacity (C1) is filtered, and resistance (R1) is connected in parallel on filter capacitor (C1) two ends, base stage and resistance (R1) phase of transistor (VT1)
Even, the emitter stage of transistor (VT1) is connected with the base stage of transistor (VT2), the colelctor electrode and transistor of transistor (VT1)
(VT2) colelctor electrode is connected, and coil one end of auxiliary reclay (KA) is connected with transistor (VT2) colelctor electrode, another
End is electrically connected with 12V direct currents.There is resistance (R2) that the coil of auxiliary reclay (KA) is connected in parallel on after being connected with light emitting diode (VD1)
Two ends.The normally opened contact for having auxiliary reclay (KA) is connected in parallel on the colelctor electrode and hair of transistor (VT2) after being connected with button (SB)
Between emitter-base bandgap grading.There is resistance (R3) to be connected in parallel between the output end of three terminal regulator 7812 and ground after being connected with light emitting diode (VD3).
Diode (VD2) is connected between the output end and input of three terminal regulator 7812.The output end of three terminal regulator 7812 is simultaneously
It is associated with output filter capacitor (C3).
During specific works, breaker (QF) is connected, contactor (KM) coil in main circuit obtains electric, contactor (KM) is main to be touched
Point closure, single phase alternating current power supply is load supplying.If customer power supply power consumption is without departing from electric current predetermined value, step-down transformer
(T) 220V alternating currents are become into 12V alternating currents, by rectifier bridge (UR2) rectification, after filter capacitor (C2) filtering, then by three ends
Voltage-stablizer 7812 is stable into 12V direct currents, and on the one hand 12V direct currents are resistance (R3), light emitting diode (VD2) is powered, and are lighted
Diode (VD2) is luminous to show user's normal electricity consumption；12V direct currents are on the other hand to auxiliary reclay (KA), resistance (R2), hair
Optical diode (VD1) is powered.When user's normal electricity consumption, resistance (R1) is partial pressure potential device, and the electric resistance partial pressure of lower end is relatively low, makes
Obtain transistor (VT1), transistor (VT2) to be not turned on, auxiliary reclay (KA) coil losing electricity, light emitting diode (VD1) does not light.
When user connects the larger electrical equipment of power or circuit short trouble occurs, the electric current increase in main circuit is a lot,
The current surge that current transformer (TA) primary side in measure loop flows through, the electric current of current transformer (TA) secondary sensing
Increase, by rectifier bridge (UR2) rectification, after filter capacitor (C1) filtering, transistor is worked as in electric resistance partial pressure increase in resistance (R1) lower end
(VT1) when base voltage is more than 1.4V, transistor (VT1), transistor (VT2) conducting, auxiliary reclay (KA) coil obtain electric,
Auxiliary reclay (KA) normally-closed contact disconnects so that contactor (KM) coil losing electricity, and contactor (KM) main contacts disconnects, and cut-out is single
Phase power supply powers to the load.Meanwhile, auxiliary reclay (KA) normally opened contact closure, 12V direct currents are continuously auxiliary reclay
(KA) coil power supply, light emitting diode (VD1) is luminous to remind the super power consumption of user or line fault.Only when reduce power consumption or
Button (SB) is pressed, auxiliary reclay (KA) coil blackout, auxiliary reclay (KA) normally-closed contact resets, contactor (KM) coil
Just can again it is electric, make its main contacts close, connect single phase poaer supply, be that user load is powered.
The utility model transistor over-current detection circuit, over-current detection circuit by transistor, contactor, auxiliary reclay,
The elements such as current transformer, step-down transformer, voltage-stablizer, rectifier bridge, filter capacitor are constituted, and circuit structure is simple, cost is relatively low；
The circuit can automatically cut off power supply when user power utilization overcurrent or supply line are short-circuited failure.
Claims (8)
1. a kind of transistor over-current detection circuit, including single phase poaer supply line (L, N), the single phase poaer supply line (L, N) passes sequentially through
Breaker (QF), fuse (FU), the main contacts of contactor (KM) are load supplying, it is characterised in that：The line of contactor (KM)
Circle is connected in parallel between single phase poaer supply line (L, N) after being connected with the normally-closed contact of auxiliary reclay (KA)；Single phase poaer supply line (L, N) two
End is connected with transformer (T) primary side, and transformer (T) secondary is filtered by rectifier bridge (UR2) rectification by filter capacitor (C2),
Input with three terminal regulator 7812 is connected, and the earth terminal of three terminal regulator 7812 is connected to the ground, three terminal regulator 7812
Output end exports 12V direct currents；Current transformer (TA) primary side is serially connected on single phase poaer supply line (L), and current transformer (TA) is secondary
While by rectifier bridge (UR1) rectification, being filtered by filter capacitor (C1), resistance (R1) is connected in parallel on filter capacitor (C1) two ends, brilliant
The base stage of body pipe (VT1) is connected with resistance (R1), and the emitter stage of transistor (VT1) is connected with the base stage of transistor (VT2), crystal
The colelctor electrode for managing (VT1) is connected with the colelctor electrode of transistor (VT2), coil one end of auxiliary reclay (KA) and transistor crystal
Pipe (VT2) colelctor electrode is connected, and the other end is electrically connected with 12V direct currents.
2. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：The transformer (T) is drop
Pressure transformer.
3. according to a kind of transistor over-current detection circuit described in claim 2, it is characterised in that：Transformer (T) primary side
It is 18: 1 with the turn ratio of secondary.
4. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：There is resistance (R2) with luminous two
The coil two ends of auxiliary reclay (KA) are connected in parallel on after pole pipe (VD1) series connection.
5. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：There is auxiliary reclay (KA)
Normally opened contact is connected in parallel between the colelctor electrode of transistor (VT2) and emitter stage after being connected with button (SB).
6. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：There is resistance (R3) with luminous two
It is connected in parallel between the output end of three terminal regulator 7812 and ground after pole pipe (VD3) series connection.
7. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：The three terminal regulator 7812
Output end and input between be connected with diode (VD2).
8. according to a kind of transistor over-current detection circuit described in claim 1, it is characterised in that：The three terminal regulator 7812
Output end be parallel with output filter capacitor (C3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621446077.2U CN206292294U (en) | 2016-12-27 | 2016-12-27 | A kind of transistor over-current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621446077.2U CN206292294U (en) | 2016-12-27 | 2016-12-27 | A kind of transistor over-current detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206292294U true CN206292294U (en) | 2017-06-30 |
Family
ID=59154996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621446077.2U Expired - Fee Related CN206292294U (en) | 2016-12-27 | 2016-12-27 | A kind of transistor over-current detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206292294U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110534000A (en) * | 2019-09-03 | 2019-12-03 | 常熟理工学院 | For the matrix form control circuit of electric fault point to be arranged |
-
2016
- 2016-12-27 CN CN201621446077.2U patent/CN206292294U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110534000A (en) * | 2019-09-03 | 2019-12-03 | 常熟理工学院 | For the matrix form control circuit of electric fault point to be arranged |
| CN110534000B (en) * | 2019-09-03 | 2021-09-28 | 常熟理工学院 | Matrix control circuit for setting electrical fault point |
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170630 Termination date: 20171227 |