AC and DC overcurrent protection and self-holding circuit

Abstract

The invention relates to an AC-DC over-current protection and self holding circuit. The AC-DC over-current protection and self holding circuit comprises an amplification circuit, an anti-phase circuit, an over-current detection circuit, a current detection resistor R8 and a relay JD, wherein one end of the current detection resistor R8 is in grounding connection, the other end is connected with a non-inverting input end of a U1A through a normally-closed point JDC of the relay JD and a resistor R7, the anti-phase circuit comprises operational amplifiers U1B, U1C and a PNP type triode Q1, the over-current detection circuit comprises a potentiometer Rw and an NPN type triode Q2, a base electrode of the Q2 is connected with a sliding end of the potentiometer Rw, a collector electrode of the Q2 is connected with a control power source through a coil JDL of the relay. The AC-DC over-current protection and self holding circuit is advantaged in that not only can AC or DC signal amplification be realized when an input signal is normal, but also input cut off can be realized when an input current is overlarge, the cut off state is further kept, but also after the overlarge current input is cut off, return to an initial state can be realized, the protection effect on circuit elements can be effectively realized, and the beneficial effect is obvious.

Description

Technical field [0001] The invention relates to an overcurrent protection circuit, more specifically, to an AC and DC overcurrent protection and self-holding circuit. Background technique [0002] In the process of supplying power to the load, overcurrent may occur due to the power supply or load. In this case, if the overcurrent cannot be automatically cut off, it is very easy to cause damage to the power supply or load or even cause a fire. Big disaster. If an overcurrent protection circuit can be added to the circuit, when the current is too large, the current path will be automatically cut off, which will not only achieve the protection of the power supply and load but also avoid the occurrence of greater disasters. After the current path is automatically cut off, it should remain in this state until The power supply is completely cut off until the power supply is restored. Summary of the invention [0003] In order to overcome the disadvantages of the above technical proble...

AI Technical Summary

Problems solved by technology

[0002] In the process of supplying power to the load, overcurrent may occur due to the reasons of the power supply or the load. In this case, if the overcurrent cannot be automatically cut off, it is very easy to cause damage to the power supply or load, or even cause a fire. big disaster

Images