Multi-purpose household appliance protection circuit diagram composed of c036

The picture shows the protection circuit of multi-purpose household appliances . The circuit consists of buck and boost circuits, delay protection circuits, relay control circuits, etc.

The buck circuit is mainly composed of YF3, BG4, BG5 and J1. When the mains voltage is normal (lower than 240V), YF3 outputs high level , causing relay J1 to close, and contact J1-1 is connected to the mains input terminal. If the mains power is higher than 240V, YF3 outputs a low level, causing J1 to release, and the contact J1-1 is connected to the buck terminal, that is, the voltage obtained by the load is 30V lower than the mains power.

The boost circuit is mainly composed of YF4, BG6, BG7 and J2. When the mains power is lower than 170V, YF4 outputs a high level, causing the relay J2 to close, and the contact J2-1 is connected to the lifting position of the transformer, that is, the load can obtain a power supply voltage 50V higher than the mains power . Normally, when the mains power is normal, the YF4 output is low level, causing J2 to be released, and the contact J2-1 is connected to the mains input terminal, that is, the load is directly powered by the mains power.

The delay protection circuit is mainly composed of the charge and discharge circuit (R6, C5), RS flip-flop composed of YF1 and YF2 , relay J3, drive circuit (BG2, BG3), etc. When the power is first turned on, because the voltage on C5 cannot change suddenly, YF1 outputs low level, correspondingly BG2 and BG3 are cut off, relay J3 does not pull in, and the load does not work. At the same time, C5 is charged (through R6). After about 6 minutes of delay, the RS flip- flop flips, YF1 outputs a high level , causing BG2 and BG3 to conduct, J3 pulls in, and the load is connected due to J3-1 supply voltage to start working.

This protection circuit can automatically adjust the AC voltage between 150~260V to the range of 184~225V, thereby ensuring that household appliances can work normally. In addition, it also has the function of delaying the power supply circuit for 6 minutes, so it can effectively protect Electrical appliances.

J1, J2, and J3 in the picture are all JQX-4 types. Their rated operating voltage is DC 12V, the pickup current is less than 20mA, and the contact load is 220V, 3A, which can fully meet the requirements of general household appliances .

During debugging, connect the input to the voltage regulator. When the voltage regulator outputs 180V, adjust W1 to make J2 close; when the voltage regulator outputs 240V, adjust W2 to release J1.