As shown for the multi-purpose household protection circuit. The circuit consists of buck, boost circuit, the delay protection circuit, relay control circuit.
Step-down circuit is mainly composed of YF3, BG4, BG5, J1 composition. When the mains voltage is normal (less than 240V) when, YF3 output high, pull the relay J1, contact J1-1 input connected to the mains. If electricity than 240V, the YF3 output low, so that J1 release, contact J1-1 connected to the step-down side, the voltage that the load be lower than the market power 30V.
Boost circuit mainly by YF4, BG6, BG7, J2 composition. When the electricity is lower than 170V when, YF4 output high, pull the relay J2, contact J2-1 to enhance the location connected to the transformer, the high electricity loads available than 50V power supply voltage. Usually normal utility, YF4 output is low, so that J2 release, contact J2-1 pick in the mains input, that is, the load directly by the municipal electricity supply.
Delay protection circuit mainly by the charge and discharge circuit (R6, C5), YF1 and YF2 composed of RS flip-flop, relay J3, drive circuit (BG2, BG3) and so on. Just power on, the voltage on C5 is not due to mutation, YF1 output low, the corresponding BG2, BG3 closing, relay J3 not pull the load does not work. At the same time, C5 to charge (via R6), after some delay after 6 minutes, RS flip-flop overturns, YF1 output high, so that BG2, BG3 conduction, J3 pull the load connected by J3-1 begin work on the power supply voltage.
The protection circuit may be between the 150 ~ 260V AC voltage automatically adjust to 184 ~ 225V range, thus ensuring the household can work, and it also has a 6-minute delay in the function of power circuits, which can effectively Protection of electrical appliances.
Figure in the J1, J2, J3 are JQX-4 type, and the rated voltage of DC 12V, pull-in current of less than 20mA, contact load for the 220V, 3A, can meet the requirements of the general household appliances.
In debugging, enter the access regulator, 180V output voltage regulator, the regulator W1, so that J2 pull; 240V output voltage regulator, the regulator W2, so that J1 release.