Analysis of Dual Relay 100~200W Fully Automatic Voltage Stabilizer

Circuit principle: The grid power supply is connected to pin 3 of transformer B through the switch and the normally closed contact of J1. R1 is the sampling resistor, BG1 and BG2 form a control circuit, and the starting control point can be changed by adjusting W. When the grid voltage is lower than 220V, the normally closed point of J1 causes transformer B to form a boost mode. The output voltage does not exceed 220V, J2 is normally closed and connects pin 5 of the transformer. If it is higher than 220V, J2 is connected to pin 4 of the transformer. When the grid voltage is higher than 220V, R1 is used to sample, control J1 to pull in, and connect to pin 5 of the transformer to form a step-down type. If the voltage at the output terminal exceeds the set value, R4 sampling is used to control the pull-in of J2, and the normally open contact is connected to pin 4 of the transformer. Component selection: The power of the voltage stabilizer mainly depends on the cross-section of the transformer core and the diameter of the enameled wire. The iron core is 19× (24~25), and the coil is 0.27~0.35 high-strength enameled wire for dense winding. No paper is needed between layers. Wind 48 turns around 1~2, 822 turns around 2~3, switch to 0.41~0.51 enameled wire from the third leg onwards, and wind 85 turns around 3~4, 4~5 each. BG1 and BG3 use 3DG low-power tubes, and BG2 and BG4 use PNP silicon medium-power tubes. There are no special requirements for resistors and capacitors.