Homemade adjustable voltage power socket

Power socket boxes are installed in different locations in each room of the home for various electrical appliances. The nominal capacity is 10A and 16A, and the appearance is shown in Figure 1 (Figure 1 is a socket box with a single socket, and socket boxes with two or three sockets are also common.) When users actually use it, they often hope that the voltage at both ends of some sockets can be adjusted to meet the different needs of electrical appliances, such as dimming of table lamps or lighting lamps, temperature adjustment of electric soldering irons, speed adjustment of fans, etc.

To do this, you only need to connect 5 components inside the socket box (see Figure 2 for connection method) to quickly and easily turn it into an adjustable voltage socket. This is a bidirectional thyristor voltage regulation circuit. According to different needs, by adjusting the resistance of the potentiometer RP, the charging speed of the capacitor C is changed, that is, the moment when the voltage on C triggers the bidirectional diode VD to conduct, that is, the conduction angle of the bidirectional thyristor VS is changed, thereby changing the voltage at both ends of the socket.

In Figure 2, RP uses a WTX-K potentiometer (470kΩ), R uses an RJ resistor (1kΩ/0.25W), C uses a CZM capacitor (0.1μF/400V), Vt3 uses a 2CTS bidirectional trigger diode, and VS uses a BTA plastic-encapsulated bidirectional thyristor (10A/400V).

When installing, first remove the fixing bolts on the socket box cover to separate the cover and the bottom box, open a small hole at the appropriate position of the cover to fix the RP, and let the RP's rotating shaft protrude a little from the cover. The bottom box has a large internal volume, which is more than enough to accommodate the above 5 components.

Finally, restore the socket box, put the knob on the shaft of RP, and adjust the knob to obtain the required different voltages.