NE555 multi-purpose delay switch power socket

The power of household appliances, lighting lamps, etc. often needs to be turned on or off after different time delays. The power socket can meet such different needs.

Working principle: The circuit is shown in the figure, which consists of voltage reduction, rectification, filtering and delay control circuits.

Press AN, 12V working voltage is added to the delayer, then the ② and ⑥ pins of NE555 are at high level, and the output of ③ pin of NE555 is at low level, so relay K is energized and works, contact K1-1 is pulled upward, then the "delay closing" socket is energized, and the "delay opening" socket is de-energized.

At this time, the power supply passes through capacitor C3, potentiometer RP, resistor R3 to "ground", charging C3. As the voltage on C3 increases, the voltage of NE555's ② and ⑥ pins decreases. When this voltage drops to 2/3Vcc, NE555's ③ pin output jumps from low level to high level. At this time, the relay will lose power and not work, and its control contact will return to its original position, then the "extended closing" socket loses power, and the "extended opening" socket gets power. In this way, different needs are met, and LED and LED2 give corresponding indications.

This circuit can work normally as long as the components are good and assembled correctly.

The delay time is determined by the value of C3 and PR+R3, T≈1.1C3(PR+R3). RP refers to the effective part. C3 can be a capacitor ranging from tens of pF to 1000μF, and the value of (PR+R3) can be 2K~10MΩ.

The withstand voltage of C1 should be ≥400V, the power of R1 should be ≥2W, the AN push button switch can be K-18, and the relay model is JQX-13F-12V. There are no special requirements for other components.