Delay switch

With the development of society, technology has gradually brought people a more convenient life. Among them, the switch socket is the one that is upgraded and developed relatively quickly. Delay switches have come out in recent years. This type of switch saves time and electricity, and is mostly used in aisles and corridors.


  • 1. What is the delay switch
  • 2. Working principle of time delay switch
  • 3. The role of delay switch

1. What is the delay switch

The time delay switch is a new type of automatic time delay Electronic switch developed to save power resources, which saves electricity and is convenient. Mainly used in stairwells, toilets and other places. The delay switches include touch delay switches, sound and light control delay switches, etc. As long as you touch the touch pad of the switch with your hand or give a sound signal, it will automatically illuminate. When a person leaves within 30 seconds to 75 seconds, it will automatically shut down, which is highly recommended by the National Ministry of Energy.

Delay switch

2. Working principle of time delay switch

The sound detection in the switch Circuit adopts the electret microphone MIC, and the Transistor T2 forms the Amplifier. When there is no sound, T2 is in a saturated conduction state. When there is sound, the microphone MIC receives the sound signal, which can cut off T2. The brightness detection is completed by the photoresistor RG. The CMOS digital integrated circuit CD4011 used in the circuit contains four 2-input NAND gates. In CD4011, except one of them is directly used as a 2-input NAND gate as a discriminating circuit, the other three are connected as inverters and used as amplifiers. D6, R6, and C4 form a delay circuit. The switch adopts thyristor T1. Diodes D1~D4 and SCR T1 form a controllable rectifier circuit. When T1 is ON, the bulb LAMP lights up; when T1 is off, the bulb goes out.

During the day, the photoresistor RG is in a low-impedance state when exposed to light, and the CD4011 (13) pin is always low. At this time, no matter if the CD4011 (12) pin is high level (the sound makes T2 cut off) or the low level (no sound T2 is saturated and turned on), the NAND output (11) pin is always high level. After three times of inversion, the output of pin (10) is low, the thyristor T1 is cut off, and the bulb does not light up. It can be seen that because the photoresistor RG is exposed to light, the bulb will not light up during the day.

Delay switch

3. The role of delay switch

1. When in use, just touch the metal piece of the switch to turn on and work, and the switch will automatically turn off after a period of time.

2. Application control, the switch automatically detects the insulation resistance to the ground, and the control is more reliable and error-free.

3. The non-contact electronic switch extends the service life of the load.

4. The human body safety voltage whose zero line Voltage is less than 36V when touching the metal sheet is harmless to the human body.

5. The unique two-system design can directly replace switches and can drive various loads (fluorescent lamps, energy-saving lamps, incandescent lamps, fans, etc.)

Delay switch