Courtesy Lights


Posted on Feb 7, 2014

This circuit is intended to let the user turn off a lamp by means of a switch placed far from bed, allowing him enough time to lie down before the lamp really switches off. Due to the low current drawing, the circuit can be supplied from 220Vac mains without a transformer. Supply voltage is reduced to 10Vdc by means of C1 reactance, a two diode rectifier cell D1 & D2 and Zener diode D3.


Courtesy Lights
Click here to download the full size of the above Circuit.

IC1 is a CMos 555 timer wired as a monostable, providing 15 seconds on-time set by R3 & C4. When SW1 is closed, IC1 output (pin 3) is permanently on, driving Triac D4 which in turn feeds the lamp. Opening SW1 operates the monostable and, after 15 seconds, pin 3 of IC1 goes low switching off the lamp.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Variable Fan Controller
    Car auto-dimmer
    Logarithmic-sweep-vco
    FM Audio Transmitter Circuit
    Automatic Rain Sensing Wiper System using 555 Timer
    12 volt switching power supply using LTC3810-5 switching regulator
    Car anti-theft alarm circuit



    Top