This project is a wonderful idea of saving electric bill when you are using a heavy wattage bulbs. With miniature components and extreme care you can build a low power lamp dimmer right into the socket.

Circuit Operation:-

Without a heat sink, Triac Q1 handles up to a 400-watt lamp.
Instead of a relativity expensive trigger diode, an ordinary neon lamp of the NE-83 or NE-2 variety can be used. (An NE-83 is treaded for dark operation and will provide more consistent operation.)
Because the neon does not trip the gate until it conducts, the lamp turns on at medium brilliance. The lamp can then be backed off to a soft glow. Because the neon drops out when the applied voltage falls below the neon holding voltage of approximately 40V the lamp cannot be adjusted as low as it can with a diode trigger.

Circuit Diagram:-

Lamp Dimmer Circuit Diagram

Component Required:-

Parts List for Lamp Dimmer

  C1, C2 - 0.068.uF, 200.VDC capacitor
  I1 - NE.83 or NE.2 neon lamp
  I2 - External lamp not to exceed 400 watts
  Q1 - RCA 40502 Triac
  R1 - 50,000.ohm, potentiometer
  R2 - 15,000.ohm, 1/2.watt resistor

Testing:- The only thing you need to adjust is to tune the potentiometer for proper operation. Always place the neon lamp near the bulbs so that light can fall on the neon lamp.

Application:- Attach the circuit right to the socket of higher wattage bulbs. Save more power and electric bill.