12V DC Light Dimmer Circuit Using 555 Timer IC

12V DC Lamp Dimmer Circuit Using 555 Timer IC

12V DC Light Dimmer Circuit Using 555 Timer IC

This is a 12 volt at 2 amp Lamp dimmer that can be used to dim a standard 25 watt bulb by controlling the duty cycle of a astable 555 timer oscillator.

12V Lamp Dimmer Circuit Diagram Using 555 Timer IC

R1 1KΩ
R2 1KΩ
R3 100Ω 2W
VR1 50KΩ Preset
C1 0.1µF (104)
C2 470µF 25V
D1 1N4001
Q1 BC140
Q2 2N2955
LAMP1 12V Light

When the potentiometer is at the up position, the capacitor will charge quickly through both 1k resistors and the diode, producing a short positive interval and long negative interval which dims the lamp to near darkness.

555 Timer IC pin configuration NE555 SA SE555 SE555C

555 Timer IC PIN Configuration

When the potentiometer is at the lower position, the capacitor will charge through both 1k resistors and the 50k potentiometer and discharge through the lower 1k resistor, producing a long positive interval and short negative interval which brightens the lamp to near full intensity.

BC140 NPN transistor pinout

BC140 PIN Configuration

The duty cycle of the 200Hz square wave can be varied from approximately 5% to 95%.

You can drive more power light using 2 or more parallel 2n2955 transistors with good heat sink.

12V DC Lamp Dimmer Circuit Using 555 Timer IC Light Dimmer Circuit using ne555 2n2955 bc140 12V Lamp Dimmer Circuit Using 555 Timer IC

Please send your ideas, which are very important for our success…

18 comments on “12V DC Light Dimmer Circuit Using 555 Timer IC
  1. question says:

    on the circuit, where does port 5 goes from the 555 ??

  2. Naje says:

    is it possible to have a digital potentiometer instead of VR1?
    I’m designing a dimmer switch which can be controlled wireless. So I have a decoder. So basically what I want is to connect the decoder, timer and the digital pot to the dimmer switch..

  3. abdul says:

    pin 5 of 555 ic should not be connected any where

  4. Er.Shahbaz Ahmad says:

    abou pot 5………
    any body tell me.[img]http://img2.orkut.com/images/milieu/1/1255866533791/475975442/ln/Z1dvx8rv.jpg?ver=1255866534[/img]

  5. TOMMY says:

    So I can drive lamp bulb 12v for 555??

    12V 2W Lamp is ok for me. I have schematic 555 for 1 led. But I want have 1 lamp bulb instead!

    S1 On lamp S2 Off Lamp. I Want have 555 on 12v.

    Resistor is 100K for 12V??


  6. MR KHAN says:

    hi ……………………….

  7. Scott says:

    I have a string of 12v LEDs will this circuit cause any flickering?

  8. bakhuram says:

    i want design disco light circuit for “HAPPY WEDDING”. so. how can i it to design ??

  9. Simon G says:


    I suggest this idea :
    Sunset/sunrise light dimmer 12v and 120v

    – Imitate a sunrise and a sunset for a 20 minutes with light bulb.
    – Between them, the light can go off, if sunlight is strong enough outside a range.

    – for 12v and, if possible, 120v.


  10. nagaraj says:

    i want full details quk.

  11. Harry says:

    Hi. Can you please explainmore about the function of both transistor in the circuit ?

  12. Aravinda says:

    how can i improve this to remote controlled dc dimmer?

  13. myo zaw hein says:

    So,useful circuit for me. Thank you.
    But i want 6Amp instead of 2Amp, can i get 12v dimmer circuit for 6Amp.

  14. Armin says:

    it did NOT worked. i have checked it hundred times but it is not dimming anything. just work with full voltage and no dimming. such a waste… please remove this and shame on you

  15. Rouzbeh says:

    nice work
    I need 4or 5 amper for output.
    how can i do change for it?

  16. ONISON says:

    can I get a circuit for power generated from a heat source like charcoal stove for lighting

  17. Saimtronics says:

    Nice Job

  18. Cornelius says:

    CAN I USE 555 FOR THAT??

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