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Dimmer/fader curcuit for mini bulb string lights

bigone5500

Apr 9, 2014
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Apr 9, 2014
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712
I want to make a circuit for the miniature string lights. I am thinking I can use a MOSFET transistor and an arduino. I did a search on google but there are so many it's hard to decide which is better.

My idea is to use PWM to control the mosfet by lowering the duty cycle.

Any suggestions?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
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I've done just that to dim some Christmas lights.

What is the voltage that the string of bulbs operate at, and what current do they draw?

PWM at high frequencies can cause interference, and at low frequencies can cause thermal stress on filament bulbs. Something around 100Hz to 1kHz should keep you away from these issues. Inductance in the wiring can cause voltage spikes, so a reverse biased diode across the load can be used to protect your mosfet.

I used a 40106 to make a variable duty cycle oscillator, but a 555 will also work (there are a plethora of other methods too.
 
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