General Question

lapilofu's avatar

How can I make an electrical current flicker?

Asked by lapilofu (4325points) October 6th, 2010

I’ve been wiring up some LEDs with 3v batteries for various art projects and I’m interested in making some of them flicker (think fake candles or fairies). Is there an easy way to do this, or do I need some fancy parts?

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6 Answers

Zyx's avatar

There’s probably loads of small devices that do this.

If you need to improvise you could insert 7/8 circular metal parts in between the wires and make them spin to interrupt the current. Wooooooh

If you have some copper wire you can run the whole deal off electro magnets and blow out half your lights.

Jabe73's avatar

There are quite a few ways to do this. Some basic electronic parts you can purchase from a Radioshack or electronics retailer will easily get you by. You can go with a 555 timer or even just use 2 capacitors, two resisters along with two of either NPN or PNP transistors.

This would be hard to explain how to do this on this forum, personally you can easily look it up on quite a few websites and they will usually show you the diagrams on how to do this. I’m not sure how knowledgeable you are with electrical/electronic components and reading diagrams.

The easiest way I can think of to tell you would be to just purchase a relay flasher from an autoparts store, purchase a small 12 volt relay and run the 12 volts from the timer to the coil of the relay (so the relay ocsillates between on/off cycle) and then just run your 3 volts through the NO/NC terminals of the relay to power the leds in your candles. You can also use resisters to lower the 12 volts itself to 3 volts. It’s been a while since I’ve been familiar with resister color codes so I would have to look this up. I will try to find an easy to understand circuit with a link to post here but you need to have basic diagram reading ability.

FiRE_MaN's avatar

yes a 555 timer is what you need.

Jabe73's avatar This is the best I could find if you can read a basic electronic diagram. It shows both the method with/without the 555 timer. I would recommend purchasing these cheap parts from a radioshack or electronics store. I would also purchase some small gauge wire (less than 22 awg) will easily work here since current isn’t an issue here. Purchase a small breadboard as well (something small you can hide).

Ron_C's avatar

@Jabe73 you are on the right track but a 555 has a tendency to create square waves which will turn the LEDs on and off rather than flicker. I guess if you connected to a RC network you could have them fade on and almost off to synthesize a flicker.

Jabe73's avatar

@Ron_C The 555 is a digital device (on/off) not analog so that will give you your square waves. You can use a 555 timer to generate other types of waves, I already made a sawtooth generator from one using other components with the timer. The 555 is pretty versatile and there are quite a few ways you can get LEDs to flicker this way. You can control the amount of time the LED stays on or off as well as using a variable capacitor in place of a regular one. You can vary things by changing resistor sizes as well.

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