• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Flickerling Lights

Not open for further replies.


New Member
Radio Shack sells small flickering bulbs,red yellow & green, that I would like to replicate using my own bulb & elecrical components
The bulbs from Radio Shack have two wires leading to the bulb and nothing else that I can see that allows the bulbs to flicker-
I would like to connect a flashlight bulb to a 9V battery and use whatever Radio Shack is using to make the flashlight bulb flicker

panic mode

Well-Known Member
Well it looks like their flasher is integrated into the bulb itself.
If you would still like to use original bulb as flasher, add one
transistor and resistor:

Connect one end of original bulb and resistor in series.
If you are using NPN transistor, make sure that resistor is
on negative side of the circuit so you can attach base
to point between bulb and resistor. Connect emiter to other
end of resistor which is actually (-). Your new bulb will be
connected from collector to (+). Note that in order for this to
work, you will have to carefully choose resistor value.
It should have voltage drop ca 0.1-0.2V higher than what is needed
to turn on transistor (this is when original flasher bulb is on).
When flasher bulb is off, current draw will be lower and voltage
drop over resistor will reduce shutting transistor and your bulb off.
Considering component count it is not big deal to make own flasher
circuit using something like 555 chip but this should work fine too.


New Member
flickering light

if you are willing to use a 12V battery, you can then buy a flasher from an automotive store. This is the same flasher that you use in the car for turning signals and the emergency lights ect....

But if you need to buy one of those, you might as well just buy it from radio shack
Not open for further replies.

Latest threads

EE World Online Articles