Make blinking LED Flashlight

Thread Starter

romeroom

Joined Apr 17, 2014
4
I am an electronics newbie. I know very little about circuits, as will be clearly evident by my question.

I have a number of LED flashlights like this . I would like to make these blink or flash.

My question is: If I introduce a blinking LED like the one shown here in series at the "beginning" of the circuit, would the flashlight blink as well?

thanks
 

wayneh

Joined Sep 9, 2010
17,498
Sadly, I don't think so. I think the LEDs in those things are in parallel. Several similar flashlights have been dissected by folks posting in this forum. Maybe one of them will chime in.

FWIW, you can get a very bright, multifunction (flashing, strobing, etc.) LED flashlight for under $10.
 

ErnieM

Joined Apr 24, 2011
8,377
Unfortunately I doubt it would work for this flashlight. With 3 AAA batteries driving 8 LEDs not all of them are wired in series, as that would take a higher voltage.

So adding one blinkie LED will not get them all to blink, maybe just one or two or half, not all. And two blinkie LEDs will not blink at the same rate.

And welcome to the forums!
 

AnalogKid

Joined Aug 1, 2013
11,056
Using a self-blinking LED as a pulse generator in a circuit is a common trick, but only in low power situations. The LED you show should see no more than 20 mA current through it, not nearly enough to power a 9-LED light. Plus, the voltage drop acros the blinker must be kept within the range of 3.0 to 3.4 V, something the standard flashlight batteries cannot do while powering their own LEDs.

Good idea, but wrong part for the job and expensive. As wayneh said, for the price of 2 blinkers you can buy a flashlight with blinking built in.

ak
 

Thread Starter

romeroom

Joined Apr 17, 2014
4
Thank you all for chiming in so promptly. Very helpful. I think LED circuitry technology is a bit more complicated than what people think.
 
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