Frustration with a flashing LED

MillenniumFalsehood · Post by **MillenniumFalsehood** » Sat Mar 12, 2011 5:17 am

A solution I see often to producing a flasher is to use a flashing LED. Well, that's good and fine. But say I've got a single power source, such as a wall wart, and I can't hook up the LED to it's own power. That causes the entire circuit to dim momentarily when the LED blinks. This is undesirable and frustrating.

Is there a way to limit the current somehow so that the LED doesn't cause this problem?

Caliber Mengsk · Post by **Caliber Mengsk** » Sun Mar 13, 2011 4:34 am

Not 100% sure, but I think adding in a capacitor (.1micro farad {.1uf}) might solve your problem. Don't quote me on this though. XD I am still fairly new to electronics, but from what I've gathered, that should do the trick... may need a larger one since it will be on for longer then just a blip.

Just a suggestion, if you have one lying around it should be to hard to put in and at least try it.

Paulbo · Post by **Paulbo** » Sun Mar 13, 2011 8:37 am

You might also try a wall wart with a higher amperage capacity.

ModlrMike · Post by **ModlrMike** » Sun Mar 13, 2011 11:06 am

What does your circuit diagram look like? It might be the position of the LED.

Sparky · Post by **Sparky** » Mon Mar 14, 2011 1:42 pm

Yes its probably your power supply doesn't have enough current for everything, so that when the flashing LED tries to power up the voltage sags on the rest of circuit causing the dimming effect on the other LEDs.

A cap might not help if the flashing LED is not off long enough to store up enough extra power to carry the flashing LED's power needs over its 'on' period.

MillenniumFalsehood · Thu Mar 24, 2011 11:15 pm

You think I should hook up a variable capacitor to it and see what capacitance I need for the job?

Sparky · Post by **Sparky** » Fri Mar 25, 2011 7:56 am

A variable cap won't do the job unless its a really big cap, since you are using the cap as a battery/energy source and most variable caps don't have much electron storage capacity (they mainly are there to provide a frequency constant).