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Steve_88
- 27th December 2011, 05:45
Hi Everyone, I hope the Holidays have been good to you!

I have a project involving a 18F252 which uses a linear 5 volt regulator (LM2936). I've quite a bit of capacitance hanging off the 5 volt output (mostly IC bypass caps, a couple 10 uf tantalum's etc). When I apply power to the board there is a small spark when I touch the power supply wires together. The regulator input only has a 0.1 uf cap, so I'm thinking I must be getting a significant current rush from the regulator output?

What if anything should I do about this? Putting a 10 ohm resistor in series with the power supply lead (12 vdc) seems to remove the spark.

Thanks,
Steve

Oops, I may need a nap soon. I also have a switched 5 vdc regulator for powering peripherals. This regulator has a 10 uf cap on the input. This guy must be the culprit....I'll check it out tomorrow.