Re: Powering a 5V and a 9V circuit from one 9V battery -- isolation help?


mp__@xxxxxxxxxxx wrote:
For size/weight reasons, I'm hoping to use a single 9V battery plus
mic2950 5V regulator to power a mini video camera (9V) and some RC
servos (5V). Unfortunately, every time the servos move, there's a burst
of interference on the video signal. There's no interference when the
camera and the servos are powered by separate batteries.
The circuit is simple: 9V battery, mic2950, camera, and RC stuff, just
wired together the obvious way. I tried adding a capacitor between
output and ground of the regulator, but that didn't have any effect.
Is there any way to eliminate the interference?
Or, is there a 5 or 6V power source that's smaller than 4AA cells, or
an alternate 9V battery that's smaller than the usual?
Thanks for your attention.


Michael

I've done this before without any problems. The camera was 12 volts
and the servos were powered from a 7805 regulator with about 100uf on
both the input and output. You dont need a fancy low-dropout regulator
for this application.

Also, watch out for any common ground connections, run both bach to the
battery seperately. Or, try physically moving the servos away from the
camera to see if the coupling is inductive from the motor coils.

Good luck,
Luhan

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