[sdiy] Power supply ripple

James Dunn james at 4thharmonic.com
Thu Nov 20 12:52:46 CET 2008


Hi all,

I have a 555 timer which is driving a solenoid and running off a 9 volt 
battery, however the negative spikes show up on the 9v power supply rail 
and therefore I'm having trouble with other circuitry I want to add. Is 
there a way to remove this ripple? I've tried caps across the 555 and 
the battery, and I've tried a 5v regulator but the ripple is still 
there. The circuit is using about 18ma, so maybe I should use a separate 
battery for the other circuit?


thanks

James



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