[sdiy] Power supply ripple

[Louis van Dompselaar]

Is the 555 the CMOS version?  If not, replace by CMOS version and you're
probably done.

The original NE555 uses way too much power.

> 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?