> > > PWM is easy to do with 555s.
> >
> >
> >You just need to remember that the ON time can't be less than the OFF
time.
> >
> >Tony
> 
> It's quite easy to get wide range (eg. <1% to >99%) PWM at a fixed
frequency
> from a 555 using a pot (diode or active steering of charge/discharge
> currents), but IMO not so easy to get voltage-driven PWM with a fixed
period.


Well, I was thinking more along the lines of just invert the output.  The
only reason I remembered is that I used a 555 for something a couple of
weeks back.  555's are great, they still work even after you hook the power
up backwards and they get a bit hot.

Tony

- And yes, I did check the polarity first.  What I didn't check was that the
leads on the meter had been swapped.  Took me ages to notice that.  No
wonder nothing worked.

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