[sdiy] Reason Eight (was discharging...^)

[Harry Bissell Jr]

Ok I confess... I do not usually discharge
voltage circuits.  I have bleeder resistors that
take them down safely (all by themselves)... 

I have been sorry (occasionally) when I work on
someone
else's design and  allow the PCB to contact a metal
object (could it be... a screwdriver on the bench) ???

I'm re-doing the capacitor experiment where I short
the
cap and record the voltage / current.  I have a big
box of 1500uF / 35V caps (so I can get a fresh one)
and my
AC current probe, and a digital scope.

I'll make photos available of the results. You will
see
discharges that occur from a single pulse to many
distinct pulses... all via arc discharge.  If someone
wants to host them (for a while) let me know and I'll
send them to you.  

Bob... I have an idea for you. I could send you some
nichrome wire that you could wrap around the shaft of
the screwdriver. You'd get a couple of ohms of
resistance... enough to take the brunt of the
discharge. It will still snap a little bit.  (I
thought
of some antistatic foam but that is WAY too high in
resistance to be practical.



--- Bob Weigel <sounddoctorin at imt.net> wrote:

> Personally..I never discharge caps in LV circuits. 
> :-)  I'll leave that 
> headache to those who do. -Bob
> 
> harrybissell wrote:
> 
> >Another reason to add to the list...
> >
> >8)  If the circuit uses voltage regualtors (78xx,
> 79xx) and the circuit
> >designer did not READ the data sheet carefully and
> provide the reverse
> >diode
> >across the input and output terminals... 
> discharging the capacitor by
> >short
> >circuit WILL destroy the regulator.
> >
> >H^) harry
> >
> >
> >
> >  
> >
>