[AMPS] Hot Switching

[Peter Chadwick]

Rich says;

>Relays need to open quickly, as well as close quickly 
>(contact bounce time included).  

Open frame relays especially seem to bounce a lot. 'Speed up' by using a
high voltage and auxiliary contacts to put resistance in series with the
coil after relay closure doesn't help the bounce. A high supply voltage and
a series resistor helps enormously to speed up a relay - or an old Teletype
machine selector magnet. For fast opening, you do NOT want a diode across
the coil. I think Rich suggested having the coil in series with the
resistor, and the diode across the lot, which is the best way. Another trick
is to use two back to back zeners across the series resistor relay
combination.

I believe reeds are better on bounce, because of the lower inertia.

73

Peter G3RZP



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