faustian.spirit wrote:
I always wonder what the difference to wiring a relay into a self
exciting circuit is...
That would work for very small relays, and slowly, but I think there
is
mechanical tuning required for 1 KHz operation. But don't quote me on
that.
Actually tried that recently when I was bored... took a small print
relay (not
really miniature, probably a reed type internally.) What I got was
around 10kHZ -
don't know how long it will survive that :) Also, a reverse Diode is
important...
without, the whole thing behaves very wildly...
A small relay won't last long in this application. If it was running at
10 KHz, the contacts were likely not opening very far. A vibrator often
has a significant mass on the armature to make it a truly resonant mass
spring assembly with fairly light damping. They operate in a limit cycle
oscillation with the stops being the NO and NC contacts. There is an
excellant reference (the Mallory Vibrator Guide) here:
The file is PW protected. Please read and follow the directions on the
site for requesting the manual-specific PW.
Choppers also are resonant, but are generally much smaller and lighter.
I think they too are lightly damped and are overdriven to ensure good
contact pressure.
-John
