18 May
2009
18 May
'09
8:17 p.m.
On May 18, 2009, at 1:32 PM, Chuck Guzis wrote:
Oh, how thoroughly bizarre. Thanks for the explanation. I'd love
to see a SPICE simulation of that.
-Dave
--
Dave McGuire
Port Charlotte, FL
I'm not
a telephony geek, but this comment prompted me to go look
at that schematic. That's a really neat little circuit. What are
the four odd components? The symbols sorta look like DIACs.
Varistors. Telco stuff was usually silicon-carbide rather than metal
oxide. Although they were used for circuit protection, and amplitude-
limiting (look inside the receiver of any 2500 series desk set), they
were also used for circuit stabilization, which is, I think, the
application in the dial circuit.