"Ignoramus19393" wrote in message
.. .
On Thu, 18 Aug 2005 19:59:23 +0100, David Billington
wrote:
If buying solid state relays check the particular part specs as they are
available in zero crossing and non zero crossing types. For what you
want in a RPC I expect the zero crossing would be most appropriate.

Thanks... what's zero crossing?

i
The point in time where a harmonic wave (can you say "sine wave") intersects
the ordinate, or "x" axis. Voltage is zero at that time thus it is
desireable for switching to occur at that time rather than earlier or later.
There can be no transient voltage at the time of zero crossing; no chance of
transient voltage damage to the switch.

Bob Swinney





Ignoramus19393 wrote:

Thanks for the tip, these switches are very interesting. I was under a
wrong impression that they require much signal current to operate.

i




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