Triacs

To: tesla-at-pupman-dot-com
Subject: Triacs
From: Max Erhard <max.erhard-at-softhome-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Thu, 02 Dec 1999 18:27:35 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

I'd like to make a remote on/off switch for my power supply. So I turned
to the relay section of the maplin (a UK supplier) catalogue, looking
for a suitable device. The only ones that made the requirements were the
solid state relays, the 25A version costing around Ł25.00, I can't
remember exactly. Then I thought about what a solid state relay consists
of, must be a triac and a few miscilaneous cheap components. 
So I turned to the semiconductor section of the catalogue and looked
under triacs. A 600v, 25A triac costing, just under Ł4.00. Now here
comes my question, is the manufacturer of solid state relays making a
600% profit or is there some cost I'm missing out. I don't know that
much about triacs.