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Path: utzoo!mnetor!uunet!seismo!rutgers!clyde!cbosgd!ihnp4!homxb!mhuxt!mhuxm!mhuxo!ulysses!sfmag!sfsup!jeffj
From: jeffj@sfsup.UUCP (J.S.Jonas)
Newsgroups: sci.electronics
Subject: Re: TTL Questions
Message-ID: <1696@sfsup.UUCP>
Date: Tue, 28-Jul-87 12:30:27 EDT
Article-I.D.: sfsup.1696
Posted: Tue Jul 28 12:30:27 1987
Date-Received: Sat, 1-Aug-87 01:50:29 EDT
References: <1395@crash.CTS.COM>
Organization: AT&T-IS, Summit N.J. USA
Lines: 29
Summary: Not enough said about SSR (Solid State Relays)

In article <1395@crash.CTS.COM>, rpluth@pnet01.UUCP writes:
> 
>     I have a couple questions about TTL logic that I hope can be
> answered here...
> 
>     1.  What's the easiest way to go about interfacing a TTL
> output (from, say, a standard S or LS AND gate) to a relay, for
> controlling anything from automobile (12VDC) to house (120VAC)

There is a great device called a Solid State Relay.
Surplus places sell them for about $1 per ampere output rating.
It's an optoisolator and triac in one case,
commonly called 'hocky pucks' because of their black cases
despite their being square.

input is usually 3-15 volts at a few milliamperes.
output controls up to 250 volts AC, 1 to 25 amperes is common.
It's got to be AC for the triac to turn off
(this is touted as a feature 'zero crossing shutoff').
Some can turn off an AC wave in the middle of a cycle.
And I found a few that can handle DC.  (probably use transistors
as the switching element).

I once used my Timex Sinclair as a light sequencer by attaching
an 8 bit latch to SSR's which blinked the lights,
by software control!

	Jeffrey Jonas
	{ihnp4 | allegra} attunix ! jeffj