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Path: utzoo!watmath!clyde!cbosgd!ihnp4!fortune!wall
From: wall@fortune.UUCP (Jim Wall)
Newsgroups: net.analog
Subject: AC current monitor
Message-ID: <5139@fortune.UUCP>
Date: Fri, 22-Mar-85 12:26:03 EST
Article-I.D.: fortune.5139
Posted: Fri Mar 22 12:26:03 1985
Date-Received: Sat, 23-Mar-85 02:14:50 EST
Distribution: net
Organization: Fortune Systems, Redwood City, CA
Lines: 21

*** REPLACE THIS LINE WITH YOUR CIRCUIT ***

     I have a tough question here.  I need a circuit to indicate
the presence of a load on an AC line. Wait, it gets more difficult.
The load can vary from 100 watts to 1000 watts, and the output 
signal must be a TTL level.  Also, it cannot drop the 110 volt
AC line by very much.  One more thing: the ground of whatever 
circuit is used will be tied to the neutral line of the AC, so complete 
isolation is not possible.

    I have been thinking along the lines of an inline inductor,
you know:  V = L(di/dt); as opposed to an inline resistor. The 
resistor will drop too much voltage at 10 Amps or not produce enough 
voltage at 1 amp. 

     Any ideas?  This is trying to be low cost, so the simpler the
better. Good Luck Mr. Phelps. Your terminal will self destruct in
10 seconds.

					-Jim (10  9   8 ...) Wall
					...amd!fortune!wall