Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!randvax!zorin!chris
From: chris@zorin.UUCP (Christopher Nielsen)
Newsgroups: sci.electronics
Subject: Current Detector?
Keywords: AC, op-amps, indication
Message-ID: <184@zorin.UUCP>
Date: 19 Jun 89 08:10:34 GMT
Distribution: na
Organization: Zorin Data Systems, Inc., Santa Monica, CA
Lines: 34

I have an interesting problem... 

I have a room, X. It has a 110V power line running to it. I want to detect
if there is any current being used in it. I don't want to place a resistor
inline, but rather, put a coil or something around the 12 guage conductor
leading to it, and some kind of amp driving a meter, or LED. Any
ideas/circuts?

I can probably run an get a clamp on type of meter, but I want this to be a
semi-permant installation, in a wall box. Hence, what I would like to have,
is a coil around the conductor in the wall box, 2 wires leading to an
external detector circuit.

Steve Ciarcia, of Byte fame, some months/years ago (I can dig it up) had
an interesting article about measuring power consumption of household
appliances with your CPU. It involved canabalizing a power strip, and
placing a number 1 paper clip inline with the outlets, and measuring the
power drop. I don't want to affect the current capacity, and don't want to
make a mess in the wall box, where I have to do my thing, though. Anyway, 
in Steve's article, his circuits would output a pulse to the CPU, each time
.1 KWH, or so would be consumed. So instead of complicated parallel/data
latch/counter arrangement, you would simply count pulses. Very interesting,
but not quite what I'm looking for...

Thanks for listening...

Christopher A. Nielsen
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           ////      P.O. Box 5669 Santa Monica, CA 90405-0669  
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