At 12:34 PM 8/30/03 -0800, you wrote:
>       I have not seen them for years.        a little  line current all
>the time, so this thing would have to distinguish between a  fraction of an
>amp, and the higher draw when the TV is actually on.  

  Use a step down transformer in reverse. Put the low voltage side
(secondary) in series with your load and connect a relay to the high
voltage side (primary). Use a transformer that has a LOW voltage output,
say 3 volts, and a current rating similar to that of the load that you're
monitoring. That should give roughly 3 volts line drop to the load being
monitored, that shouldn't affect the load. The relay needs to roughly match
the output (primary side). You'll have to play with the ratings and you
may need to put a dropping resistor in series with the relay to decrease
it's sensitivity. The transformer should have low voltage output when
little current is flowing to the load (the load is off). When the load is
on and drawing appreciable current then the output voltage will rise and
engage the relay.

   Joe


   Or is  there a
>commercial product that will do the job?   Thanks in advance.   Syd H. Levine
>AnaLog Services,  Inc.
>  270-276-5671
>   270-276-5588
>  [EMAIL PROTECTED]
>  www.logwell.com  

-- 
Author: Joe
  INET: [EMAIL PROTECTED]

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