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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, November 29, 2011 08:14 PM
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High DC Current Indicator
designed by David A. Johnson, P.E. |
| A while back, someone
requested a simple method to indicate when 20 to 50 amps of DC current was flowing
through a wire. The circuit below works well and is about as simple as you can
get. A sensitive reed relay from
www.Jameco.com acts as the current sensor. |
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| The
magnetic field produced by such a current is enough to close the relay contacts, if
one or two turns are wound around the relay. The turns do not have to be tight. I was
able to close the contacts with two turns about 2 inches in diameter with 20 amps. A
simple LED and resistor can be used to indicate the current by tapping into the
automotive +12v supply. |
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Johnson, P.E. about this circuit |
