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Current Source / Current Sink Alarms Circuits
Designed by David A. Johnson, P.E.
Last Updated on:
Sunday, July 27, 2008 07:41 PM
Master Category List - Dave's Circuits
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- 1 AMP CURRENT INJECTOR
When you need to measure resistance down to a few micro ohms, this circuit works great. It is powered from two "C" cell batteries and is designed to inject a well regulated one amp of
current into the unknown resistance. By measuring the voltage drop across the resistor with a digital voltmeter, the resistance value can be accurately measured. The circuit also is equipped
with a low battery monitor. Published in Popular Electronics, November 1992
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- 6v NMH/NiCd Battery Tester
I designed this circuit to test rechargeable six volt battery packs under constant current conditions. As designed, the circuit applies a 10
amp load to the battery pack. A heat sink must be used on the main power transistor.
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NEW
Computer Controlled 100ma Current Source
(July 11, 2008)
Often in industrial control systems a constant
current source is needed, which is controlled by a computer and referenced
to circuit ground. The circuit below converts a zero to 5v signal from a
computer’s analog output into a current, with a full scale of 100ma. The
circuit shown requires a 9v DC supply but any voltage from 9v to 12v will
work.
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- Constant Current LED Driver
Bob Pease from National Semiconductor came up with this circuit and I have used it many times. It maintains a constant current through one
or more LEDs. A single resistor controls the desired current.
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More Current Source / Current Sink Circuits
Master Category List - Dave's Circuits
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