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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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- 4 – 20ma Current Loop Tester
This circuit injects an adjustable current through a wire loop. Using a digital current meter, the current can be adjusted from near zero to over 24 milliamps.
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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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