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Subject: Re: DC current sensing circuit
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Date: 03/30/02 at 5:33 PM
Posted by: John Dunn - Consultant
In Reply to: DC current sensing circuit posted by Jerry on 03/26/02 at 11:26 PM:
Consider running the low end of your power source into an op-amp summing junction instead of to ground, with the non-inverting op-amp input itself at ground. A feedback resistor from the inverting input to the output will scale that current to a signal voltage you can use as your current monitor. If you use a very large feedback resistor, you can sense very small currents and if you shunt that large resistor with a diode limiter, you can keep the op-amp from hitting its rail voltage limit at higher currents.
Can you follow this? I've seen it done before.
John Dunn - President
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