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Subject: Re: Current Sensing Circuit Help!
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Date: 10/15/02 at 5:37 PM
Posted by: Russ Kincaid
In Reply to: Current Sensing Circuit Help! posted by laet on 10/15/02 at 9:05 AM:
The LM336 is not going to work, it is a 2.5 volt reference. The LM339 or LM393 comparator is the thing to use. You need a sense resistor and a bias voltage in order to discriminate between current and no current. Set the bias voltage at 10 millivolts at the minus input of the comparator. Choose a sense resistor that will provide 20 millivolts at the positive input, relative to ground. Connect the LED in series with a suitable resistor from the output to VCC.
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