Led Millivoltmeter

Posted on Jan 2, 2013

This circuit uses a dc amplifier (324) in a bar-graph circuit that uses an LM339 Quad comparator IC to sense dc levels.

Led Millivoltmeter
Click here to download the full size of the above Circuit.

The LEDs will light every 100 mV. The 324 op amp is configured to provide a gain of 100 to increase this sensitivity to 1 mV. Two auxiliary LEDs indicate "power on" and "xlOO" gain setting.

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