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Quad operational amplifier

LM324 Working Principle

Learn how LM324 works with an illustrated explanation and practical readings.

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LM324 at a glance

Follow the labeled connections and functional stages

LM324 working principle: illustrated functional stages, basic circuit and connections
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How it works

3 stages · Explore one step at a time

Step 1 / 3

Sense the input difference

Each differential input stage responds to IN+ minus IN−. Open-loop gain is very high, so practical linear circuits use negative feedback.

Step 2 / 3

Set gain with two resistors

For the non-inverting connection, gain is 1 + Rf/Rg. With 30 kΩ and 10 kΩ the nominal gain is four.

Step 3 / 3

Respect the analog limits

The output cannot reach the positive supply rail. Input range, output load, slew rate and bandwidth all limit how closely the real output follows the ideal result.

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