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Single differential voltage comparator

LM311 Internal Circuitry

Explore the internal circuitry and functional stages of LM311.

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Inside LM311

A differential decision stage and an accessible output transistor.

LM311 compact internal cutaway shows IN+2 and IN−3, a gain and decision stage, balance5 and strobe6, collector7 and emitter1, supplies8 and4.
Functional cutaway; output emitter and negative supply are distinct contacts.

Explore the circuit

Select a stage to see its role and connections

Differential input

Compare the input voltages within the permitted common-mode range.

Balance and strobe

Optional external networks adjust offset or release the output. Their electrical drive requirements matter.

Collector and emitter

The output transistor has both contacts available. The external circuit sets its return and HIGH level.

Component view