Integrated circuit (IC)

A whole circuit in one package.

Schematic letter: U
Unit / key rating: Depends on the model

Pinout

Pin 1: The pin to the left of the half-circle notch or next to the dot mark. The numbers increase counter-clockwise.

Real photos

The same IC (NE555) in two packages: DIP-8 and SOIC-8

What is it for?

An integrated circuit combines many transistors, resistors and capacitors on a single piece of silicon.

The 555 timer, the LM358 op-amp and the 7805 regulator are the ICs you'll meet most often as a beginner.

Things to watch out for

⚠ Use a socket instead of soldering the IC in. Replacing it after a fault becomes much easier.

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