Without this effect, the modern rock music would be hard to imagine: The Distortion (= distortion) effect.
Originally it was simply the fact that their guitarist (then only) Roehrenverstaerker extremely wide turning up and thus overloaded. This gives the Overdrive tone depending on the severity of a singing, screaming or screeching sound brutal, but has used the match quite an interesting dimension.
Electrically usually pretty easy to build, there are a number of possibilities to create this effect. Here are some links with schematics

Here you will find Schematic Circuit Diagram for DIY and further information on Distortion
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Distortion with Operationsverstaerker unf diodes	www.rabbathrecordings.com/Distortion.html
Various collection Fuzz / Overdrive / Distortion schematics	hem.passagen.se/robin2/effects.htm
Various distortion approaches	users.chariot.net.au/~gmarts/ampovdrv.htm