Thyristor (SCR) symbol
Also called SCR, Silicon controlled rectifier
A diode that only starts to conduct when its gate is triggered, then stays on until the current falls to zero.
ANSI / IEEE
IEC 60617What the thyristor (SCR) symbol means
A diode that only starts to conduct when its gate is triggered, then stays on until the current falls to zero.
ANSI and IEC symbols
Where you see it
Controlled rectifiers, soft starters, DC drives and crowbar protection.
Related symbols
Frequently asked questions
What does the thyristor (SCR) symbol look like?
On ANSI drawings: A diode with a gate lead from the cathode side. In IEC 60617: The same diode with a gate.
Is the thyristor (SCR) symbol the same in IEC and ANSI?
Yes, it is drawn the same way in most legends.
Where is a thyristor (SCR) used?
Controlled rectifiers, soft starters, DC drives and crowbar protection.
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