Collector-emitter voltage

Collector-emitter voltage is denoted by U _CE

The collector-emitter voltage or U _CE indicates how high the voltage drop between the collector and emitter of a bipolar transistor is.

As long as the transistor is completely blocked, i. that is, when there is no base-emitter voltage, i.e. U _BE  = 0 V, the full operating voltage of the transistor drops at the collector-emitter path.

If, on the other hand, a transistor is fully turned on (with a silicon transistor usually at U _BE  = 0.7 V), a small part of the operating voltage still drops across the collector-emitter path. In the fully controlled state, one speaks of the saturation voltage of a transistor, which is also referred to as U _{CE sat} . A common value for a silicon transistor is U _{CE sat}  = 0.2 V, for Darlington transistors around 0.9 to 2.5 V.

The collector-emitter layer behaves like a high-voltage Zener diode. The characteristic value for U _{CE max} is noted in the data sheet of a transistor. The transistor breaks down above U _{CE max} . If the current is not limited, it will destroy the transistor.

See also

• Collector-emitter current
• Base-emitter voltage

literature

• Ulrich Tietze, Christoph Schenk, Eberhard Gamm: Semiconductor circuit technology . 13., rework. Edition. Springer, Berlin 2009, ISBN 3-642-01621-9 .