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Topic: why common emitter configuration is most widely used as an amplifier (Read 1 time) previous topic - next topic

hi...

why common emitter configuration is most widely used as an amplifier


KeithRB

(I would like to point out, that for high-frequency class-C amplifiers, Common-Base is really popular for NPN Bipolar transistors. Of course, the biasing is pretty easy...)


Grumpy_Mike


hi...

why common emitter configuration is most widely used as an amplifier

Because it shows the highest gain for a given transistor. Common collectors have a voltage gain of 1 and a common base has a low gain.

oric_dan

Because you can easily control a device, like a relay/etc, that needs much higher current
than a microcontroller I/O pin can supply. In general, a 5V pin cannot provide enough
current to even drive a common 5V relay.

In addition, it allows you to control devices that require different voltage levels, such as
a 12V relay.

That's for simple on-off control. If you want to actually amplify "signals", that's something
else again, in which case you want a more reliable amplification-value, see Emitter
degeneration section here,
http://en.wikipedia.org/wiki/Common_emitter

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