Arduino Forum

Using Arduino => General Electronics => Topic started by: diaryrashid on Feb 11, 2013, 08:35 pm

Title: why common emitter configuration is most widely used as an amplifier
Post by: diaryrashid on Feb 11, 2013, 08:35 pm
hi...

why common emitter configuration is most widely used as an amplifier
Title: Re: why common emitter configuration is most widely used as an amplifier
Post by: KeithRB on Feb 11, 2013, 08:38 pm
IT is easy to bias and it has the most gain.
Title: Re: why common emitter configuration is most widely used as an amplifier
Post by: KeithRB on Feb 11, 2013, 08:40 pm
(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...)
Title: Re: why common emitter configuration is most widely used as an amplifier
Post by: diaryrashid on Feb 11, 2013, 08:47 pm
thx buddy
Title: Re: why common emitter configuration is most widely used as an amplifier
Post by: Grumpy_Mike on Feb 11, 2013, 08:53 pm

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.
Title: Re: why common emitter configuration is most widely used as an amplifier
Post by: oric_dan on Feb 11, 2013, 09:10 pm
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