transistor question

[zalzon]

Two questions to clear up my understanding of circuits and transistors
:

1) Is it true that transistors in common emitter amplifier circuits
increase both the voltage AND current of the input AC signal?

2) Is it fair to say that part of DC in the circuit is being used to
amplify the AC signal. That is some of the dc takes on the
characteristics of the AC by rising and falling in response to the AC
signal voltage at the base. The remaining DC is then filtered out.
Is that right using a capacitor. Is that right?.

Please I just need simple (preferably a yes on both answers to the
above questions, not the full explaination on how transistors work.
This is just to confirm if my understanding of transistors is on the
ball.

Thanks.

 

[John Popelish]

zalzon wrote:

Two questions to clear up my understanding of circuits and transistors
:

1) Is it true that transistors in common emitter amplifier circuits
increase both the voltage AND current of the input AC signal?
A common emitter amplifier has the potential for both current and

voltage gain. The details of the surrounding circuit determines if
the whole circuit has both current and voltage gain.

2) Is it fair to say that part of DC in the circuit is being used to
amplify the AC signal. That is some of the dc takes on the
characteristics of the AC by rising and falling in response to the AC
signal voltage at the base. The remaining DC is then filtered out.
Is that right using a capacitor. Is that right?.

That is the general idea. The transistor converts some of the DC
supply energy into signal frequency energy, and wastes the rest.
There are several ways to keep the supply out of the input and output
paths, coupling capacitors being one way.

Please I just need simple (preferably a yes on both answers to the
above questions, not the full explaination on how transistors work.
This is just to confirm if my understanding of transistors is on the
ball.

Then, yes and yes.

Thanks.

--
John Popelish