hey guys..i'm new here..nice to join this forum
could you please help me.
i have a problem for my homework, what is the difference between DC signal transistor signal amplifier and AC signal transistor amplifier ???

thanks a bunch

 

DC amplifier amplifies DC voltages (and AC if the specifications allow). However, an AC amplifier amplifies only AC voltages.

 

thanks a lot mik3
is there any other difference ???
in my opinion, DC amplifiers amplifies the currents but AC amplifiers amplifies the voltage, is that correct?

 

in my opinion, DC amplifiers amplifies the currents but AC amplifiers amplifies the voltage, is that correct?

No, you are wrong. Both types can amplify voltage or current depending on their design.

Another difference is that you can easily cascade AC amplifiers without amplifying the bias voltage because of the coupling capacitors. With DC amplifiers cascading is more complicated if you do not want to amplify the bias voltage.

 

being more confused..

transistor will work on DC, right?
so how can it amplifies the AC ?

i'm sorry, i know this is a very basic question..

 

By proper biasing of the transistor it can amplify AC signals.

 

being more confused..

transistor will work on DC, right?
so how can it amplifies the AC ?

i'm sorry, i know this is a very basic question..

Without the DC (biasing) of the transistor, then the AC cannot be properly amplified, because the proper amplification of an AC signal is really the DC bias of the transistor fluctuating in step with the AC signal coming in.

Its like in a swimming pool, when the water is completely still, (steady state) ,the water represents the DC bias, and then you move your hand up and down in the water, as your hand moves up and down in the water your hand displaces the water and the water takes on a shape (small wave), in step with the movement of your hand.

So it could be looked at with a AC signal it displaces ,if you would, the DC (steady state) of the DC current flowing.

This is NOT what happens electrically but I'm just using this as an analogy .