i need help on a electrical circuit question someone please help it's about amplifiers !!
can you kindly click on this link:
https://picasaweb.google.com/112726639548856651169/Circuit#5808575506891246354
I need to produce a report, comparing the two circuits. how would the difference in the circuit affect how they run, and what would happen to the output?
(difference: C2 & R4)
I really need help on this i was struggling for days....
Thanks!
can you kindly click on this link:
https://picasaweb.google.com/112726639548856651169/Circuit#5808575506891246354
I need to produce a report, comparing the two circuits. how would the difference in the circuit affect how they run, and what would happen to the output?
(difference: C2 & R4)
I really need help on this i was struggling for days....
Thanks!
-
They are both bias methods, but the second is by far the better one.
The use of the emitter bypass cap is independent of the circuit, it could be used on either one, so with the cap, the gain is higher. Without the cap, the gain is lower but more stable as you have negative feedback. Actual difference in gain depends on the circuit values.
To address the bias method, the first is not very stable, as changes in the HFE of the transistor change the bias point, perhaps enough to drive the transistor into cutoff or saturation, where the circuit will not operate at all. And HFE is very temperature dependent, and also changes from unit to unit. Exactly how much this circuit will change depends son the values and the transistor.
Why the bias is better for the first and not the second, would take too long to go into here. There are plenty of articles online. I'll reference one for you.
PS. that graphic is almost unreadable. I had to work on it with a graphic editor to get it to a readable state. That will limit the number of answers you will get.
The use of the emitter bypass cap is independent of the circuit, it could be used on either one, so with the cap, the gain is higher. Without the cap, the gain is lower but more stable as you have negative feedback. Actual difference in gain depends on the circuit values.
To address the bias method, the first is not very stable, as changes in the HFE of the transistor change the bias point, perhaps enough to drive the transistor into cutoff or saturation, where the circuit will not operate at all. And HFE is very temperature dependent, and also changes from unit to unit. Exactly how much this circuit will change depends son the values and the transistor.
Why the bias is better for the first and not the second, would take too long to go into here. There are plenty of articles online. I'll reference one for you.
PS. that graphic is almost unreadable. I had to work on it with a graphic editor to get it to a readable state. That will limit the number of answers you will get.