Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

cutoff frequency for given transistor

Status
Not open for further replies.

electronics_kumar

Advanced Member level 2
Joined
Nov 29, 2004
Messages
657
Helped
34
Reputation
68
Reaction score
9
Trophy points
1,298
Location
Tamilnadu
Activity points
5,552
for transisitor having a coupling capcaitance of 10 microfarad in output there exists a resistance between this capa and ground ie it is load resiatance of 2k hms.in the collector it is having a resisatance of 3kohms..how to calculate the cutoff frequency
 

v_c

Advanced Member level 2
Joined
Oct 11, 2005
Messages
511
Helped
113
Reputation
226
Reaction score
37
Trophy points
1,308
Location
Chicago, IL, USA
Activity points
8,224
The cutoff frequency f_t for a transistor should be given in its datasheet.
This frequency determines the frequency response of the transistor parameters like the current gain β for a BJT.

Are you asking for the corner frequency of the circuit surrounding it? I think a circuit diagram is in order here -- you have not mentioned if you have FET or a BJT. Also, you will need to know the bias points in order to calculate the ac equivalent circuit for the transistor.
 

flatulent

Advanced Member level 5
Joined
Jul 19, 2002
Messages
4,626
Helped
489
Reputation
980
Reaction score
150
Trophy points
1,343
Location
Middle Earth
Activity points
46,689
I think that you are asking for the low frequency 3 dB point. This is 1/(2piRC) where R is the sum of the resistances connected to both sides of the capacitor.

In your case this is 5 k total so the lower frequency would be 3 Hz.
 

electronics_kumar

Advanced Member level 2
Joined
Nov 29, 2004
Messages
657
Helped
34
Reputation
68
Reaction score
9
Trophy points
1,298
Location
Tamilnadu
Activity points
5,552
v_c said:
The cutoff frequency f_t for a transistor should be given in its datasheet.
This frequency determines the frequency response of the transistor parameters like the current gain β for a BJT.

Are you asking for the corner frequency of the circuit surrounding it? I think a circuit diagram is in order here -- you have not mentioned if you have FET or a BJT. Also, you will need to know the bias points in order to calculate the ac equivalent circuit for the transistor.



it composed of BJT...
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top