Hello for all ..
I wanna know how to get operating frequency of transistor BC107 from datasheet !?? ..
I had searched about it for many times but had got transient frequency and noise frequency , Is there any relation between them and operating freq !?
And Is the operating freq a critical low freq or no , if no What is the critical low frequency ?? ..
Thanks
Sorry for annoyance

 

Step 1.
Include datasheet in your post.

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Welcome to All About Circuits, Hussein.

Check the datasheet for a parmeter called and that is highest frequency you should expect to get out of it. The given on a datasheet from Multicomp is 150 MHz.

The only critical low frequency I can think of is the frequency at which the junction temperature, and thus base-emitter voltage and gain are modulated by instantaneous power dissipation. This is a source of distortion in some applications.

 

@DickCappels, what does the frequency transition graph tells us?
Is there any difference between the "t" and "T" in "ft" ?


Allen

 

Answering the fT vs ft question is above my pay grade. I don't know of any formal difference.

The Transition Frequency graph tells the ft as a function of frequency for a specified test setup, which is usually some grounded emitter configuratioin. Thanks for posting the graphs. I looked for graphs in the Multicomp and Philips datasheets and did not find one.

 

Hello,

The siemens datasheet shows graphs for the different Vce values:



Bertus

 

Hello,

Motorola also shows a similar graph.
I copied the BC107 pages from the manual:





Bertus

 

From the graph, is it correct to say that when Vc=10V, Ic=25mA, it has unity gain at 350MHz?

I always thought that BC107 is only good for Audio Frequency. For RF, we'll use BFxxx...

Allen

 

The coding BCxxx was used to indicate that the device was primarily designed for low frequency operation, Audio pre-amplifiers and such like.
They were not generally intended for use at frequencies greater than a few hundred KiloHertz.
The prefix BFxxx denoted transistors designed for r.f applications and many are happy working at 150 mHz or more.
A BC 107 may be fine in an audio pre- amp, but if used as an r.f amplifier in a receiver at say 30mHz , it would be far too noisy and practically useless compared to a transistor designed for low noise r.f amplification.

 

Step 1.
Include datasheet in your post.

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Thanks bro .. our great brothers had attached datasheet

 

From the graph, is it correct to say that when Vc=10V, Ic=25mA, it has unity gain at 350MHz?

(Some text removed for clarity)

Allen

Yes.