EMRFD Message Archive 15001

Message Date From Subject
15001 2018-08-14 06:58:07 Ravi Miranda TIA Amplifier replacement transistors

Having read the note here: http://w7zoi.net/bidirectional_matched_amplifier.pdf

Would it mean that I could replace the 2N3904 with say a 2N2222 or
maybe the S9018 or KSP10TA
any NPN Si?


Would the biasing need changes?

Many thanks for your time.

Best 73


I'm here to add more value to the world than I'm using up.
15002 2018-08-14 10:56:33 kb1gmx Re: TIA Amplifier replacement transistors
First why?

And  yes on the ksp10 depening on what your doing. Its likely bias may 
have to be adjusted.

15003 2018-08-14 11:06:21 w7zoi Re: TIA Amplifier replacement transistors
Hi Ravi,

Yes, you can use about any small signal transistor with similar or higher bandwidth.   Keep the biasing that is shown, for that establishes the behavior of the stages.      You can't use just ANY NPN, but close.     

Good luck.

Wes, w7zoi

15004 2018-08-14 11:35:35 Ravi Miranda Re: TIA Amplifier replacement transistors
Hi  Allison

I have come across a batch of them so thought I could put them to use? 

Just my thinking that the S9018 would be useful because of the higher fT but it may not be worth the trouble

I had a batch of the KSP lying around, so thought I'd have a go with those. 

Many thanks