[time-nuts] how to find low noise transistors

Richard (Rick) Karlquist richard at karlquist.com
Fri Jul 24 22:38:02 EDT 2015



On 7/24/2015 11:58 AM, Brooke Clarke wrote:
> Hi Charles:
>
> Does hFE (DC) have much relevance to this?  Would hfe (AC) be the
> important one?

Only insofar as DC current gain is an upper bound on AC current gain.
If your operating frequency is less than f-sub-t divided by beta,
then DC current gain = AC current gain.

Rick


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