Bert wrote:
what transistor will have even lower noise than the than low noise BC 109.
Generally speaking, the baseband noise of a bipolar transistor is most strongly influenced by the transistor's base spreading resistance. Of course, the transistor also needs to have whatever other characteristics are required in the application circuit -- in particular, adequate current gain and transition frequency at the operating point and sufficiently low input capacitance -- and these may be mutually exclusive with lowest base spreading resistance.
The 2SD786 and MPSA18 may be good candidates. That said, I seriously doubt you will get usefully better phase noise by using a "better" transistor in this location.
Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
