Advanced Member level 5
Hello, I am building a small QRP amplifier for HF and I was wondering if there is any common transistor more powerful than pn2222 in the same small plastic case (TO-92)?
A PN2222 has a maximum allowed collector current of 600mA. That is for continuous DC that has no frequency. At 100MHz its minimum current gain is only 2.5 which is not much better than a piece of wire.
MPS3866 is probably more powerfull
but also you should understand than (in rf)
that output power of a mps918
will be always better than a pn2222
I have seen some TO-92-like cases which have an itty
bitty "power tab" sticking out, presumably to help with
thermal impedance (you might even be able to solder to
a better sink). But why is TO-92 so important, while other
can and tab styles aren't considered?
You can also, I believe, find press-on heat sinks for TO-92
devices which will at least improve upon free-air heat
You want a fT which exceeds your desired forward gain
times signal frequency.