Beta Comparisons on Output Transistors

[approse]

Hopefully this won't come across as tooooo ignorant a question but... in going thru the OP trannys on one of my 9090's I figured out all by myslf I really didn't know how closely the beta gains should be to each other or if there is a "limit". In this example the standard 2sc1116a varied, at 10ma bias from 56 to one that was 82. 2 were 76 and the rest were between 56 and 64........ is this something I should be looking for on a datasheet somewhere or is there an accepted variance range? All the trannys checked out in every other test I have available...... Icbo and Vcb. I've noticed "usually" brand new trannys vary some but usually within 10 points in my testing so far. 'Preciate the help!

 

[EchoWars]

Don't sweat it.

New transistors will likely measure closer, but all in all, the linearity of the amp does NOT depend on the beta of the output devices (to a first approximation) for a variety of reasons, including the emitter resistors which force current-sharing between devices of unequal gain.

 

[approse]

Thanks EW,

I was wondering if there was an answer there...... I had missed the first sentence entirely. I was surprised though in one instance to see lower powered outputs 15011's showing greater gain at lower bias than either the 11116's or mj21194's. THat is until I looked at the gain curves.. the higher powered units have a higher bias curve. Sure is fun !