Originally posted by BroMikey
if the beta is matched exactly or +/-5% then you are very close, your trannies are way off. another way to do this if you really want to take the time is find the transistor that opens the least, then use resistors on the base to match the rest to that one. what we are matching is how much current the junction passes for a given current on the base. so if you have a 100 and a 105 add resistance to give you 100. that is the hard way...... you can decide what you want to use for your base resistor, say 22 ohms, then change the resistance of the other 3 to get the same current flowing thru it.
so take the 99 and clamp the other ones down. I have NEVER done this, for me this is just theoretical but I have heard it talked about before.
Tom C
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