Transistor Matching Circuit

    This is a very simple circuit for matching transistors.  I would recomend the use of a 4 1/2 digit voltmeter.  Idealy, you need 0.1mV resolution.  Also, do not handle the transistors with your fingers.  I pick them up by the leads with a pair for pliers.  If you heat them up with your fingers, you will through the reading off.  What I did is I built the circuit on one of the breadboard things.  I put in a transistor, measure the voltage at both currents, write them down on a piece of paper, and then tape the transistor next to the readings.

    Also, you need to do this when the temperature is not chaning very fast.  I generally do it early in the morning.