This 9 V battery eliminator was found in Radio Electronics magazine from June 1966. The transistor is of medium power and must be equipped with a small heat sink.
We found this circuit in the 1994 Linear Applications Handbook by National Semiconductor. The...
This General Electric circuit is from the 80's. The PUTs used in this meter are not common...
Texas Instruments REF33x Voltage References can be obtained from Mouser Electronics. These small...