Found in the July 1994 Electronics Now magazine, this circuit drives a relay up to 12 V depending on the power supply. The transistor can be general purpose.
This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset...
The purpose of this 1-transistor amplifier is to allow the use of a milliammeter in an application...
We found this circuit in an old General Electric documentation. In fact, PUTs are not common...