This circuit was found in a Popular Electronics from the 90's. The transistors are general-purpose types and the loaded load depends on the voltage and must have a maximum current of 100 mA.
The pair of transistors matched in a single LM114 enclosure is not a common component today. The...
Today we can call this circuit a baby monitor. It is a microphone amplifier found in a publication by...
With this regulator we can have currents of up to 4 amps with 5V at the output. The transistor can be...