This circuit was found in the January 1999 issue of Electronics Now magazine. The circuit uses an integrated circuit from the period and has earphone listening.
The transistor can be a modern equivalent and the transformer is the type of output found on an...
The output voltage of this unit is approximately 1.4 V less than that of the chosen zener. The...
We found this circuit in an English publication from the 80's. The circuit uses current components like...