This configuration was found in an English magazine from 1965. It is valid for any junction FET. The input impedance is 5.5 M ohm higher than conventional stages.
This useful benchtop power supply uses a single LM350 integrated circuit as a regulator. The...
If the input voltage falls below 12 V the LED glows up. Other voltages can be monitored by...
The circuit shown is only for analog telephone lines. I found it in Popular Electronics (1991). It...