This circuit is from a 1980's documentation for telecommunications. The circuit is used in SSB and the diodes must be suitable types for the application. The audio input is low impedance.
The purpose of this circuit is to add millivolt scales to a common multimeter. Used transistors are...
We find this circuit in the 80's own component manual. The power supply should be from 4 to 30 V...
This interesting circuit was obtained from a 90's EDN. What it does is generate negative voltages...