With a 475 V supply, this amplifier published in Radio Electronics magazine in January 1958 offered good power. The amplifier used 4 tubes.
This stethoscope or hearing aid amplifier has excellent gain. It was found in Popular Electronics from...
We found this circuit in the National Semiconductor's Linear Applications Handbook of 1994. The...
Found in a 1979 documentation, this circuit measures resistances on 5 linear scales. The precision is...