Found in a Popular Electronics from the 90s, this circuit can be adapted to use modern operational amplifiers. The output voltage is the square root of the input voltage.
This is the receiver for the previous circuit we found in the December 1992 Radio Electronics...
We found this configuration with CMOS-compatible output in the 1994 National Semiconductor Linear...
This 70 kHz oscillator is used to erase tapes in pre-recording. The circuit is from 1968 General...