This circuit has a gain of 6 dB for low frequencies from 85 Hz and can be used in a mini subwoofer. The circuit is from a Radio Electronics from March 1990.
We found this circuit in a Popular Electronics of the 90s. Its purpose is to detect when it locks...
This circuit is from a time when this type of feature was not common in line cars. The pulse...
We found this inverter in a Popular Electronics from the 1980s. The output is not perfectly...