This detector with ultra-low deviation was found in an American documentation from the 90s. Operational amplifiers are from that time. The power supply must be symmetrical.
The circuit in the figure is a current regulator with adjustment in the range of 0 to 3 amps. The...
This filter with the operational 741 passes the frequency range between 300 Hz and 3,400 Hz. This...
Taken from an Electronics Now from the 90s, this circuit generates signals whose frequency depends on...