Designed for the audio track, this circuit was found in a Popular Electronics from the 90's. Other operational can be used and R7 can be 470 k. The frequency is 1 kHz.
This circuit is from the 1993 Linear Technology Applications. We can implement the same oscillator...
This filter was found in Texas Instruments documentation from the 1980s. The circuit uses a common...
Found in a 1968 documentation, this small amplifier was very popular at the time being used in...