This simple audio generator with the 741 was found in a 90sTexas Instruments. The circuit generates sinusoidal signals from 15 Hz to 150 kHz in 4 bands, as shown in the diagram.
This circuit is from an Electronics World of 1964. The circuit can be made with modern...
June 2017 - Kemet T521's new high voltage capacitors with capacitances up to 330 uF and voltages...
This circuit was found in a 1999 English magazine, but can be easily assembled with BC548...