This CMOS generator with the 4018 IC was found in a November 1976 Radio Electronics magazine. It uses a 741 op-amp as the audio amplifier.
This circuit was found in an American documentation from the 80's. The components are from that...
The circuit shown is from the Texas Instruments optoelectronics manual. It is intended for audio...
This circuit drive an LED with constant current determined by the values of the resistors of 10...