In the original publication of the 90s a 556 consisting of a double 555 is suggested. The circuit drives a speaker with good power. The power transistor shall be fitted with a heat sink.
This circuit generates rectangular signals from 2 Hz to 20 kHz using an operational amplifier. The circuit...
This circuit was found in a publication in 2002 and can be powered by voltages from 5 to 12 V. The...
This fast inverter amplifier with high input impedance uses operational amplifiers from the 80's,...