This circuit generates rectangular signals from 2 Hz to 20 kHz using an operational amplifier. The circuit is from 1984 Radio Electronics. The power supply must be symmetrical.
We found this circuit on the internet. The components are current, and the time depends on C1...
This circuit was found in an English publication of 1982. The operational can be replaced by an...
With this luminous remote control, which we found in a 1990 publication, using a flashlight you...