This simple circuit can work with either 4.5 V or 6 or 9 V if a 1k resistor is added in series with the set of LEDs. The circuit is from an old French publication.
This oscillator provides a 1 MHz rectangular signal determined by the capacitors used. The circuit...
Using the ICM7555, CMOS version of the 555, this circuit produces a 1 kHz signal. The circuit has...
We found this circuit generates signals from 200 Hz to 62 kHz and can be used to repel mosquitoes and...