This circuit generates a strong audio tone that scares away mosquitoes. Care must be taken that, due to its potency, it can also cause discomfort to very close people and domestic animals.
This circuit, shown in the figure, can operate from 4 to 100 MHz, based on a 2N2222 transistor or...
We found this circuit in a 1988 publication. A touch of the sensor causes the relay to trip and...
This dual flasher for high brightness LEDs was found in an American documentation from the 90's....