Found in a documentation from the 90's, this circuit uses only one integrated circuit. The resistors in series with the LEDs depend on the power that can be between 5 and 12 V.
This small power supply is suitable for powering devices using 9V batteries. The circuit uses...
Found in a 90s Silicon Chip documentation, this circuit provides a current of 3 A and the voltages...
This sensor triggers an oscillator emitting sound when a magnet is approached by a reed switch....