This circuit was obtained in an old Elektor and can be adapted to use white power LEDs. The transistor must be equipped with a heat sink. The circuit has a battery charger.
The oscillator shown generates a rectangular output signal at a frequency of 5 MHz, determined by the...
Found in a Popular Electronics - January/February 1969 this circuit was intended to increase the...
Found in a radio amateur magazine of the 1980s, this circuit uses components that can still be...