To power small projects, we found this circuit in the Radio Electronics magazine of May 1977. The transistor must be equipped with a heat sink.
Using red LEDs with ignition voltages of the order of 1.5 V we can make a multiple voltage...
The frequency range of this generator depends on C which can have values between 1 nF and 1 uF....
This circuit is from a 1972 Motorola publication. The used transistor can still be found, but it...