This circuit is from an 80's Radio Electronics. The circuit has several output options for 50 mA currents with load indicator through LEDs.
Published in 1988 in Hands On Electronics, this circuit converts the 12 V of a battery into 120 V AC...
The current accross the LED as function of the resistor value is given by the formulas. The...
This circuit was found in an old 1980s valve documentation. The circuit can directly replace a...