This circuit is powered by a voltage of 4.5 V, being common in radios of the 60's. The circuit is from Mullard's transistors reference manual.
Using red LEDs with ignition voltages of the order of 1.5 V we can make a multiple voltage...
a This circuit was obtained from a 1978 Practical Wireless. It causes a low-power 1.5V lamp to...
The circuit presented was taken from an old English publication in 1981, but it can be easily...