This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
This circuit was obtained in 1974. It serves to indicate the tuning of stations on a common...
This experimental amplifier was found in the 1960 Mullard transistor reference manual. The...
This circuit for 40 V systems was found in a Linear Technology application manual. The circuit...