This commercial radio with 3 earphone listening transistors was manufactured in Japan in the 1960s. The medium-wave circuit uses germanium transistors and is powered by a 9 V battery.
Found in a 90s 73 magazine, this circuit provides an output of 1.5 A with 24 V from a 12 V source....
The simple low voltage source that can be used as a battery eliminator, shown in the figure was...
This two-station intercom was found in documentation from 1966. R4 should be experimentally...