5-tube commercial radio (T1619E)

This commercial superheterodyne receiver was found in a 1949 Radio Electronics. The circuit uses battery.

Continuous Multimeter (CB19739E)
The operational amplifier used in this application is not the most common today. The circuit is...
Monostable 7555 I (CB18970E)
In the figure we have the way to trigger a 7555 CMOS monostable with a positive pulse. The time...
1926 Crystal Receiver (CB11876E)
This circuit was found in a 1926 German publication. It is a crystal or galena (D) receiver. The...