We have many tube tester circuits in this section. This one came out on a Radio Electronics from 1949 and has a very elaborate configuration with toggle switches.
For the 7 to 10 MHz band L1 is formed by 3 turns of 22 to 28 AWG wire in a ferrite core 15 to 20...
We found this interesting timer circuit or CMOS timer in a 1988 publication. The circuit is still...
This audio mixer was found in an old American documentation. The potentiometers are 1M and the...