Magic eye test (T424E)

This circuit tests the 6AF6 magic eye indicator tubes. The circuit is from modern documentation that suggests tube circuits for modern experiments.

50 ohm Line Driver LM3900 (CB5056E)
The gain of this amplifier is 10 times and the excursion to the output voltage is 6.0 V (peak to...
Transistor gain meter (CB20522E)
This circuit was found in a publication in the 1950s, mainly applying to germanium transistors of the...
Simple MW Radio 2 (CB4360E)
Originally this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...