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.
We found this circuit in the Electronics Experimenter Handbook magazine from 1993. L1 has 2 = 2...
This circuit, from an old Argentine publication, provides 6 W of output from an output of less...
Unlike the previous detector circuit, this includes the inverter not requiring a high voltage...