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.
Found in an Electronic Design from the 90's, this circuit uses common components. The circuit is...
When the sensor receives light, the relay closes its contacts and remains so even after the light...
This circuit produces pulses of 90 V at intervals that can reach 5 minutes. The circuit is from a...