Featured in the February 1949 Radio Electronics magazine, this benchtop instrument generates multi-range audio signals. The circuit has 6 tubes including the rectifier.
This circuit is from Popular Electronics of the 90's. It makes use of NO and NC sensors. The relay...
Based on TTL logic this circuit can vary both the frequency and the pulse width of a rectangular signal....
This circuit was found in an old English publication. The circuit makes use of general-purpose transistors....