Microphone Mixer (T1349E)

Found in a February 1949 Radio Electronics magazine, this dual tube mixer has 4 inputs. Power must come from a 250V source.

Audio Oscillator (CB11068E)
This circuit is from an Italian magazine Radio Elettronica of January 1977. The circuit shows how...
Timer 555 (CB24994E)
This is one of the possible timer configurations with the 555. We found it in October 1986 Radio...
2 to 10 000 Hz Programmable Clock (CB6461E)
This circuit was found in a 1969 US documentation. It provides a signal that can be externally...