The LM3909 tone generator integrated circuit of this application is uncommon nowadays. The circuit can operate on a single battery and is very sensitive.
This circuit uses an unusual electromechanical component: a mechanical blade resonator. The...
This circuit from a Japanese publication in 1968 uses germanium transistors from the time like the...
Found in a 90s Electronic Design, this circuit can provide a relatively high-power output. The basic...