This circuit is from an ancient American documentation. The transistors are of the time and the circuit uses a special sensor to detect the trigger point to produce spark plugs.
Mouser Electronics is now shipping DA14585, a kit for the development of voice remote control...
Found in a 1980s documentation, this circuit uses a photo-Darlington. There must be an optical...
This circuit can operate in a 100 dB range with signals of up to 100 MHz frequencies. Similar...