This 1967 Philips circuit recognizes a light signal (visible or infrared) modulated by tone. The circuit makes use of components of the time that are equivalent to the current BCs.
This circuit was suggested by Sprague Electric in an 80's documentation. The circuit uses a...
This micro AM radio will tune strong stations in the frequency range between 530 and 1,600 kHz....
The circuit shown in the figure generates a signal between 50 and 100 MHz and can therefore be...