This circuit converts infrared pulses into audio and can be used in an experimental telegraphic link. The circuit is from a Popular Electronics from the 90s.
April 2017 - Littelfuse's new two-way discrete TVS diodes for protection against ESD up to 30 kV...
Found in an English documentation from 1989, this circuit is intended for equalization of cassette...
We can also use the 4011 on this CMOS circuit that makes use of a crystal headset. The power...