Found in a Popular Electronics from the 90's, this circuit detects the approach of objects by the reflection of the radiation emitted by the LED. The relay is a 12 V sensitive type.
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...