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.
This amplifier was found in a 1969 Mullard documentation. The circuit uses transistors that have as...
This circuit was developed to test suspect 4001 and 4011 integrated circuits. The circuit is from...
This traditional detector configuration is from an old publication where the MC1555 is the...