Found in a 1992 book, this circuit is intended for operation with audio signals. Equivalent operational amplifiers can be used. The optical coupler is an unusual type today.
This circuit was found in a Popular Electronics from the 90s. The components used are all common...
This circuit is from a 60's documentation. The circuit uses components from the era and serves to...
One pulse in the output is produce at each 5 pulses applied to the input. The circuit uses CMOS...