This circuit decodes a 1800 Hz tone used in communications. The circuit is from an American documentation for radio amateurs of the 80's. Equivalent component can be used.
June 2016 - It can be obtained from Mouser Electronics the new gate driver optocoupler from...
This variable gain circuit for analog video signals was found in a 90s Linear Technology...
This circuit is from a 1976 publication, but it can be assembled with modern components. For the...