This circuit is from an American publication of the 80's. It makes use of components of the time. However, the circuit is the basis for a modern shield application since the input is TTL.
This circuit was found in a 1967 US documentation. It shows how to build a gain control by digital...
This LED special effects circuit was found in the February 1992 Radio Electronics magazine. The...
Found in a Motorola documentation from the 70s, this circuit makes use of transistors of the time....