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.
This circuit is quite old, from 1964, but can still be mounted with BC558 transistors. The circuit is...
This circuit is from a 1965 General Electric manual. It uses components from the time that admit...
This system of sequential lights for shop windows, discotheques, stores, does not use integrated...