DTMF Decoder (CB25048E)

This circuit was found in the 1987 Radio Electronics magazine. The components used are integrated circuits of the time.

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Monostable MC1455 (CB14583E)
The integrated circuit used is a version close to the 555 manufactured by Motorola. The circuit shown...
Fish Atractor (CB13179E)
The circuit shown is from an American publication from 1970. It produces a tone that attracts fish...
60 second relay delay (CB7233E)
Suggested by General Electric documentation from 1968, this circuit activates a relay after 60...