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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Ultra low active cycle (CB9078E)
This astable multivibrator has an active cycle of 30,000: 1. We found it in a 1970 EEE. The...
Sound Effects Generator (CB25050E)
Found in the June 1987 issue of Radio Electronics magazine, this circuit uses well-known CMOS...
Buffered Astable (CB24344E)
This circuit with increased power output was found in the November 1974 Radio Electronics...