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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Beat Frequency Oscillator (CB4212E)
This beat frequency oscillator or BFO was found in an American 1980s documentation. The circuit is...
Sensitive TTL Opto Trigger (CB14671E)
We found this setting in the Texas Instruments opto-electronics manual. The bipolar can be the...
On Off Control (CB15047E)
This bistable control uses a 4069 as bistable. The circuit can drive relays up to 100 mA with the...