Yoda Man Posted January 5, 2022 Report Posted January 5, 2022 I purchased from China small cd4017 rotating sound driven LED kit for my grandson. Unfortunately I cannot get it to work I suspect it is the speaker as I have tested and or substituted all of the other components and they seem fine. I can get it flashing by moving the positive and or negative lead against the power input wires. But nothing else happen when sound is applied. Th schematic from the seller is useless but I found a schematic elsewhere and I hope that someone might have a suggestion? Quote
HarryA Posted January 7, 2022 Report Posted January 7, 2022 I gather you are using the output from your speaker as input rather than a microphone. In the simulator I get, with zero signal, about 580mv dc at the transistor base and 600mv dc output (pin14). Using 1k sine wave at 10mv as input I get, at the transistor base, a signal between say 670 - 690mv, At the output pin14 0 to 3.5v. Using a 2SC2412K in the simulator which I believe is similar to the 9014. Quote
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