Help please with this 4017 Kit

Yoda Man

Aug 15, 2016
9
Joined
Aug 15, 2016
Messages
9
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?

Screenshot from 2022-01-05 09-34-38.png

Screenshot from 2022-01-05 09-39-49.png

 

HarryA1

Mar 4, 2009
481
Joined
Mar 4, 2009
Messages
481
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.circuit.png

 Using a 2SC2412K in the simulator which I believe is similar to the 9014.

waveforms.png

 
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