This question refers to the book Make electronic's experiment 18.
I have included a picture below.
S1,S2,S3: tactile switches
IC5,IC6,IC7: 555 timers
IC1: 4026 counter
quote from the book:
When the output from IC7 goes from positive to negative, it will trigger the reset of IC6, flipping its output negative, which allow the count to begin
The capacitor C4 communicates the sudden change from positive to negative, but the reset of the time it blocks the steady voltage from IC7 so that it won't interfere with IC6
My question: How does IC6's pin 4 get negative voltage or grounded? I thought C4 would only accumulates positive current from IC7's pin 3 and release it to IC6's pin 4.
I thought the capacitor should be hold fixed to connect one pin to positive, and another to negative. From what i can see the IC7's pin 3 is switching from positive current and then to ground on one of the pin of C4.