Hello again,
Yep that link is working now.
I see your decade counter has an oscillator on the clock input comprising Capacitor (1uF) , Schmitt Nand 123 and the 1 meg resistor. Probably left alone the LEDs just sequence on (a sort of knight rider thing)
Anyway down to buisness.
So you want that when the S1 switch is depressed on your quiz circuit then this is counted by the decade counter.
Solution 1
As you see that when S1 is pressed the input into Pin 4 of IC2 goes from 0v (pulled low by R1) to Vcc (9v) i.e. positive going.
Your decade counter (4017) is clocked on pin 14 by a positive going waveform.
To clock the decade counter, simply disconnect (remove) the input to the counter (pin 14) and connect that to the jubnction of the switch, resistor R1 and pin 4 of IC in the quiz game circuit.
If done when you press S1 the input into your counter will go from low to high and your counter will clock on one.
If you still wish the LED on your counter to work then disconnect the output from the NAND gate (pin 3) on the decaded counter at the T junction of the second NAND gate and pin 14. And at that junction connect it to pin 4 of IC 2 (as before). When you press the S1 switch not only will it clock the counter but the 9v will be inverted by the second NAND and light the LED.
So that was the easy stuff. But be warned all may not be well. Switches have a tendancy to bounce and your counter may count more than once for each S1 key press, so you may need an antibounce circuit (a lockout circuit). However you can sometimes get a way with a capacitor. Just place a suitable value (it may require experimentation) across R1 on your quiz game circuit. When the key is pressed the capacitor will charge (an if small enough almost instantaneously) so any subsequent bounces will not be registered.
If it does not work then you may need to make an antibounce circuit using a NANd network.
Solution 2
Another method is to take the output from IC2 that lights the S1 LED. From the circuit it appears that pin three is the output and lights LED1. The output is Negative going in that it goes from high to low when you press the S1 key.
For you counter to count this, Remove the capacitor and resistor connected to pins 1&2 of the NAND gate on your decade counter and discard them.
Connect PIN3 of IC2 (4042) to pins 1&2 of the Schmitt triggered NAND on your counter.
When LED1 lamp lights (pin 3 low) this low is inveretd by the 1&2&3 pinned NAND and fed as a rise to the clock input of the counter and the counter clocks on one.
Differences between solutions
Solution 1 will count each time the S1 key is pressed.
Solution 2 will count each time S1 is pressed first.
i.e. providing its pressed before the other 3 keys. Any help ?, yes no let me know.
Regards
