Decade counter with display II
74HC00, 74HC02, 74HC191, 74HC4511
We're now going to build a decade counter that can count 12 numbers from 0 to 11, using one LED display and one LED (LED 1) for indicating the carry from 9 to 10.
When you finish assembling, turn power ON, and press S1 and S2 at the same time. The LED display shows 0 and LED 1 goes out to indicate the preset condition.
Press S1 a number of times, and LED 1 lights up to indicate the carry when the number 9 on the LED display changes to 0.
Press S1 again, and you'll see the number 1 on the LED display, which actually means 11.
If you press S1 once again, LED 1 goes out and the LED display returns to 0.