build traffic light with timer

Thread Starter

rayan.m

Joined Mar 4, 2023
4
I have a project traffic light. I build a clock circuit using 555 IC as bellow. I need to count from the given time to 0. for example 120. can anyone help me? i build this circuit using 74190 IC and 7447 BCD to 7-segment. but it doesn't count with the given input(999 - 0).Screenshot (54).png
 

macman23

Joined Jan 6, 2023
13
To implement a countdown from 120 to 0, you would load the value 120 (in BCD) into the counter using the PL inputs, and then connect the RST input to a push button or switch. Each time the button is pressed, the counter will count down by one until it reaches 0.
 

Thread Starter

rayan.m

Joined Mar 4, 2023
4
I have a project traffic light. I build a clock circuit using 555 IC as bellow. I need to count from the given time to 0. for example 120. can anyone help me? I build this circuit using 74190 IC and 7447 BCD to 7-segment. but it doesn't count with the given input(999 - 0) and I need to connect this to 3 LED as green, yellow and red working with timer.
 

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