Hey All,,

Need a help from the expert of you. I have a project to build an up/down counter with ic 555 timer and using any ic for the counter. I choose CD4510, because it is presetable up/down counter. The task is to build a counter, when the input voltage is greater than 3V, it will count up 0-15. Otherwise, less than 3V it will count down, 15-0. For counting up from 0-15, it is successfull run. However, it gets stuck when I tried to count down from 15-10. I have preset the input number of two counter as 0001 (1) and 0101 (5) as well have set the PRESET ENABLE to HIGH, but it didnt count down. I need help from someone to correct my project.

I attached the picture of my circuit design. Please anyone help me to figure it out the problem. Thank you in advance..

 

You cannot leave R on the 4510 uncommitted. Use a pull-down resistor.

What does the 74LS244 do?

 

Well,, R is set to LOW to start counting, if it is HIGH it will be RESET, isnt it?

The 74LS244 is IC Buffer,, but for this case, just ignore, because so far doesnt give any effect to the circuit.

The thing that I wonder is only the counter cant start counting.

 

My problem actually is on preset number. When I set PRESET ENABLE to LOW and I didnt set any input for counting, it works to count down from 9-0. However, when I set number 5 (0101) to start counting down and set PRESET ENABLE to HIGH, the counter didnt count down. I really need some helps to figure it out.

Thank you

 

I thought you needed expert help.

Working on a simulator is quite different from working with real components.
You need a pull-down resistor at R.

The 4520 counter cannot count down if UP/DOWN is high.

4510 is a BCD counter. Values of 10-15 are not valid states.

 

Yes, exactly. The simulation gets sometimes problem for me.

So, you meant, I need to change my IC Counter? Last time, when I tried for counting up, I changed the IC Counter to 4029 (Presetable Up/Down Counter), it worked to count up when I set the number on the input. But, since the output from this counter is Hexadecimal, so after counting 9 (1001), it did go blank no show 0 (0000). I have used 4511 for the decoder to 7 segment display.