0
\$\begingroup\$

I used a cd-4511 decoder for my seven segment display circuit. It was a simple circuit, just to get familiar with how the 7 segment display and the decoder operate. However, upon sliding the switches, nothing happens.

enter image description here

(I have 5 switches and 4 or gates that are unused, but i plan to use them in the future as part of this circuit).

Tinkercad shows the function of all the pins on ICs (power, ground etc..) So I don't think thats where I have messed up...

What is going wrong with the connections then?

Tinkercad simulation link:https://www.tinkercad.com/things/7Y2irqYYjJy

\$\endgroup\$
0

3 Answers 3

1
\$\begingroup\$

After adding current limiting resistors change the 7-segment setting from common anode to common cathode.

\$\endgroup\$
1
  • \$\begingroup\$ This is so embarrassing, I missed that the decoder was in common anode mode all along. Thank you so much. \$\endgroup\$
    – satan 29
    Commented May 14, 2021 at 11:50
2
\$\begingroup\$

You need a resistor for every segment of your LED display. Otherwise the LEDs are shortening the driver outputs.

\$\endgroup\$
-1
\$\begingroup\$

Tinkercad is not a tool that would be used by many of the professionals on this site, and your cartoon diagram is hard to decipher. So, I think it will be up to you to debug this.

I'm guessing that Tinkercad gives you some way to check the logic level or voltage at a signal node. Begin by verifying that everything that should be connected to power or ground is in fact connected. Then check your switches and make sure they work. Make sure that all of the segments of the LED work if you connect its pins to power and ground (ignoring current issues for now). After that you can start putting the switches in some given state and verify that the IC outputs are what the datasheet says they should be. Somewhere along the line you will find something that doesn't look right...that will point to your real problem.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.