Should I add a transistor or not?

Hi,


Is it necessary to add an transistor to the output of my four bit adder. I want to add an led to show the 5 bit output. Should I add a transistor or or just directly connect the anode to the output and cathode to ground

Please help.

Thanks!



I didn't find the right solution from the Internet.



References:

www.circuitlab.com/questions/zu8pr32c/should-i-add-a-transistor-or-not/

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