BINARY DIVIDER - not working

[michelle29]

View attachment 67779

working fine on the simulation program, PROTEUS ISIS. but when i place it on breadboard. the quotient and remainder LEDs won't even light up.

can't figure out what's the problem, maybe some loose connections.
are there any factors, aside from connections, that may contribute to this project not working?

 

[alec_t]

What is U6A? CMOS IC?
Have you connected its power pins correctly?
Do its Q outputs actually go high at all (check with DMM or scope)?
Can U6A provide enough current for the LEDs?

 

[michelle29]

oh sorry. yes, you are correct it's a CD4015 CMOS IC. yes, i've checked the connections for its sources. but i have a problem with 4015, the pins that are not used, should i leave them floating? or should i connect it to the GND or SOURCE?

thank you so much

 

[alec_t]

With any CMOS IC unused inputs should be connected to GND or +V; never left floating, which can give unpredictable results. An output pin of a CD4015 can only supply a few mA. Not enough to give much light unless the LEDs are high-efficiency (ultra-bright) types.