Is the 74 series comatible with 74LS series?

Question

I am making a circuit in which a 74LS counter output is fed into a 74 series decoder to be fed into a seven segment display. I am getting some bugs . Could this be a compatibility issue. Is the 74 series compatible with 74LS?

Answer 1

Mixing 74 series and 74LS series shouldn't cause a problem. It's unlikely to be an issue unless you have a timing map that exceeds the upper frequency limit of 74LS.

Answer 2

The output of 74LS can sinjk generally 4 mA. Check whether the load provided by 7400 is within this. Generally each unit load of TTL is 1.6mA (to be sinking by source ).

Check with decoder data sheet.

But yes, the problem is unlikely to be due this.

Answer 3

there should not be any compatiblity problems, you may have fulty wires or the devices are fulty.



but you should ask a profetional in electronics.