Count limiting circuit

darrenbkl said:

ivanljh said:

Hi… I thought what we want to achieve is “when the binary output from the counter in the same as the binary number set with the switches the output of the comparator will go high”? So lets say the output at Q0 and SW1 is set to ‘low’, we won’t be able to get a ‘high’ at its output.

you are using XNOR gate,when the inputs are the same,output is HIGH.

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DOH! You are right. I completely missed the 0=0 stated, even as I did thew truth table:

The logic output of the XOR + Inverter is:

A B C
0 0 1 True (invalid) ...not invalid
0 1 0
1 0 0
1 1 1 True

Ken

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