The XOR gate - Digital Logic gates
The Exclusive OR gate or EX-OR gate is useful as a
controlled NOT gate, if one input is a control signal the EX-OR gate
becomes either a buffer or NOT gate for the other input according to
control.
This feature is used in driving LCD displays. The CD40xx
CMOS family can work at even 3V-9V-12V DC and consume low power. The
speed is not as fast as 74xx TTL family. It is good for simple portable
battery powered circuits. The 74HCTxx series is good for low power and
high speed but will work at 5V. When you have problems interfacing CMOS
and TTL use 74HCTxx family.
XOR Gate Simulation
This gate EX-ORs the two inputs A and B, The Output is
high only if either A or B is high, output goes low if both inputs are
high or low. There may be a EX-OR gate with many inputs, if the number
of inputs that are high is a odd number then output will be high, for
even number of high inputs output will be low.
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to try out the
demo of the gates below.
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A
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Q
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|
 |
 |
|
B |
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Toggle the red buttons above to apply a
'high' or 'low' to inputs A and B and watch the output Q.
Truth table
| A
|
B
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Q
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0
|
0 |
0
|
| 0 |
1 |
1 |
| 1 |
0 |
1 |
1
|
1 |
0
|
Related Reading
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