# XOR Gate malfunctioning

I have an XOR gate wired (74LS136) and I don't think it is working properly. Here is the table I think it should be outputting:

|X|Y||O|
-------
|0|0||0|
|0|1||1|
|1|0||1|
|1|1||0|

1 is a High
0 is a Low


I think this is the right output for the gate, but this is not what I'm getting. This is what I am getting out of my XOR gate:

|X|Y||O|
-------
|0|0||0|
|0|1||~|
|1|0||~|
|1|1||0|

1 is a High
0 is a Low
~ is nothing


When I probe the output pin I get neither a high nor a low, it says no current. I have tried a couple different chips from the same manufacturer but they all have the same result. Is this normal for an XOR gate? Is this chip suppose to be doing this? Am I using the wrong chip?

• I'm not used to being able to measure "nothing"! Though, ironically, "floating" turns out to be the closest thing to "nothing". Just wondering what you were using to measure the output with. – gbarry Feb 23 '12 at 0:51
• @gbarry I thought the same thing. "No Current" would imply to me that he is doing a current measurement. But there should be no current also when he measured low. Even if it was voltage measurement I am sure it would still read some voltage value. – Kellenjb Feb 23 '12 at 2:02
• it was not a voltage meter, it was a digital high/low probe, i didnt know about floating so i described it as no current/nothing – John Feb 23 '12 at 3:37