How to know if my logic IC is fried?

[Agnivesh]

NOOB question:
My friend asked me to help him with a science project. The idea is just to make an OR gate using a 74HC03 quadNAND gate IC. He had previously connected it to a 9V battery, and NOT a 5V supply. Does that do any damage? Could it have fried the IC or is it safe to use it with 9V?
And also, is there a way to be sure that the IC is not fried? Like testing resistance between pins or continuity or something else?

[amyk]

7V absolute maximum according to the datasheet. Definitely NOT recommended to operate with 9V.

The way to test it is to check that the gates function as expected and within spec. Some damage may have occurred that isn't evident but may cause failure later on.

[SH@RK]

I do not know if there is any special test but you only need to test each gate

So put your IC in a breadboard

then wire it as in this pictures



then add an LED to the output pin and to the ground (so it will turn on when the output is 1 )



just check if this table is true ---- If output same as table your IC is not damaged

[Agnivesh]

thanks everyone for helping me out!!

[hlavac]

Just get a new one to be sure, they are dirt cheap...

[vk6zgo]

Usually,if you have cooked a particular gate,its resistance to ground will be different to the other gates,but in this case you might have killed the whole thing.

As hlavac says,get another one--just treat 'em like 14 legged fuses!

[deephaven]

Also be aware that these chips are Open Drain outputs which means you will have to have a pull-up resistor to see any output.

If you want something that runs directly off 9 volts, use CMOS logic.