NAND, OR and XOR device detection through gate test

The following gallery is of Gate test of logic ICs.I was given three ICs that were NAND, OR and XOR IC. And I had to identify them on basis of gate test.

The following test is of a Quadruple 2-input ____ gate. That is IC 74xx. 74xx is also known as 74HCxx, 74LSxx etc. These names are for differentiating different dye used in the semiconductor.

I have hooked GND to pin7 of the IC, and VCC(+5V) to pin14 of the IC. This is standard pinout of supply pins for logic ICs. I’ve connected 8 inputs to the inputs of the 74xx IC and the respective 4 outputs are connected to 4 logic probes.

Here red LED means logical 1 and green LED means logical 0. All the three unknown ICs have same pinout in terms of input/output.

They have inputs in pin1, pin2 and output in pin3, then input in pin4,pin5 and output in pin6, and so on.

This is the test of the first IC.

I’ve given signal inputs to the IC as 00, 01, 10, 11 in the four gates. And the output was shown as 1,1,1,0.

So, the truth table for the IC becomes,

A  B   Y
0 0    1
0 1    1
1 0    1
1 1    0

Hence the IC was determined to be the NAND gate.

The next test gave the following result,

A  B   Y
0 0    0
0 1    1
1 0    1
1 1    1

So, it is an OR gate.

The next test gave the following result,

A  B   Y
0 0    0
0 1    1
1 0    1
1 1    0

So, it is an XOR gate.

2 Responses

  1. Milaan panda says:

    ***Helo,Arup sorry 2 say in this page.i am trying 2 make a generetor using a Dc motor.(6v)
    &..I hope runing another Dc Motoro..whith this curent.my theory is 2motor runing it self.is it posible.??i was using a diod..&battry.bt i am falior.how is posible.??****plzzz help me…

    • Arup says:

      This is not possible. By the principle of energy conversation, some energy is lost to heat when the conversion occurs. So, the motor will have less current than it put in the dynamo. Hence, it’s impossible.

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