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Lab 1: Digital Logic GatesRebecca Sontheimer

ECEN 248511

TA: Mehnaz RahmanDate: September 17, 2014

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Objectives:In this lab I learned about basic breadboarding techniques and wiring (and how to

troubleshoot). I also learned how to use integrated circuits on a breadboard and explore

basic logic gates such as NOT, AND, OR, NAND, NOR, and XOR. The lab alsofamiliarized me with lab equipment such as a multimeter, data sheets, power supply, etc.Design:

NOT

ANDOR

NAND

NORXOR

Results:Overall, the lab was successful. In the beginning of the lab, there was a bit of

troubleshooting I had to do to figure out what the correct configuration was. Once Ifigured out how to properly connect wires and how to place the IC, things went more

smoothly. For each integrated circuit I had to manipulate and configure the breadboard

circuit to match with the correct logic gate. For example, the NOT gate only has oneinput and one output, therefore only required a certain wiring configuration. However the

AND gate has 2 inputs, therefore two wires had to be attached to the correct pins.

Regarding the data sheet, not all ICs had the input and output at the same pins. This

required looking up the diagram of the IC and making sure the orientation was correct. Ifthe setup was not right, one could potentially burn the IC, which would affect results.

With each IC, I measured whether the output was high or low (high meaning on

or 1 and low meaning off or 0). The correct range for high values is 3.9V4.2 V.The correct range for low values is 91.9mV. Not all of my values matched this a range.

This is most likely due to the fact that some ICs are damaged or the multimeter did not

get a correct reading.

Table 1: Truth Table for Invertor (NOT gate)

A (H/L) Y (volts) Y (H/L)

Low 4.4 V High

High 107 mV Low

The table above represents the correct outputs of the NOT gate as measured with the

multimeter. A NOT gate inverts the input, therefore these results are correct.

Table 2: Truth Table for AND & OR Gates

A (H/L) B (H/L) AND2 (V) AND2 (H/L) OR2 (V) OR2 (H/L)

L L 94 mV Low 126.2 mV Low

L H 96 mV Low 4.41 V HighH L 96 mV Low 4.41 V High

H H 4.41 V High 4.41 V high

The table above represents the correct outputs of the AND and OR gates as measuredwith the multimeter. These results follow along with the correct truth tables of these logic

gates.

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Table 3: Truth Table for NAND, NOR, XOR Gates

A

(H/L)

B

(H/L)

NAND2

(V)

NAND2

(H/L)

NOR2

(V)

NOR2

(H/L)

XOR2

(V)

XOR2

(H/L)

L L 3.95 V High 4.41 V High 107 mV LowL H 3.96 V High 103.4 mV Low 4.4 V High

H L 3.99 V High 104 mV Low 4.4 V High

H H 205.1 mV Low 87.8 mV Low 107 mV Low

The table above represents the correct outputs of the NAND, NOR and XOR gates asmeasured with the multimeter. These results follow along with the correct truth tables of

these logic gates. However, for the NAND gate, the first set of pins was damaged and

gave me the wrong multimeter reading. I then had to move onto the second gate to get the

correct reading.

Conclusion:In this lab I explored the function of several of the basic logic gates. I learned how

to implement them on a breadboard with integrated circuits. I tested the output voltage ofthe circuit and made sure that these values corresponded with the truth table each logicgate represented. I also learned how to follow the lab manual, how to breadboard, how to

use the lab equipment, and how to properly design and test a circuit.

Questions:

1. What did you like most about the lab assignment and why? What did you

like least about it and why?

I liked that the lab manual was very helpful and made the lab straightforward. The

thing I liked least about this lab was that we had to be independent.

2. Were there any section of the lab manual that were unclear? If so, what was

unclear? Do you have any suggestions for improving the clarity?

No, the lab was very clear and straightforward.

3. What suggestions do you have to improve the overall lab assignment?

I would suggest bullet points for the steps, rather than full paragraphs that youhave to read and scan to find what step is next.