Lab 1: Digital Logic GatesKatherine Morales

ECEN 248 – 506TA: Kartic Bhargav

Date: February 16, 2015

Objectives:In this lab, I will learn about different gates and their behaviors. I will also learn how to wire these gates correctly to be able to compute a truth table. This lab will allow me to familiarize myself with breadboards, logic inverter gates, multi-meter, and a power supply.

Design:The first part of the lab requires a 74ALS04 (inverter) NOT gate to be placed on the breadboard.

NOT Gate

Then the VCC and the GND are identified on an inverter gate, as pictured above. The multimeter is used to calculate the volts of the gate. To calculate the high input, a wire is connected from the input to the plus side of the breadboard. To calculate the low input, the wire is connected from the input to the minus side of the breadboard. The output is a low if the voltage is around 90mV and the output is a high is the voltage is around 3-4V.

These steps are repeated for the AND, OR, NAND, NOR, XOR gates.

AND Gate: OR Gate:

NAND Gate: NOR Gate:

XOR Gate:

Results:The results of the lab came out exactly as expected. No changes are necessary to make to fix the circuit. The circuit behaved the way it did because the wires were properly placed so that the outputs would be similar to the outputs the gates usually have.

Truth Table for Inverter (NOT gate)A (high/low) Y (volts) Y (high/low)

Low 3.989 V HighHigh 77.9 mV Low

Truth Table for AND & OR GatesA (H/L) B (H/L) AND2 (V) AND2 (H/L) OR2 (V) OR2 (H/L)L L .145V L .129V LL H .145V L 4.391V HH L .145V L 4.413V HH H 4.399V H 4.391V H

Truth Table for NAND, NOR, & XOR GatesA (H/L) B (H/L) NAND2

(V)NAND2 (H/L)

NOR2 (V)

NOR2 (H/L)

XOR2 (V)

XOR2 (H/L)

L L 4.134V H 4.969V H .118V LL H 4.143V H .01V L 4.373V HH L 4.144V H .01V L 4.379V HH H 105.5mV L .01V L .122V L

Conclusion:In this lab, I used a breadboard, different inverter gates, wires, and a multimeter to verify the binary outputs of the different gates. I learned how to use inverter gates properly and how to verify the binary codes for a truth table. I learned how to use a breadboard, which will be useful in later labs when we go into deeper circuitry.

Questions:1. I liked that once you understood how to work the breadboard and the circuit wiring to get data, the

rest of the lab was simple and quick. Once I was able to figure out what I was doing and why I was doing it, I was able to finish the lab smoothly. I disliked how there were no examples on how to properly do the lab. If the lab experiment had a small section on a similar, worked out example rather than just an explanation, the lab would have been easier to understand.

2. The lab manual was very thorough and easy to understand. I would have appreciated an example or two to keep the students moving on the right path. Overall, the lab manual clearly stated what needed to get done and how to go about doing that.

3. My main suggestion is adding in examples that the students could base their work off of. I feel like this would help students work at a more efficient pace.