WEEK

We are going to explore electricity and electronics.

GOALS (This week will be a continuation of week 4):

       Build an RS flip flop using two NAND gates.

       To be able to understand the RS truth table based on measurements.

       To be able to understand the truth table based on the truth table for the NAND.

       To use the RS flip-flop in conjunction with a switch to make an electronic signal that can be counted.

 

       To build a counter that counts how many times we flip a switch.

       To understand how binary numbers work.

I recommend that you glance at the material below but try to think about binary numbers after you have built your circuit. For many the circuit will provide a very practical starting point so that the theory makes more sense.

As we count the light turning on and off we can observe the led display of the counter chip. There are four outputs labeled A, B, C, and D. In the table below I will illustrate the observed pattern as you count using the circuit. Remember that with binary numbers we only have two symbols (0,1= on, off ) while with decimal we have 10 (0,1,2,3,4,5,6,7,8,9). When we run out of symbols we need to add another column. With ten symbols we run out at 10, 100, 1000 while with binary we run out at 2,4,8,16

D

C

B

A

Binary

representation

Decimal

representation

 

off

off

off

off

0000

0

all lights off represents zero

off

off

off

on

0001

1

for both reps increment 1s column

off

off

on

off

0010

2

decimal use next symbol, binary need to use a new column

off

off

on

on

0011

3

binary shows one 2 and one 1

off

on

off

off

0100

4

binary shows one 4

off

on

off

on

0101

5

 

off

on

on

off

0110

6

 

off

on

on

on

0111

7

 

on

off

off

 

1000

8

 

on

off

off

on

1001

9

 

on

off

on

off

1010

10

 

 

Here is another very interesting number system the balanced ternary. (Not required reading)

 

QUIZ *******

 

QUIZ *******

In order to receive a grade of A you must successfully complete the lab portion of the course, read prelab material, and pass the lab quiz. In order to pass you must get 75% of the questions correct.

In order to receive a grade of B you must successfully complete the lab portion of the course. The quiz is optional. For fun feel free to try the quiz.

You are not allowed to consult with other students while taking the quiz. You will be given a limited time period to complete the quiz. You may refer to any written material.

You may take the quiz at any time during the week but only once.

The quiz will be available starting on the day you cover the material and ending one week later.

 If you have troubles please discuss the difficulties with DRG.

You are not allowed to consult with other students while taking the quiz. The quiz will be available at least from lab until following lab. You will be given 30 minutes to complete the quiz and you may refer to any written material.

USE LON CAPA