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 flipflop 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.