Assignment #7
Part I - Car Circuit (10 Marks)
Built into almost every car is a simple circuit that alerts the driver by “Buzzing” when the
the door is opened and the key is in the ignition. The car will also buzz, when the car is in
drive and the driver has not buckled the seatbelt.
Design a circuit that consists of the following components:
AND Gates
OR Gate
NOT Gate
Buzzer
4 Switches (one for each input (hint: bold letters))
a) Sketch the circuit. Use MS paint or pen and paper. Label each switch. (5 Marks)
b) Do a truth table for this circuit. (3 Mark)
c)Write the Formula. (2 Marks)
Part II - Ohm’s Law (20 Marks)
The Relationship of Voltage, Current, and Resistance is governed by this equation
V=IxR
where:
V = voltage in volts (V)
I = current in amps (A)
R = resistance in ohms
or:
V = voltage in volts (V)
I = current in milliamps (mA)
R = resistance in kilohms (k)
1. Read more about voltage and current on this page:
http://www.kpsec.freeuk.com/voltage.htm#seriesparallel
2. Run the tutorial on this page:
http://www.wisc-online.com/objects/index_tj.asp?objID=DCE8104
3. Try the simulator:
http://phet.colorado.edu/simulations/veqir/VeqIRColored.swf
Example Problem:
A nine volt battery supplies power to a cordless curling iron with a resistance of 18 ohms.
How much current is flowing through the curling iron?
Solution
V=IxR
9 = I X 18
I = 9/18
I = 0.5 Amps
Therefore, 0.5 Amps is flowing through the curling Iron.
Par II :
Questions: (20 Marks)
Research Ohm’s Law and answer the following questions.
1.
The rate of electron flow is measured in (a) amperes (b) volts (c) ohms.
2.
In a circuit, voltage and current are (a) directly proportional, (b) inversely proportional,
(c) not proportional.
3.
According to Ohm’s Law, what effect will cutting the resistance have on the current?
4.
If the voltage stays the same and the resistance is ¼ of its original, what will happen to the
current?
5.
Using your equation for Ohm’s Law, answer the following. Current equals __________
divided by _____________.
6.
If the power source is set at 6V and R is 2 ohms, the current =___________
7.
V=5volts, R= 10 ohms, I= ____________.
8.
Voltage = ____________ times_____________.
9.
If the current in the circuit is 7 amps and the resistance is 2 ohms the voltage
=___________.
10.
R = 30 ohms, I = 3A, V=__________
11.
Resistance= ______________ divided by _____________.
12.
If the power source is 12 V and the flow of electrons is 3A, what is the resistance?
13.
V= 6V, I= 18A, R=__________
14. A 110 volt wall outlet supplies power to a strobe light with a resistance of 2200 ohms. How
much current is flowing through the strobe light?
15. A CD Player with a resistance of 40 ohms has a current of 0.1 amps flowing through it. How
many volts supplies the CD player?
16. Complete the following chart (4 marks)
Part III
Calculate the Resistance needed to safely operate the LED in this diagram (10 marks)
Part IV
Using MS Paint, complete the following Ohm’s Law Calculator. Use a different background color
for each section (light colors). Search Google images for “Ohm's wheel” to research.
Print and submit. (10 marks)
Ohm’s Law