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Powering an LED

  • One fuel cell does not generate enough voltage to power anything of interest. Just like you would connect 2 or 4 AA batteries in series to power a portable CD player, it is necessary to connect multiple fuel cells to generate larger voltages.
  • Pair up with another group and connect the positive terminal of one cell to the negative terminal of the other cell using the wires with alligator clips. Now connect the unwired positive terminal to the positive (longer lead) of the red LED. The unwired negative terminal should be connected to the negative (short lead) of the red LED. At this point the LED should be lit. If you do not see any light, you should use the multimeter to check the voltage generated by the two cells in series and verify that it is greater that 1.5V. If you do not measure any voltage verify that you have wired everything correctly.

Figure 5: Powering an LED circuit.

Powering a small motor

  • While two cells in series generate the proper voltage to operate the motor, they cannot source enough current to run a motor longer than a few seconds. By putting cells in parallel more current can be obtained.
  • You will need two sets of two cells in series as described in the “Powering an LED” section (4 groups are needed for this part).
  • Take the positive connection from each series cell and connect to one terminal of the electric motor. Take the negative connection from each series cell and connect to the other terminal on the electric motor. At this point the motor shaft should begin to turn. If not, check the wiring and verify that you are applying at least 1.5V. It is also possible that 2 parallel cells will not generate enough current. Additional cells can be added in parallel to generate more current.

Figure 6: Powering a motor circuit.

Pre-lab: (total 10 points)

Name(Print then sign): ___________________________________________________

Lab Day: ___________________Section: ________TA__________________________

This assignment must be completed individually and turned in to your TA at the beginning of lab. You will not be allowed to begin the lab until you have completed this assignment.

1.Fill in the blanks:

Fuel cells are used for direction conversion of the energy of combustion reactions to ______________. A fuel cell is a ______________ in which electricity is generated by a combustion reaction. A fuel cell provides a ______________ voltage that can be used to power motors, lights or any number of electrical appliances.

2.T or F At the anode, oxidation of the fuel takes place.

3.T or F The fuel cell emissions will be nothing but water vapor.

4.T or F The efficiency of fuel cells, chemical-to-electric energy conversion, is approximately 40%.

Review of series and parallel circuits:

In a series circuit, the electrons in the current have to pass through all the components, which are arranged in a line. Consider a typical series circuit in which there are three resistors of value R1, R2, and R3.

There are two key points about a series circuit:

  • The current throughout the circuit is the same.
  • The voltages add up to the battery voltage.


VT = V1 + V2 + V3

From Ohm’s Law:

  • VT = IRT;
  • V1 = IR1;
  • V2 = IR2;
  • V3 = IR3

Þ IRT = IR1 + IR2 + IR3


RTot = R1 + R2 + R3

5.In the circuit below, the current is 100 mA.

(a) What is the current in each resistor?

(b) What is the voltage across each resistor?

(c) What is the total resistance?

(d) What is the battery voltage? 

Parallel circuits have their components in parallel branches so that an individual electron can go through one of the branches but not the others.  The current splits into the available number of branches.

In this case, the current will split into three.   For a parallel circuit:

  • The voltage across each branch is the same.
  • The currents in each branch add up to the total current.

From this:

Itot = I1 + I2 + I3

From Ohm’s Law:  I T = V ; I1 = V; I2 = V; I3 = V

RT R1 R2 R3

Þ V = V + V + V

RT R1 R2 R3

Þ 1/RTot = 1/R­1 + 1/R2 + 1/R3

6.This question refers to the circuit below.

(a) What is the total resistance of the circuit?

(b) What is the current through each resistor?

(c) What is the total current? 

For resistors in both series and parallel, follow these guidelines:

  • Work out the total resistance of the parallel combination.
  • Work out the total resistance of the circuit by adding your answer in the previous step to the values of the series resistors.

7.What is the single resistor equivalent of this circuit?

Report (80 points)

Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’ work (including your laboratory partner) or misrepresent your own data (see honor code).

The following tables and questions should be answered in your written report. Please put the information in the relevant section of your report (i.e. observations and results, discussion)

What would happen if zinc screws were used instead of brass?

What is the purpose of the palladium coating on the anode?

What is the purpose of the palladium coating on the cathode?

What fuel cell worked best?

Explain, in detail, why you think that the best fuel cell worked better than the others?

Debate fuel cells.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Honors chemistry lab fall. OpenStax CNX. Nov 15, 2007 Download for free at http://cnx.org/content/col10456/1.16
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