Introduction to Electronics
The purpose of this lab is to understand basic electronic measurements, components, and test
equipment. The majority of electronic instrumentation is based on the concepts of current, potential
rence, and resistance.
Current (I) is the time rate of flow of charge through a device. The SI unit of current is the
ampere (amp or A).
Potential difference (
ΔV, often abbreviated as V) is the electrical potential energy per unit
charge. The SI unit of potential difference is the volt (V).
Resistance (R) is the ratio of potential difference to current. The SI unit of resistance is the
Note on terminol
ogy: Distinguish between a quantity and its SI unit. Avoid referring to current as “amperage” and
potential difference as “voltage”.
Add these two terms to the list of banned expressions in lab reports.
Electrical components and test equipment can be conn
ected together in either series or parallel
configurations. Two components are “in series” if they are connected to each other end
end and no
other component is connected to that junction. Two components are “in parallel” if they are
connected at both e
In this lab, you will investigate some simple electronic circuits and components. At the end of this lab,
you should be able to read the color code on a resistor and use a digital multi
meter to measure
resistance, potential difference, and current.
You will also do a simple test of Ohm’s law.
Equipment You Procure
Equipment from Kits
2 digital multi
9V battery connector
) Using the color
code chart provid
compute and record the
of each resistor.
Convert the percentage error to an absolute error.
meter as an
(see instructions on the
measure and record
resistance of each re
estimation of the error
experimental resistance (see instructions on the last page).
theoretical and experimental
. Do the resistor
work as advertised?
3) Create a c
1000 ohm resistor,
, 9V battery, 9V battery
a digital multi
meter configured as a 20V voltmeter (see instructions on the last page), and a
meter configured as a 2
0 mA ammeter (see instruc
tions on the last page).
Be very careful to use the ammeter correctly since it is very easy to blow a fuse.
choose to take a photograph of your configuration without the battery connected and e
mail it to your
4) Measure and record the
Include an estimation of the
error for both the
) Divide the measured
measured resistance to
Propagate the error in the calculations according to the general lab instructions.
Compare to the value measured in step
Did Ohm’s law make a correct prediction?
The digital multi
meter in the upper right corner is
configured as an ammeter at the 20 mA setting. It reads
9.31 ± 0.02 mA or 0.00931 ± 0.00002 A. The digital multi
meter in the lower right corner is configured as a voltmeter
at the 20 V setting. It reads 9.21 ± 0.02 V. Connect the battery last so that you
can reduce the risk of damaging your
Resistor Color Codes
First find the tolerance band. It will typically be red (2%), gold (5%), or silver (10%) and slightly separa
ted from the other
bands. Starting from the opposite end, identify the first band and write down the number associated with that color. Now
'read' the next color and write down the number associated with that color. Now read the third or 'multiplier' band
write down that number of zeros.
Meter as an Ohmmeter
The digital multi
meter should come with 2 cables. Plug the red one into the hole labeled
“V/Ω”. Plug the black cable into the hole marked “COM”. Turn the dial to the region marked
“OHM” and the setting that is the lowest possible and still above your expe
Place the red lead and the black lead at opposite ends of a resistor or group of resistors that is
not connected to anything else
. The reading displayed will be the resistance in units as
specified by the setting. If the setting is 200, th
en the resistance will be measured in Ω. If the
setting is 2K, 20K, or 200K, then the resistance will be measured in kΩ. If the setting is 2M or
20M, then the resistance will be measured in MΩ.
Meter as a Voltmeter
Place the cables in the sa
me holes as with the ohmmeter. Turn the dial to the
region marked “DCV” for DC circuits or “ACV” for AC circuits. Choose a
setting that is the lowest possible and still above your expected potential
difference. Place the leads at opposite ends of a circuit
element or combination of
elements and observe the potential difference or potential difference across the
circuit element or combination of elements in units as specified by the setting. If
the setting is 200m, then the potential difference will be measu
red in mV. If the
setting is anything else, the potential difference will be measured in V.
Meter as an Ammeter
Please be careful using the digital multi
meter as an ammeter because it is a sensitive
device. Plug the red cable into the hole
. Plug the black cable into
the hole marked “COM”. Turn the dial to the region marked “DCA” for DC circuits or
for AC circuits. Place the ammeter “in series” with the circuit element you wish
to measure current through. To place the ammeter “in series” with the circuit element,
disconnect one connection to the circuit element, then connect one lead to the circuit
element and connect the other lead to the point where the circuit element used to be
connected. The ammeter should now measure the current in units as specified by the
setting. If the ammeter setting is 200μ, then the current will be measured in μA. If the
ammeter setting is 2m, 20m, or 200m, then the current will be measured in mA. If the
current setting is 2, then the current will be measured in A.
Note: Never connect an ammeter “in parallel” to a circuit element of interest because it might blow a fuse a
definitely not measure the current through the circuit element. Please consult with your instructor if this is not clear.
Error with the Digital Multi
You may a
ssume that the last digit displayed is ±2 unless
you have evidence otherwise. Thes
e error estimations must be
made specific to each measurement in your reports.
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