PASCO EM-8812 Resistance Apparatus - Manual (Page 6)

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R e s i s ta n c e A p p a r a t u s M e a s u r e m e n t P r o c e d u r e
6
Measurement Procedure
1. Turn on the power
supply and adjust the
applied voltage to
established the
desired current (I)
through the wire.
2. Place the reference
probe on the “0 cm”
mark.
3. Move the slider probe
to any point on the wire. Read the length ( ) in centimeters from the scale on the
apparatus. This is the length of wire over which the voltage is measured.
4. Read the voltage (V).
In a typical experiment, you would make several measurements of V while varying
one other parameter (such as I, , the wire diameter, or the wire material).
Fuse
If current greater than 2 A is applied to the apparatus,
the fuse will open and require replacement. The fuse is
located on the underside of the apparatus. To remove
it, pull it straight out. The apparatus includes a spare
fuse taped to the underside.
The fuse is an 2 A mini-blade fuse, which can be pur-
chased at automotive supply stores.
Stacking
To stack two or more apparatuses for storage, turn the
clamp screws to be “horizontal” (as illustrated). Push
the reference probe to the right as far as it will go (a lit-
tle to the right of the “0 cm” mark) and push the slider
probe to anywhere left of the “24 cm” mark.
About the Experiments
The experiments in the manual represent three examples of how the apparatus can be
used, ranging from a simple exploratory lab (Experiment 1) to more advanced
(Experiment 3). Teachers’ notes and sample data for all three experiments appear on
page 15–17.
Experiments 2 and 3 refer to specific power supplies, sensors, and software; however
variations of these experiments can be done with equipment available in most physics
teaching labs.
22
RESIST RESISTANCE ANCE APP APPARA ARATUS TUS
0 4 24 1 2 3 5 6 7 9 8 10 11 12 13 14 15 16 17 18 19 20 21 23 cm
Slider probe Reference probe
on “0 cm” mark
Fuse Spare fuse
24
RESIST RESISTANCE ANCE APP APPARA ARATUS TUS
0 4 1 2 3 5 6 7 9 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 cm
Screws “horizontal”
for stacking
Probes pushed
toward center