Items needed for demonstration
- 2 Cenco Lecture Table galvanometers
-- yes the old ones, but they do the job!
- One configured for voltage, 5 V max
- One configured for current, 1 A max
- 2 legible signs
- Voltage (across)
- Current (through)
- Three C-cells with 2 interchangable conducting "duds"
- Light bulb (and spare!)
- Two 3 ohm power resistors
- Numerous wires and clip leads
- Graph paper transparency
- Three colored transparency markers
- Observe illumination of light bulb with 1, 2, and 3 batteries in series.
- Measure voltage across bulb and current through bulb under 3 different
I believe that it is preferable to measure with arbitrary units at this
point in the course!
- Plot voltage and current on overhead transparency as collected.
- Try straight line fit -- do not forget to draw it through origin.
- Observe "droop."
- Repeat measurements on one 3 ohm power resistor.
- Observe better straight-line dependence -- linear porportionality
- Repeat measurements on two 3 ohm power resistors connected is series.
- Observe good straight-line dependence with different slope.
- Discuss bulb "droop" in light of 3 ohm and 6 ohm behavior.
Fewer batteries -> lower voltage -> lower current -> less brightly illuminated
of data plotted on viewgraph
by hand as collected SCEN167.
- Computer plot of data,
as it might appear in print.
Back to SCEN103 Home Page.
Comments, suggestions, or requests to firstname.lastname@example.org.
Last updated Sept. 8, 1996.
Copyright George Watson, Univ. of Delaware, 1996.