SCEN103 Demonstration 1

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 battery configurations. 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.

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Comments, suggestions, or requests to ghw@udel.edu.

"http://www.physics.udel.edu/~watson/scen103/demo1.html"
Last updated Sept. 8, 1996.
Copyright George Watson, Univ. of Delaware, 1996.