5F20.u1 - Resistance Light Board
Demonstrate how different power light bulbs behave in series and in parallel.
InstructionsThere is a board built as shown above. Connect to 110-V AC and start with equal bulbs on the left and right, say two 25-watt bulbs on the left and two 100-watt bulbs on the right. Note that the 25-watt bulbs burn brighter than the 100-watt bulbs since they have 2/5 of the voltage across them. Place a shorting wire across AB and note that there is no change. With this shorting wire in place, short out one of the bulbs and note the result. Repeat the same procedure with the wire AB removed.
Note that if it is necessary to replace one of the bulbs it may be necessary to replace the other bulb of the same size in order to keep them matched.
Note: Relative brightness is not a good measure of power in all cases here. It doesn't always come out the way it should. Probably due to change of R with temperature