5F20.50 - Series and Parallel Resistance with Bulbs (Gray's Lights)
Demonstrate how light bulbs (resistors) behave in series and in parallel.
Obtain equipment for "Gray's Lights" demo. Screw in the threaded brass rods into the wooden base and connect each one to an electrode of the black power supply using banana cables and momentary contact switch. The black power supply should be set to 12V. Plug in the power supply to the cart, and the cart into the wall or bench outlet.
Connect lightbulbs in various arrangements. Turn on power supply, and press down on the momentary contact switch to give power to the circuit.
Demonstrators can make different combinations of the light bulbs to show either series, parallel, or mixed circuits, by the variation in brightness of the light bulbs.
Light bulbs are used as resistors in the demonstration of series and parallel circuits. Their brightness depends on the current flowing through them which varies with their arrangement.