Low cost competition

Apparatus Title: Gray's Lights

Abstract: Gray's Lights is a quick, easy way to show light bulbs in series and in parallel. The unique clip-on set-up allows limitless combinations of light bulbs and the vertical nature of the display makes it easy for the class to see.

Equipment required to construct apparatus:

Item Source/Store Part Number Cost: ·

• 2 (two) brass rods 4.75 · wood base 1.00 ·
• 3 (three) aluminum blocks 2.00 ·
• 4 (four) 12-V parking lamps GE1156 12.00 ·
• 4 (four) lamp sockets 24.00 ·
• 8 (eight) 30-A alligator clips 16.00 ·
• 3 (three) banana plugs 3.00 ·
• 3 (three) panel mount sockets 1.50 ·
• wire wrap wire roll 0.50

Description: Gray's Lights is simply a stand with two long vertical rigid rods. One rod connects with the positive terminal of the power source and the other with the negative terminal. Each light bulb base is soldered to a flexible wire with clips on both ends. Each piece of wire is just long enough to be connected between the rigid rods. Many can be connected in parallel. For series, just make a chain of bulb-wire segments by clipping them together. Then connect the ends of the chain to the two rigid wires. To demonstrate a short circuit, use another plain piece of wire wrap wire with clips on the ends and connect to the rods. If there is already a bulb circuit in place, the addition of the simple wire will show students what happens when a short occurs (bulbs dim, smoke and fire!).