Basic Idea:

• Measure the electric potential difference around two charges, and infer the direction of the electric field.

	What:	How Many:	Where:
	Conducting paper mounted on foam board	1	Majors storeroom, shelf E1
	Double-pencil probe	1	Majors storeroom, shelf E1 In the box with the conducting paper
	Digital multimeter	1	Majors storeroom, shelf A3
	DC battery (9volt, C, D, or AA)	1	non-Majors storeroom, shelf L3
	Wires, 24" long	2 1 red, 1 black	Look around
	Widow maker	1	non-Majors storeroom, shelf L3
	Centimeter-ruled graph paper	1 sheet per person	Physics office
The following component is shared:
	GS Sola Electric ±15 volt DC Power Supply (preferred)      or 40 volt DC Power Supply	1	Majors storeroom, shelf C2 or C3
	Wires	3 1 red, 1 black, 1 green	Look around
	Banana-to-pin adapter	3	Majors storerooom, shelf B2

Computers Needed?

• No.

• Lab Setup (see this page for detailed photos):

  

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• Pencil Probe:

  

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• Conducting paper connection — Connect conducting boards as shown. The wire that leads to the left-hand screw is marked with a piece of tape; make sure this screw is connected to the positive terminal. All boards should be connected so that the left hand screw has the positive voltage (when the student is facing the front of the lab).

• Power Supply — Conducting paper connection using GS Sola Electric power supply (preferred) Note: These connections should only be made by Jeff, or another faculty member! This supply is used to provide voltage to the lab. Connect it to port #5 or 6, on instructor's bench. Make sure master power supply in storeroom is disconnected. Use banana-to-pin adapters to connect wires to power supply. All left-hand terminals on the conducting paper have been marked with tape. Make sure this is the positive "charge". Testing: Connect ground wire of meter to green ground terminal of power panel, and touch positive wire to each screw head. Should read ±15 volts. Voltage across terminals should be 30 volts. Make sure that the nuts on the boards are finger tight!

  (If using a 40 volt power supply, use setup figure below)

  

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• Power Supply — Conducting paper connection using 40 volt power supply Note: These connections should only be made by Jeff, or another faculty member! The power supply is used to provide voltage to the lab. Connect it to port #5 or 6 on the instructor's bench. The voltage should be set to 24 volts (providing ±12 volts), and the current set very low (close to zero). Make sure that the nuts on the boards are finger tight!

  (If using GS Sola Electric power supply, use setup figure above)