5F10.10 - Ohm's Law

Code Number:
Demo Title:
Ohm's Law
Series and Parallel Resistors
Area of Study:
Electricity & Magnetism
Dry Cells (4) or 12 Volt Car Battery, Resistors (Assorted), Multimeter (2), Spare Lamp Bulbs, Calculator, Circuit Board with Velcro Fasteners, Lamp Sockets with Velcro Fasteners, Power Supply to Use in Place of the Batteries if Desired, Key Switches, and Hot Plate Heating Element.

Video Credit: Jonathan M. Sullivan-Wood

Hook the resistors or light bulbs into parallel and series pairs. Attach a Multimeter to each type circuit for measuring of voltages or resistances.  Use an ammeter and a voltmeter when doing the Ohm's Law demos. Voltage dividers may also be constructed with this equipment.

Ohm's law can also be demonstrated very well with the hot plate heating element.  DC voltage is easier to work with when doing this demonstration so use a 0-20 volt or 0-150 volt power supply.  Measuring the current, voltage and/or ohms and substituting into the V=IR equation gives you very accurate results.  This example can be found in Physics by Cutnell and Johnson Fifth Edition on p. 593.

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Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.