1. Measuring Voltage, Current and Resistance Lab Summary Voltage (symbol = V)  the force which pushes electrons through a circuit resulting in electrical current flow.  Magnitude expressed in units of Volts (V)  Named after Count Alessandro Volta who invented first voltaic cell  Measured using voltmeter or multimeter (DMM)  Higher voltage means stronger force

2. Measuring Voltage, Current and Resistance Lab Summary Current (symbol = I)  The amount of electrons flowing past a point in a conductor in a certain amount of time. Current is considered a rate since associated with time.  More electrons flowing means greater current  Magnitude measured in units = amperes (A)  Named after Andre Ampere who discovered that a magnetic field forms around a wire when a current passes through it (theory of electromagnetism)  Measured using an ammeter or multimeter (DMM)  1A=6.24x10 18 e -  2 types of current: 1. Alternating (AC): changes direction/polarity many times per sec 2. Direct (DC): flows in 1 direction only

3. Measuring Voltage, Current and Resistance Lab Summary Resistance  Opposition to the flow of current  Each component in a circuit creates resistance but some more than others. Resistance results in heat, light or motion given off  Resistors are components designed especially to resist (decrease amount of current going from one component to another) Why?  Magnitude measured in ohms ( Ω )  Named after Georg Simon Ohm who discovered relationship between voltage, current and resistance…. known as Ohm’s Law: R=V I Brown,gold,black,black Orange,orange,orange,gold Green,blue,brown,gold Black,green,yellow,purple Black,green,blue,black Brown,green,red,green

4. Activities  OLL#10: Complete Problems 1-2,5-6,9-10 at the link below: http://www.wisc- online.com/objects/index_tj.asp?objID=dce11904 Note: Use GFS and write out your solution on a piece of paper first. Then check your answer on the site

5. Activities cont.  Activity: a)Find the resistance of each of the 6 resistors on the previous slide. Use the colour chart to find your answers. b) Find the resistance of each of the 4 different resistors in the container at your table