2 nd Hour Agenda

1. 2nd Hour Agenda Teaming Batteries Introduction to Ohms Law EGR 101

2. Collaborative Learning • Positive Interdependence • Share responsibilities (sink or swim together) • Be sure that all team members learn the material • Your success is linked to the success of your teammates • Involve each team member • Each team member’s efforts are required for success • No “free riders” EGR 101

3. Code of Collaboration • Every team member is responsible for the team’s progress and success! • Attend all classes and team meetings • Be on time • Come prepared • Carry out assignments on schedule • Be an active listener • Listen to and show respect for the contributions of the other team members • Constructively criticize ideas, not people • Resolve conflicts and avoid disruptive behavior EGR 101

4. Code of Collaboration • Avoid disruptive side conversations • Only one person speaks at a time • Everyone participates, no one dominates • Be brief and to the point • Avoid long anecdotes and examples • Set a norm for behavior • “Code of Conduct” for your team EGR 101

5. Out-of-Class Team Activity • Work together to develop your own team’s Code of Conduct • What do you expect of each other?Make your expectations explicit (like attending all meetings, arriving on time, prepared, etc) • What are the consequences if someone fails to meet expectations? • Due at the beginning of class next Tuesday EGR 101

6. Where Does Current Come From? • The free electrons in a conductor need to be replaced when they move through the conducting medium (the wire). • These electrons are replaced by electrons from a source of energy such as a battery. EGR 101

7. Circuit Components • Batteries + + EGR 101

8. Source of Voltage in a Battery • A chemical reaction within the battery separates positive and negative ions(charged atoms) • When the battery is connected to a circuit, the negative charge move toward the positive charge and a current is produced • The amount of current is constrained by the resistance of the circuit EGR 101

9. Example of A Battery The source of energy E in (Joules) releases charges Q in (Coulombs) Voltage (V) – the difference in potential that uses E = one Joule (J) of energy to move a charge Q = one coulomb (C). EGR 101

10. Current Direction We will adopt “Conventional Flow” for all of our work! EGR 101

11. Mathematical Relation • E: Energy required to move charges in Joules (J). • Q: Charge value in Coulombs (C). • V: Voltage or potential difference across the battery's posts in volts (V). • Thus, V = E / Q. • In units: 1 Volt = 1 Joule/Coulomb EGR 101

12. Team In-class Activity (15 minutes) • A 10 V source uses 2 Joules of energy per second. Calculate the current being used by the source. • Hint, turn the word problem into equations; write down what you know. EGR 101

13. When batteries are connected with their polarities in the same direction, they are in a series-aiding arrangement. EGR 101

14. When batteries are connected with their polarities in the opposite direction, they are in a series-opposing arrangement. EGR 101

15. In Class Activity • What is the total voltage between terminals A and B in the figure below?Which terminal is at a higher potential? A B 9V 4V 15V EGR 101

16. Introduction to Ohm’s Law • A 1 Ohm resistance limits the current to 1 Amp when 1 Volt is applied. V = I.R EGR 101

17. Ohm’s Law • Three forms: • Use the form that best describes the quantity that you are trying to determine EGR 101

18. Determine the Current I + _ EGR 101

19. Determine the Voltage + _ EGR 101

20. Determine the Resistance + _ EGR 101