1. 1 18 Overview resistor & capacitor circuits Kirchoff’s Rules voltmeters & ammeters household circuits & safety Homework: 17, 27, 31, 33, 55, 67, 71, 85

2. 2 Connection Types ______ ______l

3. 3 junctions & loops Current value ______________ at __________________. Ex. Point b is a junction A closed path is called a ___________ Ex. b  c  d  e  b

4. 4 Equivalent Resistance The ______________ of a network of resistors is called the _____________________. The equivalent circuit is the circuit made by replacing the network with an equivalent resistance valued resistor.

5. 5 Resistors in Series

6. 6 Resistors in Parallel

7. 7 What happens to the equivalent resistance of a series network as more resistors are added to it? 1.increases 2.decreases 3.stays same 4.cannot be determined

8. 8 What happens to the equivalent resistance of a parallel network as more resistors are added to it? 1.increases 2.decreases 3.stays same 4.cannot be determined

9. 9 Ex. Find a) equivalent resistance of the circuit. B) the current in and voltage across each resistor, c) the power dissipated by each resistor.

10. 10 Ex. Find a) equivalent resistance of the circuit, b) the current in and voltage across each resistor, c) the power dissipated by each resistor.

11. 11 Calculate the equivalent resistance:

12. 12 Kirchoff’s 1 st Rule 1) current into junction = current out Ex. I = I 1 +I 2 __________________

13. 13 Kirchoff’s 2 nd Rule 2) voltage change around any loop is ____ Ex. -I 2 (6)+I 1 (4) = 0 _________________________

14. 14 Measuring Devices become __________of the circuit being measured each device has ________________ (ideally) the meter’s resistance should ____________ the resistance of the circuit

15. 15 Voltmeters used in ____________ with a circuit element (circled V in diagram) (ideally) the voltmeter should have ____________ internal resistance /

16. 16 Ammeters used in __________ (circled A in diagram) (ideally) the ammeter should have ______ internal resistance /

17. 17 RC Circuits any circuit with a resistor and a capacitor Time constant = RC s =  ·F Ex. 50ohm, 2F RC = 100s /

18. 18 Charging a Capacitor V

19. 19 Ex. R=100, C=0.5, V = 6.0 How long for capacitor to get to 4.0 volts? RC = (100)(0.5) = 50 seconds Equation: solve for t:

20. 20 Discharging a Capacitor

21. 21 Ex. R=80, C=1.0, Vo = 5.0 How long for capacitor to get to 3.5 volts? RC = (80)(1) = 80 seconds Equation: solve for t:

22. 22 Household Circuits US: _________ @ _____________ Europe, etc.: 220 @ ______ hertz ground wires allow excess current to go into the ground (safety feature). circuit breakers & fuses stop the current flow if it passes a certain value (safety).

23. 23 Summary series & parallel circuit analysis junctions, loops & Kirchoff’s Rules RC circuits voltmeters & ammeters household circuits & safety