1 / 16

Ohm’s Law Definition Whiteboards An Elaborate Analogy

Ohm’s Law Definition Whiteboards An Elaborate Analogy. + -. A. R. Ohm’s Law V = Voltage (like pressure) I = Current (like flow rate). V. R = V I R = Resistance in ohms (  ) V = Voltage in Volts (V) (pressure) I = Current in Amps (A) (flowrate). + -. A. R.

carly-atkins
Download Presentation

Ohm’s Law Definition Whiteboards An Elaborate Analogy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ohm’s Law • Definition • Whiteboards • An Elaborate Analogy

  2. + - A R • Ohm’s Law • V = Voltage (like pressure) • I = Current (like flow rate) V • R =V • I • R = Resistance in ohms () • V = Voltage in Volts (V) (pressure) • I = Current in Amps (A) (flowrate)

  3. + - A R • Ohm’s Law - The way I think of it • V = Voltage (like pressure) • I = Current (like flowrate) • R = Resistance to flow V • I =V • R • R = Resistance in ohms () • V = Voltage in Volts (V) (pressure) • I = Current in Amps (A) (flowrate)

  4. + - A Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 Gray 8 White 9 Gold 5% Silver 10% No color 20% R Ohm’s Law V • I = V • R • R = Resistance in ohms () • V = Voltage in Volts (V) (pressure) • I = Current in Amps (A) (flowrate) • Demo - pass around resistors • (two properties - power and resistance) • Demo - power supply, resistor, light bulb • (show increase/decrease V, and R)

  5. Ohm’s Law + - A 120. mA 12.0 V • R =V • I • R = Resistance in ohms () • V = Voltage in Volts (V) (pressure) • I = Current in Amps (A) (flowrate) R= ?? Example 1: What is the resistance in the circuit above? R = V/I = (12.0 V)/(.120 A) = 100.  Example 2: If there is a 220  resistor in the circuit above, what is the current? R = V/I, I = V/R = (12.0 V)/(220 ) = .05454 = .055 A or 55 mA

  6. Whiteboards 1 | 2 | 3 | 4 | 5 | 6

  7. What is the resistance of a light bulb if it draws 250 mA of current from a 6.15 V battery? (1000 mA = 1 A) • Given: • R = V • I • R = ?? • V = 6.15 V • I = .250 A • R = 24.6  W 24.6 

  8. What current will flow if you plug a paperclip with a resistance of .065  into a 12 V source? • Given: • R = V • I • R = .065  • V = 12 V • I = ?? • I = 184.6 A W 180 A

  9. What voltage do you need to push 1.5 Amps of current through a 210 ohm resistor? • Given: • R = V • I • R = 210  • V = ?? • I = 1.5 A • V = 315 V W 315 V

  10. What current flows through an 8.1 ohm speaker when there is a voltage of 3.45 V? • Given: • R = V • I • R = 8.1  • V = 3.45 V • I = ?? • I = 0.425925926 • I = .43 A W .43 A

  11. An unknown resistor draws .0128 Amps of current from a 23.9 V source. What is the resistance? • Given: • R = V • I • R = ?? • V = 23.9 V • I = .0128 • R = 1867.1875 • R = 1870  W 1870 

  12. A 1200 ohm resistor is hooked up to an unknown voltage source, and it draws 87.5 mA of current. What is the voltage? • Given: • R = V • I • R = 1200  • V = ?? • I = .0875 A • V = 105 V W 105 V

  13. A 670 ohm resistor is connected to a 1.5 V battery. What time will it take for 3.0 C of charge to flow from the battery? • Given: • R = V • I • I =q • t • R = 670  • V = 1.5 V • I = ?? • q = 3.0 C • t = ?? • t = 1340 s W 1340 s

  14. A 3.0 V battery with a capacity of 350 mAh (350 milli amp hours) is drained in 4 hours and 27 minutes. What is the resistance of the circuit that it is attached to? • Given: • R = V • I • I =q • t • R = ??  • V = 3.0 V • I = ?? • q = (.350e-3)(3600) = 1260 C • t = 4*3600 + 27*60 = 16020 s • R = 38.14286= 38 W 38 

  15. + - Symbols A Cell. + and -, Infinite current, R = 0, what’s really inside A Battery of cells A resistor A voltmeter, R = infinity V3 An ammeter, R = 0 A3

  16. + - An analogy Water in pipes: Electrons in wires: Flow rate (GPM) Current (Amps = C/s) Pressure Voltage Constriction Resistance Constant P Pump Batteries/Cells Current convention Restriction Wires are superconductors R1 A3 R2

More Related