1 / 28

Welcome Back Minions

Welcome Back Minions. Put books on the floor. Only note taking material is to be on your desk. Quick Review. Objectives. What is Ohm’s Law? What are the basic features of an electric circuit? How many paths can currents take in series and parallel circuits?

mayten
Download Presentation

Welcome Back Minions

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. Welcome Back Minions Put books on the floor. Only note taking material is to be on your desk.

  2. Quick Review

  3. Objectives • What is Ohm’s Law? • What are the basic features of an electric circuit? • How many paths can currents take in series and parallel circuits? • How do you calculate electric power and the energy used by an appliance?

  4. Starting off… • Understand electric circuits • First understand the relationship between: • Current • Voltage • Resistance

  5. Ohm’s Law • Ohm’s Law • Resistance is equal to the voltage divided by the current Resistance = Voltage ÷ Current Ω = V ÷ A

  6. Ohm’s Law • Different ways to figure this out… • Remember: • Resistance = Ohms (Ω) • Voltage = Volts (V) • Current = Amps (A) Resistance = Voltage ÷ Current (or) Ω=V÷A Current = Voltage ÷ Resistance (or) A=V÷Ω Voltage = Current ∙ Resistance (or) V=A∙Ω

  7. Example of each… • Circuit has a resistance of 30 ohms and a current of .06 amps. How many Volts are there? • Voltage = Current ∙ Resistance (or) V=A∙Ω • V= A (Ω) • V= .06 (30) • V= 1.8 • 1.8 volts

  8. Example of each… • In a circuit there is a 0.5 Amp current in the bulb. The voltage across the bulb is 4 volts. What is the bulb’s resistance? • Resistance = Voltage ÷ Current (or) Ω=V÷A • Ω = V ÷ A • Ω= 4 ÷ 0.5 • Ω= 8 • 8 ohms

  9. Example of each… • A waffle iron is running on a voltage of 120 and the resistance is 10 ohms. What is the current? • Current = Voltage ÷ Resistance (or) A=V÷Ω • A= V ÷ Ω • A= 120 ÷ 10 • A= 12 • 12 amps

  10. Features of a Circuit • Three Features • Circuits have devices that are run by electrical energy. • A circuit has a source of electrical energy. • Electric circuits are connected by conducting wires.

  11. Diagramming a Circuit

  12. Series Circuit • In a series circuit, there is only one path for the current to take.

  13. Series Circuit • Disadvantage • Break in the circuit from a burned out bulb! • Light bulbs are dim as opposed to just one alone. • Each bulb is a resistor!

  14. Parallel Circuit • In a parallel circuit, there are several paths for a current to take.

  15. Parallel Circuit • Interesting fact… • When you add a branch to a parallel circuit the overall resistance decreases. • But if a resistance decreases, the current increases.

  16. What will happen? • Questions about the diagram below…

  17. So far… • Formula for resistance: • 1) A=V÷Ω • 2) V=A∙Ω • 3) Ω=V÷A • Resistance = Voltage ÷ Current (or) Ω=V÷A

  18. So far… • Formula for current: • 1) A=V÷Ω • 2) V=A∙Ω • 3) Ω=V÷A • Current = Voltage ÷ Resistance (or) A=V÷Ω

  19. So far… • Formula for voltage: • 1) A=V÷Ω • 2) V=A∙Ω • 3) Ω=V÷A • Voltage = Current ∙ Resistance (or) V=A∙Ω

  20. So far… • What kind of circuit is this? 1) Parallel 2) Magnetic 3) Series

  21. So far… • What kind of circuit is this? 1) Parallel 2) Magnetic 3) Series

  22. Electric Power • Power • The rate at which energy is transformed from one form to another. • Unit of power is the “watt” (W).

  23. Calculating Power • Power = watts (W) • Voltage = volts (V) • Current = amps (I) • … The letter “i”? • I = “Intensity” of the Current Power = Voltage x Current W=V∙I

  24. Example… • A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb? • Power = Voltage x Current • Power = 120 x 0.5 • Power = 60 • 60 watts or 60W

  25. Review… • What is Ohm’s Law? • 1) Resistance is equal to the voltage divided by the current. • 2) An Ohm cannot be created nor destroyed. • 3) A current seeks the path of least resistance

  26. Review… • What are the basic features of an electric circuit? • 1) Run by electrical energy, has an electrical source, and connected by insulating wires. • 2) Run by electrical energy, has an electrical source, and connected by conducting wires. • 3) Resistance = Ohms (Ω); Voltage = Volts (V); Current = Amps (A)

  27. Review… • How many paths can currents take in series and parallel circuits? • 1) Series provides several paths while parallel is one continuous circuit. • 2) Parallel and series are one continuous circuit. • 3) Series is one continuous circuit while a parallel provides several paths.

  28. Review… • How do you calculate electric power and the energy used by an appliance? • 1) Power = Voltage ÷ Current • 2) Power = Voltage x Current • 3) Power = Current × Resistance

More Related