1. “Introduction to Circuits”
Unit 10 Part 1:
“Introduction to Circuits”
Go over Unit 10 Rubric!

2. Using the materials provided to your group…
“Light The Bulb”
Using the materials provided to your group…
See if you can make the light bulb light in 4 different ways.
You have 5 minutes!!!
MIT graduates attempt...

3. CIRCUIT CHALLENGE
MIT graduates attempt...

4. Current vs. Static Electricity
In current electricity, electrons are continuously moving; different from static
Because the charges are flowing (moving), they have the ability to do work

5. Electron Flow through a Lightbulb

6. Electrons flow in a circular path from positive to negative
Electric current in a circuit +
Electrons flow in a circular path from positive to negative

7. Basic Parts of a Circuit
Source of electric energy (battery or wall outlet)
Wires
Device that uses the energy (light bulb, etc.)

8. Circuit Symbols Resistor Battery Voltmeter Light bulb Wire Ammeter
Any object that uses the energy
Voltmeter
Measures voltage between 2 points, placed in parallel, very high resistance
Ammeter
Measures current, placed in series, very low resistance
Battery
Energy source
Light bulb
Wire
A conductor that provides a path for the electrons to travel along
Switch
Controls whether the circuit is open or closed V1 A1

9. In order for electricity to move through a circuit it must be closed
Open or Closed?
In order for electricity to move through a circuit it must be closed
If a circuit is open then the electricity cannot flow
Switches are objects that are used to determine whether a circuit will be closed or opened
open

10. “Describes the relationship between Voltage, Current & Resistance”
Ohm's Law
“Describes the relationship between Voltage, Current & Resistance”
Current (Amps)
Voltage (Volts) V I R = x
Resistance (Ohms or Ω)
“For a given resistance, the voltage is proportional to the current flow.”

11. Voltage (V)
Def : the energy each electron has to move it through a circuit to do work
Unit: Volts (V)
Symbol: V

12. Voltage If
= 1.5 volts
6 V ?V
3.0V

13. Current (I)
Def : the number of electrons passing a point per second in a circuit; “Rate of flow”
Unit: Amperes (amp)
Symbol: I
It is measured using an ammeter A

14. Resistance is the opposition to the flow of charge
Symbol: (R)
Unit: ohm (Ω) Measured by an ohmmeter Ω

15. “Describes the relationship between Voltage, Current & Resistance”
Ohm's Law
“Describes the relationship between Voltage, Current & Resistance”
Current (Amps)
Voltage (Volts) V I R = x
Resistance (Ohms or Ω)
“For a given resistance, the voltage is proportional to the current flow.”

16. Questions: Sample problems:
A fluorescent light draws 0.25 amps of current when connected to a 120 V source. What is the resistance of the light?
What voltage is needed to cause a current of 50 amps through a resistance of 20 ohms?
What happens if we have two or more light bulbs connected?

17. Mini-Project: Due Before Final
Students in Mr. Penmoon class just happened to be nominated to work with the Lord of the Ring team for the up coming season in ‘’the land of the lord of the ring” where there is no electricity.
Our task is to use our knowledge to help them harvest the energy from the sun. “Concept of Photoelectric Effect”
We need to come up with the plan. We need to know how much energy is needed daily for work. And what type of circuit (series or parallel) to implement for the most efficient.

19. R Current (Amps) Voltage (Volts) Resistance (Ohms or Ω) Ohm's Law I V
Current (Amps)
Voltage (Volts)
Resistance (Ohms or Ω) I V R = /

20. What is the voltage of this battery?