1. CALCULATING ELECTRICITY TODAY WE ARE GOING TO LOOK AT CURRENT VOLTAGE RESISTANCE

2. Ok lets begin Look at this video below lets see what we learn http://www.youtube.com/watch?v=KvVTh3ak 5dQ&feature=related

3. “Answer me this” From the video look at the following questions –C–Can you define current –C–Can you define voltage –C–Can you define resistance –W–What are the units of measurement of each

4. Current Current is the flowing of negative charges from one point to the other The symbol for current is I The unit of measurement of current is amperes(amps) Current is measured using an ammeter

5. Voltage The force or energy involved in pushing the charges around is referred to as E.M.F. Across electrical components there are energy differences called Potential difference or VOLTAGE The symbol for Voltage is V The unit of measurement is Volts(V) Voltage is measured using a voltmeter

6. Resistance Resistance is the opposing of the flowing of current The symbol of resistance is R The unit of measurement is Ohms(Ω) Resistance can be measured using a multimeter however R can be calculated

7. The Relationship between I, V & R Well some dude came up with this law that makes us calculate R Ohms law- the current flowing in a conductor maintained at a constant temperature is proportional to the potential difference(voltage) between its ends Well all that means is simply V= IR

8. “The triangle to remember”

9. Let’s practice Calculate the current flowing through a circuit is the voltage is 9 V and the resistance is 3 ohms.

10. Ok Good effort, here’s my answer What do I want to find –C–Current-I What do I have – V=9V & R=3Ω What do I know – V=IR Then I solve 9=I * 3 I= 9/3 I= 3 A

11. Let’s practice Calculate the voltage flowing through a bulb if the current passing through it is 15 A and the resistance of the bulb is 3Ω.

12. Ok Good effort, here’s my answer What do I want to find –V–Voltage-V What do I have – I=15A & R=3Ω What do I know – V=IR Then I solve V=15*3 V=45V

13. Let’s practice Calculate the resistance in a circuit if the voltage of the power supply is 4.5 V and the current flowing through is 1A

14. Ok Good effort, here’s my answer What do I want to find –R–Resistance-R What do I have – I=1A & V=4.5V What do I know – V=IR Then I solve 4.5=1*R R=4.5/1 R=4.5Ω

15. Why do we need this Understanding values helps know how much electricity is required to make something work It helps us to determine safety since can calculate the amount of electricity flowing through an electrical component so this would not happen to us http://www.youtube.com/watch?v=M4qzMbp y0ks http://www.youtube.com/watch?v=M4qzMbp y0ks

16. Current in parallel and series Series – Current flowing through components in series is the same through each component Voltage – Current flowing through a parallel circuit splits up and recombine at the connecting points

17. Voltage in series and parallel Series – The voltage across components in series is different because “potential difference” charges across each component Parallel – The voltage is the same across things in parallel

18. JUST FOR YOUR REVIEW http://www.youtube.com/watch?v=bnzmVAa 46xg&feature=fvwrel http://www.youtube.com/watch?v=bnzmVAa 46xg&feature=fvwrel http://www.youtube.com/watch?v=LOEiA9yA h6E&feature=related http://www.youtube.com/watch?v=LOEiA9yA h6E&feature=related