1 / 27

Unit 8

Unit 8. SERIES-PARALLEL CIRCUITS. In the last two units we discussed loads connected in series and in parallel. In this unit we will learn how to deal with series and parallel loads in the same circuit. Voltage in a combination circuit. Kirchhoff's law of voltage is still true.

loe
Download Presentation

Unit 8

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. Unit 8

  2. SERIES-PARALLEL CIRCUITS

  3. In the last two units we discussed loads connected in series and in parallel.

  4. In this unit we will learn how to deal with series and parallel loads in the same circuit.

  5. Voltage in a combination circuit. • Kirchhoff's law of voltage is still true. • However the voltage across any parallel branch must be considered as only one voltage drop. • Et= E1+E2+E3....

  6. In this example how many voltage drops are there?

  7. Current in a combination circuit. • Kirchhoff's law of current is still true. • All the current that goes into a node comes out.

  8. Total current will flow into R1 and then at point B the current splits some will go through branch 1 and the rest will go through branch 2. • The two branch currents will come back together a point C.

  9. Before solving for any individual voltage drops or currentwe must know the total resistance, total voltage and the total current.

  10. We will use two formulas to help us find total resistance .

  11. Steps to analyze a complex combination circuit

  12. Determine which resistances are in series and which are in parallel

  13. Start with the parallel circuit the most distant from the power source • Calculate the equivalent resistance (Rq = ) • equivalent resistance is the total resistance of a bank of parallel resistances

  14. Redraw circuit into a simple series circuit using Rq instead of the bank parallel resistances

  15. Combination circuit redrawn to a series circuit

  16. Now that all resistances are in series use this formula to find the total resistance • Rt = R1+ Rq.… • Rt = 100 + 50 • Rt = 150

  17. Now that we know Rt and Et (which is usually a given) we can calculate It by using Ohm’s law • It=Et / Rt • It = 12 / 150 • It = .08 A • It = 80 mA

  18. When all totals for E,I and R are known we can calculate the individual voltage drops and use the voltage drops to help calculate the current at the individual resistances

  19. Look back at the redrawn series circuit • How many voltage drops do we have ? • Two is correct.

  20. The current flowing through R1 and the resistance of R1 can be used to calculate the voltage at R1

  21. Now that the voltage and resistance are known for each resistance we can use Ohm’s Law to calculate the current at the remaining resistances

  22. The end

More Related