How Things Work - How Everything Works

Electric Power Distribution Question: Electric power reaches the University via high voltage transmission lines. What fraction of the electric charges traveling on those transmission lines pass through this room? 1. About 1% 2. About 0.01%

3. Exactly 0.0% Observations About Power Distr.

Household power is AC (alternating current) Power comes in voltages like 120V & 240V Power is transmitted at high voltage Power transformers are visible everywhere Power substations are visible on occasion Ohms Law The currents passing through most wires and other devices experience voltage drops

In an ohmic device, the voltage drop is proportional the current: voltage drop = resistance current where resistance is constant for the device Power in Ohmic Devices A calculation: power consumption = voltage drop current voltage drop = resistance current

power consumption = resistance current2 Impact of the calculation: Wires waste power as heat Doubling current quadruples wasted power Power Transmission Power delivered to a city is: power delivered = current voltage drop

Power wasted in transmission wires is: power wasted = resistance current2 For efficient power transmission: Use low-resistance wires (thick, short copper) Use low current and high voltage drop Voltage Hierarchy High voltage is dangerous High current is wasteful

Use the following hierarchy: low voltage circuits in neighborhoods medium voltage circuits in cities high voltage circuits across the countryside Use transformers to transfer power Transformer Alternating current in

one circuit induces an alternating current in a second circuit Transfers power between the two circuits Doesnt transfer charge between the two circuits Current and Voltage

Power arriving in the primary circuit must equal power leaving the secondary circuit Power is the product of voltage current A transformer can change the voltage and current while keeping power unchanged! Step Down Transformer Fewer turns in secondary circuit so

charge is pushed a shorter distance Smaller voltage rise A larger current at low voltage flows in the secondary circuit Step Up Transformer More turns in

secondary circuit so charge is pushed a longer distance Larger voltage rise A smaller current at high voltage flows in the secondary circuit Question:

Electric power reaches the University via high voltage transmission lines. What fraction of the electric charges traveling on those transmission lines pass through this room? 1. About 1% 2. About 0.01% 3. Exactly 0.0%

Recently Viewed Presentations

  • Early Years Quality Improvement December 2007 1 Contents

    Early Years Quality Improvement December 2007 1 Contents

    Early Years Quality Improvement December 2007 1 parents do not have a strong enough voice in the market or value quality as an important part of choosing early learning for their child the quality of early learning is not a...
  • Exact Recovery of Low-Rank Plus Compressed Sparse Matrices

    Exact Recovery of Low-Rank Plus Compressed Sparse Matrices

    Context. Network cartography. Image processing. Among competing hypotheses, pick one which makes the fewest assumptions and thereby offers the simplest explanation of the effect.
  • Communication following an Acquired Brain Injury

    Communication following an Acquired Brain Injury

    Spiky profile. Variability in skills over time. Comprehension very dependent on levels of fatigue and attention. Word finding difficulties. Rigidity of concept formation. Difficulty learning time concepts. Difficulties with abstract language. Conversation initiation. Disinhibition when speaking
  • EMERGENCY MANAGEMENT IN ONTARIO A pause to look

    EMERGENCY MANAGEMENT IN ONTARIO A pause to look

    EMERGENCY MANAGEMENT IN ONTARIO. A pause to look back, look sideways, and look forward. Alain Normand, 2019
  • JEOPARDY! Click Once to Begin Template by Bill

    JEOPARDY! Click Once to Begin Template by Bill

    Bill Arcuri, WCSD Chad Vance, CCISD. Click Once to Begin. JEOPARDY! To change the question and answer slides, select the question or answer text box and type in your own questions and answers. To play, click on a question on...
  • MF Program Evaluation EEC

    MF Program Evaluation EEC

    MF CAM = 5+ attached dwellings where the deed restricted property qualifies for CAM measures though the CAM Program . MF = 5+ attached dwellings where the site does not want, does not qualify for or does not have a...
  • 1979- 2019 - idahoassocbilingualed.com

    1979- 2019 - idahoassocbilingualed.com

    assessment oflearning is generally equated with: high-stakes tests administered on an annual basis that are tied to state accountability. paper or on-line tests given on an interim basis that are tied to district accountability. end-of-chapter tests for packaged curriculum that...
  • Buddhism  2nd Indian Religion  Buddhism  founded by Buddha

    Buddhism 2nd Indian Religion Buddhism founded by Buddha

    10 Realms - Buddha at the top - goes all the way down to the depraved souls (kind of hell) ... Buddhism for a time becomes persecuted in India because of that. Exchange of Ideas. Ideas/knowledge of different beliefs and...