* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Electricity Theory
Survey
Document related concepts
Chemical potential wikipedia , lookup
Alternating current wikipedia , lookup
Electrochemistry wikipedia , lookup
Electrical resistivity and conductivity wikipedia , lookup
Electric charge wikipedia , lookup
General Electric wikipedia , lookup
History of electrochemistry wikipedia , lookup
Potential energy wikipedia , lookup
Electric current wikipedia , lookup
Electrical resistance and conductance wikipedia , lookup
Static electricity wikipedia , lookup
Electrostatics wikipedia , lookup
Transcript
Electricity Theory VIR PIV and Capacitors!!! PEg Energy When an object is at some height in a gravitational field it is said to have gravitational potential energy, PEg Energy Like gravitational fields causing masses to have potential energy, Electric Fields cause charges to have electric potential energy, PEE PEE is a type of mechanical energy MEtotal = KE + PEg + PEs + PEE Energy To give something PE you must do work (apply force over a distance) on the something (raising up in g-field) For PEE to occur a FE must be applied by either a. An E-Field (uniform) b. A pair of charges Energy Uniform E-field W PE Fd F Eq PEE qEd B A Line Color Red: E-Field Black: Equipotential lines Blue: charge displacement Energy Pair of Charges W PE Fd q1q2 F kc 2 r q1q2 PEE kc r Electric Potential PEE V q Any point in an electric field is said to have Electric Potential, V. However, only a Difference V PE in PE is measurable q (remember zero point) so we talk of electric potential unit Volt, V difference AKA potential J difference, ΔV. 1V=1 C Potential Difference Potential Difference Potential Difference Back to the zero point A convenient zero point to chose in a circuit or any electric system is the “ground” Battery (cells) A battery produces electricity by transforming chemical energy into electrical energy Battery Carbon Electrode Sulfuric Acid + Zinc Electrode Capacitor A capacitor is a storehouse of charge and energy that can be reclaimed when needed for a specific application A capacitor will only charge to the potential difference between the terminals of the battery Capacitance Capacitance, C: The ability of a conductor to store energy in the form of electrically separated charges Capacitance is the ratio of charge to potential difference Q C V unit Farad, F C 1F=1 V Capacitance Capacitance depends on size and shape A C 0 d 0 permittivity of free space, 8.85x10 A Area of one plate d distance between plates 2 -12 C 2 Nm Capacitor Energy stored in a capacitor 1 1 2 U energy QV CV 2 2 Electric Current Movement of electric charge Rate of charge movement Q I t unit Ampere, A C 1A=1 s Charge Movement Charge Movement Circuit Analogy Types of Current AC Alternating current charges continuously change direction forward and back at 60 Hz Example: outlets (approx 120 V) DC Direct current charges move in one direction Example: batteries AC-DC Debate births the Electric Chair Resistance Resistance is the impedance of the motion of charge through a conductor The ratio of potential difference across a conductor to the current it carries V R I unit ohm, V Js 1 1 1 2 A C Ohm’s Law V IR Resistance Depends on: Length, cross sectional area, material, and temperature L R A resistivity, m L length, m A cross sectional area, m2 Resistance and Temp Resistance and Thickness Resistor An electronic element that provides a specified resistance. A current or voltage REGULATOR Power (it’s Electric!) Power: Rate at which work is done. OR Rate at which energy is transformed Electric Power: The rate at which charge carriers convert PEE into non-mechanical energy P IV unit watt, W J 1W=1 s Reading and Homework Read Chapter 17 pp 593 - 625 HW due on test day: p 599 1-3; p 601 2, 3, 5-9; p 607 1 – 4 (B); p609 1 – 5 p 615 1 – 6; p 616 2-4, 7,9 p 621 1 – 5 Extra Practice p 626 – 628 11, 20 – 54