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Voltage Current and Power. Static Electricity – electrical energy at rest. Dynamic Electricity – Transfer of energy from a source to a Load. Alessandro Volta. 1799 he had developed the so-called voltaic pile, a forerunner of the electric battery,
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Voltage Current and Power Static Electricity – electrical energy at rest. Dynamic Electricity – Transfer of energy from a source to a Load.
Alessandro Volta 1799 he had developed the so-called voltaic pile, a forerunner of the electric battery, which produced a steady stream of electricity. In honor of his work in the field of electricity. The electrical unit known as the volt was named in his honor. Volt – Measurement of Electromotive Force (EMF) The Letter Symbol for Volt is E Example Voltages: Dry Cell = 1.5v Car Battery = 12v House Outlet = 120V
Andre Ampere He developed a quantitative relationship for the strength of a magnetic field in relation to an electric current (Ampere's theorem) and propounded a theory as to how iron becomes magnetized. Ampere also devised a rule governing the mutual interaction of current-carrying wires (Ampere's law) and produced a definition of the unit of measurement of current flow, now known as the ampere. The ampere is the unit for measuring electric current. Ampere (amp) – measure of the volume of electrons moving through a circuit. 1A = 6,280,000,000,000,000,000 electrons per sec Or 6.28 x 1018 electrons/sec The letter symbol for Amp = I
Requirements – Must have sufficient amount of both voltage and current to activate a load. Flash light battery vs. Car Battery Could you start a car with Flash light batteries?
Small and Large Voltage Amounts Giga (G) 1,000,000,000 = Thousand Million Mega (M) 1,000,000 = Million Kilo (K) 1,000 = Thousand Milli (m) .001 = Thousandths (1/1000) Micro (m) .000 001 = Millionths Nano (h) .000 000 001 = Billionths Pico (r) .000 000 000 001 = Trillionths
Direct Current – D.C. 9v Voltage always has the same fixed polarity.
120 v -120 v Sinusoidal A.C. Alternating Current – A.C. Has changing polarity (+ -) Produced by generators (power plant) or alternators (car) Frequency - #cycles / sec = 1Hz Cycle House current = 60 Hz Radio Am = KHz Fm = MHz Radar = GHz
AC – Used for Power Transmission - Motors - (induction) Electro Magnetism Solenoid – “pulling magnet”
AC is made when a magnetic field passes by a conductor (wire). This produces a current in the wire. A coil is usually used to intensify the effect.
Direct Current – used in most electronic equipment How Made: D.C. Generators – chemical cell (batteries)- Contain electrolytes – Chemical solutions that contain ions. Cells have a positive plate (Anode +) and a negative Plate (Cathode -) Electrons flow from: Cathode (-) to Anode + which makes current
Two or more cells in series form a battery. + + cell + + 1.5 v cell battery 4.5vbattery A cell that uses a liquid solution is a WET Cell A Cell where the electrolyte is absorbed into paper or changed into a paste is called a dry cell.
D.C. Thermo Electric Generator- If a junction of two dissimilar metals is heated, a small DC current will be produced. A Thermocouple works on this idea. (furnace/oven) control.
How Direct current is made from alternating current. Conversion from A.C. to D.C. ---> uses Diodes 1 Diode – Half-wave rectifier
4 Diode- Full wave Rectifier – uses 4 diode network rectifies both halves of A.C. Signal.
Using capacitors in a rectified signal tends to smooth out the ac bumps.