Unit 2 Electrical Quantities and Ohms LawObjectives:Define a coulomb.Define an ampere.Define a volt.Define an ohm.Define a watt.

Unit 2 Electrical Quantities and Ohms LawObjectives:Compute electrical values using Ohms law.Discuss basic types of circuits.Use the Ohms wheel charts.

Unit 2 Electrical Quantities and Ohms LawA coulomb is a quantity measurement for electrons. One coulomb contains 6.25 x 1018 electrons, or 6,250,000,000,000,000,000 electrons.

Unit 2 Electrical Quantities and Ohms LawThe ampere is a measurement of the amount of electricity that is flowing through a circuit.One ampere (A) is defined as one coulomb of electricity flowing past a given point in one second.

Unit 2 Electrical Quantities and Ohms LawCompare and contrast these two systems.

Unit 2 Electrical Quantities and Ohms LawThere are two theories about current flow. Electron flow theory describes current flow from negative to positive. Conventional current flow theory states electrical current flows from positive to negative.

Unit 2 Electrical Quantities and Ohms LawConventional current flow theory and electron flow theory.

Unit 2 Electrical Quantities and Ohms LawElectrons moving from atom to atom.

Unit 2 Electrical Quantities and Ohms LawElectrical sources are divided into two basic types:Direct Current (DC) which is unidirectional (one way). Alternating Current (AC) which is bidirectional (two way, or back and forth).

Unit 2 Electrical Quantities and Ohms LawA complete path must exist before electricity can flow through a circuit. A circuit with a complete path for electrical flow is called a closed circuit. If the circuit path is incomplete or broken, this is called an open circuit.

Unit 2 Electrical Quantities and Ohms LawA simple switch closes and opens an electrical circuit.

Unit 2 Electrical Quantities and Ohms LawA short circuit has an unintended shorter pathway.

Unit 2 Electrical Quantities and Ohms LawThe basic principle of the instantaneous effect of electric impulses.

Unit 2 Electrical Quantities and Ohms Law The impulse of electricity can travel faster than light. It would take light 1.3 seconds to travel around the earth 10 times. If a wire were wrapped around the earth 10 times, when the switch was closed the light would come on almost instantly.

Unit 2 Electrical Quantities and Ohms LawA volt or voltage is electrical pressure.

Unit 2 Electrical Quantities and Ohms LawAn ohm is the unit of resistance or opposition to the flow of electricity.

Unit 2 Electrical Quantities and Ohms LawThe watt is the unit of electrical power.

Unit 2 Electrical Quantities and Ohms LawForce equals flow rate times pressure.

Unit 2 Electrical Quantities and Ohms LawAmperes times volts equals watts.

Unit 2 Electrical Quantities and Ohms LawCommon power units.

Unit 2 Electrical Quantities and Ohms LawOhms law states that in a DC (Direct Current) circuit, the current is directly proportional to the voltage and inversely proportional to the resistance.E(volts) = I(amps) x R(ohms)

Unit 2 Electrical Quantities and Ohms LawOhms Law Symbols:P is the symbol for Watts.E is the symbol for Volts.I is the symbol for Amperes.R is the symbol for Resistance or Ohms.

Unit 2 Electrical Quantities and Ohms LawOhms Law states that it takes one volt to push one ampere through one ohm.E = VoltsI = Amps

E = I x RR = Resistance

Unit 2 Electrical Quantities and Ohms LawUsing the Ohms law chart.

E = I x RI = E / RR = E / I

Unit 2 Electrical Quantities and Ohms LawAdding P (watts) to the Ohms law chart.

P = E2 / RP = E x IP = I2 x RR = E / IR = P / I2R = E2 / PI =I = P / EI = E / RE = E = I x RE = P / I

Unit 2 Electrical Quantities and Ohms LawRemember:E = EMF, or voltageI = intensity of current, or amperageR = resistance in ohmsP = power in wattsE(volts) = I(amperes) x R(ohms)P(watts) = I(amperes) x E(volts)

Unit 2 Electrical Quantities and Ohms Law

Unit 2 Electrical Quantities and Ohms LawMetric Units

Unit 2 Electrical Quantities and Ohms LawReview:A coulomb is a quantity measurement of electrons.An ampere (A) is one coulomb per second.Either the letter I, which stands for intensity of current flow, or the letter A, which stands for amperes, can be used in Ohms law formulas.

Unit 2 Electrical Quantities and Ohms LawReview:Voltage is referred to as electric pressure, potential difference, or electromotive force. An E or a V can be used to represent voltage in Ohms law formulas.An ohm () is a measurement of resistance (R) in an electric circuit.

Unit 2 Electrical Quantities and Ohms LawReview:The watt (W) is a measurement of power in an electrical circuit. It is represented by either a W or a P (power) in Ohms law formulas.Electric measurements are generally expressed in engineering notation.

Unit 2 Electrical Quantities and Ohms LawReview:Engineering notation differs from the standard metric system in that it uses steps of 1000 instead of steps of 10.Before current can flow, there must be a complete circuit. A short circuit has little or no resistance.