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Pengukuran ListrikModul I Besaran Listrik

VoltageCurrentResistancePowerInductanceCapacitanceImpedancePower factor

Electrical Quantity

VoltageVoltage, otherwise known as electrical potential difference or electric tension (denoted V and measured in units of electric potential: volts, or joules per coulomb), is the electric potential difference between two points or the difference in electric potential energy of a unit test charge transported between two pointsThe volt (symbol: V) is the SI derived unit for electric potential (voltage), electric potential difference, and electromotive force.

VoltageThe volt is named in honor of the Italian physicist Alessandro Volta (17451827), who invented the voltaic pile, possibly the first chemical batteryA single volt is defined as the difference in electric potential across a wire when an electric current of one ampere dissipates one watt of power.

Voltage Hydraulic AnalogyA simple analogy for an electric circuit is water flowing in a closed circuit of pipework, driven by a mechanical pump. This can be called a water circuit. Potential difference between two points corresponds to the water pressure difference between two points. If there is a water pressure difference between two points (due to the pump), then water flowing from the first point to the second will be able to do work, such as driving a turbine. In a similar way, work can be done by the electric current driven by the potential difference due to an electric battery: for example, the current generated by an automobile battery can drive the starter motor in an automobile. If the pump isn't working, it produces no pressure difference, and the turbine will not rotate. Equally, if the automobile's battery is flat, then it will not turn the starter motor.

AC VoltageIn alternating current (AC, also ac), the flow of electric charge periodically reverses direction.

Mathematic of AC VoltageAn AC voltage v can be described mathematically as a function of time by the following equation:

where:Vpeak = the peak voltage (unit: volt), = the angular frequency (unit: radians per second) t = the time (unit: second).The peak-to-peak value of an AC voltage is defined as the difference between its positive peak and its negative peak. The peak-to-peak voltage, usually written as Vpp or Vp-p = 2Vpeak

Mathematic of AC VoltageAC voltage is often expressed as a root mean square (RMS) value, written as VRMS. Root mean square also known as the quadratic mean, is a statistical measure of the magnitude of a varying quantity.

DC VoltageIn direct current (DC, also dc), the flow of electric charge is only in one direction.

Muatan elektrik ion bergerak berlawananMurni DC (Batre) tanpa rippleKalo pake rectifier = ada rippleMakin kecil ripple, makin bagus rectifier

CurrentAn electric current is a flow of electric charge through an electrical conductor. Electric charge flows when there is voltage present across a conductor.In electric circuits this charge is often carried by moving electrons in a wire.The SI unit for measuring an electric current is the ampere, which is the flow of electric charges through a surface at the rate of one coulomb per second. (I = Q/T)

CurrentThe conventional symbol for current is I, which originates from the French phrase intensit de courant, or in English current intensity. This phrase is frequently used when discussing the value of an electric current, but modern practice often shortens this to simply current.

The symbol was used by Andr-Marie Ampre, after whom the unit of electric current is named, in formulating the eponymous Ampre's force law which he discovered in 1820.

CurrentA flow of positive charges gives the same electric current, and has the same effect in a circuit, as an equal flow of negative charges in the opposite direction. Since current can be the flow of either positive or negative

charges, or both, a convention for the direction of current which is independent of the type of charge carriers is needed. The direction of conventional current is defined arbitrarily to be the direction of the flow of positive charges.

Current-Electromagnetism (Lorentz Law)Electric currents cause many effects, notably heating, but also induce magnetic fields, which are widely used for motors, inductors and generators.Electric current produces a magnetic field. The magnetic field can be visualized as a pattern of circular field lines surrounding the wire that persists as long as the current flows.

Magnetism can also produce electric currents. When a changing magnetic field is applied to a conductor, an EMF is produced, and when there is a suitable path, this causes current to flow.

ResistanceThe electrical resistance of an electrical conductor is the opposition to the passage of an electric current through that conductor; the inverse quantity is electrical conductance, the ease at which an electric current passes.Electrical resistance shares some conceptual parallels with the mechanical notion of friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S).

Resistance Hydraulic AnalogyThe current flowing through a wire is like water flowing through a pipe, and the voltage drop across the wire is like the pressure drop which pushes water through the pipe. Conductance is proportional to how much flow occurs for a given pressure, and resistance is proportional to how much pressure is required to achieve a given flow

Pipa = resistansi

Air makin naik, tekanan makin tinggi, hambatan tinggi.15

ResistanceAn object of uniform cross section has a resistance proportional to its resistivity and length and inversely proportional to its cross-sectional area. All materials show some resistance, except for superconductors, which have a resistance of zeroThe resistance (R) of an object is defined as the ratio of voltage across it (V) to current through it (I), while the conductance (G) is the inverse:I total = R1xR2 xV/ R1+R2R parallel < R terkecil

ResistanceFor a wide variety of materials and conditions, V and I are directly proportional to each other, and therefore R and G are constant (although they can depend on other factors like temperature or strain). This proportionality is called Ohm's law, and materials that satisfy it are called "Ohmic" materials.Objects such as wires that are designed to have low resistance so that they transfer current with the least loss of electrical energy are called conductors. Objects that are designed to have a specific resistance so that they can dissipate electrical energy or otherwise modify how a circuit behaves are called resistors.

ResistanceThe resistance R of a conductor of uniform cross section can be computed as:

The resistivity of metals typically increases as temperature is increased

Rho = Hambatan Jenis

Ohms LawOhm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance one arrives at the usual mathematical equation:

Electric PowerElectric power is the rate of doing work, measured in watts, and represented by the letter P. The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage) difference of V is:

where:Q is electric charge in coulombst is time in seconds I is electric current in amperesV is electric potential or voltage in volts

Electric PowerIn the case of resistive (Ohmic or linear) loads, Joule's law can be combined with Ohm's law (V = IR) to produce alternative expressions for the dissipated power:

where R is the electrical resistance in ohm

InductanceInductance is the property of a conductor by which a change in current in the conductor "induces" (creates) a voltage (electromotive force) in both the conductor itself (self-inductance) and in any nearby conductors (mutual inductance)A changing electric current through a circuit that has inductance induces a proportional voltage which opposes the change in current (self inductance). The varying field in this circuit may also induce an e.m.f. in a neighbouring circuit (mutual inductance)

InductanceThe term 'inductance' was coined by Oliver Heaviside in February 1886. It is customary to use the symbol L for inductance, in honour of the physicist Heinrich Lenz. In the SI system the unit of inductance is the henry, named in honor of the scientist who discovered inductance, Joseph Henry.The relationship between the self inductance L of an electrical circuit in henries, voltage, and current is:

where v denotes the voltage in volts and i the current in amperes

CapacitanceCapacitance is the ability of a body to store an electrical charge. A common form of energy storage device is a parallel-plate capacitor. In a parallel plate capacitor, capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the separation distance between the plates.

The SI unit of capacitance is the farad (symbol: F), named after the English physicist Michael Faraday

Capacitancea 1 farad capacitor when charged with 1 coulomb of electrical charge will have a potential difference of 1 volt between its plates

ImpedanceElectrical impedance is the measure of the opposition that a circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current (AC) circuit. Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. It is necessary to introduce the concept of impedance in AC circuits because there are other mechanisms impeding the flow of current besides the normal resistance of DC circuitsReaktansi dan Resistansi

ImpedanceThe impedance caused by these two effects is collectively referred to as reactance and forms the imaginary part of complex impedance whereas resistance forms the real partThe symbol for impedance is usually and it may be represented by writing its magnitude and phase in the form

Resistance vs. ReactanceResistance and reactance together determine the magnitude and phase of the impedance through the following relations:

Resistance is the real part of impedance

Reactance is the imaginary part of the impedance

Complex PowerEngineers use the following terms to describe energy flow in a system:Real power (P): watt [W]Reactive power (Q): volt-ampere reactive [var]Complex power (S): volt-ampere [VA]Apparent Power (|S|), the magnitude of complex power S: volt-ampere [VA]Phase (), the angle of difference (in degrees) between voltage and current

Complex PowerIn the diagram, P is the real power, Q is the reactive power (in this case positive), S is the complex power and the length of S is the apparent power.Real power moves energy, so it is the real axis.Reactive power does not transfer energy, so it is represented as the imaginary axis of the vector diagram. Since reactive power transfers no net energy to the load, it is sometimes called "wattless" power

Power FactorThe ratio between real power and apparent power in a circuit is called the power factor.For two systems transmitting the same amount of real power, the system with the lower power factor will have higher circulating currents due to energy that returns to the source from energy storage in the load. These higher currents produce higher losses and reduce overall transmission efficiency. A lower power factor circuit will have a higher apparent power and higher losses for the same amount of real power.

Power FactorThe power factor is unity (one) when the voltage and current are in phase.Where the waveforms are purely sinusoidal, the power factor is the cosine of the phase angle () between the current and voltage sinusoid waveforms.It often will abbreviate power factor as cos for this reason.Example: The real power is 700 W and the phase angle between voltage and current is 45.6. The power factor is cos(45.6) = 0.700. The apparent power is then: 700 W / cos(45.6) = 1000 VA