Essay About Circuit Element And Voltage Sources

Electrical Circuits
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Light propagation is simply described by a ray which indicates a path of light energy.Voltage is the enery per unit charge created by charge seperation.v=dw/dq  —->  v= The voltages in volt (V)                               w= The energy in joules (J)                               q= The charge in coulombs(C)Current is the rate of charge flow.i= dq/dt —-> i= The current in amperes (A)                          q= The charge in coulombs (C )                           t= The time in seconds (s)Power is the energy per unit of time.p= dw/dt —-> p= The power in watts (W)                             w= The energy in joules (J)                              t= The energy in Time (s)p=dw/dt=(dw/dq)(dq/dt)=vi  —-> p= The power in watts (W)                                                                      w=The energy in joules (J)                                                                       t=Time in seconds (s)p>0 —> means that the power is being absorbed or dissipated by circuit element.p<0 ---> means that the power is being generated or delievered by the circuit element.When the current is flowing the directionof voltage drop, i.e, from + to –  —>p=vi.Substitute the value for the voltage and current in the power equation. If p>o  —>absorbed or dissipated. If p<0 ---> delivered or generated.A circuit schematic is a diagram representing a set of interconnected circuit elements: voltage sources, current sources, and resistors.Each element in the schematic is modeled and presented by a symbol.Lines connecting the symbols in the schematic can be considered as wires with zero resistance.An Ideal basic circuit element is a two terminal componet that can not be subdidvided and is described mathematically in terms of its voltage and current.Passive sign convention: whenever the reference direction of the current is in the direction of the voltage drop across its terminals, use a positive sign in any expression relating voltage to the current. Otherwise, use a negative sign.There are 5 idea basic circuit elements: Voltage sourceCurrent sourceResistorCapacitorInductor(Vs)(+,-): Ideal independent voltage source(Is)(->): Ideal independent current source(Vs=uVx)(+,-): Ideal dependent voltage-controlled voltage source(Vs=pIx)(+,-): Ideal dependent current-controlled voltage source(Is=aVx)(->): Ideal dependent voltage-controlled current source(Is=bIx)(->): Ideal dependent current-controlled current source*(u,p,a,b all stand for greek symbols)The R-L Circuit An electrical circuit whose total resistance is R ohms and whose self-inductance, shown schematically as a coil, is L henries ( hence the name ” R-L circuit”).  There is also a switch whose terminals at a and b can be closed to connect to a constant electrical source of V volts.