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Electronics ReferencesOhm's and Joule's LawsNOTE: the symbol "V" is sometimes used to represent voltage instead of "E". In some cases, an author or circuit designer may choose to exclusively use "V" for voltage, never using the symbol "E." Other times the two symbols are used interchangeably, or "E" is used to represent voltage from a power source while "V" is used to represent voltage across a load (voltage "drop"). Kirchhoff's Laws"The algebraic sum of all voltages in a loop must equal zero." Kirchhoff's Voltage Law (KVL) "The algebraic sum of all currents entering and exiting a node must equal zero." Kirchhoff's Current Law (KCL) Series circuit rules* Components in a series circuit share the same current. I_{total} = I_{1} = I_{2} = . . . I_{n} * Total resistance in a series circuit is equal to the sum of the individual resistances, making it greater than any of the individual resistances. R_{total} = R_{1} + R_{2} + . . . R_{n} * Total voltage in a series circuit is equal to the sum of the individual voltage drops. E_{total} = E_{1} + E_{2} + . . . E_{n} Parallel circuit rules* Components in a parallel circuit share the same voltage. E_{total} = E_{1} = E_{2} = . . . E_{n} * Total resistance in a parallel circuit is less than any of the individual resistances. R_{total} = 1 / (1/R_{1} + 1/R_{2} + . . . 1/R_{n}) * Total current in a parallel circuit is equal to the sum of the individual branch currents. I_{total} = I_{1} + I_{2} + . . . I_{n} Series and parallel component equivalent valuesSeries and parallel resistancesSeries and parallel inductancesSeries and Parallel CapacitancesCapacitor sizing equationInductor sizing equationTime constant equationsValue of time constant in series RC and RL circuitsTime constant in seconds = RC Time constant in seconds = L/R Calculating voltage or current at specified timeCalculating time at specified voltage or currentAC circuit equationsInductive reactanceCapacitive reactanceImpedance in relation to R and XZL = R + jXL ZC = R  jXC Ohm's Law for ACSeries and Parallel ImpedancesNOTE: All impedances must be calculated in complex number form for these equations to work. ResonanceNOTE: This equation applies to a nonresistive LC circuit. In circuits containing resistance as well as inductance and capacitance, this equation applies only to series configurations and to parallel configurations where R is very small. AC powerDecibels 