E. Definitions
A couple of definitions of terms. It might come in handy, but personally, I believe the formulas in the next appendix are more useful.
Ampere (A): Is the SI unit for current I. It is defined in terms of the charge of an electron via 1 C = 1 A·s.
Capacitor: An electronic component that stores energy in the form of an electric field. It resists a sudden change in voltage.
Conductance (S): The inverse of resistance. Measured in siemens, which are the inverse of ohms, 1 S = 1/Ω.
Coulomb (C): The elementary charge e of the electron is defined to be -1.602 176 634 × 10^−19 Coulomb.
Current (I): The movement of charge carriers, usually electrons, in an electric field. It is measured in amperes.
Henry (H): The SI unit for inductance.
Impedance (Ω): A more generalized form of resistance, also valid for AC type current. The impedance of a device can vary with the frequency of the electricity applied. A perfect resistor will have a constant impedance for all frequencies. Capacitors and inductors have varying impedances at different frequencies. It is measured in ohms.
Inductor: An inductor is a device that stores energy in a magnetic field. It opposes a sudden change in the flow of current.
Joule (J): The work required to exert a force of one newton (1 N) for one meter (1 m), 1 J = 1 N·m.
Ohm (Ω): A measure of resistance or impedance, 1 Ω = 1 V/A.
Power (P): Voltage times current, measured in watts. The amount of work being done per unit time.
Resistance (Ω): Properties of a circuit that impede the flow of electrons. Resistance converts electrical energy into phonons that are given off as waste heat. Resistance is measured in ohms.
Volt (V): A potential due to an electric field. One volt is defined as one joule of work per one coulomb of charge, 1 V = 1 J/C.
Voltage: Is the difference in electric potential between two points in an electric field. It is measured in volts.
Watt (W): A measure of power (P). A watt is a joule (1 J) of work done in a second (1 s). 1 W = 1 J/s
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