Summary
Electric current is created when a potential difference (an electric field) set up
between the ends of a piece of wire cause the electrons in the wire to drift
through the wire with a net movement of charge.Resistance differs from material to material. A conductive material offers less
resistance to the flow of electrons. Resistance is represented by the equation. If the current is large, the resistance is low; if the current is small,
resistance is high.
Electric circuits are paths along which electrical energy is released (as from a
battery or other source of electrical energy). Electrical energy can only be
released when the current has a complete conducting path available from one
side of the potential difference to the other.Power is the rate at which energy is released. Use the formula P = IV. This
equation is relevant for the power delivered by the battery to a circuit as well
as for resistors. Resistors dissipate energy as heat.Circuit analysis is a way to specify the current, voltage, and power associated
with each element in a circuit (batteries, resistors, and connecting wires).Combinations of resistors occur in a series (one after the other) or in parallel
(side-by-side).Resistance–Capacitance (RC) circuits are simple circuits for charging a
capacitor. An RC circuit consists of a battery which holds the potential energy
that will charge the capacitor, a switch that closes the circuit and allows the
current to flow, as well as a resistor that will use the energy to produce heat.