Current and Resistance Lecture Notes

This flashcard set covers key concepts, definitions, and relationships in the study of electric current, resistance, circuit diagrams, and components such as capacitors and resistors.

Simple Circuit

A basic electric circuit consisting of a power source, such as a battery, connected to electrical components like light bulbs.

Circuit Diagram

A graphical representation of an electrical circuit, showing the components and their connections, using standardized symbols.

Direction of Current

Current conventionally flows from the positive terminal to the negative terminal of a battery.

Current (I)

The flow of electric charge in a circuit, quantified as charge per unit time (ΔQ/Δt). The unit is Ampere (A).

Ohm’s Law

A fundamental relationship in electrical circuits where the current (I) is equal to the voltage (V) divided by the resistance (R); expressed as I = V/R.

Resistance (R)

A measure of the opposition to the flow of current in a circuit, dependent on the material and dimensions of the conductor.

Resistors

Circuit components designed to provide a specific resistance, used to control current flow.

Equivalent Resistance in Series

The total resistance of resistors connected in series is the sum of their individual resistances: Reqs = R1 + R2 + R3 + …

Equivalent Resistance in Parallel

The total resistance of resistors connected in parallel, where voltage across each resistor is equal, is given by: 1/Reqp = 1/R1 + 1/R2 + 1/R3 + …

Power (P)

The rate at which energy is transferred or converted; in electric circuits, it can be calculated by P = IV, where I is current and V is voltage.

Kirchhoff’s Loop Rules

Principles for analyzing complex circuits which include the junction rule (current conservation) and loop rule (voltage conservation).

Capacitors in Parallel

Capacitors connected in a way that each one is directly connected across the same voltage, allowing for the total capacitance to be summed: Ceqp = C1 + C2 + C3.

Capacitors in Series

Capacitors arranged such that they share charge, leading to a total voltage that is the sum of the voltages across each capacitor.

Charging of a Capacitor

When a capacitor is connected to a battery, it charges up to a voltage proportional to both the battery voltage and its capacitance.

Discharging of a Capacitor

The process where a capacitor releases its stored charge, typically through a resistor, causing the current to flow until the charge is depleted.