Unit 3: Direct Current (DC) Circuit Analysis

Direct Current (DC)

Electric charge flows in only one direction.

Kirchhoff's Rules

Fundamental conservation principles for analyzing complex circuits.

Junction Rule

The sum of currents entering a junction must equal the sum of currents leaving it.

Loop Rule

The algebraic sum of potential changes around a closed loop must be zero.

Equivalent Resistance

The total resistance of a network of resistors, allowing simplification of circuit analysis.

Resistors in Series

Components arranged in a single continuous path with the same current flowing through them.

Resistors in Parallel

Components arranged in different paths connecting the same two nodes, with the same voltage across them.

Power in Circuits

The rate at which electrical energy is converted into other forms.

Internal Resistance

The resistance within a battery that affects the voltage output.

Electromotive Force (EMF)

The ideal voltage generated by a battery.

Terminal Voltage (V_T)

The actual voltage measured across the battery terminals when current flows.

Ohm's Law

Relationship between voltage (V), current (I), and resistance (R), expressed as V=IR.

Conservation of Charge

Charge cannot be created or destroyed; it is conserved in circuits.

Conservation of Energy

Energy cannot be created or destroyed; it is conserved within circuits.

Voltage Drop

The reduction in voltage as electric current moves through a resistor.

Potential Change

The difference in electric potential energy per unit charge between two points.

Series Circuit

A circuit where resistors are connected in a single path, leading to a cumulative voltage drop.

Parallel Circuit

A circuit where resistors are connected across the same voltage source, allowing current to split.

Power Dissipation

The loss of electrical energy, typically as heat, in circuit components.

Total Current

The sum of the currents flowing through all the branches in a parallel circuit.

Negative Result in Current Calculation

Indicates that the assumed direction of current was incorrect.

Current Direction

The assumed flow of charge (positive to negative) in circuit analysis.

Resistance Formula (Series)

Req = R1 + R2 + R3 + … for resistors in series.

Resistance Formula (Parallel)

1/Req = 1/R1 + 1/R_2 + … for resistors in parallel.

Power Calculation (Current)

P = I^2 R, useful when current is constant in series.

Power Calculation (Voltage)

P = (Delta V)^2/R, useful when voltage is constant in parallel.