Physics: Energy, Electricity, and Semiconductor Fundamentals

Scientific Model

A simplified representation used to predict behavior.

Scientific Theory

A well-supported explanation of why phenomena occur.

Scientific Law

A rule describing consistent natural relationships.

Energy Conservation

Energy cannot be created or destroyed, only transformed.

Mechanical Energy

Sum of kinetic and potential energy.

Kinetic Energy (KE)

Energy of motion.

Potential Energy (PE)

Stored energy due to position or configuration.

Thermal Energy

Energy associated with random molecular motion (heat).

Entropy

Measure of energy spread/disorder.

Graveyard of Energy

Term for thermal energy because it's difficult to reconvert into useful work.

Perpetual Motion Machine

Impossible machine that violates energy or entropy laws.

Energy Transformation

Conversion of energy from one form to another.

Electric Charge

Amount of electrical matter (measured in Coulombs).

Voltage (V)

Energy per unit charge.

Current (I)

Rate of flow of electric charge.

Resistance (R)

Opposition to current flow.

Ohm's Law

Relationship between voltage, current, and resistance: V = IR.

Electric Power (P)

Rate of energy transfer: P = IV.

Series Circuit

Same current flows through all components.

Parallel Circuit

Same voltage across all branches.

Equivalent Resistance

Total resistance of a circuit.

Ohmic Device

Device with linear I-V relationship.

Non-Ohmic Device

Device with curved I-V relationship.

I-V Curve

Graph of current vs voltage.

Voltage Drop

Loss of voltage across a component.

Wire Resistance

Real wires reduce voltage and power delivered.

Conductor

Material where electrons move freely.

Insulator

Material where electrons are tightly bound.

Semiconductor

Material with controllable conductivity.

Valence Band

Energy band of bound electrons.

Conduction Band

Energy band where electrons conduct current.

Band Gap

Energy separation between valence and conduction bands.

Fermi Level

Energy level that predicts electron occupancy.

Doping

Adding impurities to control conductivity.

N-Type Semiconductor

Doped to add free electrons (donors).

P-Type Semiconductor

Doped to create holes (acceptors).

Majority Carrier

Most abundant charge carrier.

Minority Carrier

Less abundant charge carrier.

PN Junction

Interface between P-type and N-type semiconductor.

Depletion Region

Charge-free region at a PN junction.

Forward Bias

External voltage reduces barrier → current flows.

Reverse Bias

External voltage widens barrier → no current flows.

Diode

Device that allows current in only one direction.

Transistor

Device that controls a large current using a small one.

Amplification

Using a small input signal to control a large output signal.

Switching

Turning current ON or OFF electronically.

Logic Gate

Circuit that performs a logical operation.

AND Gate

Output = 1 only if both inputs = 1.

OR Gate

Output = 1 if at least one input = 1.

NOT Gate

Output is opposite of input.

NAND Gate

NOT of AND.

NOR Gate

NOT of OR.

XOR Gate

Output = 1 if inputs differ.

XNOR Gate

Output = 1 if inputs are equal.

Truth Table

Table showing all possible input-output combinations.

Half Adder

Adds two bits (sum + carry).

Full Adder

Adds two bits + carry-in.

SR Latch

Stores one bit of memory using feedback.

LED (Light Emitting Diode)

Emits light when electrons recombine.

Photovoltaic (PV) Cell

Converts light into electrical energy.

Photon

Particle of light energy.

Photoelectric Effect

Light ejects electrons from material.

Threshold Frequency

Minimum frequency needed to eject electrons.

Work Function

Minimum energy to remove an electron.

Light Intensity

Number of photons hitting a surface.

Open-Circuit Voltage

Maximum voltage available from a solar cell.

Photon Energy

Energy proportional to frequency.

Flowchart

Diagram showing logical steps in a program.

Decision Diamond

Flowchart block for yes/no logic.

Loop

Repeating logic structure.

setup()

Runs once when Arduino starts.

loop()

Runs continuously.

pinMode()

Sets a pin as input or output.

digitalWrite()

Sends HIGH or LOW signal.

digitalRead()

Reads HIGH or LOW.

analogRead()

Reads analog voltage (0-1023).

Voltage Divider

Converts resistance changes into voltage changes.

LDR (Light Dependent Resistor)

Resistance changes with light.

Ultrasonic Sensor

Measures distance using sound waves.

Time of Flight

Time for sound to return from an object.

delay(ms)

Pauses program for set time.

float

Variable type for decimal values.

Serial.println()

Sends data to serial monitor.

Magnetic Field

Region where magnetic forces act.

Ampere's Law

Current produces magnetic field.

Magnetic Flux

Amount of magnetic field passing through an area.

Faraday's Law

Changing magnetic flux induces voltage.

Lenz's Law

Induced current opposes the change that produced it.

Electromagnetic Induction

Voltages produced by changing magnetic fields.

Eddy Currents

Circular induced currents in conductors.

Generator

Converts mechanical energy into electrical energy.

Motor

Converts electrical energy into mechanical energy.

Speaker

Uses magnetic force to vibrate air.

Microphone

Converts sound vibrations into electrical signals.

Regenerative Braking

Uses a motor as a generator.

Alternating Current (AC)

Current reverses direction periodically.

Direct Current (DC)

Current flows in one direction only.

Transformer

Device that changes voltage using induction.

Primary Coil

Input side of transformer.

Secondary Coil

Output side of transformer.