Tutorial 1 ( Electronics for CHP )

Electrical Fundamentals

Basic Concepts

Voltage (V): Defined as the electric potential energy per unit charge, measured in volts (V). It indicates how much work can be done per unit charge that moves between two points in an electric field. The formula for voltage is expressed as V = A (3/0), where A denotes amperes.

Current (I): The flow of electric charge in a circuit, represented by the formula I = Q/t, where Q is the electric charge and t is time. Current is measured in amperes (A) and is crucial for determining how much electrical energy is transported through a circuit.

Circuit Components

Sources of Voltage or Current:

• Voltage Sources: Such as batteries or power supplies that provide stable voltage.

• Current Sources: Deliver a constant current regardless of voltage fluctuations.

• Sources can be categorized into:

  • Independent Sources: Deliver constant voltage or current regardless of other circuit elements.

  • Dependent Sources: Their output is dependent on other voltages or currents in the circuit.

Elements in Circuits:

• Various components, including:

  • Resistors: Impede current flow, measured in ohms (Ω).

  • Capacitors: Store electrical energy, measured in farads (F).

  • Inductors: Store energy in a magnetic field, measured in henrys (H).

• Grounding is a critical concept that provides a reference point in a circuit, denoted where V = 0.

Ground and Circuit Types

Ground: Represents a zero voltage reference point in a circuit, essential for safety and accuracy in measurements.

Types of Current:

• DC (Direct Current): Current flows in one constant direction, typically found in batteries.

• AC (Alternating Current): The current periodically reverses direction, commonly used for power distribution in homes and industries.

Basic Electrical Components

Resistors:

• Components that resist the flow of current, calculated using Ohm's law.

• Types include: Fixed resistors, variable resistors (potentiometers, rheostats).

Capacitors:

• Used to store energy temporarily in an electric field, critical for filtering applications in power supplies.

• Types include ceramic, electrolytic, and tantalum capacitors.

Coils/Inductors:

• Components used to store energy in a magnetic field, fundamental in filtering applications and energy storage.

Circuit Analysis Fundamentals

Nodes:

• Points in a circuit where two or more circuit elements are connected.

Branches:

• Parts of the circuit between two nodes containing at least one circuit element.

Meshes:

• Closed loops in a circuit that do not encompass any other loops, essential for applying mesh analysis techniques.

Ohm's Law and Circuit Rules

Ohm's Law

• Fundamental principle: V = I * R.Where V = Voltage, I = Current, R = Resistance, establishing the relationship between these key parameters.

Voltage and Current Dividers

• Series Resistors: The voltage across components in series can be calculated using the voltage divider formula: U₁ = (R₁/(R₁ + R₂)) * V_total, where V_total is the total voltage supplied.

• Equivalent Resistance for series circuits: Req = R₁ + R₂

• Parallel Resistors: Utilize the current divider principle, calculated as: 1/Req = 1/R₁ + 1/R₂ + ... and total current: I_total = I₁ + I₂.

Example Calculations

Total Equivalent Resistance:

• For Series Resistors: Req = R₁ + R₂

• For Parallel Resistors: Req = 1/(1/R₁ + 1/R₂)

Solutions to Example Problems

Problem Example (a)

Given values: 45V,

1. Utilize current division principles to calculate:

• Is = 10A, indicating total current at the source.

Problem Example (b)

Conduct calculations for varying resistances:

• Req = 30Ω across parallel differing components and apply current division principles to find:

• Is = 6.67A.

Additional Circuits Examplified

Evaluate circuits with varied current inputs, e.g., a 20mA input across calculated resistances. Utilize this to determine potential division of current outputs across multiple branches, reflecting on real circuit behavior.