1.4.1 BASIC ELECTRONIC CIRCUIT

Electronic Circuit is a complete path containing electronic components through which electric current can flow to perform a specific function.

A basic electronic circuit is an interconnection of individual components (such as resistors, transistors, capacitors, inductors, and diodes) connected by conductive wires or traces through which electric current can pass.

An electronic circuit is a closed path that allows electric current to flow from a power source, through various components, and back to the source. For current to flow, the circuit must be complete (closed) — any break in the path stops the flow.

For continuous current flow, a circuit must form a closed loop.

• Closed Circuit: An uninterrupted path that allows current to flow from the power source through the load and back to the source.
• Open Circuit: A break in the path (e.g., an open switch) that stops the flow of current.
• Short Circuit: An unintended low-resistance connection that bypasses the load, causing excessive current flow that can damage components or pose a safety hazard.

Basic requirements of a circuit:

1. Power source – provides the electrical energy (battery, power supply)
2. Conductors – wires that carry current between components (usually copper)
3. Load – a component that uses the electrical energy (bulb, resistor, motor)
4. Control device (optional) – a switch to open/close the circuit

Types of basic circuits:

• Series circuit – components connected end-to-end in a single path; current is the same everywhere, but voltage divides across components
• Parallel circuit – components connected across common points; voltage is the same across each branch, but current divides

1.4.2 Parts and Functions of a Circuit

Every functional electronic circuit consists of several essential components categorized by their primary role in controlling and directing electrical energy:

1. POWER SOURCE (ENERGY PROVIDER)

• Function: Supplies the electrical energy (voltage and current) needed to drive electrons through the circuit.
• Examples: Batteries (DC), power supplies, solar cells, or AC wall outlets (via adapters).

2. CONDUCTORS (PATHWAY)

• Function: Provide a low-resistance path for electric current to travel between components.
• Examples: Copper wires, printed circuit board (PCB) copper traces, or breadboard connections.

3. CONTROL DEVICES (SWITCHES)

• Function: Regulate, turn on, turn off, or direct the flow of current through the circuit.
• Examples: Push buttons, toggle switches, relays, and transistors (when acting as electronic switches).

4. LOAD (CONSUMER OF ENERGY)

• Function: Consumes electrical energy and converts it into another form of useful energy (light, heat, sound, or mechanical motion).
• Examples: Light-emitting diodes (LEDs), electric motors, speakers, or heating elements.

5. PROTECTIVE DEVICES

• Function: Protect the circuit components from overcurrent, overvoltage, or short-circuit damage.
• Examples: Fuses, circuit breakers