WNCOMP1 – Lesson 5: LEDs and Switches

Electrical Circuit Components

• A switch controls the flow of electricity in an electrical circuit, allowing or interrupting the current.
• Brightness of an LED is determined by the current flowing through it; higher current equals greater brightness.
• A resistor limits the flow of electric current in an electronic circuit to protect components from damage.
• Color bands on a resistor indicate its resistance value and tolerance, crucial for proper circuit design.

LED and Resistor Function

• LED functionality is dependent on polarity; it must be connected correctly in a circuit to light up.
• A resistor in an LED circuit prevents excessive current which can damage the LED.

Types of Switches

• Mechanical switches operate using physical movement, while electronic switches use electronic mechanisms to control electrical flow.
• SPST (Single Pole Single Throw) switches have one input contact and one output contact, ideal for simple on/off applications.
• SPDT (Single Pole Double Throw) switches can connect a single input to one of two outputs, allowing for more complex circuit configurations.
• A switch can be normally open (NO) or normally closed (NC), controlling the circuit's default state.

Switch Functions and Configurations

• The main role of a SPDT switch is to toggle between two different circuit paths or outputs.
• Types of switches can be classified by their method of actuation, such as mechanical or electronic.
• DPST (Double Pole Single Throw) switches control two circuits simultaneously and typically have four terminals.
• Difference between a DPST switch and two SPST switches lies in their integrated control of two circuits with fewer physical components.
• In the OFF position, a DPST switch prevents current from flowing through both circuits it controls.

Specific Switch Types

• Push button switches momentarily activate the circuit when pressed, often used for temporary functions.
• Toggle switches maintain their position, offering a stable on/off state compared to the transient nature of electronic switches.
• Limit switches are used to detect the presence or position of an object, providing feedback in control systems.
• Float switches control liquid levels by using buoyancy to manage electrical circuits based on fluid presence.

Sensing and Control Components

• Temperature switches commonly use thermistors or bimetallic elements as heat-sensing components.
• Microcontrollers provide more functionality than microprocessors in embedded systems due to integrated components and I/O ports.

General Electronics Knowledge

• Breadboards are essential in electronics for prototyping circuits, allowing components to be connected easily without soldering.
• Active electronic components include transistors, diodes, and integrated circuits that require external power to operate.
• The Arithmetic Logic Unit (ALU) in a microprocessor performs arithmetic and logical operations, crucial for computation.
• The newest generation of embedded systems leverages advanced technologies such as system-on-chip designs and multicore processors for enhanced performance.
• Pressure switches are critical in industrial applications to monitor and control system pressure for safety and efficiency.