WNCOMP1 – Lesson 5: LEDs and Switches

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Questions and Answers

What is the main purpose of a switch in an electrical circuit?

To interrupt the current flow in the circuit (correct)

To measure the resistance in the circuit

To control the brightness of an LED

To increase the current flow in the circuit

What determines the brightness of an LED?

The amount of current flowing through the LED (correct)

The type of material used in the LED

The size of the LED

The color of the LED

What is the purpose of a resistor in an electronic circuit?

To store electrical energy

To control the flow of current in the circuit (correct)

To amplify the current in the circuit

To convert electrical energy into light

What is the purpose of the color bands on a resistor?

To indicate the resistance value and tolerance of the resistor Signup and view all the answers

What is the relationship between the polarity of an LED and its function?

The polarity of an LED determines the direction of current flow through it. Signup and view all the answers

What is the purpose of a resistor in a circuit with an LED?

To protect the LED from damage due to excessive current Signup and view all the answers

What is the key difference between mechanical and electronic switches?

Mechanical switches require physical contact, while electronic switches do not. Signup and view all the answers

Which type of switch has one input contact and one output contact?

SPST switch Signup and view all the answers

What is the key feature of a SPDT (Single Pole Double Throw) switch?

It has one input contact and two output contacts. Signup and view all the answers

Which type of switch can be either normally open or normally closed?

SPST switch Signup and view all the answers

What is the main purpose of a SPDT switch in most circuits?

To connect the input between two choices of outputs. Signup and view all the answers

Which type of switch is classified based on the method of actuation?

Manual, limit, and process switches Signup and view all the answers

What is the main function of a double pole single throw (DPST) switch?

To control two separate circuits simultaneously. Signup and view all the answers

How many terminals does a DPST switch have?

Four Signup and view all the answers

What is the main difference between a DPST switch and two separate SPST switches?

A DPST switch operates the two contacts simultaneously. Signup and view all the answers

What is the state of a DPST switch when it is in the OFF position?

Both switches are open. Signup and view all the answers

What is the main function of a push button switch?

To provide momentary contact when pressed. Signup and view all the answers

What is the main difference between a toggle switch and an electronic switch?

Toggle switches are mechanical, while electronic switches are solid-state. Signup and view all the answers

What is the primary function of a limit switch?

To detect the presence, absence, or motion of an object instead of human operation. Signup and view all the answers

What is the primary purpose of a float switch?

To control the level of liquid or water in a tank or sump by detecting the float's position. Signup and view all the answers

Which component is commonly used as a heat-sensing element in temperature switches?

A bimetallic strip that operates on the principle of thermal expansion. Signup and view all the answers

What is the primary advantage of using a microcontroller over a microprocessor in embedded systems?

Microcontrollers require less additional hardware components. Signup and view all the answers

What is the primary purpose of a breadboard in electronics?

To test ideas by developing preliminary models (prototyping). Signup and view all the answers

Which of the following is an example of an active electronic component?

Transistor Signup and view all the answers

What is the primary function of the Arithmetic Logical Unit (ALU) in a microprocessor?

To perform arithmetic and logic operations. Signup and view all the answers

Which generation of embedded systems is known for introducing technologies like system-on-chip, reconfigurable processors, and multicore processors?

Fourth generation Signup and view all the answers

What is the primary purpose of a pressure switch in industrial applications?

To sense the pressure of hydraulic systems and pneumatic devices. Signup and view all the answers

Study Notes

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.

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Description

Learn about LEDs (Light-Emitting Diodes) in this lesson. Understand the basics of how they work, their different types, and how to use them effectively, with a focus on polarity. Date: February 29, 2024. Format: PPT & Discussion.