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Why do we need to know this stuff?
Basic electronics concepts and skills are essential for understanding how electronic devices work and for designing and building your own electronic devices. Computer science skills can also be helpful, as they can be used to program and control electronic devices. Here are some of the benefits of learning basic electronics concepts and skills:
Understand how electronic devices work: Basic electronics concepts and skills will help you to understand how electronic devices work, from simple circuits to complex systems. This knowledge can be useful for troubleshooting and repairing electronic devices, and for designing and building your own devices.
Design and build your own electronic devices: With basic electronics concepts and skills, you can design and build your own electronic devices, such as robots, drones, and home automation systems. This can be a fun and rewarding hobby, and it can also lead to a career in electronics engineering or other STEM fields.
Develop important problem-solving and critical thinking skills: Learning basic electronics concepts and skills requires problem-solving and critical thinking skills. These skills are transferable to other areas of your life, such as school and work.
By learning these basic concepts and skills, you will be well on your way to understanding and using electronics in your everyday life.
At the end of this unit, you should be able to:
Explain the concepts voltage, current, resistance and power
Understand how to use Ohm's Law
Be able to use a multimeter to measure voltage, current and resistance
Have a good understanding of basic electronics components and schematic symbols
Can read basic datasheets and use the information in a basic design
Can read and create basic circuit diagrams using appropriate conventions
Understand the concepts of open and closed circuits
Understand the concepts of series and parallel circuits
Understand Kirchhoff's current and voltage laws
Use a breadboard to prototype circuits - See Circuit Construction Techniques
Can use a simulation program such as Tinkercad Circuits but preferably one that uses schematics to create circuits (Tinkercad can convert circuits but uses the wrong conventions).
Basic Electrical Principles
Basic Electrical Principles
Basic Electrical Principles
Basic Electrical Principles
These are four of the most important concepts in electronics, and understanding them is essential for designing, building and operating electronic circuits. By understanding the relationship between these four quantities, we can design circuits that consume less energy and that are less likely to overheat. If you need background information on the concepts of electricity and electronics go to the Fundamentals of Electricity page.
Voltage
Current
Resistance
Power
Voltage is the difference in electrical potential between two points. It is measured in volts (V). Think of voltage as the pressure that pushes electrons through a circuit.
Voltage is used to power electronic devices, such as smartphones, laptops, and TVs. It is also used to transmit electricity over long distances.
Current is the flow of electrons through a circuit. It is measured in amperes (A). Think of current as the speed at which electrons flow through a circuit.
Current is used to drive electronic devices, such as motors and solenoids. It is also used to generate heat, as in electric heaters and stoves.
Resistance is the opposition to the flow of current through a circuit. It is measured in ohms (Ω). Think of resistance as the friction that slows down the flow of electrons through a circuit.
Resistance is used to control the flow of current through a circuit. This is used in a variety of applications, such as dimming lights and controlling the speed of motors.
Power is the rate at which electrical energy is consumed or transferred. It is measured in watts (W). Think of power as the amount of work that electricity can do in a given amount of time.
Power is used to calculate the amount of energy that an electronic device consumes. This is important for designing energy-efficient devices and for preventing devices from overheating.
Ohm's Law
Ohm's Law
Ohm's Law relates the voltage, current, and resistance in a circuit. It states that the current through a resistor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the resistor.
In other words, the current through a circuit is determined by the voltage applied to the circuit and the resistance of the circuit.
V = I x R
Electricity and electronics are essential to modern society. They power our homes and businesses, connect us to the world, and make our lives easier and more efficient.
So, what does this all mean?
Basic Example of where the above are used:
Basic Example of where the above are used:
On the right is a basic circuit diagram with standard symbols. The conventions used helps us to read and understand the design. In the next sections we will learn more about convention and how the circuit works. The LED is connected in series with the resistor and the power supply. The resistor limits the current flowing through the LED and protects it from damage. To turn on an LED, we need to apply a voltage across it that is greater than its forward voltage. The forward voltage of an LED varies depending on the color of the LED, but it is typically around 2 volts.
We want to limit the current flowing through the LED to 20 milliamps although 10mA is preferred as it will help to extend the life of the LED and prevent it from overheating. Using Ohm's Law, we can calculate the value of the resistor as follows:
R = VR/I
VR = 9 - V(Forward voltage of the LED) = 7V
Therefore,
Test Yourself
In this example we are going to check how accurate we were with the previous example. We do have to make one change. Resistors have standard values, and you can learn more about it in the next section. For this exercise we choose 680 Ohm.
Note: This is where we have two options. We can test it on a breadboard, my preferred way is to test it on a simulation, such as Yenka, Circuit Wizard or Tinkercad Circuits. I would like students to understand convention in electronics and Tinkercad Circuits does not follow those rules but it is a good way to check that you have build the circuit correct.
Build the following circuit on a breadboard with a 9V battery, 680Ohm resistor and a red or green LED(You will understand later why). It is a good habit to use the colour convention but sometimes we don't have the right wires. Later on you will learn more about breadboard skills but for now just build it up.
What is a LED?
A light-emitting diode (LED)(link to LED page) is a semiconductor device that emits light when an electric current passes through it.
In an LED, current flows from the positive side, called the anode, to the negative side, called the cathode. This direction of current flow is essential for the LED to emit light. If the current is applied in the opposite direction, the LED will not emit light.
This is all about current flow. As you can see on the right. Current is "pushed" by the voltage from the positive end of the battery, through the breadboard, LED, resistor and back to the negative side of the battery. This is called a closed circuit. The LED is on because the current is flowing the right way, anode to cathode.
The next step is to measure the current and voltage to ensure it is within the theoretical boundaries and specifications of the components. If you are not sure how to use a multimeter go through that unit to help you.
How does the measurements compare with the calculated values? For three reasons it will never be exactly the same but as long as it is close:
Resistor tolerances
Battery voltage
Multimeter accuracy and range chosen
Electronic Circuit Theory
Electronic Circuit Theory
Circuit design acts as the blueprint for electronic systems, guiding us in understanding how electrical currents move.
In the realm of circuits, we distinguish between open circuits, where current is blocked, and closed circuits, where it flows freely. The setup of the path for electricity further unfolds through parallel and series circuits. As we delve into refining our designs, we turn to Ohm's Law, linking voltage, current, and resistance – a crucial guide for achieving the right balance in our circuits.
Additionally, we consider power to ensure our circuits operate efficiently. To deepen our understanding, Kirchhoff's Voltage and Current Laws come into play. These laws help us analyse complex circuits by describing how current and voltage behave within different parts of the circuit. In this way, circuit design becomes a blend of fundamental principles and practical application, shaping the technology that powers our world.
Open and Closed Circuits
Open and Closed Circuits
Open and closed circuits are fundamental concepts in electronics, describing the state of a pathway for electric current to flow within a circuit.
Open Circuit:
In an open circuit, the pathway for electric current is interrupted or incomplete. This means there is a gap or break in the circuit that prevents the flow of electricity. In practical terms, it is like an open switch where the contacts are not touching, or a break in a wire.
Closed Circuit:
In contrast, a closed circuit is a complete pathway that allows electric current to flow without interruption. The circuit is closed when there is a continuous and unbroken path for the current to travel. This typically occurs when a switch is closed, completing the connection, or when there are no breaks in the wires forming the circuit.
In simpler terms, think of a circuit like a loop. If the loop is complete and unbroken, allowing electricity to flow, it's a closed circuit. If there's a gap or break in the loop, preventing the flow of electricity, it's an open circuit. Understanding these concepts is crucial for designing and troubleshooting electronic systems.
Series and Parallel Circuits
Series and Parallel Circuits
Series and parallel circuits are two basic configurations in which components (such as resistors, bulbs, or other devices) can be connected within an electrical circuit.
Series Circuit
In a series circuit, components are connected end-to-end, forming a single pathway for the electric current to flow. The same current flows through each component because there is only one path. If you break the circuit at any point, the entire circuit is interrupted, and no current can flow.
Characteristics
The current is the same through all components.
The total voltage across the circuit is the sum of the individual voltages across each component.
The total resistance is the sum of the individual resistances.
Example: Christmas lights connected in series – if one bulb goes out, the entire string may go out.
Parallel Circuit
In a parallel circuit, components are connected in separate branches, and each component has its own pathway for electric current. The current is divided among the different branches. If you disconnect one branch, the current can still flow through the other branches.
Characteristics:
The voltage is the same across all components.
The total current is the sum of the currents through each branch.
The reciprocal of the total resistance is equal to the sum of the reciprocals of the individual resistances.
Example: Home electrical outlets – devices plugged into different outlets operate independently.
In summary, series circuits provide a single path for current, and the components share the same current, while parallel circuits offer multiple paths for current, and the voltage is the same across all components.
Understanding these configurations is essential for designing and analysing electrical circuits.
See LINK for information on resistance
Electronic Circuits
Electronic Circuits
In this section you will build up a range of circuits on a breadboard. To make it easier, you can simulate it on Tinkercad Circuits first, before using a real breadboard. Use a standard BC547/8.
Flasher Circuit - How 2 transistor LED flasher oscillator works
Motor driver: Don't look at code but the information about H bridges are good
Test Yourself
Create an LDR switch. If it is dark, turn an LED on.
More Complex Circuits
More Complex Circuits
Astable Multivibrator (Flasher Circuit)
Astable Multivibrator (Flasher Circuit)
In this exercise, we are constructing a simple two-transistor flasher circuit on a breadboard. The two transistors in the circuit each control one LED.
https://wild-bohemian.com/electronics/flasher.html
555 Timer
555 Timer
The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element - https://en.wikipedia.org/wiki/555_timer_IC
This website has detailed info and circuits about timers. There are three modes: Monostable, Astable and Bistable. These are described here.
The resistor and capacitor values can be determined using the 555 calculator.
These are cheap, reliable and have a wide variety of applications. Students should understand how a combination of resistors and capacitors interact with the timer IC.
Test Yourself
Build a Bistable Mode timer circuit and see how it works. Using an LED on the output can help to visualise what is happening.
When the Trigger Button is pressed, the LED turns on. When the reset button is pressed the LED turns off. The circuit on the right was simulated with Circuit Wizard.
Try to do the monostable and astable timer by yourself.
OPAMPs
OPAMPs
An operational amplifier ("op-amp") is a very high-gain IC amplifier with two inputs and a single-ended output. They were originally made from discrete components and were designed to solve mathematical equations electronically, by performing operation such as addition, subtraction, inversion, integration, differentiation etc.
Nowadays, in IC form, they have many uses, one of the most important being as high-gain DC and AC voltage amplifiers. A typical op amp contains twenty transistors as well as resistors and small capacitors.
Test Yourself
Find a circuit online and see if you can build and test it.
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