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Electronics vs electricity
Electronics vs electricity
These two concepts are not the same. So, what is the difference?
You have to be able to:
Describe electricity and where it is used
Describe electronics and name examples
Explain what the difference is between electricity and electronics
Static Electricity
Static Electricity
Static electricity is the result of an imbalance between negative and positive charges in an object. These charges can build up on the surface of an object until they find a way to be released or discharged. One way to discharge them is through a circuit. ... The electrons cling to your body until they can be released. - https://www.loc.gov/everyday-mysteries/item/how-does-static-electricity-work/
Science made Simple is a website that explains how it works
AC vs DC
AC vs DC
There two types of current and voltages: AC and DC. It is important to understand how these influence the functionality of an electronic circuit.
You have to be able to:
Describe what AC is?
Describe what DC is?
Explain the difference between AC and DC?
Explain why AC and DC exist?
Describe the different applications of AC and DC current
Ohm's law
Ohm's law
Ohm's Law is a formula used to calculate the relationship between voltage, current and resistance in an electronic circuit.
Describe voltage and the units of voltage
Describe current and the units of current
Describe resistance and the units of resistance
Understand the relationship between voltage, current and resistance
Know Ohm's law and how to use it to do simple calculations
Ohm's Law Explained - More videos to explain the concept.
Electric Current
Electric Current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. ... The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second. -https://en.wikipedia.org/wiki/Electric_current
Power
Power
Power is the rate which work is done. In electronics that is really important as the power rating of components will determine if the circuit will function reliable and components are not destroyed because their power rating is too low.
Describe what power is
Understand the relations between power, voltage, current and resistance
Know how to identify the units of power
Frequency
Frequency
Frequency describes the number of waves that pass a fixed place in a given amount of time. So if the time it takes for a wave to pass is is 1/2 second, the frequency is 2 cycles per second or 2Hz.
Describe what frequency is
Describe how do you determine the frequency of a signal
Know what the unit of frequency is
Conductors, Semiconductors and insulators
Conductors, Semiconductors and insulators
The use of conductors, semiconductors and insulators determine how we can create various electronics circuits.
You have to be able to:
Explain the difference between conductors, semiconductors and insulators
Identify examples of these and why they are used in the specific application
Circuits and symbols
Circuits and symbols
Schematic circuits use symbols to show components and different electronics designs.
You have to be able to:
Describe open and closed circuits
Understand the concept of series and parallel circuits
Identify various components in terms of how they look and their symbols
Understand the concept of circuit diagrams
Use a simulation program to model various circuits
Other Links:
Circuit Wizard (Need to get unlock code from Mr Thew or Mrs Dunn)
More information under Simulations and Programming Applications
Basic Electronic Components and Circuits
Basic Electronic Components and Circuits
You have to be able to:
Describe various components and explain their function
Create basic circuit diagrams using symbols
Simulate a basic circuit diagram using Yenka or similar. Examples of circuit diagrams include series and parallel circuits, voltage dividers, switching circuits, sensors, motor drivers etc
Understand the concepts of Kirchoff's voltage and current laws
Construct these diagrams on prototype boards and compare with simulations and theory
Identify inputs and outputs of circuits
Understand how to debug and faultfind circuits
Analyse existing design as a basis for future designs
Earth Confusing?
Earth Confusing?
Have a look at this page to help you understand the concept better.
Resistors
Resistors
These components are probably on the the most used components in electronics. Their values are measured in ohms (Ω), they do what they say (they resist current flow), and they have two main uses:
Voltage Divider (getting the correct voltage to part of a circuit)
Current Limiter (eg: protecting an LED from blowing up)
but more on these two things later...
Initially, we're just going to focus on basic 'linear' resistors - but as you can see from above there are a lot of different types for different tasks. Their main purpose is to control the current.
There are five things that are important when using resistors:
- Standard Values
Firstly, resistors have standard values that are shown by colour codes. Always make sure you check or measure the value to ensure you know what the resistor value is. This webpage have activities that may help you learn these. A useful tip regarding the multiplier is to think of it as the number of zeros. For example:
brown black black is 1 then 0 then 0 zeros (or no zeros). Or just 10 - so 10Ω (ohms).
green blue yellow is 5 then 6 then 4 zeros. So its 560000Ω. Substitute 'k' for 3 zeros: 560kΩ
You can also use a color code calculator to help you.
- Parallel Resistors
Resistors can be connected in parallel as shown on the right to make up "new" resistor values or depending on other components use in a circuit. The new resistance will always be lower than the lowest resistor used to make it.
The simplest parallel resistor arrangement is two resistors of the same value, which will give 1/2 the resistance (ie: two 10kΩ resistors in parallel will give you 5kΩ). This expands neatly - three 10kΩ resistors gives 1/3, or 3.33kΩ. Four would be 1/4 and so on. Important to note is that the voltage over these resistors are the same. More information here.
- Series Resistors
Resistors can be connected in series as shown to make up "new" resistor values or depending on other components use in a circuit. The new resistance is simply the sum of the resistors used. For example, two 10kΩ resistors in series would give you 20kΩ. Important to note is that the current through these resistors are the same. More information here.
Types of Resistors
Types of Resistors
There are a number of different types of resistors commonly. Most commonly used are SMT (surface mount), carbon composite, metal film and wire wound. They are manufactured different to provide different characteristics and uses. More information about various resistor constructions can be found here or here.
Resistor Power Ratings
Resistor Power Ratings
Apart from the resistor value, the power rating is a very important factor to keep in mind to ensure the resistor does not overheat or fail. Normally power rating are shown in different sizes. More information here.
Light Dependent Resistor (LDR)
Light Dependent Resistor (LDR)
An LDR is a variable resistor who's resistance is changed by the level of light on its surface.
Although the amount of resistance has a relationship to the amount of light, it is not linear, ie: twice the light does not necessarily mean twice (or half) the resistance. More info in the reference.
Some good links to help with your understanding of capacitors:
How Stuff Works - How Capacitors Work
Sparkfun - Capacitors
Electronics Tutorials - Introduction to capacitors
Very good explanation on You Tube - What is a Capacitor? (below)
Capacitor simulation from PHET Interactive simulations.
Capacitors
Capacitors
A capacitor is a passive, two-terminal that is used to store electrical charge. Basically it consist of two metal plates separated by an insulator called a dielectric. When a capacitor is connected across a voltage, current flows into the plates for a short time. We call this "the becomes charged up". It will store this charge, even if the source of the voltage is removed. The capacitor will now have voltage across it because of the charge now stored on its plates. This effect is used in a variety of circuits including power supply filtering, frequency oscillators, radio receivers.
A good analogy for a capacitor is provide by How Stuff Works. There is a simulation circuit in Yenka showing how the capacitor charge and discharge.
There are a number of different types of capacitors:
Dielectrics capacitors - normally variable capacitors used in transmitters and receivers
Film Capacitors - high power applications
Ceramic capacitors - Resonant circuits, DC-DC converters, used on brushed DC motors to minimise RF noise.
Electrolytic Capacitors - Power supply filtering, filters in audio amplifiers
Diodes
Diodes
The key function of the diode is to control the direction of current flow. Current can only flow in one direction through a diode.
Diodes have many useful applications for example:
Rectifying a voltage, such as turning AC into DC voltages. For example a bridge rectifier. This is also a good explain of the ful bridge rectifier.
Isolating signals from a supply
Voltage Reference
Controlling the size of a signal
Mixing signals
Detection signals
Lighting
Lasers diodes
Transistors
Transistors
Transistors are used in almost all electronic devices to amplify or switch signals. Many people are using electronics either as part of their jobs or as a hobby. There are many websites and books that describe how transistors works. This is a list of some of the more interesting ones:
Sparkfun is also a good place to learn about transistors
The following transistor circuits can be created easily using the standard BC547. Make sure you do simulate it on Yenka:
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.
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.
Yenka Simulations
Yenka Simulations
Complete this tutorial to help your understanding of the various components and circuits.
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