S3 Design basic circuits using discrete components
Initial skills rating *
September 2011
I do not even know what a discrete component is, so my initial skill’s rating has to be no stars. My first task has to be to find out what a discrete component is.
*
I now know a discrete component is a component with a single function. When used in an electrical circuit in different combinations they can be used to produce a variety of outcomes. So discrete components are to electronics what eggs and flour are to cooking. Some definitions refer to discrete components as elemental components or single components. Discrete components include: diodes, resistors, transistors and capacitors.
9th March 2012
Although I have been using discrete component over the last few months I still have very little understanding about each component and its function. I have decided to take a closer look and find out more.
What is a diode?
A diode is a device that controls the direction of flow of electrical energy. It has a low resistance to the flow of electrical energy in one direction and a high resistance to the flow of electrical energy in the opposite direction.So a diode is to electricity what a non return valve is to mechanical engineering.
Types of diodes
There are many different types of diode. Probably the most common type of diode is the LED or light emitting diode. These can be seen glowing all around your home when electrical appliances are left in standby mode. They come in a variety of shapes, colours, sizes and brightness consuming different levels of power. Many produce a static light while others have set flashing frequencies due to built-in blinking internal chips.
The main thing to remember about LEDs when using them in circuits is that they have two terminals. These can be seen as pins projecting from a little plastic casing. The longest leg is the anode or positive terminal and the shorter leg is the cathode or negative. On the little dome shaped LEDs when viewed end on a little flat can be seen on the edge of the casing on the negative side of the LED. I really like the little saying our tutor gave us at the beginning of this course to remember which way round the cathode and anode went, ‘the negative has a little bit missing’. I think of it in terms of after a light has been emitted a little bit of energy is missing from the circuit. It has certainly worked for me.
Although I have been using discrete component over the last few months I still have very little understanding about each component and its function. I have decided to take a closer look and find out more.
What is a diode?
A diode is a device that controls the direction of flow of electrical energy. It has a low resistance to the flow of electrical energy in one direction and a high resistance to the flow of electrical energy in the opposite direction.So a diode is to electricity what a non return valve is to mechanical engineering.
Types of diodes
There are many different types of diode. Probably the most common type of diode is the LED or light emitting diode. These can be seen glowing all around your home when electrical appliances are left in standby mode. They come in a variety of shapes, colours, sizes and brightness consuming different levels of power. Many produce a static light while others have set flashing frequencies due to built-in blinking internal chips.
The main thing to remember about LEDs when using them in circuits is that they have two terminals. These can be seen as pins projecting from a little plastic casing. The longest leg is the anode or positive terminal and the shorter leg is the cathode or negative. On the little dome shaped LEDs when viewed end on a little flat can be seen on the edge of the casing on the negative side of the LED. I really like the little saying our tutor gave us at the beginning of this course to remember which way round the cathode and anode went, ‘the negative has a little bit missing’. I think of it in terms of after a light has been emitted a little bit of energy is missing from the circuit. It has certainly worked for me.
There are many other diodes available. Until today I did
not even know they existed. I would not say I thought LEDs were the only
diode but I had no idea there were so many types or even that there is such a the variety of
LEDs. There are: laser diodes,
photodiodes, pin diodes, PN junction, scottky diodes, step recovery diodes,
tunnel diodes, varactor or vericap diodes and zener diodes. Details of all
these diodes and how they work can be found at www.radio-electronic.com
Generally speaking a diode is a semi-conductor and due to the different compositions of diodes different outcomes are achieved. For example photodiode detects light and converts it to electricity. As much as I would like to record everything I have just read explaining how the diodes all work I know that would take me too long so I think it would be best to use the hyperlink.
Generally speaking a diode is a semi-conductor and due to the different compositions of diodes different outcomes are achieved. For example photodiode detects light and converts it to electricity. As much as I would like to record everything I have just read explaining how the diodes all work I know that would take me too long so I think it would be best to use the hyperlink.
What to do next?
It is clear to me that there are so many discretem components and it is possible to learn a huge amount about each but this is not practical for this length of course. I have decided to take a look at BBC bite size to give me an idea of the basics I need to know.
BBC Bitesize
The discrete components listed by BBc bitesize include resistors, transistors, LEDs, Capacitors and relays. This gives me a starting point. Some of which I have covered in different areas of my audit.
Getting my names muddled.
I keep calling transistors thermistors. I think this may be because to me the words are similar. I am not clear in my own mind of the difference between the two componenets. I think maybe if I know understand the function of each component then I may be less likely to get them confused.
What is a thermistor?
A thermistor is a type of resistor specifically designed to have a predictable change in resistance depending on the temperature surrounding it. Although all electrical components are affected by the changes in temperature it is only the thermistor that is designed to have a significance predictable response. If the resistance of a component is known at a specific temperature conversely a temperature is known at a specific resistance. Thermistors are used in temperature sensing circuits. Example: thermostats used in domestic heating systems will contain a thermistor. Thermistors are semiconductors.
Think therm - think thermal- think relating to heat.
Think therm - think thermal- think relating to heat.
What is a transistor?
A transistor is also a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductive material with at least three terminals:the base, the emitter and the collector.