I won't get into very much detail with all this stuff, cause it is not meant to be exhaustive but instead just a useful overview to get you familiar with the different components.
While they might not seem as interesting as other things, resistors are the foundation of all electronics.
|Unit:||Ohm, KilOhm, MegOhm etc|
|Ability:||limit current & voltage
Resistors are used to limit current and voltage. Resistors work by disipating electricity as heat. A space heater is basically just a big resistor that gets hot and warms up your room in the winter. Similar to how when you exercise, your body gets hot and you sweat, resistors also get hot when they are doing work (usually not noticeably).
You will often hear resistors compared to a "valve" or "hose". I personally don't find this very helpful, and really think this analogy should be gotten rid of. The way that I think of resistors which has been most helpful, is to think of them as adding "flavor" to a circuit:
A circuit that just has one voltage and current running through it is not very interesting, but a circuit with many different voltages and currents in different parts of it is complicated, it has personality, and specifically, it is doing complicated work.
The value of a resistor can be read from the color markings on it. I'm not going to tell you about how to find out how to read the markings. For me, I look the markings up a lot online, there are charts you can print off on how to read them - mostly I have just memorized the color codes.
Capacitors are a bit more complicated, but really awesome.
There are many different kinds of them too:
|Unit:||Farad, microFarad, nanoFarad, etc|
Capacitors are literally just batteries. They store electricity in them until they are full, and once they are full they let it out.
You might justifiably get a bit excited when you hear the word store, and you should! What storage means is keeping something over time, and as you are probably aware, time goes forward instead of backwards, so the ability to store something like voltage to use later greatly expands being able to do really interesting things - for instance the brain's ability to store information allows us to do all kinds of weird stuff.
The main thing capacitors are used for is filters. Filters let through certain frequencies and keep out others. Capacitors are often used in parallel with a DC supply to filter a power supply to keep unwanted high frequency noise out of the circuit or prevent sudden power surges, all of which protects the circuit.
They are also used in series to the positive line to block Direct Current, ensuring against a constant flow of electricity between two points, which means they are useful to protect against short circuits and excessive stress on circuitry caused by prolonged Direct Current.
Because of their ability to change over time, they are also very useful in building oscillators and multivibrators.
This is just meant to be cover the basics of capacitors, so I'll leave things at that. You can see some examples of how they are used in my page about filters or the $5 synthesizer page.
Much like us women, electricity naturally goes both ways. We don't come out of the womb (or test tube) liking One Direction. Diodes conduct electricity like a traffic light conducts traffic, to go one way.
|Ability:||conducts electricity in one direction
There isn't much to say about diodes other than that they prevent current from flowing in one direction. The primary other thing about them is the different types which are suited for different applications.
Power diodes are used to protect circuitry by ensuring that the wrong polarity is not allowed, which would damage the device. Signal diodes are rated for far smaller voltages (around 1 volt, never more than 5) and are used in digital logic. A Zener diode does allow current to flow "backwards", but only after a certain voltage threshold is passed.
Then, obviously, you have light-emitting diodes, which are really cool because lights are fun, but they can also serve a dual purpose as indicators for troubleshooting problems in a circuit.
In fact, if you look at very old electronics, all of the diodes in them were light-emitting! With some old electronics, if they are turned on and opened up you can see the diodes inside glimmering. This looks beautiful, but it also made repairing things much easier because you could tell from the diodes what was going wrong. Sadly, nowadays consumer electronics aren't typically built to be repaired, but rather just thrown away and replaced, so this is pretty rare with modern tech.
For the most part, the black power diodes like the ones above are the type you'll want to use unless you are really getting technical. Just make sure that if you are operating anywhere above 3.5 volts that you use current-limiting resistors in series with your LED's because most LED's are only able to handle around one to four volts!
??? I have no idea what inductors are or what they are used for ???
|Unit:||Henry (no seriously.. milliHenry, microHenry, etc..)|
Wikipedia says they are mainly used to block AC current and let DC through, and some other things. You mainly find a lot of them in radios and TV's because they are often used for filtering and tuning radio frequency oscillators. I've never found a need to use them as opposed to just using capacitors, so you are on your own if you want to learn about them lol
These are the most AWESOME component ever, but they take a long time to understand and get used to using. They can get complicated.
|Ability:||amplifier, logic / switching
There are for the most part two types of transistors: NPN and PNP. The N's and P's refer to the orientation of the semiconductive material inside them. Transistors are basically two diodes put together, that allow current to flow depending on certain logical conditions.
Transistors can be used as amplifiers, they can be used as voltage-controlled switches, there are many different types and uses, and I can't even scratch the surface here. I recommend just looking up simple single or double transistor circuits and reading the schematics to get an idea of how they work, that really is the best way in my opinion, as opposed to listening to someone talk about how they work.
Transistors are, as you have probably heard, the fundamental building block for computers. That is because they can perform binary logic which is what computers use to do computing stuff. I somewhat attempt to describe binary logic and its uses on this page.
IC's (integrated circuits) & microcontrollers
An integrated circuit is exactly what it sounds like: an entire working circuit miniaturized and put in a convenient package. Microcontrollers are a type of IC that is an entire computer on a chip.
|Name:||IC / microcontroller|
|Ability:||anything you can imagine
By far the most common IC you will come across is the Op-Amp. I may eventually make an entire page on op-amps, but all you really need to know is that an Operational Amplifier is not merely an amplifier like the volume knob on your stereo (do people actually even use things with volume knobs anymore? huh...) an op-amp is like a more complicated transistor which performs logical operations. You can really think of op-amps as a mathematical function, and their output is the product of that function. They have two inputs, and based on what voltages are at those inputs they make a different output. They are ubiquitous because they are just really useful.
The other IC you will come across is probably a proprietary microcontroller unit (MCU). These may or may not be covered up by a glob of black epoxy. Unfortunately, because of patents, intellectual property, capitalism and stuff, there isn't really much you can do with most of the IC's you will find in recycled electronics because the "software" on them is often specifically designed to work for a very narrow purpose and usually can not be copied, modified or sometimes even known at all.
The major problem with this is that, apart from op-amps there are very, very few general-purpose IC's. They tend to be single-purpose and highly specialized devices. As a result, most IC's can't be recycled or reused unless you are willing to spend a lot of time and energy into finding the datasheet for an IC, learning the specific and unique properties of that particular IC, and constraining your design to fit that one device, and this assumes you are able to actually remove the IC from the board without damaging it in the first place, which is pretty difficult.
As stated above, microcontrollers are a specific type of IC that is literally an entire computers shrunk into a chip. This means they have all the things a computer needs: a ROM that is the "operating system", which has RAM to store information, a Central Processing Unit (CPU) that performs calculations, and peripherals to interface with external devices.
Before there was Arduino, there were different hobbyist microcontrollers like the PIC series. Because of the enormous cost of the complicated equipment to make them, IC's and microcontrollers are usually far outside the realm of anything the average person can create themselves, although there are Feild-Programmable Gate Arrays that can be designed entirely from scratch and re-writeable MCU's like Atmel and PIC. I will eventually make some pages about Arduino etc.