A simple guide to electronic components.

A simple guide to electronic components.


This video is just the basics of electronic components, what they look like and what they actually do – and how they work in fact So let’s start with one of the most common, the one that I just picked up there the resistor So this is a one thousand Ohm resistor I can tell that from the color bands on it, and we’ll look at that later on how the color bands are interpreted However the function of a resistor if I use the water analogy because the water analogy is very good If you have a pipe With water flowing through it and part of that pipe is narrowed down to a section Then that will restrict the flow of water through that pipe Say for instance the main water pipe coming into the house. If you put a very thin Pipe in line with that, even a fairly short one then it would really Restrict the flow of water coming in because the water would want to flow through quite quickly But it would be forced in through this narrow channel and the resistance Posed by that narrow channel would limit the water flow in the same way that a resistor Does exactly the same to electricity it limits the flow of electricity? the flow of Current and In this case with the water analogy the pressure of the water equals the voltage and it’s quite interesting that the chinese sometimes refer to the voltage as pressure and it is that’s exactly what it is and the flow of the water equals the current So the higher the flow the higher the current Now the construction of a resistor is usually in the case of these ones this is a carbon film resistor and You get metal film, Carbon film, wire wound but one of the most common is just carbon film or the metal film and they have a little ceramic Tube which is coated with either the metallized coating or a carbon coating up to a Specific thickness and the thicker the carbon coating on it and the the type of the composition they’re putting on it the more conductive it will be but then they can fine-tune that they actually cut a spiral round it and that creates a long thin path of the carbon and That increases the value of the resistance and once they’ve done that they put a metal cap in the end with the leads coming off and they dip it in a sort of…. I suppose it’s a lacquer really and Typically with the carbon film resistors which are my favourite, they’re one of the easiest to read it’ll be this sort of beige coloured I’m not sure. What would you call that color? I’ve never really thought about that Beige let’s call it beige it’s sort of rich beige and the metal film Resistors, which I don’t like because they’re usually blue and they’re really hard to read. The blue color makes the color bands…. It’s very…. it makes it easy to mix colors like orange and brown because they’ve got such a dark background But I’ll go into those colors afterwards, so that’s the function of a resistor I’m not going to go into too much at the moment because at the end of the video I’ll cover things like ohm’s law, but I don’t want to bore the pants off you so let’s move on to capacitors. Oh – I should I should continue and say about the resistors the function of resistor is To limit the current flow so say for instance you had An led you wanted an led to light from a battery if you connected the led straight across the battery it would burn the led out in most instances but if you put a resistor in series with the let’s just draw as a physical Led and you hook across the plus 12 volts and zero Volts Then by choosing the resistor value you can actually limit the current to the correct value of the led they’re also used for things like time delays you might have a Resistor charging up a capacitor you know it trickles the current into it until the voltage reaches a certain level and then that could be used as a timing function, and you also get variable resistors where effectively it’s a Carbon track Connected at both ends are only really you only need to use a connector one end and with a wiper that actually wipes around that track so you know depending on its position that will vary the resistance, so Let’s move on to capacitor now Because they’re quite interesting so a capacitor in its most basic form is a layer of insulating material with a conductive surface on each side and The best way to describe a capacitor in the water flow theory is a chamber with a diaphragm in it that stops the water flowing directly through and That diaphragm can flex a certain amount in either direction So say for instance, you’ve connected it across a battery The positive charge would flow in at this side, and it would cause it to flex over to the negative side It doesn’t actually physically work like this but this is a good way to describe it and if you reverse the polarity then that charge that amount that filled up would then be pushed out the other side and it would flex the other way and this allows capacitors to be used to basically hold a charge of electricity or in the case of the AC capacitors that you often see me using these in my led lamps that diaphragm it means that on the AC on each half wave when the polarity swaps that will let through a small amount of energy the electrons will flow back and forth through it, but not just pass right through like a short circuit So to describe a capacitor to actually show you what a capacitor does let’s make one. So I’ve got a bit of a cardboard here. This is a standard six by four photo a piece of photo material and I’ve got two bits of metalized films, so let’s say stick the metalized film on either side, so We’ve got a metal electrode, and I’m sticking it onto the insulator the dielectric and This is old aluminium tape I think that don’t seem to stick very well But that’s alright. It will do what we need to do and Then the other side of this I’ll stick the other bit of tape, and that’s the other electrode and This is the physical construction. That’s used throughout all capacitors They’re all pretty much like this, but not using cardboard and aluminium foil So let’s get that pretty much as close to the other one alignment as possible and the actual the two factors determine the capacitance here are the area of metallization that’s in parallel with other one and How thick the insulator is is in between them you think you know this cards. It’s you know it’s very thin so it’s going to be quite a You know it’s going to be a Modestly high-value capacitance, but that’s not true This is not going to be a high value of capacitance at all so let’s put this round let’s be optimistic and say 200 Nano Farad and I’ll connect it one side and the other side and The capacitance is actually… Oops! I’m not making contact I’m connecting on to the adhesive side here my capacitor measures One point. Oh that’s terrible isn’t it it’s one point eight Nano farad. It’s not very high at all and if I was to cut this in half, so the actual to prove that the area of the foil affects the capacitance if I get a pair of scissors Scissors, and I cut this in half right now So it’s one point eight three if I cut that in half It’s halved the capacitance. It’s now point eight, and if I cut that again in half, it’ll go down to about point four Which it has so that’s basically how the capacitor works. It’s basically an insulator the two metal plates on either side and the area of the metallization and the thinness of the separator is what Determines the capacitance and to get the value of capacitance up the it means that in reality for components like this little hundred keep in mind that I managed what was that just a couple of nano farad this one is rated 100 Nano farad and If you look at things like this one this is an electrolytic capacitor which is rated 470 Micro Farad, which is a massive capacitance and to achieve that … let’s get the notepad back in again To achieve the higher capacitance they often make the capacitors multi-layer, so this is something I just printed out, I designed on the computer as a printed circuit board design sort of layout But I just did it as a sort of graphic and if you can imagine that the blue is layers of insulation in the ceramic capacitors and these are metallized sort of plates then by alternating the pole sort of creating a comb of them with insulators and then putting a Metallization down the end to connect them all together you can create Quite a large capacitance in a small area just by making a multi-story capacitor so to speak and That’s still the layers of insulation in these it’s still going to be super thin you’d need a microscope probably to see all the layers where you are going for a High voltage capacitor the size has to go up these are also 100 Nano farad. So you look at this one. It’s 109 fire It’s really small, but it’s a low voltage one when you’re increasing the voltage you have to increase the thickness of the dielectric the insulation between them and To make this type of capacitor these are metallized film capacitors and it’s a film that’s metallized on one side and they take two strips of it, and they basically sandwich them together and the plastic aspect of it is the insulator and the metallization is the electrode and to fit a lot in a small area they then actually just spiral the take a big long strip and they spiral it round into a small area, and that’s what creates the sort of larger area and The thickness of the plastic film itself will Determine the voltage rating This is a ceramic disc capacitor usually quite low values. It’s usually one of the simplest and it usually is just a disc of Ceramic with a conductive layer on both sides and then an electrode that just comes across and comes off and then it’s dipped in insulation, but you think that even this one this one is rated 10 nano farad and it’s rated [1000] volts, but To get that 10 nano farad the installation must be really really thin in the inside. I’ve never actually opened one of these up Let’s open one of them up right now and take a look. Ohh. Not the thing to do with your snips That is so it really is wafer thin in there. It’s so thin that most of the thickness of that is the protective coating That is super thin in there. I don’t know if you can even see that it just looks like a line So electrolytic capacitors are one of the more exciting capacitors, and I don’t mean that in a good way the electrolytic capacitors to achieve such a high capacitance they contain a liquid electrolyte and they have a a very thin foil inside and the foil to create an extremely thin insulator they form an oxide layer on the aluminum foil in there and That means it really is like Micron thick which means that they can get a very high capacitance in a small area, but to couple onto that surface. They have to use a liquid [electrolyte] which then because … if you looked at the Foil it would look all pitted and mottled with that oxide coating so to get a good coupling They use a liquid that just fills in those gaps and that’s one of the downsides of well one of many of the downsides of the electrolytic capacitors because traditionally and all the old say for instance, all the old video games from the 80s Tend to suffer problems after a while with what’s called drying of the electrolytics, so they still measure the correct capacitance but their equivalent of resistance the resistance to current flow through them changes it increases and What that means is that They stop doing their job properly. When you get the large values like this. They’re usually used to smooth ripple so say for instance you had the output from the mains was rectified and you had a big peaky, Sort of like the The AC full wave rectified AC waveform. Which is like the two sides of a sine wave then by putting this across that it then just reduces it to a very slight ripple and a nice smooth DC voltage and as that Capacitor dries out over time that ripple will get bigger, and it ultimately starts causing problems when it dips down So low that the electronics can’t sustain normal operation, and that’s when you have to change capacitors However, that’s a more of an issue with Modern electronics because whereas in the old days the capacitors only had to deal with a 100 Hertz or 120 Hertz, just mains frequency rectified Nowadays the capacitors have to deal with the output from switch mode power supplies which is like thousands of Hertz tens of thousands of hertz and it means that they actually heat up and they Dissipate more energy. They’re just put under a lot more stress, and if you look at the top of this one you’ll see this little cross on it, and that’s a safety vent because When these fail what actually happens is that oxide coating is Can be perforated and that’s really common if you accidentally connect them in reverse because it relies in the polarity to keep that Oxide coating intact when you connect them in reverse that fails, and then suddenly you’ve basically got this Liquid filled thing just connected across the power supply with no current limiting it just basically it turns into a sort of resistor and it boils the electrolyte and when that happens the top will either sort of if you looked at it from the side bulge up and but if it goes too far that x that’s etched on to the Top will split open and it will vent out the top and the other option there if it doesn’t do that is sometimes it blows the whole can off and it just makes a mess it gives out a vapor of the electrolyte, which is slightly caustic and it Can unravel the foil across the room it can go off with enough Force to actually cause injury if it hits you So you have to be kind of careful with electrolytic capacitors? so erm… What have we covered? Let’s look at diodes now Diodes come in various flavors. They are used for various functions you get signal diodes rectifier diodes and light emitting diodes The function of a diode is to allow current to flow in One direction, but not the other So the symbol for a diode. oh, I didn’t mention the symbol for a capacitor was that basically representing the two metal plates with an air gap in between and in the case the electrolytic the That has the positive and negative are marked with The positive being the sort of just the empty box and the negative being the filled box just for the polarity reference However moving on to the diodes the symbol for a diode is very easy. It’s very self-explanatory In the water equivalents thing it would be a pipe with a one-way valve in it So the water could only floor one way in this case you have the anode of the diode and the cathode spelt with a “K” I’m not sure why they do that there must be some reason. I’ve never really investigated that too much but Current will flow positive from the anode it will flow through the diode to the negative but if you try reversing the polarity very little current if any will flow through that diode in reverse and The main values you have to consider with diodes are the current you want to flow through them say for instance This is a one amp diode. That’s rated to handle one amp flowing through something like a 1N4148 signal diode it’s not designed for anything major. It’s just designed for say rectifying small electrical signals, so it’s only rated about 100 milliamps or so if that and The other Factor is the peak inverse voltage that’s what voltage it will block coming in the wrong direction so supposing if you did connect Well this one is a 1N4007 It’s rated 1000 volts so that means that it will block 1000 volts going the wrong Direction But if you were to exceed that dramatically it will avalanche and it will start conducting the opposite Direction So you have to choose the correct diode for the job. This is a silicon diode which typically has a when it’s forward passing current in the correct direction positive to negative it will typically have a voltage drop of about point 6 volts and Sometimes you know it depends on the voltage rating actually sometimes go up to one volt and it also depends on the current flowing through it you get Schottky diodes which have a much lower forward voltage of between 0.2 to 0.5 volts and in Cases of rectification that lower voltage actually makes them much more efficient the light emitting diode our Favorite type of Diode really is a diode junction That is optimized. It behaves like a normal diode, but when it’s forward biased when the currents flowing through it, it emits light and the very first leds were actually Here are some here, they look just like the 1N4148 diodes these are actually leds they look just like ordinary glass diodes, but these are really vintage leds and when you pass current through In the correct direction a little red dot glows inside them it’s very very dim but they were purely for printed circuit board indicators these days of course leds are used for illumination and have evolved greatly but one of the things you have to note with LEDs is they don’t have a very high – because they’re purely Optimized for emitting light they don’t have a high reverse blocking voltage it’s usually just about five volts So if you were to connect the polarity wrong in this and exceed about five volts then in the case of the white, blue, green leds that may damage them but with red ones they may end up just conducting but not lighting in the wrong direction but not suffer damage and so [em] let’s say the other diodes zener diodes a zener Diode is a diode used for voltage regulation or Voltage to provide a voltage reference.
It will act like a normal diode if you pass current through in the normal direction And it drops roughly about 0.6 volts, but you get them say for instance You want a 5 volt supply you get a 5 volt zener and when you apply a reverse current positive flowing down to negative. It will actually start conducting fairly Precisely at 5 volts So if you limit the current through the resistor That limits the current flow then the voltage will just sit round about 5 volts, and that’s often used to provide Very simple power supplies and regulation in circuitry Let me think what’s next. I think we may actually be going in the direction of the resistors again and…. Oh, let’s look at transistors The world of transistors is huge. There are so many different types of transistors you get the small transistors you get the big transistors One of the most common ones I tend to use for small projects is just a little BC547 and the equivalent in America may roughly be a 2N3904 and for simplicity I’m just going to show the basic NPN silicon transistor one of the oldest fashioned type transistors about and the symbol for it is this You get three pins and if you ever want to find out what the pinout for your Transistor is if you’re not sure just go on google and the number in – like 2N3904 Google it look for images, and you’ll find pictures of the transistor with the actual pin Designations usually just printed under them it just makes it very easy to find data like that, so it’s got three pins it’s got the base pin. It’s got the collector pin and the emitter pin in the case of an NPN transistor. It’s usually switching something down to the ground rail the negative rail or the zero volt rail and it’s used as an amplifier or switch. Supposing for instance you had a small tungsten lamp and you had say a a five volt supply. If you wanted to control that lamp if you want to turn the lamp on and off? But you only had very limited current available you can use a transistor and as soon as you exceed about 0.6 volts Because it’s silicon again. That’s the standard silicon junction voltage Above the ground Rail here the zero volts and a Modest current the Transistor typically has a value called a gain It’s got a voltage rating a gain rating and a power dissipation rating there are lots of other ratings But really let’s keep it simple and say you know because in most instances when you’re using transistor It’s going to be an NPN and it’s going to be like this So say for instance you’ve got a gain of a hundred and that lamp’s going to pass 100 milliamps to light fully Then you want to pass at least one milliamp Into the base here and that will then be multiplied by the gain of the transistor And it will switch the lamp so it’s basically it’s like a relay but it’s got no moving parts And it’s a little electronic switch. You know, it’s just a really handy little thing and you can also use them in other formats like for voltage or current regulation things like that, but Just knowing the basic Operation that you know as soon as the the base has X-amount of current going in at roughly about 0.6 Volts above the emitter here then the collector current will flow that’s all you really need to know it’s just to get started other types and resistors are things like the This one pictured here is a mosfet, and they’re optimized for Switching really high loads, and that one is you know I chose the STP36NF06L for my rGB controllers because one of the nicest things about it is that it can handle a lot of current and it’s on state resistance is so low that It doesn’t impede the flow of current when it’s turned on To such a level that’s there It doesn’t really get very warm you can pass you can use it to switch quite a modest current without having to worry even about applying the Heatsink to because traditional transistors would have a slight voltage drop across them and that would result in the heat dissipating, so Mosfets are much better for that they also have an extremely sensitive input But they generally require much higher voltage on their gate as they call it too actually Turn on but the current flow is virtually zero there. That’s required to turn these on. It’s a sort of capacitive effect, so They’re quite amazing things you also get a hybrid that The Mosfets are not as robust as the traditional Let’s see bipolar transistor like this one So you get a hybrid called an IGBT insulated Gate Bipolar Transistor, which is almost like a Traditional transistor with low gain but with one of these transistors on the front of it So it’s very easy to turn it on and it Can switch massive currents and it’s a really robust transistor, but you can find all that online if you actually look for it This is just a basically guide, so let’s now look into things like Ohm’s law. Ohm’s law Which is just a couple of formulas – really easy and the best way to remember them is with a triangle “V” equals “I” times “R” where “I” let’s Draw that out a wee bit wider and put what they actually are voltage Equals current, which is “I” times resistance which is ohms? He said drawing right out the triangle. Okay? That’s all right and an application of this would be Supposing you had a 12 volt supply and you had three LEDs so there’s the three LEDs and each one is dropping about two volts each and You want to choose a resistor that is going to limit the current So that’s zero volts over there. You want to choose a resistor it’s going to limit the current through these leds to ten milliamps, so Across the leds you’ve got six volts dropped across the resistor because it’s 12 volts supply you get a six across the LEDs and you’re going to have six across the resistor to drop So to work out the choice of the resistor value in Ohms You would R equals V over I Sorry, I should mention here V equals IxR but the reason I’ve drawn a triangle voltage equals current times resistance But if you want to reverse that formula resistance equals voltage divided by current and current equals voltage divided by resistance that’s why I’ve drawn in the triangle here, so Voltage equals current times resistance and for the other ones you divide the one above it Much as you’d write it. If you’re actually doing a Mathematical formula “R” equals “V” over “I” and “I” equals “V” over “R” It’s just an easy way to remember how they relate to each other So to calculate the resistor equals voltage to be dropped over the current so it’s six volts to be dropped six volts Divided by the current you want which is 0.01 amp which is ten milliamps so if you bring the calculator in for that I Don’t need to use the calculator But I will use the calculator for this six volts divided by 0.01 (ten milliamps) equals 600 Ohms Six hundred Ohms now that’s not a standard resistor value the six hundred Ohms. You would have to use the nearest standard value which might be 560 ohms or 680 Ohms and The other way this form that can be used is… if you are trying to measure how much current is flowing through some existing leds say four instance, you’re measuring some led tape and You might find that actually putting an ammeter in series with it – because a voltage drop across the resistor in series with the leds is So low you might find an ammeter actually skews the reading a bit so say for instance you’ve got a 12 Volt supply and It’s feeding more leds, but you don’t know the voltage across leds, and you don’t know the current through them But there’s a resistor and you do know the value of the resistor So if that’s say for instance a 330 ohm resistor 330 Ohm resistor and you measure the voltage across that while the LEDs are running and you measure 5 volts and To calculate how much current is flowing through that whole circuit You would use the formula “I” equals “V” over “R”. So that’s the voltage dropped across the resistor Divided by the value of the resistor, which is 330 Ohms equals so that’s a 5 volts divided by the 330 Ohm resistor value Equals point zero one five so the answer is its drawing about 15 milliamps. The 50mA is passing through that whole circuit, so it’s useful be able to do it that way. Now with resistors there are a couple of variables with them you can choose the resistance value say for instance this is a 1 kilohm (1000 ohm) and You can also choose the power rating because if you use too small a resistor It can actually go up in smoke. Would you like me to demonstrate that? I think you would like me to demonstrate that. Let’s use this Handily placed 10 Ohm resistor. I’ve got here. Which is just trying to escape, it must know what’s about to happen to it. So this has a 10 ohm resistor. It’s color code is Brown Black Black 1 0 and a No zeros at the end, so I’m going to connect it across 12 volts and when I do that it’s going to grossly exceed its power rating. A current of about 1 amp is going to flow through it which means it’s going to dissipate about 12 watts while it’s only rated quarter watt so it’s going to be the best part of 50 times its rating so let’s see what happens. It’s smoking Glowing and it just burst into flames and failed. OK, would you like to see that again? Yes, you would So let’s get another 10 ohm resistor here Hook it up, and we’ll see it burst into flames again Lots of smoke and my workshop is now absolutely stinking So yes, so you have to choose the correct power rating for resistors. How’d you work that out? That’s where another formula comes in – very simple triangle again “P” power equals current times the voltage so say for instance let’s choose an example of this Interesting 10 watt red, LED which has a voltage when it’s operating of about nine volts and Requires about 1 amp, which you know to give it the power rating of the led itself That’s the nine volts times 1 amp is nine watts. so to calculate if we were to actually put a resistor at 12 volt supply again and choose our resistor to limit the Current through this to the 1 amp So let’s see here’s the I’ll just draw a huge big LED I’m not going to draw what’s in it – there’s a three by three array, but the voltage across that is about nine volts, so we get three volts to drop across the resistor and if we go back to the original formula R equals V over I We’ve got three volts divided by the one amp. We need so that’s going to be about 3 Ohms But to actually work out the power rating of it We have to multiply power equals the current through the resistor times the voltage across it, so this has got three volts across it at one amp so it’s going to dissipate three watts, but we’d actually better choosing a higher power resistor And it’s not a terribly efficiently way to drive the LED, but it works. It’s very very simple and I’d probably choose a 5 watt resistor because you want it to stay cool. You often see resistors that have just been pushed too far on printed circuit boards. You know they’ve been Designed and they’ve said I need a 1 watt resistor they use a 1 watt resistor and instead of the nice color code It’s basically the whole thing is just brown and the circuit board shows heat round it as well. So it’s good to dissipate – get rid of that heat. The colour codes This is the color code for resistors now a resistor has markings on it – in the case of This one here this 1000 Ohm resistor. It’s got one band here. Which is brown It’s got a black band actually let’s let write it like that black And it’s got another band which is red and then at the end. It’s got a band which is gold The gold band at the end indicates the tolerance but what’s really important for us is the first three bands and this The one of them the gold one indicates the tolerance in this case, it’s 5% tolerance, and it just means that It’s going to be within 5% of the – if you measured the resistance of this it’s a thousand ohms It’s going to be you know within 5% of 1000 Ohms The color code itself is worked out like this – The first line is the first number – the first band is the first number so in the case of Brown it means 1 so that’s one The black means zero and the red means two but the third code is actually a multiplier So in the case the red one it means there’s two zeros two zeros equals 1000 Ohms. If you had a forty seven ohm resistor It would be yellow for the four violet for the Seven and then because there are no zeros after that it would be a black band. Yellow violet black would be forty seven ohms. If it’s going to be a much lower value like four point seven Ohms, you’ll get Basically a divider either gold or silver where the first two digits if it’s followed by a gold band it will be a first digit point second digit and so for instance four point seven would be a Yellow Violet gold and it would be four point seven or for even lower values you Can’t see if I really come across silver often it’s zero point and then the first two bands so that would be in the case of the four and seven the yellow and violet it would be 0.47 Ohms very small value. So there are ways to remember this the one I was taught with is:- Billy Brown Revives On Your Gin But Values Good Whisky. That’s basically the colors in sequence the first letter of the colors Starting at zero and going up to nine and this is one of these things that It seems a bit daunting when you have to remember a color code like this But the more you do it the easier it gets and there are really rude ones. I mean it’s helpful when the first word Is actually the color because the first two? Letters are “B” unfortunately, so Billy Brown the brown indicated the brown color but you also get the really rude one Black Boys Ride Our Young Girls, But Virgins Go Without. Which is strangely the rude ones are the easiest ones to remember? I mean, I would try and be politically correct and say you must only use really polite ones But to be honest the ruder ones. I mean by all means you guys If you’re familiar with the color code, and you have one that you like to remember things by no matter How rude it is within reason put it in the comments down below? But the ruder ones are just the easiest to remember and once you’ve you know After you’ve been using resistors and doing you know reading the color codes for a while You’ll just end up you’ll just look at a resistor and go 1K (1000 ohms) just look at it And just instantly know the value It’s how it is. The same color code is sometimes used on older capacitors, and it’s still used on inductors which look very much like resistors and so That’s just a summary. I mean, I’m not going to go into too much detail because it would get boring very very quickly But this is just the basics of what you need to know how to work out the power rating of a resistor if you’re driving quite a heavy load with it. In most instances of standard quarter watt resistor is fine and How to choose the resistance value to limit current to whatever you want through leds and things that. So fundamentally, that’s it Just hopefully that’s sort of helped And I’ve not over complicated it as I sometimes do, and that’s put some of the jigsaw pieces together. Because as you understand it and as you build stuff with electronics and to be honest the best way to learn electronics is buy kits Build them, blow them up. Have little incidents, try and fix them Maybe fix them successfully, and that way you’ll just suddenly – everything will just fall into place and You’ll suddenly realize that Without even noticing it that you suddenly know how all these components work and what they do and how to select them It’s just a natural thing that evolves over time.