most people learning electronics will know these as resistors but not everyone will know the huge array of different kinds that enable Electronics to do an astounding number of functions in this video we'll go over all of the most common resistors we'll understand how they work and what makes them tick and most importantly we'll simplify them and understand the fundamentals to have the best understanding possible the first collection of resistors we're going to look at is fixed value resistors these are resistors that are designed to maintain a single resistance value the most common fixed resistors are
through hole resistors SMD resistors and wire round resistors the first type we'll look at is the most common for custom projects tinkering and prototyping these are through hole resistors they're intended to be used on a circuit board with through holes or a breadboard for rapid prototyping there are three main types of through hole resistors solid carbon carbon film and metal film resistors solid carbon resistors they're usually only found in very old electronics and this is because they're prone to failure and are expensive to produce compared to the other two common options today carbon film and
metal film resistors are the most used through hole resistors today and they both have a similar construction these resistors have a ceramic core this core is coated in a conductive material that be pure carbon or pure metal usually nickel chromium this film then has a helical groove cut into it and then two metal end caps are placed with the leads finally the the resistor is coated in an insulating layer typically epoxy now let's go back a bit to that helical groove cut into the resistor if we cut into a couple of resistors a 10 ohm
and a 1 million Ohm resistor we can clearly see that the higher resistance unit has significantly more grooves in it making the resistance greater this is what allows the resistance to be changed this is due to the combination of a thinner path and a longer path on the resistor between metal and carbon film resistors metal film resistors are considered to be superior this is because they have better tolerances stability and overall have better attributes however carbon film resistors are still really good and they could be a cheaper decent quality option especially for tinkering and prototyping
at home now every resistor of every kind will have its own specific resistance determined in ohms but when you have a resistor like this how do you determine the resistance you could determine it by just using a multimeter and simply measuring how much resistance it has and you can figure out the ohms that way or or you could use the color code on the resistor body itself if you look at the body we have an array of colors on it resistors will have anywhere from 3 to 6 colors and there's 12 different colors each symbolizing
a distinct value and changing meaning by position on the body we've designed our own color decoder and we've included it in our resistor guide link below in this example we have a black green silver and finally gold using our decoder we can see that black is zero green five and silver a multiplier of 0.01 finally the gold is a tolerance of 5% so we just do a simple multiplication 5 * 01 tells us that this is a05 Ohm resistor with a 5% tolerance using a multimeter might seem like the easier option but there are cases
where you can't use a Multimeter somewhere where a color code is important is when reading it off a circuit board reading it with a multimeter could give you a false reading as there are other paths for the electrons to flow through on the circuit board with less resistance making you believe either the resistance is not working or it has the wrong resistance in this case the best way to read the resistor is by using the color code another common thing is that resistors vary in size the larger the resistor the more heat dissipation it can
handle and consequently the larger the resistor the more watts it can handle to figure out your resistor power capacity you'll have to check out your manufacturer's data sheet which will specify what it's rated for alternatively you can measure the resistor which gives a somewhat close approximation to the watt capacity and we've included a guide to this in our resistor guide as well we also have fusible resistors typically this type of resistor will have a white line at the very end of the color code a fusible resistor as you might imagine acts like a fuse to
protect the circuit so instead of the resistor potentially Catching Fire Burning Up or altering its working properties the resistor will break before reaching excessively high temperature or power additionally a white or blue body usually indicates a a non-flammable or fusible resistor as well another thing also worth mentioning is that there are specialized resistors these are typically only seen in military or highly specialized cases these resistors are very expensive have very high tolerances and oftentimes also indicate a failure rate on the color code however as I mentioned these are expensive and very uncommon so it's not
really something we're going to look at moving on to the next common fixed value resistor is wire wound resistors these come in an array of different forms each with its own purpose these are generally known as power resistors which optimize for heat dissipation and power capacity though Precision wire wound resistors are also somewhat common these resistors are made of a ceramic core with a nickel chromium wire wrapped around it usually encased in resin or other insulating material for example in this case we have a wire round resistor with an aluminum casing that acts like a
heat sink to increase power rating another common wire wound resistor are ceramic encased these resistors are rated for operating at high temperature environments finally many wire round resistors are used for real stats and potentiometers but this goes in a different category a little later on in the video as these are not fixed value resistors so we'll come back to these later in the video the next resistor is by far the most common unmanufactured circuit boards and that is surface mounted resistors these are Precision resistors prioritizing tolerances and stability while sacrificing power Capac capacity and heat
dissipation in other words these are not designed for a lot of power surface mounted resistors also known as SMD resistors are the smallest we'll look at today these are typically attached directly to conductive pads on a circuit board this reduces the required space and allows for greater use of both sides of a circuit board now these resistors will vary in size from small to extremely small requiring a microscope to take a decent look at it and even this resistor is not the smallest SMD resistor out there now some of these bigger ones can be installed
by hand but these tiny ones are nearly impossible to do by hand and require specialized machines to install these and of course just like most other resistors the greater the size of the resistor the more heat dissipation and Watts it could handle to determine the power capacity you'll have to reference the data sheet from the manufacturer or you could get a close approximation on our resistor guide surface mounted resistors are constructed of a ceramic base on which a metal oxide film is deposited this film will get a laser edged groov it which will control the
resistance then metal contacts are placed on each side and finally the body is coated in an epoxy or glaze insulator many of these resistors will have printed on them the value of the resistor but there's a specific way to read these numbers the two most common code formats are digit system and e96 resistor with digits are read similarly to through hole resistors where the first digit are the numbers and the last the amount of zeros you add or the multiplier this resistor for example is 8201 so the numbers are the first three 820 and the
last number being the multiplier meaning 10 this means that this is an 8,200 Ohm resistor these resistors will also often have a capital R which states a decimal point like this for example is at 47 r0 we simply replace the r with a decimal point and we get 47.0 ohms resistor the other common method is e96 which is more complicated and requires either a very good memory or reference chart for the values like this in this case it's a simple matter of matching up the numbers for example a resistor that says 01 C you just
match it with the code in this case 01 meaning 100 and the letter C in this case 100 meaning a 01 c e a96 SMD resistor is 10,000 ohms and those three are the most common fixed value resistors next we have an array of adjustable and variable resistors first we'll take a look at the common manually adjusted resistors there are two main kinds which are potentiometers and real stats potentiometers are typically known as these and are often referred to as pots there are also larger higher demand potentiometers and much smaller finer option known as trimmers
or trim pot a potentiometer is essentially a resistor which is tapped at some point throughout the resistor this is why the symbol for a potentiometer looks like a regular resistor with a line tapped into the middle of it potentiometers are constructed off a circuit board which has three terminals placed on it and a round strip of resistive material between the two terminals on each end this resistive material gives us the option to tap the resistor at any point throughout the resistor allowing us to adjust the amount of resistance we want the next component of a
potentiometer is what's known as a slider brush or wiper this is a metal contact that will slide on the surface and transfer into the center contact terminal so as we turn this we increase or decrease the resistance on the center terminal and this gives us a potentiometer this allows us to make a voltage divider by grounding the terminal at the end the resistive material on these devices can be linear or logarithmic this just means that the resistance can change across the strip and not be the same linearly which is useful for audio controls and other
applications potentiometers will have a letter on them indicating the type of curve they are in this case we have B which is simply a linear potential iometer going back a bit to trim pots we can break One open and see that it's essentially a tiny version of the potentiometer the main difference is that we have a helical screw which turns a gear slowly for fine adjustments on the device so essentially it's just a very small fine adjustment version of the potentiometer next we have rats this is a rat yes it's also a potentiometer and what's
interesting here is that how you use it is what determines whether it's a potentiometer or riat so all potentiometers can be riats but not all riats can be used as potentiometers the main difference here is that the rat acts like an adjustable resistor while a potentiometer Taps a resistor now the difference here is that a rat or an adjustable resistor will act as a current limiter while a potentiometer acts as a voltage divider changing the voltage the next type of resistors we have are in environment-based resistors now these resistors aren't manually adjusted but instead they
react to certain conditions in the environment to change their resistance the most common of these resistors are therm ldr resistors and VAR first let's take a look at therm it's a resistance that change based on temperature these sensors are generally made of semiconductor material which is typically metal oxides using Cobalt manganese or nickel these semiconductors change their resistance as temperature changes it's also important to note that thermostats are not linear this means that if we try to determine temperature linearly by the resistance will have considerable errors in other words a device like this used to
determine temperature needs to perform some complicated equations to display the correct information and again there's a lot that goes into this but it's a topic for another video next we have photo resistors these are also known as ldr resistors meaning light dependent resistors an ldr is constructed out of a ceramic base which has a conductive material deposited on it usually made of cadmium sulfate for light or lead sulfate for infrared then two metal terminals are placed on either side this conductive material holds on to electrons when in dark conditions however when exposed to photons the
material becomes more conductive allowing electrons to flow between the metal leads as you can see here as I put shade over the resistor are resistance changes so we can use these as light meters although the most common use for these are automatically engaging lights at night or engaging or disengaging other devices in the presence or absence of photons or in other words light next we have VAR these resistive devices are used to protect circuits from high voltage surges known as transients transients are momentary surges or spikes in voltage or current that could damage circuits these
events are common for a multitude of reasons all the way from static on your hands to lightning hitting nearby power sources these devices are volt sensitive variable resistors in other words their resistance changes based on voltage these devices are built by a complex ceramic crystalline structure with suspended metal oxide usually zinc that acts as what's known as a PN Junction but essentially this device has very high resistance and this is true until the device experience a set voltage across the terminals at which point the resistance becomes biased on in other words the resistance switches from
being very high to very low what this allows for is that if that voltage exceeds the desired level this will open and ground that current so that it doesn't go through the circuit and damage components you'll usually find these devices and power supplies computers and most sensitive equipment we have spent months working constantly on this video and resistor guide designing the artwork and ensuring quality information this guide is a perfect digital or physical reference for working with resistors referencing formulas functions refreshing memory size charts and many more explanations that go beyond the contents of this
video we've also designed a cool mug for Tinkers and makers with a useful reference on the resistor color code you could have on hand as you tinker and drink your beverage of choice I do want to mention that this document is not required to continue to enjoy our content though it is the best way to support the channel and help us continue to make the best content possible we'll continue to explore resists and a lot more in future videos
