Hi there. So far we have seen and created or practiced how we can create a single sided PCB, as well as how we can design and develop a double sided PCB. Now, going further with Eagle, we have to see how we can use SMD components. And for that we have to understand why we use SMD components, how they look like, and what are the basics. Let's get started. This is a small picture I have purposefully put over here to give you an idea of what is assembly and why we use it.

So generally, through one component looks like this. It gets it gets drilled onto the PCB from one layer to the other layer. And then it takes a lot of space like this. This is a register on the similar terms. This is also a resistor, which is an SMD or for sale or it's also called at surface Mounting device, this SMD resistor takes quite a lot of less space as compared to this one. And it gets soldered on the same side where it's placed.

So it's a very big difference or there is a very big amount of space saving whenever we use SMD as compared to through home. So let's get started, what is SMD? Or what is surface mount technology. It's a technique of connecting circuit components to a PCB, where the solder joint forms using pad on a PCB and metal pin of the component. So there is no need to use a hole or a physical hole to be made in the PCB for creating the connection while comparing the surface mount and through hole, the surface mount takes a lot of less space and through hole takes a bit more space but it's easier. So on a tour PCB, uses holes to mount the circuit board which is is very easier for hand surgeon, but it takes more space surface mounting technique uses pads to mount the circuit component onto the board.

It's a little difficult to handle shoulder and there is a big advantage that it takes very less space the component itself is very smaller as compared to the through hole component. This is the differences between surface mountain through hole components as empty parts almost all of the parts are available in assembly format nowadays every manufacturer who is developing an LED or let's say who is developing a particular IC mostly semiconductor manufacturers, so, almost every IC is available as SMD version so there is a through hole version as well as an SMD version. So you will get assemblies of ICS capacitor resistors inductors LVDS, as well as some connectors, assemblies primarily are used when there is a space concern. And if you open up your mobile phone, sometimes you might even see that there is Through whole component at all, and almost everything is SMT. Day by day the usage of SMB is increasing and there might come a time where we will not see this through hole components anymore.

But don't worry for now and for analysts coming 4050 years we'll see them. So as discussed why assembly it's smaller, faster, cheaper, safe space, and once it saves space, that's what ultimately saves the Pacific cost also, and many new products are only available in surface mounting type package. For example, those gyroscopes, you might have seen our accelerometers, some specific microcontrollers specializes and sensor sizes this come only in SMT package, so there are multiple versions of them. The PCB footprint of our PCB package of an assembly component looks like this. This is the most common package of resistors and capacitors and the package have their specific codes just like that. Whole packaging as somebody has their specific course.

So 0000603080512060603 literally specifies the dimension so the length is 0.06 inch or 1.5 mm and the width is 0.03 inch or point eight five which is very small 1206 is a package which has point 06 point 12 inch width and 3.2 mm height or sorry point 12 inch width and point 06 inch width. It is possible to hand soldier but those services comfortable. I have seen people with a lot of practice to even soldier 0805 and 003 also by their hands. I have not turned such before I can soldier 1206 and I hope you will also find it comfortable to soldier one to zero subsets pretty big package, you can hold it in a tweezer very comfortable As far as the transistors and diodes they are generally present in this kind of packages. So, this assembly transistors and diodes mostly share the same type of package which is also called as a suti 23.

So, this is an SOC 23 package line which consists of three pins, but if it is a diode it only consists of two usable pins, but number one is actually useless but it has to be there to physically support the board on to the PCB whereas, the transistor usually looks like this this is the outline of BC at phase seven transistor. So, it has got this three pins and this is the distribution of those three pins. Usually every components datasheet will give you look for the datasheet of your Dyer transistor for identifying the pins if you are using any assembly packages, most of the ICS also come this image is taken from sparkfun.com. So, these are the different packages of ISIS. So, there is a PDP package and then there is the LCC package. So, this is through And this is SMD one, the Commonwealth ticker fb 44 where there are 11 pins on one side and similarly there are such four sides so they're bad gives it four different pins then SS o p 2814 on each side.

So P eight or so eight as well as this is 28 pin MLP. So these are some common IC packages present in SMD. As a general practice through hole on a board are placed on one side and assemblies are also placed onto the same side. But depending upon the requirement you can place the assemblies from either side of the board is comfortable to be soldered on any side there is the actual benefit of using a double sided PCB, you can place your components on both sides. So, that's about the assembly components here is your project. So this is I'll show you how to create a schematic This is an ft 232 USB to TTL converter.

So we have to design this board using SMD components, all of them has to be assembly components. These are the packages for the ICS resistors, capacitors salaries and fuse that we are using. So find out all those components, and we have to create a schematic out of this and then create a layout for it. So, let's get started.