About SMD The abbreviation "SMD" stands for "Surface Mount Device". SMD is an assembly technology used to solder electronic components to a circuit board. These components are soldered to flat surfaces and are located on the top surface of the circuit board. SMD technology allows the use of smaller and lighter components than the previously used "through-hole" technology. This allows more dense and compact designs to be made. SMD is widely used in the design of small and portable devices, especially mobile phones, computers, televisions and other electronic devices. SMD welding is the process of soldering electronic components to circuit boards using surface mount technology. SMD welding is carried out using materials and equipment such as solder paste, soldering machine or soldering oven. Additionally, correct component placement and placement methods are also important to the success of SMD welding. The SMD welding process begins by applying solder paste to the legs of the component that need to be soldered. The component is then placed on the circuit board in the right place and in the right orientation. Using a soldering machine or oven, the solder paste on the component's legs is melted and the component is soldered to the circuit board. This process is used for surface mount components and makes circuit boards smaller and denser. Electronic Material Case Types: What is SMD Resistor: SMD fixed resistors are generally black and flat elements. Color codes are used to find the values of carbon resistors. In SMD resistors, the resistance value is found through the numbers written on the resistor. The calculation method for the values of SMD resistors is the same as that of carbon resistors. When finding the value of a resistor consisting of three-digit numbers, the first two values of the numbers read are written exactly as they are, and the third number is the multiplier. For example, the value of an SMD resistor marked 122 is 122 = 12 x 102 = 1200 Ω = 1.2 KΩ. If the number written on the SMD resistor has 4 (four) digits, the first three values of the read digits are written exactly as they are, while the fourth number is the multiplier. For example, the value of an SMD resistor marked 1764 is 1764 = 176 x 104 = 1760000 Ω = 1760 KΩ = 1.76 MΩ. In addition to numbers, the letter R is also used in the values written on the SMD resistor. The letter R in front, behind and in the middle of the numbers represents a comma. For example, the value of an SMD resistor labeled 6R2 is 6R2 = 6.2 Ω. The physical dimensions of SMD resistors are proportional to the power to be consumed on them. SMD resistors are generally produced between 0.03 and 1 W. 3 digit SMD Resistor codes: As in the 3-color DIP sheath resistor codes, the first 2 digits are the numerical value, the third digit is the multiplier, that is, the number of zeros we need to add to the value. If the multiplier is “0”, the first numerical values are valid. Their tolerance is 5%. Example: 332 is written on the SMD resistor, we change the last digit, that is, two, to zero, it becomes 3300, that is, 3300 OHM thousand OHM 1k, that is 3300-OHM 3.3K. 330 is written on the resistor. If the first 2 digits are numeric, the third digit is ignored because the multiplier is "0" and is ineffective. In this case, the resistance value is 33-OHM. For SMD resistors with a 3-digit code, a comma and “R” are added instead of a dot for fractional OHM values. Example: 4.7-OHM resistor is written as 4R7. For low value resistors such as 0.22-OHM, 0.47-OHM, "R" is added to the beginning R22: 0.22-OHM R47: 0.47-OHM 4 digit SMD Resistor codes: In 4-digit SMD resistors, the first three digits are the numerical value and the fourth digit is the multiplier, that is, the number of zeros we need to add to the value. If the multiplier is “0”, the first numerical values are valid. Their tolerance is 1%. Example: 1001 is written on the SMD resistor, the last digit is one, we convert it to zero, it becomes 100+0, that is, 1000-OHM thousand OHM 1k, that is, the value of our resistor is 1K. resistance. value 100-OHM For SMD resistors with a 4-digit code, “R” is used for fractional OHM values and values below 100-OHM. Example: 4R70 is written for 4.7OHM, 47R0 is written for 47-OHM. Note: SMD resistors with only "0" on them have no value, direct short circuit, that is, a jumper is used instead of a jumper wire. They can withstand instantaneous high currents according to their power. According to the data sheet information of Yeago company, the rated current through the 0805 sheath SMD resistor is; 2A max.; It is said that it can pass 5A current. “SMT Resistor Code Calculator” Online pages provide ease of reading. * https://www.m4ems.co.uk/smt-codes.php * https://www.electricallearner.in/smd-resistor-code-calculator * https://www.utmel.com/tools/smd-resistor-code-calculator?id=33 * https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-smd-resistor-code SMD Resistor Powers: In the past, the most commonly used SMD resistor type was the 1206 case, that is, the standard 1/4W type found in all electronic equipment stores, then 0805 and much smaller cases began to be used. The table shows the powers of SMD resistors and the comparison of the most used 1/4w, 1/8w resistors. Integrated resistor (Parallel resistor) Some SMD resistors have the numbers 0 or 0000 written on them. These resistors As can be seen from the figures, it has a zero ohm value and does not cause any difficulty in flowing current. However, there is a limit to the current that can flow through them. When this limit is exceeded, they burn and break the circuit. With these features, it can be easily understood that they act as a fuse in the circuit. These resistors are also called fuse resistors. By burning themselves, they prevent other elements in the circuit from deteriorating and causing more severe damage. SMD trimpot: What is SMD Capacitor? Capacitors are basic electrical and electronic circuit elements created by insulating material placed between two metal layers, taking advantage of their ability to store electrical charge within the electric field. SMD capacitors, which are small in size and take up very little space, are used as capacitors in circuits produced with surface mount technology. SMD Ceramic Capacitor Codes: SMD ceramic capacitors are low capacity and non-polar. It is the most commonly used SMD capacitor type in surface mount technology. SMD ceramic capacitors can be distinguished by their brown or khaki green sheath structure. However, there is generally no code on SMD ceramic capacitors. SMD ceramic capacitors have SMD codes consisting of one or two letters and a number. The letters and numbers in the code on the SMD ceramic capacitor indicate the capacity value in picofarads (pF). For example, the capacity value of an SMD ceramic capacitor coded K3 is K3=2.4 x 10^3 pF=2400 pF=2.4 nF. Some manufacturers write a letter in front of the code indicating the capacitor value to identify themselves, other than a letter and a number. For example, in an SMD ceramic capacitor coded KA2, the letter K indicates that the capacitor is produced by Kemet company, and the code A2 indicates that the capacity value is A2 = 1.0 x 10^2 pF = 100 pF. SMD Electrolytic Capacitor Codes: It is the other most commonly used capacitor type among SMD capacitors. These capacitors are usually polarized and very high capacity. The capacity value of SMD electrolytic capacitors is shown with numbers in μF. For example, the code 22 16 V indicates that the capacitance of the capacitor is 22μF and the operating voltage is 16 volts. In some SMD electrolytic capacitors, the capacity value and operating voltage values are specified by coding. This code consists of one letter and three numbers. The letter in the first digit indicates the operating voltage (volts). Numbers indicate the capacity value in picofarads (pF). The first two of these numbers determine the capacity value, and the third determines the multiplier. For example, the operating voltage of the SMD electrolytic capacitor coded A226 is 10 volts and the capacity value is 226 = 22 x 10^6 pF = 22 x 10^3 nF = 22 μF. SMD transistors are assembled in the same way as other SMD components when mounted on a circuit board. This allows for higher density and smaller size circuit boards. Other advantages of SMD transistors include better thermal performance, lower parasitic capacitance, and lower inductance. SMD transistors are mostly used for high-speed and high-frequency applications, for example in radio frequency (RF) circuits, portable electronic devices, and computer motherboards. SMD transistors, a wide range p-channel, n-channel, Darlington, high power and other types of transistors are available. Standard names for chips such as resistors and capacitors are often given by writing the width and length of the element side by side in inches or metric units. For example, a chip element with a length of 1.6 mm and a width of 0.8 mm is measured in metric units. It is called the 1608 case. If the element is a resistor, it is called R1608 or 1608R. Similarly capacitors 1608C or C1608; The inductance is L1608 or 1608L. However, most of the time, the sheath dimensions of SMD elements are written in inches (1 inch = 2.54 cm). In other words, an SMD element with dimensions of 1.6 x 0.8 mm is called 0603 because its inch equivalent is 0.06" x 0.03". The other most commonly used capacitor types among SMD capacitors are those made of electrolytic and tantalum materials. These capacitors are generally produced in polar form and it is possible to obtain very high capacity values. It is easy to distinguish electrolytic and tantalum SMD capacitors. Both types have markings indicating polarity and the numbers indicating their values are written directly on them without the use of coding. These numbers determine the value of the capacitor in μF. SMD Coils: SMD coils are another passive circuit element that can be found on motherboards, although they are not used as much as resistors and capacitors. SMD coils do not carry any codes on them. Large-sized SMD coils can be easily distinguished by their structure consisting of wires wound on a cylinder. Cores with air, iron or ferrite cores can be found. The most important feature that distinguishes these coils, produced in standard sheath structures, from capacitors is that their color is black. SMD Fuses:
