User:Bizzyditch/sandbox

COMPONENT IDENTIFICATION

GENERAL INFO

This page is intended to be used by beginners who wish to learn how to read not only old tech thru-hole resistors and capacitors, but surface mount as well. The user should be able to read them by the resistor and capacitor color codes, as well as the alpha-numeric code that is typically used on surface mount components. The user will be able to differentiate between thru-hole and surface mount, as well as being able to identify their schematic symbol(s). This includes resistors, capacitors, diodes, transistors and more.

All companies strive for quality in everything they do, this includes component identification. As well as learning, how to identify components, another way to ensure quality, specifically in the boards we assemble is by following the Standard IPC-A-610 REV E Class III.

SECTION 1.1 Resistor Fundamentals

When you just start working with resistors you might wonder, what is a resistor? or what exactly is the resistance of a resistor? Whenever you are working on circuits containing resistors, ohm’s law describes the fundamental behavior of resistors. Kirchhoff’s law can be used to analyze networks of resistors.

Resistors have several properties besides their rated resistance, such as their temperature coefficient, resistor noise and power rating. These resistor properties can be important to take into account depending on the application.

SECTION 1.2 Resistor Standards & Codes

Resistors are used and manufactured by thousands of companies and people worldwide. Therefore, several standards exist which help to harmonize resistors throughout the world.

To identify the value of axial resistors, a resistor color code is used. This color code consists of several colored bands. Surface mount resistors are identified by a numerical resistor code. The nominal values of resistors are also standardized. Several ranges of preferred resistor values are available. Another important aspect of resistor standardization is the use of standardized resistor symbols. The IEC standard symbol of a fixed value resistor is shown.

SECTION 1.3 Resistor Types

Several different types of resistor exist. The most used resistors are fixed value resistors, but also variable resistors are very common. The most used variable resistors are the potentiometer and rheostat. On the other hand, there are a lot of resistors which have a variable resistance which is dependent on external factors such as temperature (thermistor), light (photoresistor), voltage (varistor) or magnetic fields (magneto resistor).