electronics components.pdf

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Electronics Components Objective: You shall be able to identifying and understanding electronic components, common configuration and how it look like. Contents: 1. IDENTIFYING ELECTRONICS COMPONENTS - PASSIVE DEVICES:

How to identify simple electronics components used on circuit boards. 2. IDENTIFYING ELECTRONICS COMPONENTS - ACTIVE DEVICES:

How to identify semiconductor electronics components used on circuit boards.


IDENTIFYING ELECTRONIC COMPONENTS - PASSIVE

When a beginner to electronics first looks at a circuit board full of components he/she is often overwhelmed by the diversity of do-dads. In these next few sections we will help you to identify some of the simple components and their schematical symbol. Then you should be able to call them resistors and transistors by identifying them. In later sections we will go into the workings of each component. Just try to familiarize yourself with the basics for now.

Electronic component are classed into either being Passive devices or Active devices.

A Passive Device is one that contributes no power gain (amplification) to a circuit or system. It has not control action and does not require any input other than a signal to perform its function. In other words, "A components with no brains!" Examples are Resistors, Capacitors and Inductors

Active Devices are components that are capable of controlling voltages or currents and can create a switching action in the circuit. In other words, "Devices with smarts!" Examples are Diodes, Transistors and Integrated circuits.

Resistors: This is the most common component in electronics. It is used mainly to control current and voltage within the circuit. You can identify a simple resistor by its simple cigar shape with a wire lead coming out of each end. It uses a system of color coded bands to identify the value of the component (measured in Ohms) *A surface mount resistor is in fact mere millimeters in size but performs the same function as its bigger brother, the simple resistor. A potentiometer is a variable resistor. It lets you vary the resistance with a dial or sliding control in order to alter current or voltage on the fly. This is opposed to the "fixed" simple resistors. (SMD)


Capacitors: Capacitors, or "caps", vary in size and shape - from a small surface mount model up to a huge electric motor cap the size of a paint can. Whatever the size or shape, the purpose is the same - It storages electrical energy in the form of electrostatic charge. We will get into the mechanics and further properties of this later. The size of a capacitor generally determines how much charge it can store. A small surface mount or ceramic cap will only hold a minuscule charge. A cylindrical electrolytic cap will store a much larger charge. Some of the large electrolytic caps can store enough charge to kill a person. Another type, called Tantalum Capacitors, store a larger charge in a smaller package. Various type of capacitors. Inductors: You may remember from science class that adding electrical current to a coil of wire produces a magnetic field around itself. This is how the inductor works. It is charged with a magnetic field and when that field collapses it produces current in the opposite direction. Inductors are used in Alternating Current circuits to oppose changes in the existing current. The mechanics of this will be described later. Most inductors can be identified by the "coil" appearance. Others actually look like a resistor but are usually green in color. Syimbol: A. Air Core, B. Iron Core, C. Powdered Metal Core. Assortments of inductors


IDENTIFYING ELECTRONIC COMPONENTS - ACTIVE

Active Devices are components that are capable of controlling voltages or currents and can create a switching action in the circuit. In other words, "Devices with smarts!" . Examples are Diodes, Transistors and Integrated circuits.

NOTE: Most Active components are semiconductors. More on this in later sections.

A Passive Device is one that contributes no power gain (amplification) to a circuit or system. It has not control action and does not require any input other than a signal to perform its function. In other words, "A components with no brains!" Examples are Resistors, Capacitors and Inductors

Diodes: Diodes are basically a one-way valve for electrical current. They let it flow in one direction (from positive to negative) and not in the other direction. Most diodes are similar in appearance to a resistor and will have a painted line on one end showing the direction or flow (white side is negative). If the negative side is on the negative end of the circuit, current will flow. If the negative is on the positive side of the circuit no current will flow.

Use: To convert AC to DC, blocking circuit and signal demodulation.

LEDs: Light Emitting Diodes: LEDs are simply diodes that emit light of one form or another. They are used as indicator devices. Example: LED lit equals machine on. They come in several sizes and colors. Some even emit Infrared Light which cannot be seen by the human eye. Use: Signaling, Indicators, Billboard, sensors etc.


Transistors: The transistor is possibly the most important invention of this decade. I perform two basic functions. 1) It acts as a switch turning current on and off. 2) It acts as a amplifier. This makes an output signal that is a magnified version of the input signal. More on transistors in later sections. Transistors come in several sizes depending on their application. It can be a big power transistor such as is used in power amplifiers in your stereo, down to a surface mount (SMT) and even down to .5 microns wide such as in a microprocessor or Integrated Circuit.

Integrated Circuit and Microprocessors (MPUs): Microprocessors and other large scale ICs are very complex ICs. At their core is the transistor which provides the logic for computers, cars, TVs and just about everything else electronic. Packages are becoming smaller and smaller as companies are learning new tricks to make the transistors ever tinier.

Various type of Transistor

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