BASIC ELECTRONIC COMPONENTS

Lead-in

· What are basic components?

· What electronic components have now become obsolete?

 1.  Practice pronunciation of the following words and underline the stressed syllable. Translate the words into Ukrainian.

Components, assembly, vital, functioning, least, diode, circuitry, oscillator, thermionic, through, differentiate, electrolytic, high-frequency, low- frequency, wound, ferrite, impedance, mutual.

Memorize the following words and word combinations. Make up your own examples.

 3. Read the text. Find examples of active and passive electronic components.

UNDERSTANDING ELECTRONICS: BASIC COMPONENTS

I

Electronic components, both active and passive are lifeline of any printed circuit assembly. They both play vital roles in the functioning of any electronic device and are different from each other.

Active electronic components are those that can control the flow of electricity. Most electronic printed circuit boards have at least one active component. Some examples of active electronic components are transistors, vacuum tubes, diodes etc. For instance, a semiconductor device called transistor, is the fundamental building block of the circuitry in mobile phones, computers, and several other electronic devices. A transistor has very fast response and is used in a number of functions including voltage regulation, amplification, switching, signal modulation, and oscillators. Transistors may be packaged individually or they can be a part of an integrated circuit. Some of the ICs have billion of transistors in a very small area. Another example is a vacuum tube, electron tube (in North America), or thermionic valve (elsewhere, especially in Britain) that is reduced to simply "tube" or "valve" in common parlance. It is a device that relies on the flow of electric current through a vacuum. Vacuum tubes may be used for rectification, amplification, switching, or similar processing or creation of electrical signals. Active components that allow flow of electricity in one direction are called diodes. Most diodes have a painted line on one end showing the direction or flow. The negative side is normally white.

Components that don’t have the ability to control current by means of another electrical signal i.e. passive electronic components include capacitors, resistors, inductors and transformers.

II

Capacitors are used in electronic circuits as energy-storage devices. They are also used to differentiate between high-frequency and low-frequency signals. A wide variety of capacitors are available, including electrolytic capacitors, basic parallel-plate capacitors, and mechanical variable capacitors. A capacitor is a passive electrical component that can store energy in the electric field between a pair of conductors called "plates". The process of storing energy in the capacitor is known as "charging". The ability of a capacitor to store charge is measured by its capacitance.

Another component, resistor, is an electrical device that resists the flow of electrical current. It is a passive device used to control, or impede the flow of electric current in an electric circuit by providing resistance, thereby developing a drop in voltage across the device.

Typically, an inductor consists of a coil of wire wound on a ferrite rod. Inductor differs from a resistor because it has low resistance (or impedance) to direct currents and low-frequency signals and it has high impedance to high-frequency signals.

A transformer transfers electrical energy between two circuits. It usually consists of two wire coils wrapped around a core. These coils are called primary and secondary windings. Energy is transferred by mutual induction caused by a changing electromagnetic field.

Electronic components are intended to be connected together, usually by soldering to a printed circuit board, to create an electronic circuit with a particular function.

 4. Answer the following questions.

1. What kinds of components play vital roles in the functioning of any electronic device? 2. What is the fundamental building block of the circuitry in mobile phones, computers, and several other electronic devices? 3. How many transistors can typical IC have? 4. What vacuum tubes may be used for? 5. What components are used in electronic circuits as energy-storage devices? 6. What kinds ofcapacitors are available nowadays? 7. How is the process of storing energy in the capacitor called? 8. What does capacitance measure? 9. What is the difference between an inductor and resistor? 10. How are electronic components connected together?

Exercises