Basic Electronics

Sources

1 . Lesson 1-BASIC ELECTRONICS (Lecture Slides)

Introduction

Electronics deals with the control of free electrons and charge carriers that flow in vacuum, gas, and semiconductor materials.¹

History of Electronics

The history of electronics is divided into two eras:

1. Vacuum Tube Era - the era which started with the invention of vacuum tubes at the first half of the twentieth century.
2. Transistor Era - the era which started with the invention of transistors at the latter half of the twentieth century.

Vacuum Tube Era

1883 - The Start of Electronics

• In 1883, Thomas Edison discovered how electric currents were conducted in a vacuum.
  • This was groundbreaking because, in a vacuum, there are no gas molecules to ionize and conduct the electricity. However, it was discovered that sufficiently heating an electrode in a vacuum can liberate the electrons—through the generated kinetic energy—from the filament’s surface.²
• Edison observed that the electric current flowed through the light bulb when he applied a positive voltage to the metal plate and filament, which were both enclosed inside a vacuum.
• The current was produced by the electron flow emitted by the hot filament. This phenomenon was referred to as the Edison Effect.

What is a Filament?

A filament is a threadlike object surrounded by the metal plates in a light bulb.

Helpful Visualization of the Experiment

https://youtu.be/J66e1X_w6i0

1895-1897 - The Discovery of Electrons

1. In 1895, Hendrik Lorentz suggested the existence of electrons.
2. In 1897, Joseph Thompson proved the existence of electrons.

1904-1926 The Discovery of Various Types of Vacuum Tubes

1. In 1904, John Fleming invented the vacuum tube diode.
   • Using the Edison Effect, John Fleming created a device which can rectify and detect radio signals.
   • Vacuum tubes enable the flow electric currents in vacuums with voltage-applied electrodes.
2. In 1906, Dr. Lee de Forest invented the vacuum tube triode.
   • Forest developed a vacuum tube that can also amplify electric signals.
3. In 1919, Walter Schottky invented the vacuum tube tetrode.
   • He created it because the inter-electrode capacitance from a triode would produce an undesired effect at high frequency operation.
4. In 1926, Benjamin Tellegen invented the vacuum tube pentode.
   • He developed it to overcome the secondary emission effect that was present in a vacuum tube tetrode.
5. In 1948, George Philbrick invented the vacuum tube op-amp.
   • This device was used in analog computers for mathematical operations.

Rectification

Rectification refers to the process of converting an AC signal to a pulsating DC one.

Transistor Era

Transistors

Transistors are devices which function like better vacuum tube triodes: they are smaller, consume less power, and lose less heat.

1. In December 1947, John Bardeen and Walter Brattain invented the point-contact transistor.
   • They invented a solid-state semiconductor device that can amplify electric signals.
2. In January 1948, William Shockley invented the junction transistor.
3. In 1959, Jack Kilby and Dr. Robert Noyce invented the Integrated Circuit (IC).
   • The device was a single semiconductor layer that combined transistors, diodes, resistors, and capacitors.
4. In 1963, Fairchild invented the IC op-amp.
5. In 1971, M.E. Hoff developed the microprocessor.
   • A microprocessor was an IC consisting of all the components of a computer’s Central Processing Unit (CPU).

Applications of Electronics

1. Communication and Entertainment
   • AM and FM radios
   • television
   • telephones
   • Internet
2. Everyday Utilities
   1. Digital calculators
   2. Advanced computers
   3. Bar code readers
3. Automotives
   1. Computer-controlled fuel injection
   2. Anti-lock brake systems
4. Manufacturing
5. Medicine
   1. Ultrasound
   2. CT scan
   3. Electrocardiograph

Components of Electronics

Electronic circuits are made up of active and passive components.

1. Active circuit components
   • vacuum tubes
   • diodes
   • transistors
   • ICs
2. Passive circuit components
   • resistors
   • capacitors
   • inductors

Footnotes

1. Materials which act as both insulators and conductors. ↩

2. Electrodes are materials used to conduct electric current. ↩