6.1 Introduction: From the Energy Age to the Signal Age
With the transition from the 19th to the 20th century, the focus of electrical engineering increasingly shifted from energy transmission to signal processing. While generators, motors, and power grids characterized the second industrial revolution, a new field emerged: electronics.
Electronic systems deal with the targeted control, amplification, and modulation of electrical signals. The basis for this was initially the vacuum tube.
6.2 The electron tube and the beginnings of electronics
The development of vacuum technology enabled the construction of components in which electrons could be moved in a controlled manner in a near-vacuum environment. The diode allowed for the rectification of alternating current, while the triode enabled the amplification of electrical signals.
Key functions of the electron tube:
- rectification
- Signal amplification
- oscillation
- High-frequency technology
The electron tube formed the basis for:
- radio receiver
- early amplifier systems
- Radar technology
- first electronic computers
However, tubes were large, energy-intensive, and prone to failure. Their limited lifespan posed a significant problem.
6.3 Fundamentals of Semiconductor Physics
The search for smaller, more reliable, and more energy-efficient components led to the research of semiconductor materials. Semiconductors are characterized by their electrical conductivity , which lies between that of conductors and insulators and can be specifically influenced.
Key physical concepts:
- Band structure model
- Valence and conduction band
- Band gap
- Electrons and holes as charge carriers
- Doping (n- and p-type lines)
The targeted doping of silicon or germanium enables the control of conductivity and forms the basis of modern semiconductor devices.
6.4 The Transistor: Revolution in Electronics
The transistor was developed in 1947. This semiconductor device could amplify and switch electrical signals without the disadvantages of the vacuum tube.
Advantages of the transistor:
- Low energy consumption
- Small size
- High reliability
- Long service life
- Mechanical robustness
The transistor replaced the vacuum tube in almost all areas of application. This marked the beginning of the semiconductor era.
6.5 Integrated Circuits
Another crucial step was the integration of multiple transistors onto a single semiconductor chip. Integrated circuits (ICs) reduced:
- Space requirements
- Energy consumption
- Manufacturing costs
At the same time, switching speed increased considerably. Miniaturization led to an exponential increase in integration density – a development often described by Moore's Law.
6.6 Microprocessor and Digital Revolution
The integration of the arithmetic logic unit (ALU), control unit, and memory onto a single chip led to the development of the microprocessor. This enabled programmable electronic systems in a compact form.
Areas of application:
- Personal Computer
- Industrial control systems
- Automotive electronics
- household appliances
- Medical technology
The microprocessor ushered in the digital revolution and fundamentally changed the economy and society.
6.7 Advances in manufacturing technology
The production of modern semiconductor components requires highly precise manufacturing techniques:
- Photolithography
- Thin-film technology
- Ion implantation
- Cleanroom technology
Structures measuring in the nanometer range place enormous demands on material purity and process control. This has made microelectronics one of the most technologically demanding industries.
6.8 Power semiconductors
Besides signal processing, semiconductors have also continued to develop in the field of power electronics. Components such as MOSFETs, IGBTs, and silicon carbide and gallium nitride transistors enable efficient energy conversion.
Application areas:
- inverter
- Electric motor controls
- Power converter
- chargers
- Photovoltaic systems
Power semiconductors combine classical energy technology with modern semiconductor physics.
6.9 Micro- and Nanoelectronics
With progressive miniaturization, nanoelectronics emerged. Transistor structures now reach dimensions in the range of a few nanometers. As a result, quantum effects are gaining increasing importance.
New materials such as graphene and two-dimensional semiconductors open up further perspectives for future components.
6.10 Societal significance
The development of electronics and microelectronics led to:
- Digitalisation of business and administration
- Automation of industrial processes
- Emergence of global information networks
- Development of modern medical technology
- Proliferation of mobile devices
Hardly any area of life remains untouched by electronic systems today.
6.11 Summary
Chapter 6 describes the transition from classical electrical engineering to modern electronics. From the vacuum tube to the transistor and on to the integrated circuit, a technological revolution took place.
Key developments:
- Control of electron flow in a vacuum
- Understanding semiconductor physics
- Miniaturization through integration
- Emergence of digital systems
- The beginning of nanoelectronics
These developments form the foundation of today's information and knowledge society.
