# Tag: Free Book on Semiconductors

• ## 1.6 Conversion From Decimal Numeration

Because octal and hexadecimal numeration systems have bases that are multiples of binary (base 2), conversion back and forth between either hexadecimal or octal and binary is very easy. Also, because we are so familiar with the decimal system, converting binary, octal, or hexadecimal to decimal form is relatively easy (simply add up the products…

• ## 1.5 Octal and Hexadecimal to Decimal Conversion

Although the prime intent of octal and hexadecimal numeration systems is for the “shorthand” representation of binary numbers in digital electronics, we sometimes have the need to convert from either of those systems to decimal form. Of course, we could simply convert the hexadecimal or octal format to binary, then convert from binary to decimal,…

• ## 1.4 Octal and Hexadecimal Numeration

Because binary numeration requires so many bits to represent relatively small numbers compared to the economy of the decimal system, analyzing the numerical states inside of digital electronic circuitry can be a tedious task. Computer programmers who design sequences of number codes instructing a computer what to do would have a very difficult task if…

• ## 1.3 Decimal versus Binary Numeration

Let’s count from zero to twenty using four different kinds of numeration systems: hash marks, Roman numerals, decimal, and binary: System: Hash Marks Roman Decimal Binary ——- ———- —– ——- —— Zero n/a n/a 0 0 One | I 1 1 Two || II 2 10 Three ||| III 3 11 Four |||| IV 4…

• ## 1.2 Systems of Numeration

The Romans devised a system that was a substantial improvement over hash marks, because it used a variety of symbols (or ciphers) to represent increasingly large quantities. The notation for 1 is the capital letter I. The notation for 5 is the capital letter V. Other ciphers possess increasing values: X = 10 L =…

• ## 1.1 Numbers and Symbols

The expression of numerical quantities is something we tend to take for granted. This is both a good and a bad thing in the study of electronics. It is good, in that we’re accustomed to the use and manipulation of numbers for the many calculations used in analyzing electronic circuits. On the other hand, the…

• ## 13.12 Tubes versus Semiconductors

Devoting a whole chapter in a modern electronics text to the design and function of electron tubes may seem a bit strange, seeing as how semiconductor technology has all but obsoleted tubes in almost every application. However, there is merit in exploring tubes not just for historical purposes, but also for those niche applications that…

• ## 13.11 Microwave Tubes

For extremely high-frequency applications (above 1 GHz), the interelectrode capacitances and transit-time delays of standard electron tube construction become prohibitive. However, there seems to be no end to the creative ways in which tubes may be constructed, and several high-frequency electron tube designs have been made to overcome these challenges. It was discovered in 1939…

• ## 13.10 Display Tubes

In addition to performing tasks of amplification and switching, tubes can be designed to serve as display devices. Perhaps the best-known display tube is the cathode ray tube, or CRT. Originally invented as an instrument to study the behavior of “cathode rays” (electrons) in a vacuum, these tubes developed into instruments useful in detecting voltage,…

• ## 13.9 Ionization (gas-filled) Tubes

So far, we’ve explored tubes which are totally “evacuated” of all gas and vapor inside their glass envelopes, properly known as vacuum tubes. With the addition of certain gases or vapors, however, tubes take on significantly different characteristics, and are able to fulfill certain special roles in electronic circuits. When a high enough voltage is…

• ## 13.8 Tube Parameters

For bipolar junction transistors, the fundamental measure of amplification is the Beta ratio (β), defined as the ratio of collector current to base current (IC/IB). Other transistor characteristics such as junction resistance, which in some amplifier circuits may impact performance as much as β, are quantified for the benefit of circuit analysis. Electron tubes are…

• ## 13.7 Combination Tubes

Similar in thought to the idea of the integrated circuit, tube designers tried integrating different tube functions into single tube envelopes to reduce space requirements in more modern tube-type electronic equipment. A common combination seen within a single glass shell was either two diodes or two triodes. The idea of fitting pairs of diodes inside…

• ## 13.6 The Pentode

Another strategy for addressing the problem of secondary electrons being attracted by the screen was the addition of a fifth wire element to the tube structure: a suppressor. These five-element tubes were naturally called pentodes.   The suppressor was another wire coil or mesh situated between the screen and the plate, usually connected directly to…

• ## 13.5 Beam Power Tubes

In the beam power tube, the basic four-element structure of the tetrode was maintained, but the grid and screen wires were carefully arranged along with a pair of auxiliary plates to create an interesting effect: focused beams or “sheets” of electrons traveling from cathode to plate. These electron beams formed a stationary “cloud” of electrons…

• ## 13.4 The Tetrode

As the name suggests, the tetrode tube contains four elements: cathode (with the implicit filament, or “heater”), grid, plate, and a new element called the screen. Similar in construction to the grid, the screen was a wire mesh or coil positioned between the grid and plate, connected to a source of positive DC potential (with…