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AEI produced an excellent series of educational booklets in the late 1950s and early 1960s and they are re-published here. The series aim was to explain the theory behind the major valve types and their applications. Interspersed within the booklets were short-form datasheets of Mazda valves that were suitable to the applications being discussed.
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See also The Story of the Valve and Valve Technology (Maplin)


From the time that Faraday discovered how to generate electricity easily and cheaply, and Edison and Swan showed how it could be made to give light that is lasting and convenient, electrons - the particles of electricity - have been in action in many thousands of homes, flowing along wires at the touch of a switch.

In recent years electricity has been made to serve us in hundreds of ways that were never dreamed of by Faraday or Swan. By causing a stream of electrons to travel across empty space we can produce new forms of lighting, generate powerful X-rays, control and detect aircraft, and last, but not least, bring entertainment to the home by radio and television.

The radio valve on which this form of entertainment depends, is the outstanding development of the (20th) century. With its aid new discoveries have been made in all branches of science, and each discovery brings new possibilities in its wake.

In this series we have tried to explain as simply as possible how the Radio valve works.

There are many types of radio valves, each designed to do a specific job efficiently and economically. First in this series, is the earliest form of valve - the diode - and we see how it has been developed into the forms which it takes in modern radio receivers.

Contents of the Series

Electrons in Diodes

The First Radio Valve
Why Was it Called a Valve
Modern Radio Valves
The Diode as a Detector
The Diode as a Rectifier
Mazda U403
Mazda D1

Electrons in the Triode

The First Triode
The AEI Mazda Valve P61
What Happens Inside a Triode?
What is a Potentiometer
Plotting the Characteristics
Interpretation of the Curves
Space Charge
Valve Parameters (ra, gm and μ)
μ (pronounced mu)
The Triode as an Amplifier
Class A Amplification
Power Output
Load Line
Class 'B' Amplification
Push-Pull Amplification
Class 'C' Amplification
Grid Current Rectification
Anode Bend Rectification
The Triode as an Oscillator

Electrons in Screened Grids, Pentodes and Beam Tetrodes

Screened Grids and Pentodes
What the Screening Grid Does
The Effect of Secondary Emission
Effect of the Screen on Valve Parameters (ra, gm, μ)
Amplification Factor (μ)
Mutual Conductance (gm)
Introducing the Pentode
Beam Tetrodes
Grid Alignment
The Use of the Beam Tetrode

Electrons in Frequency Changers

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Electrons in Picture Tubes

Electrons in Picture Tubes
Historical Development
Basic Form of the Cathode-ray Tube
Motion of Electrons
Electrostatic Fields
Equipotential Surfaces
Production and Control of the Electron Beam
The Cathode
The Grid and Anode
Control of Beam Intensity
Crossover Point
Triode Gun
Tetrode Gun
Focusing The Beam
Magnetic Focus
Electrostatic Focus
Beam Deflection
Magnetic Scanning
Scanning Angles
Flatter Screens
The Fluorescent Screen
Where the Beam Current Goes
Overcoming Ion Burn

Electrons in Shadow-Mask Colour Tubes

Electrons in Shadow-mask Colour Tubes
Colour Displays
From Camera to Viewer
Building up the Colour Picture
Three-tube Projection System
The Shadow-mask Tube
Three Tubes in One
Keeping the Colours in Register
Colour Selection
Colour Correction
Construction of the Shadow-mask Tube
The Glass Envelope
The Electron Gun Assembly
Depositing the Screen
Tube Assembly
Colour Purity
Purity and the Deflection Process
Purity Adjustment Sequence
Magnetic Shielding and Degaussing
Effect of Convergence on Purity
Radial Static Convergence
Blue Lateral Magnet
The Need for Dynamic Convergence
Field Frequency Dynamic Convergence
Line Frequency Dynamic Convergence
Grey Scale Tracking
Black and White Operation
Modulation of the Beam
Setting up Sequence
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