Nobody has any doubt that valve amplifiers produce a remarkably beautiful sound. They have a lively, deep, clear, and expressive sound, and dynamically they do not appear to have any limitations. The author investigates, in a systematic theoretical approach, the reasons for these beautiful properties. He develops new models for power valves and transformers, thus enabling the designer to determine the properties of the amplifier during the design process. Mathematical models for the coupling of power valve(s) and output transformer are provided. These will generate new insights in a special kind of distortion: the dynamic damping factor distortion (DDFD). With mathematical models in the complex domain, especially the properties at the limits of our hearing range (from 20 Hz to 20 kHz) are investigated and the minimal stability criteria for the amplifier are formulated. The often-applied negative feedback in amplifiers is extensively modelled and discussed in relation to our hearing appreciating. And after all this theory a fine selection of special amplifiers is presented and discussed.
You will notice in this book that the author not only writes about amplifier technique, but tells about the way the development of valve amplifiers can have an influence on your daily life; even the usefulness of patents is discussed. Summarizing: new theories and solutions for perfect audio with valve amplifiers. Not only the professional and the DIY-er but everyone who wants to understand valve amplifiers will read this book with much pleasure.
A Toolbox for Audio Lovers and Engineers
Without any ambition to reach scientific levels, this book aims to be a toolbox for both audio lovers and high-end equipment designers. The elementary theory presented is the bare minimum for readers to grasp the operation and practical use of electrical, electromagnetic, physics, and electronic operations available in the designers’ toolbox. Each tool is explained in a minimum of words and theory without needless coverage of underlying equations or figures.
The book chapters guide you through the process of designing quality amplifiers with vacuum tubes, from the very beginning, considering both technical and subjective requirements – in theory and practice.
The book is a compilation of the author’s notes used in his professional and educational career but was nevertheless primarily written as a result of true love for the audiophile hobby.
A Toolbox for Audio Lovers and Engineers
Without any ambition to reach scientific levels, this book aims to be a toolbox for both audio lovers and high-end equipment designers. The elementary theory presented is the bare minimum for readers to grasp the operation and practical use of electrical, electromagnetic, physics, and electronic operations available in the designers’ toolbox. Each tool is explained in a minimum of words and theory without needless coverage of underlying equations or figures.
The book chapters guide you through the process of designing quality amplifiers with vacuum tubes, from the very beginning, considering both technical and subjective requirements – in theory and practice.
The book is a compilation of the author’s notes used in his professional and educational career but was nevertheless primarily written as a result of true love for the audiophile hobby.
Valve Amplifiers are regarded by many to be the ne plus ultra when it comes to processing audio signals. The combination of classical technology and modern components has resulted in a revival of the valve amplifier. The use of toraidal-core output transformers, developed by the author over the past 15 years, has contributed to this revival. The most remarkable features of these transformers are their extremely wide frequency ranges and their very low levels of linear and nonlinear distortion.
This book explains the whys and wherefores of toroidal output transformers at various technical levels, starting with elementary concepts and culminating in complete mathematical descriptions. In all of this, the interactions of the output valves, transformer and loudspeaker form the central theme.
Next come the practical aspects. The schematic diagram of a valve amplifier often appears to be very simple at first glance, but anyone who has built a modern valve amplifier knows that a lot of critical details are hidden behind this apparent simplicity. These are discussed extensively, in connection with designs for amplifiers with output powers ranging from 10 to 100 watts. Finally, the author gives some attention to a number of special valve amplifiers, and to the theory and practice of negative feedback.
In summary, this book offers innovative solutions for achieving perfect audio quality. Do-it-yourself builders, as well as persons who want to gain a deeper technical understanding of the complex world of audio transformers, valve amplifiers and audio signal processing, will find this book a rich and useful source of information.
50+ Android Apps with Raspberry Pi, ESP32 and Arduino
This book is about developing apps for Android compatible mobile devices using the MIT App Inventor online development environment. MIT App Inventor projects can be in either standalone mode or use an external processor. In standalone mode, the developed application runs only on the mobile device (e.g. Android). In external processor-based applications, the mobile device communicates with an external microcontroller-based processor, such as Raspberry Pi, Arduino, ESP8266, ESP32, etc.
In this book, many tested and fully working projects are given both in standalone mode and using an external processor. Full design steps, block programs, circuit diagrams, QR codes and full program listings are given for all projects.
The projects developed in this book include:
Using the text-to-speech component
Intonating a received SMS message
Sending SMS messages
Making telephone calls using a contacts list
Using the GPS and Pin-pointing our location on a map
Speech recognition and speech translation to another language
Controlling multiple relays by speech commands
Projects for the Raspberry Pi, ESP32 and Arduino using Bluetooth and Wi-Fi
MIT APP Inventor and Node-RED projects for the Raspberry Pi
The book is unique in that it is currently the only book that teaches how to develop projects using Wi-Fi and Node-RED with MIT App Inventor. The book is aimed at students, hobbyists, and anyone interested in developing apps for mobile devices.
All projects presented in this book have been developed using the MIT App Inventor visual programming language. There is no need to write any text-based programs. All projects are compatible with Android-based mobile devices. Full program listings for all projects as well as detailed program descriptions are given in the book. Users should be able to use the projects as they are presented, modifying them to suit their own needs.
This rigid end effector plate is designed to be in place of the standard AxiDraw pen-lift Z stage, and provides an alternative mounting scheme for mounting various things to the end of the AxiDraw's arm, for applications where greater rigidity is important but the lifting ability of the standard Z stage is not required.
The rigid end effector is custom machined from aluminum, and provides six M3 tapped holes and two M4 tapped holes for mounting what ever it is that you would like to mount to the end of the AxiDraw, to use it as a 2D robot arm. The hole pattern is compatible with the AxiDraw pen clip, so you can, if you like, mount the AxiDraw's pen clip to this end effector.
Installation is straightforward, but requires a Pozidrive PZ2 screwdriver, not included*. Remove the AxiDraw's pen clip, and then remove the pen-lift Z stage by removing two screws with the PZ2 screwdriver. Install the rigid end effector plate in its place, using the two included mounting screws and the PZ2 screwdriver. You may wish to also tie back or fully remove the AxiDraw's cable guides, which normally extend to power the pen-lift stage.
Specifications
Material: Anodized 6061-T6 aluminum
Size: 1.97 x 1.38 x 0.19 inches (50 x 35 x 4.8 mm)
Weight: Approximately 11 g
Mounting hardware: included (Two M4x12 pozidrive-head self-tapping screws)
Compatibility
All AxiDraw V3 family pen plotters
AxiDraw V3/A3
AxiDraw SE/A3
AxiDraw MiniKit models
This book discusses the basic components of any alarm system.
All alarm systems have two basic functions. First, they monitor their environment looking for a change such as a door or window opening or someone moving about in the room. Second, they alert the legal owner or user to this change. The system described in this book uses a scanning type software to detect intruders. It behaves like a guard dog, pacing up and down the fence line on the lookout for either an intruder or a familiar person. If you have an alarm key, you can disarm the system and enter.
With the scanning method, the software is easy to write and explain. It can scan eight alarm zones plus two special fire zones in about one second.
You don’t have to be an electrical engineer to install an alarm system, just a decent carpenter, painter, and plasterer! Because this alarm system runs on 12 volts, you don’t have to be a licensed electrician either to install it. The alarm system presented here uses Python software on the Raspberry Pi combined with some elementary electronic circuits. The code described in the book, as well as CAD files and a bill of materials for the alarm panel, are available for free downloading. The book provides the reader with examples of typical configurations coming straight from the author‘s experience. After reviewing the hardware components typically used in common alarm systems, the author shows how to plan one yourself.
To implement a modular alarm, no matter if it is for a single house or for a business or restaurant, the book shows how to skillfully combine a Raspberry Pi with small auxiliary electronic circuits. These are not installation instructions but food for thought that will enable readers to find a solution to their needs.
This book discusses the basic components of any alarm system.
All alarm systems have two basic functions. First, they monitor their environment looking for a change such as a door or window opening or someone moving about in the room. Second, they alert the legal owner or user to this change. The system described in this book uses a scanning type software to detect intruders. It behaves like a guard dog, pacing up and down the fence line on the lookout for either an intruder or a familiar person. If you have an alarm key, you can disarm the system and enter.
With the scanning method, the software is easy to write and explain. It can scan eight alarm zones plus two special fire zones in about one second.
You don’t have to be an electrical engineer to install an alarm system, just a decent carpenter, painter, and plasterer! Because this alarm system runs on 12 volts, you don’t have to be a licensed electrician either to install it. The alarm system presented here uses Python software on the Raspberry Pi combined with some elementary electronic circuits. The code described in the book, as well as CAD files and a bill of materials for the alarm panel, are available for free downloading. The book provides the reader with examples of typical configurations coming straight from the author‘s experience. After reviewing the hardware components typically used in common alarm systems, the author shows how to plan one yourself.
To implement a modular alarm, no matter if it is for a single house or for a business or restaurant, the book shows how to skillfully combine a Raspberry Pi with small auxiliary electronic circuits. These are not installation instructions but food for thought that will enable readers to find a solution to their needs.
The Raspberry Pi High Quality Camera is an affordable high-quality camera from Raspberry Pi. It offers 12-megapixel resolution and a 7.9-mm diagonal sensor for impressive low-light performance. The M12 Mount variant is designed to work with most interchangeable M12 lenses, and the CS Mount variant is designed to work with interchangeable lenses in both CS and C mount form factors (C mount lenses require the use of the C-CS adapter included with this variant). Other lens form factors can be accommodated using third-party lens adapters.
The High Quality Camera is well suited to industrial and consumer applications, including security cameras, which require the highest levels of visual fidelity and/ or integration with specialist optics. It is compatible with all models of Raspberry Pi from Model B onwards.
Specifications
Sensor
Sony IMX477R stacked, back-illuminated sensor
Resolution
12.3 megapixels
Sensor size
7.9 mm sensor diagonal
Pixel size
1.55 x 1.55 μm
Output
RAW12/10/8, COMP8
Back focus length of lens
2.6–11.8 mm (M12 Mount variant)12.5–22.4 mm (CS Mount variant)
Lens sensor format
1/2.3” (7.9 mm) or larger
IR cut filter
Integrated
Ribbon cable length
200 mm
Tripod mount
1/4”-20
Included
1x Circuit board carrying a Sony IMX477 sensor
1x FPC cable for connection to a Raspberry Pi computer
1x Milled aluminium lens mount with integrated tripod mount
1x C to CS mount adapter
3x Lens locking rings
Required
M12 Mount Lens
The Raspberry Pi High Quality Camera offers higher resolution (12 megapixels, compared to 8 megapixels), and sensitivity (approximately 50% greater area per pixel for improved low-light performance) than the existing Camera Module v2, and is designed to work with interchangeable lenses in both C and CS Mount form factors. Other lens form factors can be accommodated using third-party lens adapters.
Specifications
Sensor
Sony IMX477R stacked, back-illuminated sensor12.3 megapixels7.9 mm sensor diagonal1.55 x 1.55 μm pixel size
Output
RAW12/10/8, COMP8
Back focus
Adjustable (12.5–22.4 mm)
Lens standards
CS MountC Mount (C/CS adapter included)
IR cut filter
Integrated
Ribbon cable length
200 mm
Tripod mount
1/4”-20
Included
1x Circuit board carrying a Sony IMX477 sensor
1x FPC cable for connection to a Raspberry Pi
1x Milled aluminium lens mount with integrated tripod mount and focus adjustment ring
1x C/CS Mount adapter
Required
C/CS Mount Lens
Features Pitch spacing is 2.54 mm (1 to 36 contacts per row) with vertical orientation Number of contacts: 40 Number of rows: 2 Gender: receptacle Contact termination type: Through hole Contact Plating: Tin plated contacts High operating temperature range of -55°C to 105°C for matte tin plated contacts Contact material is phosphor bronze Black glass filled polyester insulator material Tiger Buy contact system Complies with UL E111594 and CSA 090871_0_000 standards
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by Lobna Belarbi
Kickstart Your Electronics Journey with Elektor’s Learning Collection
Whether you're new to electronics or aiming to level up your embedded skills, Elektor’s Learning Collection delivers expert-curated kits, courses, and hands-on bundles. The first...
