From SRPP and Mu-Follower to OTL Designs
Tube amplifiers suffer from distortion. Fortunately, circuits such as the SRPP amplifier, mu-follower, and beta-follower produce minimal distortion even at output voltages of 50 to 100 Vpeak.
These designs are often published with errors. Without a sound understanding of the theory, it is easy to arrive at a flawed design.
In the first section of this book, we investigate the origin of distortion, while in the second we investigate the design of and SRPP and a mu-follower.
On the internet we can find the most exotic designs. Evaluating them teaches us that these designs often make matters worse rather than better. In the chapter on incorrect SRPPs and mu-followers, we sometimes see bizarre and misguided designs where using a simple single-triode amplifier would perform much better.
Push-pull output stages also exist. A great number of them are examined, and their similarity to the SRPP is discussed. This is done especially with the help of the theory behind the OTL based on the ‘mother’ of all OTLs, the Philips HF303.
Finally, attention is given to frequency characteristics and technical matters such as the supply voltage and the filament power supply.
To illustrate these points, there are a few designs covering the subjects discussed.
This book presents much new theory that has not been published before. It is often an eye-opener, showing that many things have a beautiful and unexpected simplicity.
From Theory to Practical Applications in Wireless Energy Transfer and Harvesting
Wireless power transmission has gained significant global interest, particularly with the rise of electric vehicles and the Internet of Things (IoT). It’s a technology that allows the transfer of electricity without physical connections, offering solutions for everything from powering small devices over short distances to long-range energy transmission for more complex systems.
Wireless Power Design provides a balanced mix of theoretical knowledge and practical insights, helping you explore the potential of wireless energy transfer and harvesting technologies. The book presents a series of hands-on projects that cover various aspects of wireless power systems, each accompanied by detailed explanations and parameter listings.
The following five projects guide you through key areas of wireless power:
Project 1: Wireless Powering of Advanced IoT Devices
Project 2: Wireless Powered Devices on the Frontline – The Future and Challenges
Project 3: Wireless Powering of Devices Using Inductive Technology
Project 4: Wireless Power Transmission for IoT Devices
Project 5: Charging Robot Crawler Inside the Pipeline
These projects explore different aspects of wireless power, from inductive charging to wireless energy transmission, offering practical solutions for real-world applications. The book includes projects that use simulation tools like CST Microwave Studio and Keysight ADS for design and analysis, with a focus on practical design considerations and real-world implementation techniques.
Elektor GREEN en GOLD leden kunnen deze uitgave hier downloaden.
Nog geen lid? Klik hier om een lidmaatschap af te sluiten.
USB-meetadaptertest stroom en signaalkwaliteit van USB-poorten
4...20 mA stroom-uitgang voor Arduino Unobetrouwbare, EMI-ongevoelige current loop-interface
Automatische stofzuigerschakelaarhoud uw werkplek schoon
DDS-generator met ATtiny
Opamp-tester v2nieuwe print – nu ook voor SMD’s
550-mW audio ‘Lamp-Amp’voor die warme buizenklank
Zekeringbewakerhoud zekeringen in de gaten met een knipper-LED
Hoogwaardige RIAA-voorversterkerhaal het beste uit uw vinylplaten!
Kalibratie voor draaitafelsArduino-gebaseerde 100/120Hz-stroboscoop
Elektor Classics: Video-versterker
Dimmer met IR-afstandsbedieningcomfortabel en elegant staande halogeen- of LED-lampen regelen
Het gebruik van switch…case bij strings in C++/Arduino IDE
Magneetzoekermet een eenvoudige Hall-effect-sensor
Raspberry Pi: slimme aan/uit-knopeen oplossing voor de Raspberry Pi tot aan model 4
Professionele tipsvan makers voor makers
Praktische projecten met de 555-timerDC-motorbesturing en snelle reactie-uitdaging
Eenvoudige ‘aan-verklikker’spaar energie met een simpele schakeling
Powerpacks parallelschakelendrie dagen ononderbroken stroom
VFO tot 15 MHzimplementatie met Raspberry Pi Pico
Vioolstemmer met ATtiny202
Elektor Classics: Video-ingangsversterker voor zwart/wit-TV
Capaciteitsmeter20 pF tot 600 nF
Quasi-analoog uurwerk Mk IItwee LED-ringen – voor uren en minuten
Niets is onmogelijk(met hulp van het Arduino-ecosysteem)
Neon dobbelsteen
Elektor Classics: RTTY-afstemhulp
Inspirerende hardware-ontwerpen voor uw ESP’s
Elektor Classics: 3 A voeding
RGB-LED’s met geïntegreerde stuurkringlicht met precisie: ICLED’s zetten de standaard
Experiment: een mixed-signal Theremin?moderne time-of-flight sensoren plus de tijdloze analoge XR2206
ESP32 audio-transceiver (deel 1)SD-kaart WAV-speler demo
Elektor infographicschakelingen en schakelingontwerp 2025
Kleine audiomixereenvoudig, veelzijdig en schaalbaar
Slimme timer voor trapverlichtingbespaar op uw energierekening!
Maak uw rolluiken slimmerVelux-hardware besturen met een ESP32 en MQTT
Solid-state voetenwarmercomfortabel en energiezuinig
Is de M5Stamp Fly-quadcopter de nieuwe Tello?
Vergroot het WiFi-bereik van de ESP32-C3 SuperMinieenvoudige en effectieve antennemodificatie
ZD-8968 hetelucht-soldeerstationbudgetvriendelijk werkpaard of gebakken lucht?
Parkeersensor-testervind defecten in het PDC-systeem van een auto
Diese Ausgabe steht allen GOLD- und GREEN-Mitgliedern auf der ElektorMagazine-Website zum Download bereit!
Sie sind noch kein Mitglied? Hier klicken!
PIO-Programmierung des Raspberry Pi PicoNeun Befehle, viele Möglichkeiten
KI aus dem Browser befreienSo nutzen Sie KI-CLIs zum Programmieren, Kompilieren und Validieren von Embedded-Projekten
Der Scrutiny DebuggerDebuggen, Visualisieren und Testen von Embedded-C/C++ Code
Sigfox-Breakout-Board (Teil 1)Ein selbst gebautes Funk-BoB
Rauscharmes Labor-Netzteil (Teil 2)Konstruktion, Montage und praktische Implementierung
Einfacher Signalgenerator mit dem RP2040Analoge und digitale Signale für rund 10 Euro
Matter und Edge-KI für die Smart Homes der ZukunftBieten die neuesten Updates von Matter und der Aufstieg der Edge-KI Entwicklern endlich die Werkzeuge, um das versprochene intelligente und vernetzte Smart Home zu schaffen?
Die SMU für alleSiglent bringt die SMM3000X-Serie auf den Markt
DifferenzdrucksensorenVorausschauende Wartung in HLK-Systemen
Security by DesignSchadensbegrenzung durch Entwicklungsprinzipien
Embedded Security ist nicht mehr optional
CRA und PQC setzen neue Prioritäten für Embedded-SicherheitWarum auch kleine IoT- und Industrie-Unternehmen einen Upgrade-Plan benötigen
embedded world 2026Interview mit Benedikt Weyerer, Executive Director der embedded world
I3C in der PraxisMit Hardware von ST und Microchip
Das BLEnky-ProjektSchnelles Prototyping für Bluetooth-Low-Energy-Anwendungen
PulsbreitensteuerungVom einfachen Thermostat bis zum geglätteten Analogsignal
AudiotronicsKlangvolle Elektronik zum Selberbauen
ESP32-Audio-Transceiver-Board (Teil 4)Taktsynchronisation – und eine kabelgebundene Option
2026: Eine KI-OdysseeDer Vibe-Coding-Kater von 2025
Symmetrische DC-LastGleichstromlast, statisch oder dynamisch und symmetrisch
Gesichter zählen mit MaixCAMEine einfache Methode zur Erfassung von Publikumsgrößen
Ready-to-use devices and self-built Arduino nodes in the 'The Things Network'
LoRaWAN has developed excellently as a communication solution in the IoT. The Things Network (TTN) has contributed to this. The Things Network was upgraded to The Things Stack Community Edition (TTS (CE)). The TTN V2 clusters were closed towards the end of 2021.
This book shows you the necessary steps to operate LoRaWAN nodes using TTS (CE) and maybe extend the network of gateways with an own gateway. Meanwhile, there are even LoRaWAN gateways suitable for mobile use with which you can connect to the TTN server via your cell phone.
The author presents several commercial LoRaWAN nodes and new, low-cost and battery-powered hardware for building autonomous LoRaWAN nodes. Registering LoRaWAN nodes and gateways in the TTS (CE), providing the collected data via MQTT and visualization via Node-RED, Cayenne, Thingspeak, and Datacake enable complex IoT projects and completely new applications at very low cost.
This book will enable you to provide and visualize data collected with battery-powered sensors (LoRaWAN nodes) wirelessly on the Internet. You will learn the basics for smart city and IoT applications that enable, for example, the measurement of air quality, water levels, snow depths, the determination of free parking spaces (smart parking), and the intelligent control of street lighting (smart lighting), among others.
Learn, Build, and Understand Electronics – with Elektor
Projects, Expert Knowledge, Archive Access, and Exclusive Discounts – All in One Membership
Would you like to learn electronics, develop your own circuits, and gain a better understanding of modern technologies? Elektor Magazine has been one of the leading sources of information for electronics engineers, developers, start-ups, and companies for 65 years. With an Elektor Green Membership, you get:
✅ The international electronics magazine Elektor (in digital format)
✅ Access to the Elektor archive with 65 years of electronics know-how
✅ DIY projects, tested circuits, in-depth reviews and tutorials
✅ Exclusive member discounts at Elektor.com
Why Elektor?
For 65 years, Elektor has stood for in-depth electronics knowledge, practical projects, and innovative technologies.
From microcontrollers and embedded systems to Raspberry Pi, Arduino, and ESP32, as well as IoT, AI, measurement technology, audio, RF, and robotics, Elektor covers the key platforms and application areas of modern electronics.
Whether you are a beginner, maker, or professional – Elektor helps you take your skills to the next level.
Who Is This Membership for?
Beginners – Start your journey into electronics with clear fundamentals and first projects
Makers – Discover new projects, ideas, and inspiration for your own developments
Professionals & Engineers – Stay up to date with modern technologies and deepen your expertise
Your Benefits at a Glance
Magazine (Digital) – Receive every issue digitally, delivered straight to your inbox
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Unlock All Elektor Benefits Today!
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❌ 8x Elektor Magazine (Digital Edition) as PDF
✅ 8x Elektor Magazine (Digital Edition) as PDF
❌ 12 Months of Access to the Full Elektor Archive
✅ 12 Months of Access to the Full Elektor Archive
❌ Access to Over 5,000 Gerber Files
✅ Access to Over 5,000 Gerber Files
❌ 10% Member Discount at Elektor.com
✅ 10% Member Discount at Elektor.com
✅ Read Elektor weekly every Friday
✅ Read Elektor weekly every Friday
ℹ️ Do you prefer reading Elektor Magazine in print? Find out everything about the Elektor Gold Membership (Print) here.
Practical Introduction to 3D Modeling from Enclosure to Front Panel
Embedding a vintage component, creating a professional looking home for a circuit board, or even designing a complex apparatus complete with a chassis – these and many other challenges turn into a stimulating pleasure with FreeCAD. Once you have internalized the basic processes, there are virtually no limits to your imagination.
Starting to use a new software is never straightforward – especially with a tool as versatile as FreeCAD. Manageable, but at the same time easily usable individual components provide the starting point in this book. Putting these components together later results in assemblies.
In the FreeCAD universe, a workable trajectory is demonstrated. The described procedure is illustrative so the examples are easily applied to custom tasks. The devices were made by the author and illustrated with photos.
Creating a 3D design is requiring some effort but the initial investment pays off soon. Besides the impressive spatial representation of the projects, the extracted drawings yield a solid base for documentation and production. Extended FreeCAD capabilities like the unfolding of sheet metal parts enormously add to efficiency and pushes models forward into practical assembly.
Soon you will definitely not want to do without FreeCAD!
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.
From Rubbing Amber to Swiping Glass
"The story of electricity, told one connection at a time."Why does rubbing amber attract dust? How did we go from that curious effect to a world where screens respond to a single touch? And how did we get from mysterious sparks to tiny chips packed with billions of transistors?
For centuries, electricity puzzled and fascinated those who encountered its curious effects—long before it even had a name. From the earliest observations of static charge to the complex electronics that shape our lives today, this book traces the gradual, and often surprising, story of how humanity came to understand and harness this powerful force.
This book offers an engaging and accessible account of the people, ideas, and inventions that transformed electricity from a scientific curiosity into the foundation of our digital age. Along the way, you’ll meet a host of inquisitive minds—some famous, others less so—whose persistence and creativity helped unravel the mysteries of the natural world and gave rise to the technologies we now take for granted.
Covering everything from Leyden jars and batteries to transistors, microcontrollers and the internet, this book presents a clear and enjoyable overview of electronics and its relatively short, yet rich, history.
Whether you have a technical background or simply a curiosity about how things work, From Rubbing Amber to Swiping Glass offers a thoughtful look at how far we’ve come—and a gentle nudge to wonder what might come next.
Like its predecessors in the 300 series of electronics projects books, 303 Circuits is aimed at the active electronics enthusiast, professional or amateur. Since the series was started in the early 1980s, many thousands of readers have found in these books that new approach, new concept, or new circuit they were looking for.
In 303 Circuits you will find new ideas, new concepts and new circuits covering the gamut of electronics. The book is arranged in subject sections to make it easier for you to find the circuit or idea you are looking for.
This bundle contains the popular Elektor Sand Clock for Raspberry Pi Pico and the new Elektor Laser Head Upgrade, offering even more options for displaying the time. Not only can you "engrave" the current time in sand, you can now alternatively write it on a glow-in-the-dark foil or create green drawings.
Contents of the bundle
Elektor Sand Clock for Raspberry Pi Pico (normal price: €50)
Elektor Laser Head Upgrade for Sand Clock (normal price: €35)
Elektor Sand Clock for Raspberry Pi (Raspberry Pi-based Eye Catcher)
A standard sand clock just shows how time passes. In contrast, this Raspberry Pi Pico-controlled sand clock shows the exact time by "engraving" the four digits for hour and minute into the layer of sand. After an adjustable time the sand is flattened out by two vibration motors and everything begins all over again.
At the heart of the sand clock are two servo motors driving a writing pen through a pantograph mechanism. A third servo motor lifts the pen up and down. The sand container is equipped with two vibration motors to flatten the sand. The electronic part of the sand clock consists of a Raspberry Pi Pico and an RTC/driver board with a real-time clock, plus driver circuits for the servo motors.
A detailed construction manual is available for downloading.
Features
Dimensions: 135 x 110 x 80 mm
Build time: approx. 1.5 to 2 hours
Included
3x Precut acrylic sheets with all mechanical parts
3x Mini servo motors
2x Vibration motors
1x Raspberry Pi Pico
1x RTC/driver board with assembled parts
Nuts, bolts, spacers, and wires for the assembly
Fine-grained white sand
Elektor Laser Head Upgrade for Sand Clock
The new Elektor Laser Head transforms the Sand Clock into a clock that writes the time on glow-in-the-dark film instead of sand. In addition to displaying the time, it can also be used to create ephemeral drawings. The 5 mW laser pointer, with a wavelength of 405 nm, produces bright green drawings on the glow-in-the-dark film. For best results, use the kit in a dimly lit room. Warning: Never look directly into the laser beam!
The kit includes all the necessary components, but soldering three wires is required.
Note: This kit is also compatible with the original Arduino-based Sand Clock from 2017. For more details, see Elektor Magazine 1-2/2017 and Elektor Magazine 1-2/2018.
