The author recounts their frustrating experience trying to replicate a classic Hall effect experiment to determine the band structure of germanium. Despite meticulous preparation and following established procedures, their results consistently deviated significantly from expected values. This led them to suspect systematic errors stemming from equipment limitations or unforeseen environmental factors, ultimately concluding that accurately measuring the Hall coefficient in a basic undergraduate lab setting is far more challenging than textbooks suggest. The post highlights the difficulties of practical experimentation and the gap between theoretical ideals and real-world results.
This report presents compact models for advanced transistors like FinFETs and gate-all-around (GAA) devices, focusing on improving accuracy and physical interpretability while maintaining computational efficiency. It explores incorporating non-quasi-static effects, crucial for high-frequency operation, into the surface-potential-based models. The work details advanced methods for modeling short-channel effects, temperature dependence, and variability, leading to more predictive simulations. Ultimately, the report provides a framework for developing compact models suitable for circuit design and analysis of modern integrated circuits with these complex transistor structures.
HN users discuss the challenges of creating compact models for advanced transistors, highlighting the increasing complexity and the difficulty of balancing accuracy, computational cost, and physical interpretability. Some commenters note the shift towards machine learning-based models as a potential solution, albeit with concerns about their "black box" nature and lack of physical insight. Others emphasize the enduring need for physics-based models, especially for understanding device behavior and circuit design. The limitations of current industry-standard models like BSIM are also acknowledged, alongside the difficulty of validating models against real-world silicon behavior. Several users appreciate the shared resource and express interest in the historical context of model development.
Researchers have created remarkably thin films of molybdenum disulfide (MoS₂) that exhibit significantly better electrical conductivity than conventional copper films of the same thickness. This enhanced conductivity is attributed to defects within the MoS₂ lattice, specifically sulfur vacancies, which create paths for electrons to flow more freely. These ultrathin films, potentially just three atoms thick, could revolutionize electronics by enabling smaller, faster, and more energy-efficient devices. This advancement represents a significant step towards overcoming the limitations of copper interconnects in advanced chip designs.
HN commenters discuss the surprising finding that thinner films conduct better than bulk copper, expressing skepticism and exploring potential explanations. Some suggest the improved conductivity might be due to reduced grain boundaries in the thin films, allowing electrons to flow more freely. Others question the practicality due to current-carrying capacity limitations and heat dissipation issues. Several users highlight the importance of considering the full context of the research, including the specific materials and testing methodologies, before drawing definitive conclusions. The impact of surface scattering on conductivity is also raised, with some suggesting it becomes more dominant in thinner films, potentially counteracting the benefits of reduced grain boundaries. Finally, some commenters are curious about the potential applications of this discovery, particularly in high-frequency electronics where skin effect already limits current flow to the surface of conductors.
"Designing Electronics That Work" emphasizes practical design considerations often overlooked in theoretical learning. It advocates for a holistic approach, considering component tolerances, environmental factors like temperature and humidity, and the realities of manufacturing processes. The post stresses the importance of thorough testing throughout the design process, not just at the end, and highlights the value of building prototypes to identify and address unforeseen issues. It champions "design for testability" and suggests techniques like adding test points and choosing components that simplify debugging. Ultimately, the article argues that robust electronics design requires anticipating potential problems and designing circuits that are resilient to real-world conditions.
HN commenters largely praised the article for its practical, experience-driven advice. Several highlighted the importance of understanding component tolerances and derating, echoing the author's emphasis on designing for real-world conditions, not just theoretical values. Some shared their own anecdotes about failures caused by overlooking these factors, reinforcing the article's points. A few users also appreciated the focus on simple, robust designs, emphasizing that over-engineering can introduce unintended vulnerabilities. One commenter offered additional resources on grounding and shielding, further supplementing the article's guidance on mitigating noise and interference. Overall, the consensus was that the article provided valuable insights for both beginners and experienced engineers.
"Anatomy of Oscillation" explores the ubiquitous nature of oscillations in various systems, from physics and engineering to biology and economics. The post argues that these seemingly disparate phenomena share a common underlying structure: a feedback loop where a system's output influences its own input, leading to cyclical behavior. It uses the example of a simple harmonic oscillator (a mass on a spring) to illustrate the core principles of oscillation, including the concepts of equilibrium, displacement, restoring force, and inertia. The author suggests that understanding these basic principles can help us better understand and predict oscillations in more complex systems, ultimately offering a framework for recognizing recurring patterns in seemingly chaotic processes.
Hacker News users discussed the idea of "oscillation" presented in the linked Substack article, primarily focusing on its application in various fields. Some commenters questioned the novelty of the concept, arguing that it simply describes well-known feedback loops. Others found the framing helpful, highlighting its relevance to software development processes, personal productivity, and even biological systems. A few users expressed skepticism about the practical value of the framework, while others offered specific examples of oscillation in their own work, such as product development cycles and the balance between exploration and exploitation in learning. The discussion also touched upon the optimal frequency of oscillations and the importance of recognizing and managing them for improved outcomes.
This post discusses the nuances of ground planes and copper pours in PCB design, emphasizing that they are not automatically equivalent. While both involve areas of copper, a ground plane is a specifically designated layer for current return paths, offering predictable impedance and reducing EMI. Copper pours, on the other hand, can be connected to any net and are often used for thermal management or simple connectivity. Blindly connecting pours to ground without understanding their impact can negatively affect signal integrity, creating unintended ground loops and compromising circuit performance. The author advises careful consideration of the desired function (grounding vs. thermal relief) before connecting a copper pour, potentially using distinct nets for each purpose and strategically stitching them together only where necessary.
Hacker News users generally praised the article for its clarity and practical advice on PCB design, particularly regarding ground planes. Several commenters shared their own experiences and anecdotes reinforcing the author's points about the importance of proper grounding for signal integrity and noise reduction. Some discussed specific techniques like using stitching vias and the benefits of a solid ground plane. A few users mentioned the software they use for PCB design and simulation, referencing tools like KiCad and LTspice. Others debated the nuances of ground plane design in different frequency regimes, highlighting the complexities involved in high-speed circuits. One commenter appreciated the author's focus on practical advice over theoretical explanations, emphasizing the value of the article for hobbyists and beginners.
This post explores Oliver Heaviside's crucial role in developing the theory of transmission lines. It details how Heaviside simplified Maxwell's equations, leading to the "telegrapher's equations" which describe voltage and current behavior along a transmission line. He introduced the concepts of inductance, capacitance, conductance, and resistance per unit length, enabling practical calculations for long-distance telegraph cables. Heaviside also championed the use of loading coils to compensate for signal distortion, significantly improving long-distance communication, despite initial resistance from prominent physicists like William Preece. The post highlights Heaviside's often-overlooked contributions and emphasizes his practical, results-oriented approach, contrasting it with the more theoretical perspectives of his contemporaries.
Hacker News users discuss Heaviside's contributions to transmission line theory and his difficult personality. Several commenters highlight his impressive ability to intuitively grasp complex concepts and perform calculations, despite lacking formal mathematical rigor. One notes Heaviside's development of operational calculus, which was later formalized by mathematicians. Others discuss his conflicts with the scientific establishment, attributed to his unconventional methods and abrasive personality. His insistence on using vectors and his operational calculus, initially viewed with skepticism, ultimately proved crucial for understanding electromagnetic phenomena. Some lament the lack of recognition Heaviside received during his lifetime. The discussion also touches upon his eccentric lifestyle and social isolation.
The post explores how the seemingly simple problem of calculating the equivalent capacitance of an infinite ladder network of capacitors can be elegantly solved using the concept of geometric series. By recognizing the self-similar nature of the circuit as sections are added, the problem is reduced to a quadratic equation where the equivalent capacitance of the infinite network is expressed in terms of the individual capacitances. This demonstrates a practical application of mathematical concepts to circuit analysis, highlighting the interconnectedness between seemingly disparate fields.
HN commenters generally praised the article for its clear explanation of how capacitors work, particularly its use of the geometric series analogy to explain charging and discharging. Some appreciated the interactive diagrams, while others suggested minor improvements like adding a discussion of dielectric materials and their impact on capacitance. One commenter pointed out a potential simplification in the derivation by using the formula for the sum of a geometric series directly. Another highlighted the importance of understanding the underlying physics rather than just memorizing formulas, praising the article for facilitating this understanding. A few users also shared related resources and alternative explanations of capacitor behavior.
In 1996, workers at a 3M plant reported encountering an invisible "force field" that prevented them from passing through a specific doorway. This phenomenon, dubbed the "electrostatic wall," was caused by a combination of factors including plastic film, shoes with insulating soles, low humidity, and a grounded metal doorframe. The moving film generated static electricity, charging the workers. Their insulated shoes prevented this charge from dissipating, leading to a buildup of voltage. When the charged workers approached the grounded doorframe, the potential difference created a strong electrostatic force, producing a noticeable repelling sensation, effectively creating an invisible barrier. This force was strong enough to prevent passage until the workers touched the frame to discharge.
Hacker News users discuss various aspects of the electrostatic wall phenomenon. Some express skepticism, suggesting the effect could be psychological or due to air currents. Others offer alternative explanations like the presence of a thin film or charged dust particles creating a barrier. Several commenters delve into the physics involved, discussing the potential role of high voltage generating a strong electric field capable of repelling objects. The possibility of ozone generation and its detection are also mentioned. A few share personal experiences with static electricity and its surprising strength. Finally, the lack of video evidence and the single anecdotal source are highlighted as reasons for doubt.
Summary of Comments ( 33 )
https://news.ycombinator.com/item?id=43545917
Hacker News users discuss the linked blog post, which humorously details the author's struggles to reproduce a classic 1954 paper on germanium's band structure. Commenters generally appreciate the author's humor and relatable frustration with reproducing old scientific results. Several share similar experiences of struggling with outdated methods or incomplete information in older papers. Some highlight the difficulty in accessing historical computing resources and the challenge of interpreting old notations and conventions. Others discuss the evolution of scientific understanding and the value of revisiting foundational work, even if it proves difficult. A few commenters express admiration for the meticulous work done in the original paper, given the limitations of the time.
The Hacker News post titled "Electron Band Structure in Germanium, My Ass" (linking to an article about supposed hidden messages in a scientific paper) sparked a lively discussion with several insightful comments.
Many commenters focused on the plausibility of the hidden message theory. Some expressed skepticism, pointing out the unlikelihood of such an elaborate scheme. They argued that the seemingly hidden message could be a result of coincidence, the author's personal style, or even a form of inside joke among researchers. These commenters emphasized the importance of Occam's razor, suggesting that the simplest explanation (no hidden message) is likely the correct one. They questioned the motivation behind such an elaborate hoax, particularly given the potential risks to the author's career if discovered.
Other commenters, while not fully endorsing the hidden message theory, entertained the possibility. They acknowledged the intriguing nature of the "evidence" presented in the linked article and discussed how, if true, it would be a fascinating example of academic rebellion or a unique form of personal expression. These commenters often focused on the cultural context of academia in the 1950s, speculating on the pressures and constraints faced by researchers at the time.
A few commenters delved into the technical aspects of the paper and the alleged hidden message. They discussed the methods used to encode and decode the message, and debated the statistical significance of the findings. Some commenters with expertise in materials science or related fields offered their perspectives on the scientific content of the original Germanium paper, providing context for the discussion.
Several commenters also explored the broader implications of such hidden messages in scientific literature. They considered the ethical and professional ramifications, and discussed the potential for similar hidden messages in other publications. This led to a discussion about the nature of scientific communication and the importance of transparency and integrity.
Finally, some comments offered humorous takes on the situation, making light of the absurdity of the hidden message theory. These comments injected levity into the discussion and provided a counterpoint to the more serious analyses.
Overall, the comments on the Hacker News post represent a diverse range of perspectives on the hidden message theory. While skepticism dominated, the discussion also included nuanced considerations of the evidence, the context, and the broader implications of such a scenario.