A Pulse Of Annoyance About Oscillators, Followed By A Flyback Of A Rant

September 26, 2023 by Jenny List 38 Comments

Everyone likes to play with high voltages, right?. Even though the danger of death goes up with every volt, it’s likely that a few readers will have at some time or other made fancy long sparks. You’re reading this so you lived to tell the tale, and we’d only ever counsel only doing so safely, but the point of this piece lies not in the volts themselves but in a touch of frustration at the voltage generators. There’s a circuit I see so often which annoys me every single time, so here if you don’t mind I’m going to deliver both a little rant and a look into flyback converters.

It’s Got Coils, so It’s A Transformer

A power supply with the lid removed, visible is a large transformer — Linear power supplies with a mains transformer are a surprisingly rare sight now. Dilshan Jayakody, CC BY-SA 2.0.

How does a transformer work? An alternating current in a primary winding induces an opposite current in its secondary winding. The voltage out is equal to the turns ratio times the voltage in. Thus if you want to make a high voltage, it’s simply a case of finding a transformer with the right turns ratio, and applying the right AC to the input.

A handy choice for a high voltage transformer has been for years a TV line output transformer, also sometimes known as a flyback transformer. You could find these in CRT displays and TVs, and they consist of a square ferrite core with a big chunky high voltage overwinding for the CRT anode circuit and a load of lower voltage windings. TV designers were always out to save on parts costs, so they often had windings for all the voltage rails inside the set as well as the anode voltage, using the timebase as a crude switching power supply. Continue reading “A Pulse Of Annoyance About Oscillators, Followed By A Flyback Of A Rant” →

Inverse Vaccines Could Help Treat Autoimmune Conditions

September 25, 2023 by Lewin Day 80 Comments

Autoimmune diseases occur when the immune system starts attacking the body’s own cells. They can cause a wide range of deleterious symptoms that greatly reduce a patient’s quality of life. Treatments often involve globally suppressing the immune system, which can lead to a host of undesirable side effects.

However, researchers at the University of Chicago might have found a workaround by tapping into the body’s own control mechanisms. It may be possible to hack the immune system and change its targeting without disabling it entirely. The new technique of creating “inverse vaccines” could revolutionize the treatment of autoimmune conditions.

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Books You Should Read: David Macaulay’s Architecture Series

September 21, 2023 by Dan Maloney 33 Comments

For a lot of us, there’s a bright line separating the books we enjoyed as children from the “real” books of our more mature years. We all eventually age out of the thin, brightly illustrated picture books we enjoyed in our youth, replacing them with thicker, wordier volumes with fewer and fewer illustrations, until they become so dense with information that footnotes and appendices are needed to convey all the information, and a well-written index is a vital necessity to make use of any of it.

Such books seem like a lot less fun than kids’ books, and they probably are, but most of us adjust to the change and accept the fact that the children’s section of the library doesn’t hold much that’ll interest us anymore. But not all the books that get a “JUV” label on their spines are created equal. Some are far more than picture books, even if the pictures are the main attraction. The books of British-born American author David Macaulay come to mind, particularly the books comprising his Architecture Series.

Macaulay’s books were enormously influential in developing my engineering sensibilities, and are still a pleasure to thumb through these many years later. I still learn something about the history of construction and engineering when I pull one of these books off the shelf, which makes them Books You Should Read.

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You’ve Got Mail: Reading Addresses With OCR

September 20, 2023 by Kristina Panos 14 Comments

Last time I delivered on this column, I told you about the USPS’ attempts to fully automate a post office. Of course, that’s a bit of a misnomer, since it took 1,500 employees to actually operate the place on a daily basis. Although Project Turnkey in Rhode Island and Project Gateway in California were proving grounds for all kinds of mail sorting and processing equipment, the act of actually reading addresses and routing mail to its final destination still required human intervention and hand coding.

Today, the post office processes hundreds of millions of mail pieces each day using various pieces of equipment. One of those important pieces of equipment is the OCR address reader, which manages to make sense of all kinds of chicken scratch.

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Scientists Call Out Apollo 17 After Investigating Moonquakes Past

September 19, 2023 by Lewin Day 35 Comments

In the vast realm of space exploration, new discoveries often emerge from old data. Thanks to advanced algorithms and keen observers, the seismic activities of our closest celestial neighbor, the Moon, have recently been thrust back into the limelight.

Thanks to the effort of the NASA crew involved in the Apollo 17 mission, it’s possible investigate these phenomena today with datasets from the past. Recently, researchers working with this data turned up some intriguing findings, and published them in a new paper. It reveals that one unexpected source of moonquakes could be the very equipment that Earth’s astronauts left behind. Continue reading “Scientists Call Out Apollo 17 After Investigating Moonquakes Past” →

The Challenge Of Weather Modification In The Face Of Climate Change

September 18, 2023 by Maya Posch 80 Comments

Over the past decades we have been able to observe a change in the Earth’s climate, caused by an increasing amount of energy being retained in the atmosphere. This in turn has affected weather systems around the globe, causing more extreme weather. As a result, the prospect of weather control is more relevant than ever for the nations which are most directly impacted by severe rain and winds. Although the concept of weather modification is not new, it used to be primarily focused on rather limited aspects, such as cloud seeding to increase precipitation.

Recent proposals such as Japan’s weather modification moonshot program seek to find ways to prevent or lessen the impact of torrential rains, typhoons and similar extreme weather events which accompany climate change. This proposal is part of Japan’s multi-topic Moonshot R&D program which seeks to advance the state of the art in a wide range of fields in a very significant way by 2050. As far as weather modification is concerned, this naturally raises many questions. Clearly we are capable of affecting the climate through emissions of e.g. greenhouse gases and large-scale construction, but are there ways in which humans can affect the climate and weather in a more refined manner that benefits society, or is this something which will remain beyond our grasp for the foreseeable future?

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Rocker Bogie Suspension: The Beloved Solution To Extra-Planetary Rovers

September 14, 2023 by Lewin Day 18 Comments

When navigating the vast and unpredictable expanses of outer space, particularly on the alien terrains of distant planets, smart engineering often underlies every major achievement. A paramount example of this is the rocker bogie suspension system. It’s an integral component of NASA’s Mars rovers and has become an iconic feature in its own right. Its success has seen the design adopted by the Indian space program and thousands of hobbyists in turn.

So, what exactly is it that makes rocker bogie suspension such a compelling design solution? Let’s dive into the engineering that makes these six-wheeled wonders so special.

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