New encapsulation technique protects electronic properties of sensitive materials

Researchers are searching for tiny components that function reliably in increasingly narrow electronic configurations. Promising elements include the chemical compounds indium selenide and gallium selenide. As ultra-thin layers, they form two-dimensional semi-conductors. So far, they have hardly been used because they degrade when they get in contact with air. A new technique allows the sensitive material to be integrated in electronic components without losing its desired properties.

Making sense of flexible sensor systems

A team of researchers have developed the world's thinnest and lightest magnetic sensor matrix sheet system that visualizes the two-dimensional distribution of magnetism on various surfaces, with a sensitivity ten times higher than that of conventional systems. The researchers consider applications of the 'skin-like' magnetic sensor to damage detection in reinforced buildings and high-precision medical diagnosis.

Nano-thin flexible touchscreens could be printed like newspaper

Taking a thin film common in cell phone touchscreens, researchers have used liquid metal chemistry to shrink it from 3D to 2D. The ultra-thin and ultra-flexible electronic material could be printed and rolled out like newspaper, for the touchscreens of the future.

AC vs DC: The difference between alternating and direct current

The difference between Alternating Current (AC) and Direct Current (DC) is simple. AC vs DC comes down to in which direction the current flows. AC is a current that alternates its direction. It goes back and forth continuously. DC is a current that flows in one direction.

Current flow in a DC circuit:

For example, a battery provides direct current. The current only flows one way out of a battery.

The current flow in an AC circuit:

In your wall sockets, you have AC. The current keeps changing direction about 50 to 60 times per second. But for many things, you have adapters that convert it into DC before it is used by a circuit.

(Although, it could as well have been DC in our walls if Edison had won the AC vs DC war back in the late 1800s against Tesla.)

AC vs DC in circuits

You usually need DC to power most things in electronics. I’ve never had the need for a power supply that outputs AC.

But you might find that you have AC in parts of your circuit. For example in audio circuits, radio circuits, or in power supplies.

The AC part is usually either a signal that represents something, like sound. Or an oscillating voltage to send a signal out into the field, like a radio transmitter.

Learn Electronics

If you’re looking to learn electronics, I recommend you focus on learning DC circuits. Knowing what AC is, is great to know. But most of the AC circuit lessons I’ve seen out there are focused on mathematical formulas – and don’t need it until you get to a more advanced level in electronics.

If you want to learn electronics from scratch, you’re invited to join us over at Ohmify. With more than 300 lessons to choose from and a friendly community of like-minded people to help you. And at the Ohmify forum, no question is too basic.

What are your biggest questions when it comes to AC vs DC? Let me know in the comments below.

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Method detects defects in 2D materials for future electronics, sensors

To further shrink electronic devices and to lower energy consumption, the semiconductor industry is interested in using 2D materials, but manufacturers need a quick and accurate method for detecting defects in these materials to determine if the material is suitable for device manufacture. Now a team of researchers has developed a technique to quickly and sensitively characterize defects in 2D materials.

New stretchable battery can power wearable electronics

The adoption of wearable electronics has so far been limited by their need to derive power from bulky, rigid batteries that reduce comfort and may present safety hazards due to chemical leakage or combustion. Researchers have now developed a soft and stretchable battery that relies on a special type of plastic to store power more safely than the flammable formulations used in conventional batteries today.

Blue-emitting diode demonstrates limitations and promise of perovskite semiconductors

Halide perovskites have garnered attention because they're highly efficient at capturing energy in solar cells and efficient emitters in diodes. But researchers failed at making perovskite LEDs that emit blue light. Chemists succeeded, but X-ray studies of the LED's structure show that it's very sensitive to temperature, humidity and chemical environment. Hence environmental and chemical control is essential for stable operation. But these properties also allow for potentially broader use, such as sensors.

Microchip capability expanded ewith new 3D inductor technology

Smaller is better when it comes to microchips, researchers said, and by using 3D components on a standardized 2D microchip manufacturing platform, developers can use up to 100 times less chip space. A team of engineers has boosted the performance of its previously developed 3D inductor technology by adding as much as three orders of magnitudes more induction to meet the performance demands of modern electronic devices.

Integrating micro chips for electronic skin

Researchers present the first fully integrated flexible electronics made of magnetic sensors and organic circuits which opens the path towards the development of electronic skin.

New material is heat-insulating and heat-conducting at the same time

Scientists have developed and characterized a novel, extremely thin and transparent material that has different thermal conduction properties depending on the direction. While it can conduct heat extremely well in one direction, it shows good thermal insulation in the other direction.

Coating helps electronics stay cool by sweating

Mammals sweat to regulate body temperature, and researchers are exploring whether our phones could do the same. The authors present a coating for electronics that releases water vapor to dissipate heat from running devices -- a new thermal management method that could prevent electronics from overheating and keep them cooler compared to existing strategies.

Designer-defect clamping of ferroelectric domain walls for more-stable nanoelectronics

Engineered defects in ferroelectric materials provides key to improved polariaztion stability, a significant step forward for domain-wall nanoelectronics in data storage. Researchers achieved stability greater than one year (a 2000% improvement).

Buckyballs can pave the way for molecular electronics

Organic self-assembled monolayers (SAMs) have been around for over forty years. The most widely used form is based on thiols, bound to a metal surface. However, exposure of these monolayers to air will lead to breakdown within a single day. Scientists have now created SAMs using buckyballs functionalized with 'tails' of ethylene glycol. These have all the properties of thiol SAMs but remain chemically unchanged for several weeks when exposed to air.

Electron spins in slowly moving quantum dots may be controlled by electric fields

A new article presents a theoretical analysis of electron spins in moving semiconductor quantum dots, showing how these can be controlled by electric fields in a way that suggests they may be usable as information storage and processing components of quantum computers.

Simple VU-Meter Circuit

I put together this Voltage Unit (VU) meter using LEDs on a breadboard the other day. It only has 4 LEDs, but can easily be expanded to more:

It’s basically a simple display for showing a value. It’s originally for showing signal level in audio circuits, but there’s no reason you can’t use it to show temperature, rain intensity, light level, or whatever other value you are measuring.

In the video above, I added a potentiometer as a voltage divider between 9V and 0V, so that the output would be somewhere in between. This way I could easily test the VU meter.

If you want it to show audio level or any other signal with very low voltage, replace the potentiometer with an amplifier.

Here’s the circuit diagram:

The Qs are NPN transistors. I used BC547.

D1-D3 are standard diodes. I used 1N4007.

R1 to R4 are there to limit the current to the LEDs, and I used 1k.

R5 to R8 are there to limit the current through the transistors. I forgot what I used, but anywhere from 1k to 10k I think should work.

The potentiometer I connected between 9V and 0V. And the middle pin I connected to the “Input Voltage” port.

If you want this, but think there are too many components, an alternative is using the LM3914 IC.

Have you built this circuit or something similar? Let me know in the comments below!

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Toward safer disposal of printed circuit boards

Printed circuit boards are vital components of modern electronics. However, once they have served their purpose, they are often burned or buried in landfills, polluting the air, soil and water. Most concerning are the brominated flame retardants added to printed circuit boards to keep them from catching fire. Now, researchers have developed a ball-milling method to break down these potentially harmful compounds, enabling safer disposal.

Colloidal quantum dot laser diodes are just around the corner

Scientists have incorporated meticulously engineered colloidal quantum dots into a new type of light emitting diodes (LEDs) containing an integrated optical resonator, which allows them to function as lasers. These novel, dual-function devices clear the path towards versatile, manufacturing-friendly laser diodes. The technology can potentially revolutionize numerous fields from photonics and optoelectronics to chemical sensing and medical diagnostics.

Researchers solve a scientific mystery about evaporation

Evaporation can explain why water levels drop in a full swimming pool, but it also plays an important role in industrial processes ranging from cooling electronics to power generation. Researchers now have reported a discovery that answers some fundamental questions about the process, which until now had remained a mystery.

An 18-carat gold nugget made of plastic

Researchers have created an incredibly lightweight 18-carat gold, using a matrix of plastic in place of metallic alloy elements.

New method gives robust transistors

A new method to fit together layers of semiconductors as thin as a few nanometers has resulted in not only a scientific discovery but also a new type of transistor for high-power electronic devices.

Exploring the 'dark side' of a single-crystal complex oxide thin film

A new study offers a nanoscopic view of complex oxides, which have great potential for advanced microelectronics.

End of year notes from Oyvind

So I just realized today that it’s not only a new year we are entering into…

We’re entering into a new decade!

I’ve been teaching electronics for about ten years now.

And it’s been a crazy ride:

From teaching a small group of students as a teaching assistant at the University – to reaching millions of people through my books, articles, videos, newsletter, workshops and online courses.

​In 2019 I focused on reinventing Ohmify.

It used to be a collection of courses.

But the thing is that you don’t learn to build your own projects with electronics by watching some videos for a week.

You need to build several projects. You need to fail. You need to learn more. Fail more. Ask for help. Then succeed. Then try something harder.

And you never “finish”.

It’s like learning to draw. Or to play the guitar. You might learn to play a song in a day. But there’s always more to learn. You can always get better. You can always learn new songs, new techniques.

​So I reinvented Ohmify to support you do this.

I developed more learning material. And I experienced with different formats:

Like weekly online workshops that I developed week-by-week. And draft lessons I published after the first draft to get feedback and questions.

All based on what you were asking for.

​But the biggest change I did was to set up a community forum…

Everyone needs to learn the same fundamentals to get a basic understanding of electronics. But after that, there are hundreds of paths to take!

Maybe you have a specific goal of lighting up some LEDs with a remote-control?

Maybe you want to custom-fit electromotors on your child’s Brio train to make it remote-controlled?

Or maybe you’re more interested in learning all the ins and outs of sensors to create your own custom weather station?

In the forum, everyone can get individual help with their own unique path.

​And not just from me.

It’s the members that really make up the community.

As we’re entering a new decade, I have no idea what the next ten years have in store for me…

But I’ll continue to develop Ohmify and help our members.

Probably launch a few crazy projects along the way.

And welcome whatever else the universe has in store for me.

Happy New Year to you!

​

Keep On Soldering!

Oyvind @ build-electronic-circuits.com

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