Static Electricity And The Machines That Make It

Static electricity often just seems like an everyday annoyance when a wool sweater crackles as you pull it off, or when a doorknob delivers an unexpected zap. Regardless, the phenomenon is much more fascinating and complex than these simple examples suggest. In fact, static electricity is direct observable evidence of the actions of subatomic particles and the charges they carry.

While zaps from a fuzzy carpet or playground slide are funny, humanity has learned how to harness this naturally occurring force in far more deliberate and intriguing ways. In this article, we’ll dive into some of the most iconic machines that generate static electricity and explore how they work.

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Hackaday Links: Some Sort Of Fool’s Day, 2018

A few years ago, writing for a blog called Motherboard of all things, [Emanuel Maiberg] wrote PC Gaming Is Still Way Too Hard. The premise is that custom building a gaming PC is too hard, because you have to source components and comparison shop. Again, this was written for Motherboard. Personally, I would have shopped that story around a bit more. Now, the same author is back again, telling us PC Building Simulator is way more fun than building a real computer. It’s my early nomination for worst tech article of the year.

Speaking of motherboards, This is a GoFundMe project to re-create the Amiga 4000 mainboard, with schematics. Building PCs is too hard, but the Amiga architecture is elegant. Some of these boards are dying due to electrolytic capacitor and battery leakage. This project is aiming to deconstruct an original A4000 board and turn it into Gerbers and schematics, allowing new boards to be manufactured. Building a PC is way too hard, but with this GoFundMe, you won’t have to design an entire system from scratch. Don’t worry, I already tipped off the Motherboard editors to this one.

Alright, story time. In 6th grade science class, the teacher was awesome. On the days when there was really no chance of any learning happening (the day before Christmas break, the last day of school), the teacher broke out the Electric Chicken. What’s an Electric Chicken? It’s a test tube rack, two wires, and a Wimshurst generator. “Here, grab ahold of this for as long as you can.” It got even cooler when you get a bunch of kids to hold hands and tell them pride is better than pain. Here’s a Kickstarter for a mini Wimshurst generator. It’s made out of PCBs! Hat tip to [WestfW] for finding this one.

It’s no secret that I get a lot of dumb press releases. Most of these are relegated to the circular file folder. It’s also no secret I get a lot of ICO announcements hitting my email. These, also, are trashed. I recently received a press release for an ICO that goes beyond anything else. ONSTELLAR is a blockchain-powered social media network for paranormal and metaphysical enthusiasts.  It’s the crypto for Coast to Coast AM listeners, UFO enthusiasts, and people who think PKE meters are real. This is it, we’ve reached peak crypto.

If you want to decapsulate an IC — and why wouldn’t you? — the usual way of doing things involves dropping acid, ego death, toxic chemicals, and a fume hood. There is another way. Here’s [A Menadue] decapping a quartz watch IC with just fire. The process is about as ‘hold my beer’ as you would expect. Just take a small butane torch, heat up a chip, and recover the die. A bit of ultrasonic cleaning later and you get a pretty clean chip. Microscope not included.

Bicycle Racing In Space Could Be A Thing

It’s 2100 AD, and hackers and normals live together in mile-long habitats in the Earth-Moon system. The habitat is spun up so that the gravity inside is that of Earth, and for exercise, the normals cycle around on bike paths. But the hackers do their cycling outside, in the vacuum of space.

How so? With ion thrusters, rocketing out xenon gas as the propellant. And the source of power? Ultimately that’s the hackers’ legs, pedaling away at a drive system that turns two large Wimshurst machines.

Those Wimshurst machines then produce the high voltage needed for the thruster’s ionization as well as the charge flow. They’re also what gives the space bike it’s distinctly bicycle-like appearance. And based on the calculations below, this may someday work!

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Wimshurst Machines: High Voltage From The Gods

Wimshurst machine demo
Wimshurst machine demo

The Wimshurst machine is one of the oldest and best known electrostatic machines, consisting of its iconic two counter rotating disks and two Leyden jars. Most often you see someone hand cranking it, producing sparks, though we’ve seen it used for much more, including for powering a smoke precipitator for cleaning up smoke and even for powering a laser.

It works through an interesting sequence of events. Most explanations attempt to cram it all into one picture, requiring some major mental gymnastics to visualize. This often means people give up, resigned to assume these work through some mythical mechanics that defy a mortal’s ability to understand.

So instead, let’s do a step-by-step explanation.

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High Voltage Please, But Don’t Forget The Current

In high voltage applications involving tens of thousands of volts, too often people think about the high voltage needed but don’t consider the current. This is especially so when part of the circuit that the charge travels through is an air gap, and the charge is in the form of ions. That’s a far cry from electrons flowing in copper wire or moving through resistors.

Consider the lifter. The lifter is a fun, lightweight flying machine. It consists of a thin wire and an aluminum foil skirt separated by an air gap. Apply 25kV volts across that air gap and it lifts into the air.

So you’d think that the small handheld Van de Graaff generator pictured below, that’s capable of 80kV, could power the lifter. However, like many high voltage applications, the lifter works by ionizing air, in this case ionizing air surrounding the thin wire resulting in a bluish corona. That sets off a chain of events that produces a downward flowing jet of air, commonly called ion wind, lifting the lifter upward.

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Arc from a flyback transformer power supply

A Cornucopia Of High Voltage Sources

Having hacked away with high voltage for many years I’ve ended up using a large number of very different high voltage sources. I say sources and not power supplies because I’ve even powered a corona motor by rubbing a PVC pipe with a cotton cloth, making use of the triboelectric effect. But while the voltage from that is high, the current is too low for producing the necessary ion wind to make a lifter fly up off a tabletop. For that I use a flyback transformer and Cockcroft-Walton voltage multiplier power supply that’s plugged into a wall socket.

So yes, I have an unorthodox skillset when it comes to sourcing high voltage. It’s time I sat down and listed most of the power sources I’ve used over the years, including a bit about how they work, what their output is like and what they can be used for, as well as some idea of cost or ease of making. The order is from least powerful to most powerful so keep reading for the ones that really bite.

Triboelectric Effect

Triboelectric series table
Triboelectric series table

You’ve no doubt encountered this effect. It’s how your body is charged when you rub your feet on carpet and then get a shock from touching a door knob. When you rub two specific materials together there’s a transfer of electrons from one to the other. Not just any two materials will work. To find out which materials are good to use, have a look at a triboelectric series table.

Materials that are on the positive end of the table will become positively charged when rubbed against materials on the negative end of the table. Those materials will become negatively charged. The further apart they are in the table, the stronger the charging.

Powering corona motor with triboelectricity
Powering corona motor with triboelectricity

An example of where I’ve used this is to power the corona motor shown here. I vigorously rub a PVC pipe with a cotton cloth, and as the pipe emerges from the cloth, a sharp wire a few millimeters away takes the charge from the pipe. You can see this corona motor being powered by other power sources in the video here.

This would be considered an electrostatic power source because charge is accumulated on surfaces. Being insulating materials, that charge can’t move around.

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Hand-Cranked Cyclotron

Okay, not actually a cyclotron… but this ball cyclotron is a good model for what a cyclotron does and the concepts behind it feel kooky and magical. A pair of Ping Pong balls scream around a glass bowl thanks the repulsive forces of static electricity.

It’s no surprise that this comes from Rimstar, a source we’ve grown to equate with enthralling home lab experiments like the Ion Wind powered Star Trek Enterprise. Those following closely will know that most of [Steven Dufresne’s] experiments involve high voltage and this one is no different. The same Wimshurst Machine he used in the Tea Laser demo is brought in again for this one.

A glass bowl is used for its shape and properties as an insulator. A set of electrodes are added in the form of aluminum strips. These are given opposite charges using the Wimshurst machine. Ping Pong balls coated in conductive paint are light enough to be moved by the static fields, and a good crank gets them travelling in a very fast circuit around the bowl.

When you move a crank the thought of being connected to something with a chain pops into your mind. This feels very much the same, but there is no intuitive connection between the movement of the balls and your hand on the crank. Anyone need a prop for their Halloween party?

If you don’t want to buy or build a Wimshurst machine you can use a Van De Graaff generator. Can anyone suggest other HV sources that would work well here?

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