Plasma Speaker - exploring properties of plasma

A device that plays music through an electric arc and can be used to present unusual properties of plasma.

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Sound can be created by unusual membranes – plasma is one of them. In this device a small electric arc will recreate any music that you wish to play. With a few additional properties you can present it’s properties and explain physical phenomena. Examine it’s temperature. See ionisation of various gasses. Learn how magnetic field affects electric arc. Visualise the convection using Jacob’s Ladder. And much more!

Plasma speaker – exploring unusual properties of plasma

During the study of properties of ionized gas, a plasma speaker set is used, which had been built by the author. The original application of plasma recreating music refers to the year 1946 and inventor Siegfried Klein, who patented it in 1946.

Plasma speaker experimental set

The electronic circuit has been accomplished basing on commonly uploaded projects of this type, without any precisely mentioned author. Before designing the scheme and the circuit board the constructor decided to support himself with the advices and experiences of other designers. This resulted in introducing new solutions improving the performance of the speaker. After the analysis, he designed a schematic and a circuit board in Eagle CadSoft. The last stage was to mount everything on an exposure board, to test it and carry out little repairs. Whole project has been carried out in the home workshop of the creator using collected materials and acquired experience in electronics.

The order of activities examining and describing the properties of plasma came up as a result of observation of different phenomena affecting plasma. In the experiment included were also interactions of everyday objects with plasma which came across as a result of search. Carried out to enrich the form of presentation to deliver as much information about plasma and its forms as possible. 

Printed circuit board design

WARNING! During the experiment a device generating high voltage and ozone is used. It may pose a threat to health or life of the users. It must be performed by an experienced or mature physician or student who will avoid any dangers. The user carrying out the experiment must be very cautious.

Before attempting to perform the experiment, we must have the basic knowledge about plasma and physical phenomena concerning it. This will help us understand the processes and physical laws ruling it better.

During the experiment important will be the concepts of:

  • Cold plasma - highly ionized gas (conducting current), due to its’ specific properties is called the fourth state of matter. It is a cloud of gas electrically neutral, with a high concentration of electrons and ions. It is present in relative low temperatures and pressures.
  • Electrical discharge – flow of current through an isolating environment due to very strong electromagnetic field (very high voltage)
  • Electric arc – a continuous electrical discharge in normal conditions
  • Fluorescence – a phenomena of emitting light by an excited (mostly by light) atom or particle

Necessary is also the acknowledgement of basic physical phenomena like:

  • Creation of an acoustic wave
  • Definition of a flame
  • Magnetic interactions and magnetic field properties
  • Optical spectrum
  • Ionization of gas in energy-saving light bulb
  • Rule of transformer and it’s ratio

To carry out the experiment is needed:

  • Plasma speaker circuit with electrodes - used as plasma source
  • Regulated laboratory voltage supply - providing the power needed for the set
  • Source of sound signal ex. MP3 player
  • A candle, ferrite magnet, probe of tonic containing quinine, whole piece of spiral energy-saving light bulb bubble, simple Jacob ladder made of wire
Schematic of the device

To understand in what way the high voltage appears at the electrodes and electric arc is produced, we need to analyze the circuit and determine the functions of each block. After simplifying, that means omitting the inessential minor circuits like filters or signalization devices the oncoming analysis is much easier.

Simplified schematic

The device works in a a folowing way: in the idle state the PWM generator produces a square wave signal with a defined length time and frequency, which are set by potentiometers. The signal generated by the integrated circuit is delivered to the gate...

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7-Zip - 3.56 MB - 07/29/2018 at 20:02


  • 1 × TL494 Power Management ICs / Switching Regulators and Controllers
  • 1 × IRFP260 Discrete Semiconductors / Power Transistors and MOSFETs
  • 1 × IRF9540 Discrete Semiconductors / Power Transistors and MOSFETs
  • 1 × BC327 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 1 × LM3914N Interface and IO ICs / Display Interface

View all 13 components

  • Exploring the properites of plasma

    Marcin Wachowiak07/29/2018 at 19:59 0 comments

    „Musical plasma” – recreating music by plasma

    After connecting the experimental kit to the source of elecrical sound signal ( in our case radio player) and setting the working parameters for the device to maintain stable arc we are able to replay the song. The chosen track is being heard by us straight from the electric arc. A variety of sound is being recreated and delivered to our ears just from the tiny plasma flame. We are able to notice that the speaker does not maintain great powers, although it consumes about 100W of power. The emitted sound is comparably as loud as if it was played from the mobile phone. What is more, we can hear that the music is not perfect as it lacks some lower frequencies. However the “colour” of the tone is a subjective feeling. It is clearly distinguishable that the speaker simply does not produce low frequecy – bass tones. When we try to play certaing kinds of music ex. dubstep ot techno, theyir sounds are completely unrecognizable. The reason why the speaker has such characteristic of produced tones is that the membrane layer role is played by the small plasma flame, which is inable to vibrate  in greater amplitude to move greater amounts of air to properly recreate basses. On the other hand the plasma speaker perfectly recreates the high pitched sounds as the plasma arc has a small inertia, which enalbes it to quiver without significant limits. In this way they may be heard as piercing and sharp.

    Plasma recreates sound due to it’s proper modulation . Depending on the input wave the PWM generator stretches or reduces the time of the output driving signal with a constant frequency and by this process it creates condensation and rarefactions of plasma, which transforms it into condensations and decondensations of air. Those changes of air density, which are defined as sound waves, come to our ears as the sensation of music.

    „Plasma compared to ordinary flame and their interaction”

    Continuing our experiment, without changing anything we place a candle end into the arc. We can observe the quick enlightning of the candle and permeate of elecrical arc and candle flame. The plasma arc is barely seen as it almost disappears in the flame. The light emmited by the flame seems multiplied and the music is played on mostly by the flame.

    The quick ignition suggests that the plasma tunel has a very high temeperature. From literature we are able to tell that in our case the plasma has about 6000K degrees. The addiditonal brightness of light is emmited by the carbon atoms, which set in the plasma area are addiditonally heated so that they emit more light than an ordinary burning candle. We can also suppose that flame is quite similar to plasma: it conducts electricity and has a high temperature. Plasma and flame are quite similar phenomena and are affected by the same physical laws, but we are not able to assert that those two objects are the same. This is because flame has much lower temperature than plasma, although it may not be seen at a first sight. (it is an argumentative case between physicians, in various articles and videos we may come across opposing statements). Huge amount of heat and various was of emitting the energy to environment turn our minds to the great amounts energy stored in plasma. Following the idea we see that after delivering the energy to states of matter they change. Firstly form solid state to fluid, then the to gass which in the end transfroms into plasma. This is why plasma is often called the fourth state of matter and where the great internal energy comes from.

    “Plasma - magnet interaction”

    To examine another property of plasma we need a stable electric arc. In this case we turn off the music signal and perform the experiment. To investigate plasma and magnetic field interaction we slowly move a ferrite magnet toward the plasma flame and observe the effects. While we slowly set position of the...

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View project log

  • 1
    Acquire all the parts and board

    Buy all the neccessary parts and produce the PCB board from the provided files.

  • 2
    Soldering and mounting

    Solder all the parts starting from the smallest and in the end mount the heatsink with the high power parts. The VU meter requires goldpins to be mounted vertically.

  • 3
    Test the circuit

    Power the board to examine if everything is fine and there are no mistakes in the assembly.

View all 6 instructions

Enjoy this project?



JohnSmith wrote 05/01/2020 at 16:51 point

That primary snubber design is very interesting, got any more information about it? What sort of voltage does it limit the peak MOSFET drain voltage to?

  Are you sure? yes | no

neotechni wrote 08/23/2018 at 17:22 point

"music reefers"

I assume you meant refers.

  Are you sure? yes | no

Marcin Wachowiak wrote 08/23/2018 at 19:50 point

Yes, that was a typo thanks!

  Are you sure? yes | no

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