"singing arc" by William Duddell. High voltage and more

Hi all! In this article I will tell you how to make a “Singing Arc” or “Ionophone”, the most beloved and popular musical gadget for beginner radio amateurs. In 1959, at the sixteenth All-Union Exhibition of Radio Amateurs in Moscow, a group of Leningrad radio amateurs B. Karateev, V. Pruits and E. Plotkin for the first time showed the world a sound-reproducing unit with an ionophone, unprecedented in those days; in some scientific sources it is called a plasma loudspeaker. This gadget was demonstrated in action, playing various melodies on it. The sound quality was excellent due to the expansion of the frequency range; unlike electrodynamic loudspeakers, this device had no mechanical distortion, the sound was reproduced from an electric arc arising between two electrodes. The source of the electric arc was a blocking generator with a voltage-increasing transformer.

List of radio parts for assembling the Ionophone or Singing Arc:

• Line scan transformer TVS-110PTs15 or TVS-90LTs5 and other similar ones from Soviet tube and transistor TVs
• Integrated timer chip NE555 or Soviet analogue KR1006VI1
• Resistors R1 50R, R2 1K, P1 10K
• Capacitors C110n, C2 100n, C3 330n
• Transistors IRFZ44, IRF470, IRF3808 and other similar ones, the more powerful the better
• The larger the computer heatsink, the better, the transistor will get very hot

This figure shows a simple circuit of an ionophone made from a line transformer.

The circuit consists of a square pulse generator built on an NE555 integrated timer with audio modulation capabilities. An important element of the high voltage generator is the line transformer TVS-110PTs15.

On the magnetic core of the transformer, it is necessary to wind a new primary winding consisting of twelve turns of copper wire with a diameter of one millimeter. A capacitor is connected in parallel to the primary winding, which doubles the length of the electric arc.

All parts of the ionophone easily fit on a small printed circuit board measuring 4 by 2.5 centimeters.

Place the field-effect transistor on the radiator from the computer. The board has a trimming resistor designed to adjust the generator frequency within the range of 12-48 KHz. The sound signal from the player or mobile phone is supplied to the fifth pin of the NE555 timer through an isolation capacitor. This allows you to control the duration of the output pulses. The third pin of the microcircuit is loaded with a powerful field-effect transistor, which drives the high-voltage transformer.

The generator supply voltage is 12 volts. A computer unit or any other with a current of at least 2 A is suitable as a power source. Despite its simplicity, the ionophone needs a slight adjustment of the generator frequency; for this, when turned on for the first time, you need to set the resistance of the variable resistor P1 to 3.2 kOhm.

Then light the arc and rotate the variable resistor P1 to achieve the maximum arc length. This completes the configuration of the singing arc. After connecting the player to the generator, we enjoy the crystal clear sound emanating from the burning plasma arc.

Then I decided to give the ionophone a more normal look. The transformer and printed circuit board with a radiator were placed on a piece of MDF. For plasma, I made a spark gap from copper wire. The result is an ionophone like this.

After playing a little, I became interested in what frequency my high-voltage generator operates at and I decided to measure the frequency by connecting an oscilloscope. It turns out that the operating frequency of the generator is 20 kHz.

This device can be used as a lighter. The arc is so hot that it easily ignites paper and heats metal objects to red.

Friends, I wish you good luck and good mood! See you in new articles!

In 1899 or 1900, English physicist William Du Bois Duddell experimented with arc lamps to reduce the unwanted sound effect they produced. However, the result was the opposite. It turned out that when an oscillatory circuit is connected parallel to the arc, self-oscillations arise in the system at the frequency of this very circuit. The arc begins to “sing”. (To be honest, it's disgusting to squeal).

For those who need this, watch the video:

To begin with, the circuit that beeps in my video.

600 V is not needed for this experiment (most of it is extinguished by ballast anyway), I just had a ready-made unit with ready-made ballast at hand. The calculated frequency of the circuit with the indicated element ratings is 2800 Hz. The pitch of the squeak is similar.

First I installed 2 graphite electrodes, then replaced the anode with a copper one. This makes the generation beep louder and more stable.

But not everything there is actually that simple. Generation occurs due to the presence of a falling section on the current-voltage characteristic of the arc. So, at a minimum, you need to get to this area. Everything influences: the material of the electrodes, the distance between them, the environment in which the arc burns, the electrical parameters of the circuit itself.

If you go even deeper, 2 oscillation modes are possible: continuous (pure sine wave of low power) and intermittent (asymmetric sine wave with periodic extinction of the arc). But if this is detailed, it would take a whole lecture. What’s remarkable about this thing is that voice radio communication was first implemented on this principle. Before this, only Morse code could telegraph.

True, in its simplest form this generator is not capable of producing a frequency above 20-30 kHz. To enter the radio range, you must, at a minimum, place the arc in an atmosphere of hydrogen or substances rich in it (alcohol, kerosene). Then, it is advisable to make the anode copper and water-cooled. A number of other special measures were also applied. These innovations were later introduced by the Swedish engineer Paulsen. Such radio stations were very common at one time (for example, the famous Shukhov Tower in Moscow) and were built with a power of up to hundreds of kW.

By the way, this principle has not been forgotten in modern radio engineering. Only instead of an arc, tunnel diodes are used, which also have a falling part of the characteristic, but allow operation even in the microwave range.

I think that's enough for now.

Such a scheme is not at all exclusive; it has long been used in homemade amateur radio designs where there is a need to obtain high voltage (electric stun guns, gauss guns, etc.). The audio signal should be fed to the control pin of the NE555 microcircuit through a film capacitor (you can also take a ceramic one), the capacitance of which will need to be selected experimentally.

The assembled device works quite reliably, but if you turn it on for a long time, the microcircuits may overheat; to avoid this, you should use either a more powerful driver, or place the microassembly on a homemade radiator.

Therefore, if you decide to assemble such a device as a souvenir, you can use a more reliable circuit.

The second option can work for quite a long time. The timer in it is powered from a reduced voltage, this ensures long-term and reliable operation without overheating the microcircuit, and the transistor driver removes the resulting overload from the microassembly. This converter is a better option, although it contains an order of magnitude more elements. The driver can use almost any complementary pairs of low and medium power, from the legendary KT316/361 to the more powerful KT814/815 or KT816/817. The device can also operate from a reduced supply voltage in the range of 6-9 volts. In my example, the circuit is powered by a 12 Volt 7A/h UPS lead battery.

An old TVS-110PTs15 type liner was used as a high-voltage transformer.

Without a signal arriving at the timer control pin, the circuit will work as a boost voltage converter. The standard windings of a line transformer will not make it possible to obtain a long arc at the output of the singing arc design, so you can wind your winding on the free side of the core. It consists of 5-10 turns of copper wire 0.8-1.2 mm.

The basis is a rectangular pulse generator built on 555 microcircuits. The circuit also uses a power switch, which is an N-channel field-effect transistor IRL3705.

There are only two active components in the circuit - a timer and a transistor; below is the pinout of the timer pins.

Winding 3-4 4 turns (winding resistance 0.1 Ohm)

Winding 4-5 8 turns (winding resistance 0.1 Ohm

Winding 9-10 16 turns (winding resistance 0.2 Ohm)

Winding 9-11 45 turns (winding resistance 0.4 Ohm)

Winding 11-12 100 turns (winding resistance 1.2 Ohm)

Winding 14-15 1080 turns (winding resistance 110-112 Ohm)

This article will look at the detailed design with a detailed description of all the components used.

I think there will be no difficulties with drawing conclusions.

The power transistor has the following pinout.

The circuit is not new; it has long been used in home-made designs where there is a need to obtain increased voltage (electric shock devices, gauss guns, etc.).

The audio signal is fed to the control pin of the microcircuit through a film capacitor (ceramic can also be used), the capacitance of which should preferably be selected experimentally.

I want to say that the device works quite well, but it is not recommended to turn it on for a long time since the circuit does not have an additional driver to amplify the output signal of the microcircuit, so the latter may overheat.

If you have already decided to make such a device as a souvenir, then you should use the diagram below.

This scheme can already work for a long time.

In it, the timer is powered from a reduced voltage, this ensures long-term operation without overheating, and the driver removes the overload from the microcircuit. This converter is an excellent option, although there are an order of magnitude more components. The driver can use literally any complementary pairs of low and medium power, from KT316/361 to KT814/815 or KT816/817.

The circuit can also operate from a reduced voltage of 6-9 volts. In my case, the installation is powered by an uninterruptible power supply battery (12 Volt 7A/h).

Transformer - used ready-made. If the installation is being assembled for shows, then it is worth winding the high-voltage transformer yourself. This will dramatically reduce the size of the installation. In our case, a line transformer of the TVS-110PTs15 type was used. Below I present the winding data of the line transformer used.

Without applying a signal to the timer control pin, the circuit will work as a step-up voltage converter.

The standard windings of a line transformer do not allow you to obtain a long arc at the output, which is why you can wind your own winding. It is wound on the free side of the core and contains 5-10 turns of wire 0.8-1.2 mm. Below we look at the location of the line transformer pins.

The best option is to use windings 9 and 10, although experiments have been carried out with other windings, but with these the result is obviously better.

In the video, unfortunately, the words are not clearly audible, but in real life they can be heard clearly. Such an “arc” loudspeaker has an insignificant efficiency, which does not exceed 1-3%, therefore this method of sound reproduction has not found wide application and is demonstrated within school laboratories.

Another interesting introductory project related to high voltage. So make yourself comfortable. During the channel video Aka Kasyan Let's put together one very educational structure - “Ionophone”, or singing to a friend. Perhaps this name doesn’t mean anything to many, but such toys are quite popular among novice radio amateurs. Radio components can be bought cheaply in this Chinese store.
We are accustomed to the fact that sound must be reproduced from a loudspeaker or speaker. The ionophone will allow you to reproduce the same sound using an ionized flow or a high-voltage arc.
And right now you will hear the music of a high-voltage arc.

In fact, the design of such an interesting toy is quite simple. It consists of a generator in the form of an NE55 microcircuit, a power unit in the form of an n-channel field-effect transistor and a high-voltage transformer from a horizontal scan of a Soviet TV.

Let's start with the generator. The NE55 chip operates as a square pulse generator with audio modulation capabilities. It is possible to adjust the frequency within 6-48 KHz using a trimming resistor on the board. The sound signal is supplied to the fifth pin of the microcircuit or the control pin through an isolation capacitor. This allows you to control the duration of the output pulses. The output of the microcircuit is loaded with a field-effect transistor that drives a high-voltage transformer.

The field effect transistor must be installed on the radiator. Suitable with a current of 20 A and a rated voltage above 40 volts. It is advisable to take 100 volt field devices. You can use available IRFZ44, 46, 48 or the like, or high-voltage ones.

Now let's move on to a line transformer suitable for a singing arc. In this version of the Ionophone circuit, this is TVS 110 PC 15. First of all, we wrap 12 turns of insulated millimeter wire around the free part of the core. In principle, the wire diameter can be from 0.7 to 1.5-2 mm. Then you need to find the output of the high-voltage winding. As a rule, this is the winding with the highest resistance. A multimeter will help in this matter. Or you can download the documentation on the Internet, where everything is shown in detail. In the case of similar line transformers, one of the terminals of the high-voltage winding is located directly on the coil - the second from the bottom. It is very easy to identify because an insulated wire is connected to it.
Next, we connect two insulated wires to the contacts of the high-voltage winding. The length of the segments is 15-20 centimeters.

Then we assemble the Ionophone board and connect a line transformer to it. Any power supply with a voltage of 5 volts and a current of 2 A will do as a power source. For the most efficient operation of the circuit, you need a power source with a voltage of 10-12 volts and a current of 2 A or higher. The singing arc can also be powered from batteries.

The sound signal is supplied from any player, tablet or mobile phone using the standard headphone jack.
Well, now let’s enjoy the spectacle. The arc not only sounds, but also changes shape. This is especially noticeable at low frequencies. Get ready for your health, but don’t forget about safety measures! More electronics masters.