✅ Do-it-yourself spark generator

High voltage generator from a transistor liner

Hello, dear friends!
Today I suggest you assemble a high-voltage generator using just one transistor from a TVS-110PTs15 line transformer with an UN9/57-13 voltage multiplier from an old color TV. The circuit is quite simple, built on the principle of blocking a generator and contains a small number of parts. Circuit of a high voltage generator from a liner on one transistor

To assemble the generator, you will need one KT819G transistor, or an imported analog TIP41C, but it is best to use MJE13009, since this transistor can withstand current up to 12 A and, accordingly, will heat up less. Personally, I used MJE13009 in my generator. Be sure to coat the transistor with thermal paste and install it on a radiator, preferably with a fan.

You will also need two 5-watt resistors. At 100 ohms and 240 ohms, the resistors in my generator got very hot and I decided to glue a small radiator with “poxy-pol”. The most important part of the generator is the TVS-110PTs15 line transformer; it is possible to use TVS-90LTs5 and other similar ones from old color, black-and-white and even tube TVs.

Linear transformer TVS-110PTs15

A couple of additional windings need to be wound on the magnetic core of the transformer. Coil L1 contains 10 turns, wound with wire with a diameter of 1 millimeter. We wind coil L2 with 1.5 millimeter wire, 4 turns in total. Both coils should be wound in the same direction. The secondary high-voltage winding remains unchanged.

Line transformer TVS-110PTs15 with two additional windings

The voltage multiplier UN9/27-13 or similar also needs minor modification. It is necessary to remove two unused terminals on it, marked in the picture with red arrows, then isolate these places with “poxy-pol”. It’s not necessary to do this, but if you accidentally touch these conclusions during the experiment... Your hair will stand on end and it won’t seem like much, of course it won’t kill you with an electric shock, there are very few amperes there, but it can burn you. A 470 ohm resistor is installed between the line transformer and the multiplier.

Voltage multiplier UN9/27-13

The arrester is made of two wires with a diameter of 1 millimeter. The distance between the electrodes is selected individually. To power the generator, it is best to use a power source from 12 to 30 volts with a current of at least 2A.

High voltage generator. Arrester

After power is applied, a powerful arc appears at the spark gap. How to measure the voltage at the output of a multiplier without a kilovolt meter? It is generally accepted that 1 millimeter of arc is 1 kilovolt, the length of the arc is 15 millimeters, which means the voltage at the spark gap is approximately 15 kilovolts.

I would like to say a few words about safety precautions. A high voltage of several tens of kilovolts is supplied to the spark gap from the multiplier, so do not touch the spark gap with your hands to avoid electric shock; even after turning off the power, high voltage remains in the multiplier capacitors. Of course, it won’t kill you with an electric shock, because there are not enough amperes, but it will hurt and possibly leave burns on the skin.

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

I recommend watching a video about how a high voltage generator works.

How to make a spark gap with your own hands - Metalist's Handbook

In 1997, I became interested in the Tesla coil and decided to build my own.
Unfortunately, I lost interest in it before I could launch it. A few years later I found my old spool, re-calculated it a bit and continued building. And again I abandoned her. In 2007, a friend showed me his reel, reminding me of my unfinished projects.

I found my old spool again, counted everything and this time completed the project.

A Tesla coil is a resonant transformer. These are basically LC circuits tuned to one resonant frequency.

A high voltage transformer is used to charge the capacitor.

As soon as the capacitor reaches a sufficient charge level, it is discharged into the spark gap and a spark occurs there. A short circuit occurs in the primary winding of the transformer and oscillations begin in it.

Since the capacitance of the capacitor is fixed, the circuit is adjusted by changing the resistance of the primary winding, changing the point of connection to it.

If set correctly, very high voltage will be present at the top of the secondary winding, resulting in impressive discharges in the air.

Unlike traditional transformers, the turns ratio between the primary and secondary windings has virtually no effect on the voltage.

Construction stages

Designing and building a Tesla coil is quite easy.

This seems like a difficult task for a beginner (I found it difficult too), but you can get a working coil by following the instructions in this article and doing a little math.

Of course, if you want a very powerful coil, there is no way other than studying the theory and doing a lot of calculations.

Here are the basic steps to get started:

Selecting a power source. The transformers used in neon signs are probably best for beginners since they are relatively cheap. I recommend transformers with an output voltage of at least 4 kV.
Making a spark gap. It could be as simple as two screws a couple of millimeters apart, but I recommend using a little more force. The quality of the arrester greatly influences the performance of the coil.
Calculation of capacitor capacity. Using the formula below, calculate the resonant capacitance for the transformer. The capacitor value should be about 1.5 times this value. Probably the best and most efficient solution would be to assemble capacitors. If you don't want to spend money, you can try making a capacitor yourself, but it may not work and its capacity is difficult to determine.
Manufacturing of the secondary winding. Use 900-1000 turns of 0.3-0.6mm enameled copper wire. The height of the coil is usually equal to 5 times its diameter. PVC drainpipe may not be the best but affordable material for a reel. A hollow metal ball is attached to the top of the secondary winding, and its bottom is grounded. For this, it is advisable to use a separate grounding, because When using common house grounding, there is a chance of damaging other electrical appliances.
Manufacturing of the primary winding. The primary winding can be made of thick cable, or better yet, copper tubing. The thicker the tube, the less resistive losses. A 6mm tube is sufficient for most reels. Remember that thick pipes are much more difficult to bend and copper will crack if it is bent too many times. Depending on the size of the secondary winding, 5 to 15 turns at 3 to 5 mm pitches should be sufficient.
Connect all the components, set up the coil, and you're done!

Before you start making a Tesla coil, it is strongly recommended that you familiarize yourself with the safety rules and working with high voltages!

Also note that transformer protection circuits were not mentioned. They have not been used and there are no problems so far. The key word here is yet.

Details

The coil was made mainly from those parts that were available. These were: 4kV 35mA transformer from a neon sign. 0.3mm copper wire. 0.33μF 275V capacitors.

I had to buy an additional 75mm PVC drain pipe and 5 meters of 6mm copper pipe.

Secondary winding

The secondary winding is covered with plastic insulation on top and bottom to prevent breakdown

The secondary winding was the first component manufactured. I wound about 900 turns of wire around a drain pipe that was about 37cm high. The length of the wire used was approximately 209 meters.

The inductance and capacitance of the secondary winding and the metal sphere (or toroid) can be calculated using formulas that can be found on other sites. Having these data, you can calculate the resonant frequency of the secondary winding: L = [(2πf)2C]-1

When using a sphere with a diameter of 14 cm, the resonant frequency of the coil is approximately 452 kHz.

Metal sphere or toroid

The first attempt was to make a metal sphere by wrapping a plastic ball in foil. I couldn't smooth out the foil on the ball well enough, so I decided to make a toroid.

I made a small toroid by wrapping aluminum tape around a corrugated tube rolled into a circle. I couldn't get a very smooth toroid, but it works better than a sphere because of its shape and the larger size.

To support the toroid, a plywood disk was placed under it.

Primary winding

The primary winding consists of copper tubes with a diameter of 6 mm, wound in a spiral around the secondary. The inner diameter of the winding is 17cm, the outer diameter is 29cm. The primary winding contains 6 turns with a distance of 3 mm between them.

How to make an electrical erosion machine for your home workshop with your own hands?

Some home craftsmen have the idea of making an electrical erosion machine with their own hands for their own workshop. The desire is explained by the fact that sometimes it is necessary to process parts with high hardness. Annealing to reduce strength is not allowed. Deformation of the part is possible and the requirements for the quality of the processed surface or other characteristics will be violated.

As a result of spark erosion, through holes are burned or markings are applied. It is possible to process a surface of complex shape specified by the electrode.

Main features of electrical erosion

The operating principle of an erosion installation for metal parts is based on the removal of the smallest particles of the material being processed by a spark discharge. As a result of a single exposure, a small hole remains at the point of contact. The more powerful the spark, the wider and deeper the depression is formed.

Spark generator circuit:

The electrical circuit of the device provides for the use of:

diode bridge, it rectifies the supplied alternating voltage from the 220 V network;
a 100 W H₁ incandescent lamp represents a resistive load;
capacitors C₁, C₂, C₃ accumulate energy to produce a one-time spark discharge.

When the circuit is connected to the network, the H₁ lamp lights up, and an electric charge accumulates on the capacitors C₁,..., C₃. When the capacitors are fully charged, the flow of electric current through the circuit stops. The H₁ lamp goes out, which serves as a signal for the possibility of a spark.

The electrode is applied to the part. There remains a gap through which breakdown occurs. A small hole is burned into the metal.

Similar actions happen many times. With each subsequent action, the electrode penetrates deeper into the metal, tearing out particles at a greater depth.

The above circuit requires about 0.5...0.7 s of time to fully charge the capacitors. The current value in the charge circuit is approximately 0.42...0.47 A. When contact is made in the discharge zone, the current increases to 7000...9000 A. At such a high value, 0.010...0.012 g of metal (steel) evaporates.

Dangerous fun: an easy-to-replicate high voltage generator

Good afternoon, dear Khabrovsk residents. This post will be a little unusual.

In it I will tell you how to make a simple and fairly powerful high-voltage generator (280,000 volts). I took the Marx Generator circuit as a basis.

The peculiarity of my scheme is that I recalculated it for accessible and inexpensive parts. In addition, the circuit itself is easy to repeat (it took me 15 minutes to assemble it), does not require configuration and starts the first time.

In my opinion, it is much simpler than a Tesla transformer or a Cockroft-Walton voltage multiplier.

Principle of operation

Immediately after switching on, the capacitors begin to charge. In my case, up to 35 kilovolts. As soon as the voltage reaches the breakdown threshold of one of the arresters, the capacitors through the arrester will be connected in series, which will lead to a doubling of the voltage on the capacitors connected to this arrester.

Because of this, the remaining spark gaps are triggered almost instantly, and the voltage on the capacitors adds up. I used 12 steps, which means the voltage should be multiplied by 12 (12 x 35 = 420). 420 kilovolts are almost half-meter discharges. But in practice, taking into account all the losses, the resulting discharges were 28 cm long.

The losses were due to corona discharges.

About details:

The circuit itself is simple, consisting of capacitors, resistors and arresters. You will also need a power source. Since all the parts are high-voltage, the question arises, where to get them? Now, first things first:

1 - resistors

Resistors needed are 100 kOhm, 5 watt, 50,000 volt.

I tried many factory resistors, but none could withstand such voltage - the arc would break through the top of the case and nothing would work.

Careful googling yielded an unexpected answer: the craftsmen who assembled the Marx generator for voltages of more than 100,000 volts used complex liquid resistors, the Marx generator on liquid resistors, or used a lot of stages. I wanted something simpler and made resistors from wood.

I broke off two even branches of a damp tree on the street (dry ones do not conduct current) and turned on the first branch instead of a group of resistors to the right of the capacitors, the second branch instead of a group of resistors to the left of the capacitors. It turned out to be two branches with many conclusions at equal distances. I made conclusions by winding bare wire over branches. Experience shows that such resistors can withstand voltages of tens of megavolts (10,000,000 volts)

2 - capacitors

Everything is simpler here. I took capacitors that were the cheapest on the radio market - K15-4, 470 pF, 30 kV (aka greensheets). They were used in tube TVs, so now you can buy them at a disassembly site or ask for them for free. They withstand a voltage of 35 kilovolts well, not a single one has broken through.

3 - power supply

I just couldn’t bring myself to assemble a separate circuit to power my Marx generator. Because the other day my neighbor gave me an old TV “Electron TC-451”. The anode of the kinescope in color televisions uses a constant voltage of about 27,000 volts.

I disconnected the high-voltage wire (suction cup) from the anode of the kinescope and decided to check what kind of arc would be produced from this voltage. Having played enough with the arc, I came to the conclusion that the circuit in the TV is quite stable, can easily withstand overloads, and in the event of a short circuit, the protection is triggered and nothing burns out.

The circuit in the TV has a power reserve and I managed to overclock it from 27 to 35 kilovolts. To do this, I twisted the R2 trimmer in the TV power module so that the horizontal power supply rose from 125 to 150 volts, which in turn led to an increase in the anode voltage to 35 kilovolts.

When you try to increase the voltage even more, the KT838A transistor breaks through in the horizontal scan of the TV, so you need to not overdo it.

Build process

Using copper wire, I screwed the capacitors to tree branches. There must be a distance of 37 mm between the capacitors, otherwise an unwanted breakdown may occur. I bent the free ends of the wire so that there was 30 mm between them - these will be the arresters. It's better to see once than to hear 100 times. Watch the video where I showed in detail the assembly process and operation of the generator:

Safety precautions

Particular care must be taken, since the circuit operates at a constant voltage and a discharge from even one capacitor will most likely be fatal. When turning on the circuit, you need to be at a sufficient distance because electricity penetrates 20 cm or even more through the air.

After each shutdown, you must always discharge all capacitors (even those in the TV) with a well-grounded wire. It is better to remove all electronics from the room where the experiments will be carried out. The discharges create powerful electromagnetic pulses.

The phone, keyboard and monitor that are shown in my video are out of order and can no longer be repaired! Even in the next room my gas boiler turned off. You need to protect your hearing. The noise from the discharges is similar to gunshots, then it makes your ears ring.

Interesting observations

The first thing you feel when you turn it on is how the air in the room is electrified. The electric field intensity is so high that it is felt by every hair of the body. The corona discharge is clearly visible. Beautiful bluish glow around parts and wires.

There is always a slight electric shock, sometimes you don’t even understand why: you touched the door - a spark jumped, you wanted to take the scissors - the scissors shot. In the dark, I noticed that sparks were jumping between various metal objects not connected with the generator: in a briefcase with a tool, sparks were jumping between screwdrivers, pliers, and a soldering iron.

The lights light up on their own, without wires. The whole house smells like ozone, like after a thunderstorm.

Technical specifications for the design of a homemade machine

To make a homemade electrical discharge machine, you need to make a number of devices that will help automate the production process.

A frame is needed; the mechanism for moving the electrode will be placed on it.
You will need a mechanism that allows you to periodically bring and remove the electrode to the material being processed.
To burn holes of different shapes you need to have a set of electrodes. Experts recommend using molybdenum wire.
For different types of main tools, you will need to change the device power and amperage. Under different operating modes, the electrical circuit diagram must allow regulation of the discharge value on the electrode. It is necessary to provide for a change in the voltage ripple frequency.
To cool the part (hardened steel cannot be overheated; tempering occurs with a decrease in hardness), coolant must be supplied to the work area. More often, ordinary water or salt solutions are used. The water simultaneously washes away sludge (destroyed metal particles).

Development of a horizontal electrical discharge machine

The installation diagram includes the main components and parts:

1 – electrode;
2 – screw for fixing the electrode in the guide sleeve;
3 – terminal for fixing the positive wire from the voltage converter;
4 – guide sleeve;
5 – fluoroplastic body;
6 – hole for lubricant supply;
7 – bed.

The unit is small in size and can be placed on a table. In the housing 5, the guide sleeve 4 can move in both directions. To drive it you need a special mechanism or device.

Electrode 1 is attached to sleeve 4, the positive wire is also connected using terminal 3. All that remains is to assemble the proposed circuit into a real installation at home. It uses the simplest equipment.

RADIO PARTS FOR ELECTRIC SHOCKER

Good afternoon friends. Many radio amateurs in personal messages are interested in where I find parts for stun guns. Today I will explain this to you in detail. Firstly, a high-voltage unit for the car’s xenon headlights.

Recently I specifically found several such blocks and now I want to tell you what kind of block we need. There are simply no unnecessary parts, since the device itself is a kind of stun gun with an output voltage of 25 kilovolts.

In it you can find low-frequency transistors of the IRFZ44 type, a spark (vacuum) gap, high-voltage capacitors with a larger capacity, capacitors for a multiplying stun gun, high-voltage diodes, a high-voltage transformer, a transformer for the shocker converter.

And I would like to draw your attention to the fact that all radio components here, including high-voltage transformers, are made at a high level and with excellent quality.

I carried out tests with a high-voltage transformer from such a block - I applied voltage to the primary winding from a capacitor with a capacity of 1 microfarad and a voltage of 1500 volts, but to my surprise, the spark from the secondary winding reached 7 centimeters, and there was no breakdown of the windings. This transformer is filled with a special resin and can last almost forever. Parts for a stun gun can also be found in a transistor or thyristor TV made in the Soviet Union.

FA, ready-made voltage multiplier, high-voltage diodes and capacitors, cores for transformers, domestic low-frequency transistors and much more. Do you need high-voltage diodes like kts106? Please! Carefully break the voltage multiplier and inside you will find 5 pieces of these diodes, besides, the multiplier can be used separately, attached to the converter and here you have a powerful stun gun, only not of pocket size.

I attached a scan of such a multiplier in the figure below.

Now AT and ATX power supplies, they contain ferrite cores for shocker converter transformers, powerful high-quality transistors and diodes. For lovers of a more powerful stun gun, I will say that in a computer power supply you can find an analogue of the famous TL494 - this is the master pulse generator, on the basis of which many voltage converters are assembled.

Also there you can find the UC3845 chip, another high-quality pulse generator, the basis for a powerful stun gun! See all photos below. I hope after the explanations you will no longer have questions about where to get radio components for a shocker, and if you still have questions, contact the forum, we are always happy to help you. AKA

Discuss the article RADIO PARTS FOR ELECTRIC SHOCKER

Brief description of a homemade installation

Electrode 1 is installed in housing 2. Its reciprocating movement is carried out by an electromagnet from coil 7. Terminal 3 is connected to the guide sleeve (positive potential is applied).

The part to be processed is mounted on the work table 4. There is terminal 5 on the table; the negative conductor is connected to it. Lubricant is supplied through tube 6 into the housing.

By turning on the converter, operating voltage will be obtained on the current-carrying wires. Additionally, voltage is applied to the induction coil 7. It creates vibration of the electrode 1, directing its movement to the right and left. Electrode 1 touches the workpiece. A current of 7000...9000 A appears in the contact zone.

Each time the tool moves towards the part, a small amount of metal is burned off. Within 10...12 minutes of operation of the electrical erosive machine, a through hole will be obtained in the part. A hole is obtained in the drill shank. It is quite difficult to drill such a hole using the usual method.

How to improve the machine?

The simplest machine made is a working model. Its purpose is to create holes in hardened parts.

In the future, you need to consider the option with a vertical electrode arrangement. Then you can install a bath underneath it. The process will occur without possible malfunctions associated with the presence of sludge that cannot be removed from the working area.

It is also necessary to consider additional mechanisms for smooth tool feeding. It may be necessary to carry out not only axial movement, but also movement of the electrode in the horizontal plane in order to carry out three-dimensional surface treatment.

Any simple machine gives ideas on how to further improve it and create a more convenient unit. The main thing is to take the first step and try to make the first sample.

Video: homemade electric spark machine.

DIY spark generator

Many of us have at least once in our lives seen photographs of High-Voltage Generators on the Internet or in real life, or taken them ourselves. Many circuits presented on the Internet are quite powerful, their output voltage ranges from 50 to 100 Kilovolts. The power, like the voltage, is also quite high. But their nutrition is the main problem. The voltage source must be of a power suitable for the generator and must be able to deliver a large current for a long time.

There are 2 options for powering high-voltage generators:

battery,
mains power supply.

The first option allows you to run the device far from the outlet. However, as previously noted, the device will consume a lot of power and, therefore, the battery must provide this power (if you want the generator to work “at 100”). Batteries of such power are quite large and a device with such a battery cannot be called autonomous. If the power is supplied from a network source, then there is no need to talk about autonomy either, since the generator literally “cannot be taken away from the outlet.”

My device is quite autonomous, since it does not consume much from the built-in battery, but due to low consumption, the power is also not great - about 10-15W. But you can get an arc from a transformer, the voltage is about 1 Kilovolt. From the voltage multiplier to higher - 10-15 kV.

Closer to the design...

Since I did not plan this generator for serious purposes, I placed all its “insides” in a cardboard box (no matter how funny it may sound, it is true. I ask you not to judge my design strictly, since I am not an expert in high-voltage technology). My device has 2 Li-ion batteries with a capacity of 2200 mAh. They are charged using an 8-volt linear regulator: L7808. It is also located in the case. There are also two chargers: from the mains (12 V, 1250 mAh) and from the car’s cigarette lighter.

Do-it-yourself safe capacitor arrester

Translated by alexlevchenko for mozgochiny.ru

Good day. When troubleshooting and repairing electronic equipment, the first step is always to discharge the capacitors present in the circuit. Otherwise, a careless repairman risks getting a boost of energy...

In the past, tube receivers and amplifiers could be found in every home. In their design, they used high-capacity capacitors, which continued to hold a dangerous level of charge for a long time even after they were disconnected from the network.

After this came the era of televisions with cathode ray tubes.

Thanks to technological progress, TVs are now equipped with flat LED screens and it may seem that all modern devices are switching to low-voltage digital circuits, but what is the problem then?

In fact, the answer lies on the surface. Low-voltage devices are powered from relatively safe linear power supplies (hereinafter referred to as LPS). They are effective, lightweight, but it is in them that the main danger lies. In other words, “a wolf in sheep’s clothing.”

The LIP rectifies the mains voltage, providing a constant voltage of about 330 V (for a mains voltage of 230 V and 170 V for a mains voltage of 120 V), after which it can be used to power one or another section/component of the circuit. It turns out to be an oil painting. Small, neat black boxes through which laptops, monitors and other devices are connected, in fact have quite high voltage levels, which can be deadly.

The filter capacitors in the power supply are charged at high DC voltage and retain their charge for a long period of time after the plug is removed from the socket. It is for this reason that there are stickers on the cases with safety warnings: “Do not open the box.”

The circuit presented in the article works with potentially dangerous voltage. Do not try to assemble it into hardware if you do not fully understand the principle of its operation and/or you do not have experience working with high voltage. In any case, you perform all actions at your own peril and risk.

Step 1: Working principle of unloading chain

On the Internet you can find quite a lot of articles/videos in which people discharge capacitors by simply short-circuiting their terminals, using a screwdriver for this purpose.

The common people have a saying: “Neither the method nor the method is important, but the result is important,” so in our case, not only the result is important, but also how it was obtained. This is exactly what I mean - this method works. It completely discharges the capacitor. But is this right or wrong...? Of course not.

This type of discharge can damage the capacitor, damage the screwdriver and cause irreparable harm to your health.

In order for the discharge to be carried out in the correct direction, it is necessary to remove the accumulated charge gradually. In principle, we do not need to wait until the discharge is complete; it is enough to wait a certain period of time for the voltage to become sufficiently low. Now we’ll figure out how long to wait.

A relatively safe residual charge level is considered to be 5% of the original.

In order for the charge level to drop to the desired level, it is necessary for a time equal to 3RC to pass (C is the capacitance of the conductor; R is the value of the resistor resistance).

Please note the “relatively safe” residual charge of 5%, it may vary. For example, for 10 kV, 5% - 500 V. For voltage 500V, 5% - 25V.

Unfortunately, we cannot simply connect a resistor (it is through the resistor that the discharge will occur) to the capacitor and wait. Why? Sitting with a stopwatch and monitoring time is not very convenient, is it?

It would be much more convenient to have a visual cue that notifies us that the discharge process is “over” and the voltage has dropped to a safe level.

On the Internet you can find a small, simple circuit for discharging capacitors with external indication. We will try to understand the principle of its operation, make changes by increasing the number of diodes and assemble the finished craft.

Use a chain of three standard 1N4007 diodes connected in series (D1, D2, D3) to set the correct fixing point where we can connect the LED with its current limiting resistor.

3 diodes connected in series will provide a voltage of about 1.6V, which is enough to turn on the LED.

The LED will remain lit until the voltage at the D3 anode drops below the combined forward voltage of the string.

We will use a low current red LED (Kingbright WP710A10LID), which has a conventional 1.7V forward voltage and turns on at a forward current of 0.5 mA, which allows us to use only 3 diodes. According to the small current flowing through the LED, the value of the current limiting resistor will be relatively high 2700 ohms 1/4 W.

The capacitor discharge resistor is a 3 W, 2200 ohm resistor that is rated for a maximum input voltage of 400 V. This is sufficient to operate with standard power supplies.

Note that if you look at the datasheet for the 1N4007 diode, you will see a nominal forward voltage of 1V, so you would think that two diodes would be enough to turn on the LED.

Not really, since the 1V forward voltage for the 1N4007 is designed to carry 1A forward current, a value we will never reach (hopefully) since that would mean we would be applying 2200V to the circuit's input. The forward current in our operating range is about 500-600 mV, so we need three diodes.

Always consider the conditions for which the parameters are specified in the datasheet. Are they used in your circuit? Maybe you shouldn't stop at the first page and continue looking at the characteristic curves!

Step 2: Correct unloading pattern

The above diagram is useful to illustrate the principle of operation, but it should not be repeated or used in practice because it is quite dangerous.

The danger lies in the way the capacitor is connected (or rather, in the correct polarity) (the Vcc terminal must be positive relative to the GND terminal), otherwise the current will not flow through the diode chain D1-D2-D3! Therefore, if you accidentally connect the capacitor incorrectly, no current will flow and the full input voltage will flow to the LED1 pins as reverse voltage. If the applied reverse voltage is higher than a few volts, LED1 will burn out and remain off. This may lead you to believe that the capacitor is not charged when it still is...

To make the circuit safe, it is necessary to provide a symmetrical path for the current when the capacitor discharges when Vcc-GND is negative. This can be easily done by adding D4-D5-D6 and LED2 as shown in the diagram.

When Vcc - GND is positive, current will only flow through D1-D2-D3 and LED1. When Vcc-GND is negative, current will only flow through D4-D5-D6 and LED2.

This way, regardless of the polarity used, we will always know whether the capacitor is charged and when the voltage drops to a safe level.

Step 3: Body

Now that we understand how the circuit works, it's time to think about the case. All this could be arranged either in the form of a probe or in the form of a small box that is convenient to keep at the workplace and connect to the capacitor using probes.

Let's make a small round box from two halves with plastic blanks. The fit was very tight, so no screws were needed.

The hole in the top of the case should be the size of the aluminum “button” that will help cool the discharge resistor.

The "button" was machined from an aluminum rod and then milled on one end to hold the resistor in place and ensure good heat transfer.

There is also a small hole that can be used to attach an optional external heatsink.

It is important to make a good fit between the “button” and the body. As you'll see in the next step, the button also helps hold all the components in place. Case dimensions 19 mm by 50 mm.

Step 4: Putting it all together

All that remains is to assemble, special attention should be paid to insulation. This kind of tension is no joke! A few points:

Note the aluminum “button” that is the conductor to the outside of the box. The “button” must be isolated from the circuit. It is recommended to use a silicon-based sealant or epoxy resin to secure the components into the case after you have tested the assembly.
The copper mesh around the resistor helps hold it securely in place in the slot and increases heat transfer to the “button.”
Use special wires that are designed for a voltage of 600V. Don’t even think about grabbing the first wire you come across that is designed for an unknown voltage.

That's all. Successful and most importantly safe discharge!

DIY electric spark machine

To change the shape and size of a metal workpiece, you can use the electrical discharge processing method. It has been used for many years in various industries, characterized by high accuracy but low productivity. To apply this processing method, you should use a special electric spark machine, which you can purchase or make yourself. The homemade version can be used in everyday life in small-scale production. The cost of making it yourself will be lower than purchasing an industrial version. Therefore, let’s take a closer look at how you can make the electric spark machine in question with your own hands, what you need for this and in what cases it can be used.

Do-it-yourself spark gap (high-voltage indicator/tester)

What does the arrester consist of? The most important thing is the body. On one side there is a contact rod on which the vehicle's armor wire cap is placed, and on the opposite side there is an adjustable cone bolt connected to a wire and a clamp at the end with which you connect to the vehicle's ground. The contact rod on the opposite side has a pointed tip, just like the one on the adjusting bolt. Between them there is an adjustable gap that you adjust to your needs. And on top of the window where you observe the spark, a transparent cover is installed. That's the whole structure.

The simplest manufacturing option consists of a regular candle, a syringe and a wire with a clamp.

Using a grinder, you need to completely cut off the threaded part with the negative electrode from the spark plug. We won't need it, since the spark should come out from the central electrode and go to the second control electrode.

Next, take a 20 cc syringe, cut off the spout and expand the hole in the center so that the spark plug electrode fits in. This can be done with a large drill or soldering iron. The electrode itself in the syringe must be glued so that there are no leaks through leaks.

It is necessary to drill a small hole in the syringe piston into which a wire with a clamp at the end is inserted. Even if you don’t have a clamp at hand, the main thing when checking the spark is to ensure good contact of the end of the wire with the ground of the car.

For convenience, you can put a scale in millimeters on the syringe, so that it is more convenient to see what the current gap between the electrodes is and not have to run after the ruler every time.

The discharger is ready! By moving the syringe plunger, you can adjust the spark gap, even during the test!

If you get confused, then instead of the piston you can insert a bushing cut from PCB with a thread in the center and screw an adjusting bolt into it with a sharp end and a wire on the head, or make a body from the same PCB, or from a PVC pipe.

As you can see, there are plenty of possibilities for imagination - go for it!

Source

The principle of the considered processing method

A special feature of processing with an electric spark unit is that the evaporation of metal occurs due to the effect of a certain charge on the surface of the workpiece. An example of such an effect is the short circuit of a capacitor on a metal plate - a hole of a certain size is formed. EDM creates a high temperature that simply evaporates the metal from the surface. It is worth noting that a machine from this group has already been used over the past 50 years in various industries. The main condition for using such an electric spark machine is that the workpiece must be made of a certain metal. In this case, it is not the degree of machinability that is taken into account, but the electrically conductive properties.

Main structural element

The EDM machine has a spark generator that acts as a capacitor. For processing, a large capacity storage element should be used. The processing principle is to store energy over a long period of time and then release it over a short period of time. The laser device also works on this principle: reducing the time period of energy release leads to an increase in current density, which means the temperature increases significantly.

Electrical circuit of an electric spark installation

The operating principle of the generator, which is installed on an electrical discharge machine, is as follows:

the diode bridge rectifies industrial current with a voltage of 220 or 380 Volts;
the installed lamp limits the short circuit current and protects the diode bridge;
the higher the load indicator, the faster the charging of the electric spark machine;
after charging is complete, the lamp will go out;
Having charged the installed storage device, you can bring the electrode to the workpiece;
after the circuit is opened, the capacitor begins to charge again;
The charging time of the installed storage element depends on its capacity. Typically, the time period is from 0.5 to 1 second;
at the moment of discharge the current reaches several thousand amperes;
the wire from the capacitor to the electrode should have a large cross-section, about 10 square millimeters. In this case, the wire must be made exclusively of copper.

The generation frequency when the electrode is supplied to an electric spark machine is 1 Hz.

How to make a spark gap with your own hands

Any laser operating in a pulsed mode requires a device that switches the energy of the laser power source to the active substance or flash lamp. In commercial lasers, the switch function is performed by a variety of semiconductor or gas-discharge devices. In particular, one of the best switches for pulsed gas-discharge lasers is a hydrogen thyratron, which allows the formation of short high-voltage pulses. There are many types of hydrogen thyratrons, designed for different currents and voltages. The photo below shows the domestic design of a hydrogen thyratron of the TGI1-1000/25 type.

This device is capable of switching a pulse current of 1000 A at an anode voltage of 25 kV. Of course, such a thing would be useful in the workshop of a laser-building enthusiast. However, this is an expensive pleasure. You can buy a hydrogen thyratron, but not everyone has the opportunity to lay out

10,000 rubles per piece. In addition, high-voltage hydrogen thyratrons are too bulky. For example, the dimensions of the thyratron shown in the photo above

110 x 160 mm. Therefore, for a homemade product, it will be easier and much cheaper to make a homemade switch, which is a spark gap.

The simplest version of a spark gap is a two-electrode uncontrolled spark gap operating in air. On the Internet you can find many descriptions of how to make such a spark gap. However, in the figure below I will show a variant of the circuit of a two-electrode arrester.

The photo below shows a cap nut (cap nut) that can be used as a spark gap electrode.

The specific dimensions of the arrester are not of fundamental importance. To obtain short high-voltage pulses, one must strive to reduce the length of the current-carrying elements of the spark gap, as well as reduce the spark gap between the electrodes of the spark gap. The larger the diameter of the spark gap electrodes (2), the higher the switching voltage at a constant length of the interelectrode gap. The arrester is connected through contacts (1), which are fixed to the current-carrying lines of the external electrical circuit. During operation of the arrester, a very loud sound noise occurs, which it is advisable to suppress so as not to irritate others (household members, neighbors, etc.). To suppress the crackling sound of the arrester, it can be placed in some closed dielectric housing. Rubber will be a good sound suppressor, but a plastic box will do the same. You can glue the body from plexiglass plates. The photo below shows a view of a homemade two-electrode spark gap. To weaken the light effect from the spark, a piece of polypropylene tube was additionally inserted into the housing.

The left electrode of the spark gap in the photo is screwed to the duralumin plate, and the right electrode is screwed onto a brass screw (or a steel one), which is held on a thread in the housing. The right electrode is fixed on the duralumin plate using a clamping nut. This design allows you to quickly change the interelectrode distance while maintaining the same position of the contact plates of the arrester. The photo below shows the arrester disassembled.

During the operation of the spark gap, the inner surface of its body becomes clogged (contaminated) with products of microdestruction of the electrodes (metal particles, oxides, etc.), which causes the occurrence of surface discharges that worsen the parameters of the spark gap. Eventually, the spark gap completely loses its effectiveness, which manifests itself in the loss of laser output. In this case, cleaning the inner surface of the arrester housing is required. When using the polypropylene tube mentioned above, cleaning the surface can be easily done using a round file.

T. Rapa's book “Experiments with Homemade Lasers” provides more efficient circuits for homemade spark gaps that have improved characteristics. These include controlled arresters, high-pressure arresters, and air-pumping arresters.

Design of an electric spark machine

There are schemes that are quite difficult to implement. The scheme in question can be implemented with your own hands. Parts for the installed generator are not in short supply; they can be purchased at a specialized store. Capacitors are also widespread, as is the diode bridge. At the same time, when creating a homemade electric spark machine, the following points should be taken into account:

on the capacitor the indicated voltage should not be less than 320 Volts;
the number of energy storage devices and their capacity are selected taking into account that the total capacity should be 1000 μF. All capacitors must be connected in parallel. It is worth considering that the power of a homemade version increases if it is necessary to obtain a stronger spark strike;
The lamp is installed in a porcelain socket. The lamp should be protected from falling; a circuit breaker with a current strength of 2 to 6 Amperes is installed;
the machine is used to turn on the circuit;
electrodes must have strong clamps;
a screw clamp is used for the negative wire;
The positive wire has a clamp with a copper electrode and a tripod for direction.

The homemade wire version has relatively small overall dimensions.

Homemade electric spark machine

Basic elements of the electrical spark equipment circuit

The diagram is represented by the following elements:

electrode;
a clamp screw used to secure the positive wire and electrode;
guide bushing;
body made of fluoroplastic;
hole used to supply oil;
tripod.

The body, which is used to connect all the elements, is machined from fluoroplastic. A grounding pin is used as a bushing, in which a threaded hole is machined along the axis for attaching the electrode. All structural elements are mounted on a tripod, which is made with the ability to change height. A hole is also created through which oil is supplied.

Electric spark machine diagram

Often cutting is carried out using a device that is powered by a starter with a coil connected to a voltage of 220V. The starter rod can have a stroke of 10 millimeters. The starter winding is connected in parallel with the lamp. That is why the lamp is lit when the capacitors are charging, and after this process is completed, it goes out. After the rod has been lowered, a spark charge occurs.

DIY small Tesla coil

In 1997, I became interested in the Tesla coil and decided to build my own. Unfortunately, I lost interest in it before I could launch it.

A few years later I found my old spool, re-calculated it a bit and continued building. And again I abandoned her. In 2007, a friend showed me his reel, reminding me of my unfinished projects.