I think that the advantages of this transformer have already been appreciated by many of those who have ever dealt with the problems of powering various electronic structures. And this electronic transformer has many advantages. Light weight and dimensions (as with all similar circuits), ease of modification to suit your own needs, the presence of a shielding housing, low cost and relative reliability (at least, if extreme modes and short circuits are avoided, a product made according to a similar circuit can work for many years).

The range of application of power supplies based on Tasсhibra can be very wide, comparable to the use of conventional transformers.

The use is justified in cases of shortage of time, funds, or lack of need for stabilization.
Well, shall we experiment? I’ll say right away that the purpose of the experiments was to test the Tasshibra triggering circuit under various loads, frequencies and the use of various transformers. I also wanted to select the optimal values ​​of the components of the PIC circuit and check temperature conditions circuit components when operating under various loads, taking into account the use of the Tasсhibra case as a radiator.

ET scheme Taschibra (Tashibra, Tashibra)

Despite large number published electronic transformer circuits, I will not be too lazy to once again post it for review. Look at Fig.1, illustrating the "Tashibra" filling.

Fragment excluded. Our magazine exists on donations from readers. The full version of this article is available only

The diagram is valid for ET "Tashibra" 60-150W. The mockery was carried out on ET 150W. It is assumed, however, that due to the identity of the circuits, the results of the experiments can be easily projected onto instances of both lower and higher power.

And let me remind you once again what Tashibra is missing for a full-fledged power supply.
1. Lack of an input smoothing filter (also an anti-interference filter, which prevents conversion products from entering the network),
2. Current PIC, which allows excitation of the converter and its normal operation only in the presence of a certain load current,
3. No output rectifier,
4. Lack of output filter elements.

Let's try to correct all of the listed shortcomings of "Taskhibra" and try to achieve its acceptable operation with the desired output characteristics. To begin with, we won’t even open the body of the electronic transformer, but simply add the missing elements...

1. Input filter: capacitors C`1, C`2 with a symmetrical two-winding choke (transformer) T`1
2. diode bridge VDS`1 with smoothing capacitor C`3 and resistor R`1 to protect the bridge from the charging current of the capacitor.

The smoothing capacitor is usually selected at the rate of 1.0 - 1.5 µF per watt of power, and a discharge resistor with a resistance of 300-500 kOhm should be connected in parallel to the capacitor for safety (touching the terminals of a charged relatively high voltage capacitor - not very nice).
Resistor R`1 can be replaced with a 5-15Ohm/1-5A thermistor. Such a replacement will reduce the efficiency of the transformer to a lesser extent.

At the output of the ET, as shown in the diagram in Fig. 3, we connect a circuit of diode VD`1, capacitors C`4-C`5 and inductor L1 connected between them to obtain a filtered DC voltage at the “patient” output. In this case, the polystyrene capacitor placed directly behind the diode accounts for the main share of absorption of conversion products after rectification. It is assumed that the electrolytic capacitor, “hidden” behind the inductance of the inductor, will perform only its direct functions, preventing voltage “dip” at the peak power of the device connected to the ET. But it is recommended to install a non-electrolytic capacitor in parallel with it.

After adding the input circuit, changes occurred in the operation of the electronic transformer: the amplitude of the output pulses (up to the diode VD`1) increased slightly due to the increase in the voltage at the input of the device due to the addition of C`3, and modulation with a frequency of 50 Hz was practically absent. This is at the load calculated for the electric vehicle.
However, this is not enough. "Tashibra" does not want to start without significant load current.

Installation of load resistors at the output of the converter for the occurrence of any minimum value current capable of starting the converter only reduces the overall efficiency of the device. Starting at a load current of about 100 mA is carried out at a very low frequency, which will be quite difficult to filter if the power supply is intended for joint use with UMZCH and other audio equipment with low current consumption in the no-signal mode, for example. The amplitude of the pulses is also less than at full load.

The change in frequency in different power modes is quite strong: from a couple to several tens of kilohertz. This circumstance imposes significant restrictions on the use of "Tashibra" in this (for now) form when working with many devices.

But let's continue. There have been proposals to connect an additional transformer to the ET output, as shown, for example, in Fig. 2.

It was assumed that the primary winding of the additional transformer is capable of creating a current sufficient for the normal operation of the basic ET circuit. The offer, however, is tempting only because without disassembling the electric current, with the help of an additional transformer you can create a set of voltages necessary (to your liking). In fact, the no-load current of the additional transformer is not enough to start the electric vehicle. Attempts to increase the current (such as a 6.3VX0.3A light bulb connected to an additional winding), capable of ensuring NORMAL operation of the ET, only resulted in the converter starting up and the light bulb lighting up.

But perhaps someone will be interested in this result, because... connecting an additional transformer is also true in many other cases to solve many problems. So, for example, an additional transformer can be used in conjunction with an old (but working) computer power supply, capable of providing significant output power, but having a limited (but stabilized) set of voltages.

It would be possible to continue to search for the truth in the shamanism around "Tashibra", however, I considered this topic exhausted for myself, because to achieve required result(stable start-up and return to operating mode in the absence of load, and, therefore, high efficiency; slight change in frequency when the power supply is operating from minimum to maximum power and stable start-up at maximum load) it is much more efficient to get inside the "Tashibra" and do everything necessary changes in the circuit of the ET itself in the manner shown in Figure 4.
Moreover, I collected about fifty similar circuits back in the era of Spectrum computers (specifically for these computers). Various UMZCHs, powered by similar power supplies, are still working somewhere. PSUs made according to this scheme have proven themselves to be best side, working, being assembled from a variety of components and in various options.

Are we redoing it? Certainly!

Moreover, it is not at all difficult.

We solder the transformer. We warm it up for ease of disassembly in order to rewind the secondary winding to obtain the desired output parameters as shown in this photo or using any other technologies.

In this case, the transformer is soldered only in order to inquire about its winding data (by the way: W-shaped magnetic core with a round core, standard dimensions for computer power supplies with 90 turns of the primary winding, wound in 3 layers with a wire with a diameter of 0.65 mm and 7 turns secondary winding with a wire folded five times with a diameter of approximately 1.1 mm; all this without the slightest interlayer and interwinding insulation - only varnish) and make room for another transformer.

For experiments, it was easier for me to use ring magnetic cores. Occupy less space on the board, which makes it possible (if necessary) to use additional components within the volume of the case. In this case, a pair of ferrite rings with outer and inner diameters and heights of 32x20x6mm, respectively, folded in half (without gluing) - N2000-NM1 was used. 90 turns of the primary (wire diameter - 0.65 mm) and 2X12 (1.2 mm) turns of the secondary with the necessary inter-winding insulation.

The communication winding contains 1 turn of mounting wire with a diameter of 0.35 mm. All windings are wound in the order corresponding to the numbering of the windings. Insulation of the magnetic circuit itself is mandatory. In this case, the magnetic circuit is wrapped in two layers of electrical tape, which, by the way, securely fixes the folded rings.

Before installing the transformer on the ET board, we unsolder the current winding of the commutating transformer and use it as a jumper, soldering it there, but without passing the transformer rings through the window.

We install the wound transformer Tr2 on the board, soldering the leads in accordance with the diagram in Fig. 4. and pass the winding wire III into the window of the commutating transformer ring. Using the rigidity of the wire, we form something like a geometrically closed circle and the feedback loop is ready. We solder a fairly powerful resistor (>1W) with a resistance of 3-10 Ohms into the gap in the mounting wire that forms windings III of both (switching and power) transformers.

In the diagram in Fig. 4, standard ET diodes are not used. They should be removed, as should resistor R1, in order to increase the efficiency of the unit as a whole. But you can neglect a few percent of the efficiency and leave the listed parts on the board. At least at the time of the experiments with ET, these parts remained on the board. The resistors installed in the base circuits of the transistors should be left - they perform the functions of limiting the base current when starting the converter, facilitating its operation on a capacitive load.

Transistors should definitely be installed on radiators through insulating heat-conducting gaskets (borrowed, for example, from a faulty computer power supply), thereby preventing their accidental instant heating and ensuring some personal safety in case of touching the radiator while the device is operating.

By the way, the electrical cardboard used in ET to insulate transistors and the board from the case is not thermally conductive. Therefore, when “packing” the finished power supply circuit into a standard case, just such gaskets should be installed between the transistors and the case. Only in this case will at least some heat removal be ensured. When using a converter with powers over 100W, an additional radiator must be installed on the device body. But this is for the future.

In the meantime, having finished installing the circuit, let’s perform one more safety point by connecting its input in series through an incandescent lamp with a power of 150-200 W. The lamp, in the event of an emergency (short circuit, for example), will limit the current through the structure to a safe value and, in the worst case, create additional illumination of the work space.

In the best case, with some observation, the lamp can be used as an indicator, for example, of through current. Thus, a weak (or somewhat more intense) glow of the lamp filament with an unloaded or lightly loaded converter will indicate the presence of a through current. The temperature of the key elements can serve as confirmation - heating in through-current mode will be quite fast.
When the converter is working properly, visible in the background daylight the glow of the filament of a 200-watt lamp will appear only at the threshold of 20-35 W.

First launch

So, everything is ready for the first launch of the converted "Tashibra" circuit. To begin with, we turn it on - without load, but do not forget about the pre-connected voltmeter to the output of the converter and an oscilloscope. With correctly phased feedback windings, the converter should start without problems.

If the start-up does not occur, then we pass the wire passed through the window of the commutating transformer (having previously unsoldered it from resistor R5) on the other side, giving it, again, the appearance of a completed turn. Solder the wire to R5. Apply power to the converter again. Didn't help? Look for errors in installation: short circuit, “missing connections”, erroneously set values.

When a working converter is started with the specified winding data, the display of an oscilloscope connected to the secondary winding of transformer Tr2 (in my case, half of the winding) will display a time-invariant sequence of clear rectangular pulses. The conversion frequency is selected by resistor R5 and in my case, with R5 = 5.1 Ohm, the frequency of the unloaded converter was 18 kHz.

With a load of 20 Ohms - 20.5 kHz. With a load of 12 Ohms - 22.3 kHz. The load was connected directly to the instrument-controlled transformer winding with an effective voltage value of 17.5 V. The calculated voltage value was slightly different (20 V), but it turned out that instead of the nominal 5.1 Ohm, the resistance installed on the board R1 = 51 Ohm. Be attentive to such surprises from your Chinese comrades.

However, I considered it possible to continue the experiments without replacing this resistor, despite its significant but tolerable heating. When the power delivered by the converter to the load was about 25 W, the power dissipated by this resistor did not exceed 0.4 W.

As for the potential power of the power supply, at a frequency of 20 kHz the installed transformer will be able to deliver no more than 60-65 W to the load.

Let's try to increase the frequency. When a resistor (R5) with a resistance of 8.2 Ohms is turned on, the frequency of the converter without load increases to 38.5 kHz, with a load of 12 Ohms - 41.8 kHz.

At this conversion frequency, with the existing power transformer, you can safely service a load of up to 120 W.
You can further experiment with the resistances in the PIC circuit, achieving the required frequency value, keeping in mind, however, that too high a resistance R5 can lead to generation failures and unstable startup of the converter. When changing the parameters of the PIC converter, you should control the current passing through the converter keys.

You can also experiment with the PIC windings of both transformers at your own peril and risk. In this case, you should first calculate the number of turns of the commutating transformer using the formulas posted on the page //interlavka.narod.ru/stats/Blokpit02.htm, for example, or using one of Mr. Moskatov’s programs posted on the page of his website // www.moskatov.narod.ru/Design_tools_pulse_transformers.html.

Improvement of Tasсhibra - a capacitor in the PIC instead of a resistor!

You can avoid heating resistor R5 by replacing it... with a capacitor. In this case, the PIC circuit certainly acquires some resonant properties, but no deterioration in the operation of the power supply is manifested. Moreover, a capacitor installed instead of a resistor heats up significantly less than the replaced resistor. Thus, the frequency with a 220nF capacitor installed increased to 86.5 kHz (without load) and amounted to 88.1 kHz when operating with a load.

The startup and operation of the converter remained as stable as in the case of using a resistor in the PIC circuit. Note that the potential power of the power supply at such a frequency increases to 220 W (minimum).
Transformer power: values ​​are approximate, with certain assumptions, but not exaggerated.
Over 18 years of work at North-West Telecom, he has made many different stands for testing various equipment being repaired.
He designed several digital pulse duration meters, different in functionality and elemental base.

More than 30 improvement proposals for the modernization of units of various specialized equipment, incl. - power supply. For a long time now I have been increasingly involved in power automation and electronics.

Why am I here? Yes, because everyone here is the same as me. There is a lot of interest here for me, since I am not strong in audio technology, but I would like to have more experience in this area.

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After rummaging around on the Internet and reading more than one article and discussion on the forum, I stopped and started disassembling the power supply. I must admit, the Chinese manufacturer Taschibra has released an extremely high-quality product, the circuit diagram of which I borrowed from the site stoom.ru. The circuit is presented for a 105 W model, but believe me, differences in power do not change the structure of the circuit, but only its elements depending on the output power:

The circuit after the modification will look like this:

Now in more detail about the improvements:

• After the rectifier bridge, we turn on the capacitor to smooth out the ripples of the rectified voltage. The capacitance is selected at the rate of 1 µF per 1 W. Thus, for a power of 150 W, I must install a 150 uF capacitor for an operating voltage of at least 400V. Since the size of the capacitor does not allow it to be placed inside the metal case of the Taschibra, I take it out through the wires.
• When connected to the network, an inrush of current occurs due to the added capacitor, so you need to connect an NTC thermistor or a 4.7 Ohm 5W resistor to the break in one of the network wires. This will limit the starting current. My circuit already had such a resistor, but after that I additionally installed MF72-5D9, which I removed from an unnecessary computer power supply.

• Not shown in the diagram, but from a Computer power supply you can use a filter assembled on capacitors and coils; in some power supplies it is assembled on a separate small board soldered to the mains power socket.

If other is needed output voltage, you will have to rewind the secondary winding of the power transformer. The diameter of the wire (harness of wires) is selected based on the load current: d=0.6*root(Inom). My unit used a transformer wound with wire with a cross-section of 0.7 mm²; I personally did not count the number of turns, since I did not rewind the winding. I unsoldered the transformer from the board, untwisted the twisted wires of the secondary winding of the transformer, there were 10 ends in total on each side:

I connected the ends of the resulting three windings together in series into 3 parallel wires, since the cross-section of the wire is the same 0.7 mm2 as the wire in the transformer winding. Unfortunately, the resulting 2 jumpers are not visible in the photo.

Simple mathematics, a 150 W winding was wound with a 0.7 mm2 wire, which we managed to split into 10 separate ends, ringing the ends, divided into 3 windings each with 3+3+4 cores, turn them on in series, in theory you should get 12+12+12= 36 Volt.

• Let's calculate the current I=P/U=150/36=4.17A
• Minimum winding cross-section 3*0.7mm² =2.1mm²
• Let's check whether the winding can withstand this current d=0.6*root(Inom)=0.6*root(4.17A)=1.22mm²< 2.1мм²

It turns out that the winding in our transformer is suitable with a large margin. Let me run a little ahead of the voltage that the power supply issued according to alternating current 32 Volt.
Continuing the redesign of the Taschibra power supply:
Since the switching power supply has current feedback, the output voltage changes depending on the load. When there is no load, the transformer does not start, which is very convenient if used for its intended purpose, but our goal is a constant voltage power supply. To do this, we change the current feedback circuit to voltage feedback.

We remove the current feedback winding and replace it with a jumper on the board. This can be clearly seen in the photo above. Then we pass a flexible stranded wire (I used a wire from a computer power supply) through a power transformer in 2 turns, then we pass the wire through a feedback transformer and make one turn so that the ends do not unwind, additionally pull it through PVC as shown in the photo above. The ends of the wire passed through the power transformer and the feedback transformer are connected through a 3.4 Ohm 10 W resistor. Unfortunately, I did not find a resistor with the required value and set it to 4.7 Ohm 10 W. This resistor sets the conversion frequency (approximately 30 kHz). As the load current increases, the frequency becomes higher.

If the converter does not start, you need to change the winding direction, it is easier to change it on a small feedback transformer.

As I searched for my solution to the conversion, a lot of information has accumulated on Taschibra switching power supplies, I propose to discuss them here.
Differences between similar modifications from other sites:

• Current-limiting resistor 6.8 Ohm MLT-1 (it’s strange that the 1 W resistor did not heat up or the author missed this point)
• Current limiting resistor 5-10 W on the radiator, in my case 10 W without heating.
• Eliminate filter capacitor and high side inrush current limiter

Taschibra power supplies have been tested for:

• Laboratory Power Supplies
• Power amplifier for computer speakers (2*8 W)
• Tape recorders
• Lighting
• Electric tools

To power consumers DC It is mandatory to have a diode bridge and a filter capacitor at the output of the power transformer; the diodes used for this bridge must be high-frequency and correspond to the power ratings of the Taschibra power supply. I advise you to use diodes from a computer power supply or similar ones.

After everything that was said in the previous article (see), it seems that making a switching power supply from an electronic transformer is quite simple: install a rectifier bridge at the output, a voltage stabilizer if necessary, and connect the load. However, this is not entirely true.

The fact is that the converter does not start without a load or the load is not sufficient: if you connect an LED to the output of the rectifier, of course, with a limiting resistor, you will be able to see only one LED flash when turned on.

To see another flash, you will need to turn off and turn on the converter. In order for the flash to turn into a constant glow, you need to connect an additional load to the rectifier, which will simply take away the useful power, turning it into heat. Therefore, this scheme is used in the case where the load is constant, for example, a DC motor or an electromagnet, which can only be controlled via the primary circuit.

If the load requires a voltage of more than 12V, which is produced by electronic transformers, you will need to rewind the output transformer, although there is a less labor-intensive option.

Option for manufacturing a switching power supply without disassembling the electronic transformer

The diagram of such a power supply is shown in Figure 1.

Figure 1. Bipolar power supply for amplifier

The power supply is made on the basis of an electronic transformer with a power of 105W. To manufacture such a power supply, you will need to make several additional elements: a mains filter, matching transformer T1, output choke L2, VD1-VD4.

The power supply has been operating for several years with a ULF power of 2x20W without any complaints. With a nominal network voltage of 220V and a load current of 0.1A, the output voltage of the unit is 2x25V, and when the current increases to 2A, the voltage drops to 2x20V, which is quite enough for normal operation of the amplifier.

The matching transformer T1 is made on a K30x18x7 ring made of M2000NM ferrite. The primary winding contains 10 turns of PEV-2 wire with a diameter of 0.8 mm, folded in half and twisted into a bundle. The secondary winding contains 2x22 turns with a midpoint, the same wire, also folded in half. To make the winding symmetrical, you should wind it in two wires at once - a bundle. After winding, to obtain the midpoint, connect the beginning of one winding to the end of the other.

You will also have to make the inductor L2 yourself; for its manufacture you will need the same ferrite ring as for the transformer T1. Both windings are wound with PEV-2 wire with a diameter of 0.8 mm and contain 10 turns.

The rectifier bridge is assembled on KD213 diodes, you can also use KD2997 or imported ones, it is only important that the diodes are designed for an operating frequency of at least 100 KHz. If instead of them you put, for example, KD242, then they will only heat up, and you will not be able to get the required voltage from them. The diodes should be installed on a radiator with an area of ​​at least 60 - 70 cm2, using insulating mica spacers.

C4, C5 are made up of three parallel-connected capacitors with a capacity of 2200 microfarads each. This is usually done in all switching power supplies in order to reduce the overall inductance electrolytic capacitors. In addition, it is also useful to install ceramic capacitors with a capacity of 0.33 - 0.5 μF in parallel with them, which will smooth out high-frequency vibrations.

It is useful to install an input surge filter at the input of the power supply, although it will work without it. As an input filter choke, a ready-made DF50GTs choke was used, which was used in 3USTST TVs.

All units of the block are mounted on a board made of insulating material in a hinged manner, using the pins of the parts for this purpose. The entire structure should be placed in a shielding case made of brass or tin, with holes provided for cooling.

A correctly assembled power supply does not require adjustment and starts working immediately. Although, before placing the block in the finished structure, you should check it. To do this, a load is connected to the output of the block - resistors with a resistance of 240 Ohms, with a power of at least 5 W. It is not recommended to turn on the unit without load.

Another way to modify an electronic transformer

There are situations when you want to use a similar switching power supply, but the load turns out to be very “harmful”. The current consumption is either very small or varies widely, and the power supply does not start.

A similar situation arose when they tried to put it in a lamp or chandelier with built-in electronic transformers instead. The chandelier simply refused to work with them. What to do in this case, how to make it all work?

To understand this issue, let's look at Figure 2, which shows a simplified circuit of an electronic transformer.

Figure 2. Simplified circuit of an electronic transformer

Let's pay attention to the winding of the control transformer T1, highlighted by a red stripe. This winding provides current feedback: if there is no current through the load, or it is simply small, then the transformer simply does not start. Some citizens who bought this device connect a 2.5W light bulb to it, and then take it back to the store, saying it doesn’t work.

And yet it's enough in a simple way You can not only make the device work with virtually no load, but also provide short circuit protection in it. The method of such modification is shown in Figure 3.

Figure 3. Modification of the electronic transformer. Simplified diagram.

In order for the electronic transformer to operate without load or with minimal load, the current feedback should be replaced with voltage feedback. To do this, remove the current feedback winding (highlighted in red in Figure 2), and instead solder a jumper wire into the board, naturally, in addition to the ferrite ring.

Next, a winding of 2 - 3 turns is wound onto the control transformer Tr1, this is the one on the small ring. And there is one turn per output transformer, and then the resulting additional windings are connected as indicated in the diagram. If the converter does not start, then you need to change the phasing of one of the windings.

The resistor in the feedback circuit is selected within the range of 3 - 10 Ohms, with a power of at least 1 W. It determines the depth of feedback, which determines the current at which generation will fail. Actually, this is the current of short-circuit protection. The greater the resistance of this resistor, the lower the load current the generation will fail, i.e. short circuit protection triggered.

Of all the improvements given, this is perhaps the best. But this will not prevent you from supplementing it with another transformer, as in the circuit in Figure 1.

When assembling a particular design, sometimes the question of a power source arises, especially if the device requires a powerful power supply, and it cannot be done without alteration. Nowadays, it is not difficult to find iron transformers with the required parameters; they are quite expensive, and their large size and weight are their main drawback. good pulsed sources power supplies are difficult to assemble and set up, so they are inaccessible to many. In his release, the video blogger Aka Kasyan will show the process of building a powerful and particularly simple power supply based on an electronic transformer. Although this video is mostly devoted to reworking and increasing its power. The author of the video has no goal to modify or improve the circuit, he just wanted to show how to increase the output power in a simple way. In the future, if you wish, all the ways to modify such circuits with short circuit protection and other functions can be shown.

You can buy an electronic transformer in this Chinese store.

The experimental one was an electronic transformer with a power of 60 watts, from which the master intends to extract as much as 300 watts. In theory, everything should work.

The transformer for the alterations was purchased for only 100 rubles at a construction store.

In front of you classic scheme electronic transformer type taschibra. This is a simple push-pull half-bridge self-generating inverter with a trigger circuit based on a symmetrical dinistor. He is the one who serves initial impulse, as a result of which the circuit starts. There are two high-voltage reverse conduction transistors. The original circuit included mje13003, two half-bridge capacitors of 400 volts, 0.1 microfarads, a feedback transformer with three windings, two of which are master or base windings. Each of them consists of 3 turns of 0.5 millimeter wire. The third winding is the current feedback.

At the input there is a small 1 ohm resistor as a fuse and a diode rectifier. Electronic transformer despite simple diagram works flawlessly. This option does not have protection against short circuits, so if you short the output wires, there will be an explosion - at a minimum.

There is no stabilization of the output voltage, since the circuit is designed to work with a passive load in the form of office halogen lamps. The main power transformer has two – primary and secondary. The latter is designed for an output voltage of 12 volts plus or minus a couple of volts.

First tests showed that the transformer has quite a lot of potential. Then the author found a patented circuit on the Internet welding inverter, built almost according to the same scheme and immediately created a board for a more powerful option. I made two boards because at the beginning I wanted to build a resistance welding machine. Everything worked without any problems, but then I decided to rewind the secondary winding to film this video, since the initial winding produced only 2 volts and a colossal current. And make measurements of such currents on at the moment This is not possible due to the lack of necessary measuring equipment.

There are already more before you powerful circuit. There are even fewer details. A couple of little things were taken from the first diagram. This is a feedback transformer, a capacitor and resistor in the starting circuit, and a dinistor.

Let's start with transistors. The original board had mje13003 in a to-220 package. They were replaced by more powerful mje13009 from the same line. The diodes on the board were of the n4007 type, one ampere. I replaced the assembly with a current of 4 amperes and a reverse voltage of 600 volts. Any diode bridges with similar parameters will do. The reverse voltage must be at least 400 volts and the current must be at least 3 amperes. Half-bridge film capacitors with a voltage of 400 volts.

It is a small metal, usually aluminum, case, the halves of which are fastened together with only two rivets. However, some companies produce similar devices in plastic cases.

To see what's inside, these rivets can simply be drilled out. The same operation will have to be performed if alteration or repair of the device itself is planned. Although, given its low price, it is much easier to go and buy another one than to repair the old one. And yet, there were many enthusiasts who not only managed to understand the structure of the device, but also developed several based on it.

A schematic diagram is not included with the device, as with all current electronic devices. But the diagram is quite simple, contains a small number of parts and therefore schematic diagram an electronic transformer can be copied from a printed circuit board.

Figure 1 shows a diagram of a Taschibra transformer taken in a similar way. Converters manufactured by Feron have a very similar circuit. The only difference is in the design of the printed circuit boards and the types of parts used, mainly transformers: in Feron converters the output transformer is made on a ring, while in Taschibra converters it is on an W-shaped core.

In both cases, the cores are made of ferrite. It should be immediately noted that ring-shaped transformers, with various modifications of the device, are better rewindable than W-shaped ones. Therefore, if an electronic transformer is purchased for experiments and modifications, it is better to buy a device from Feron.

When using an electronic transformer only for power supply, the name of the manufacturer does not matter. The only thing you should pay attention to is the power: electronic transformers are available with a power of 60 - 250 W.

Figure 1. Diagram of an electronic transformer from Taschibra

Brief description of the electronic transformer circuit, its advantages and disadvantages

As can be seen from the figure, the device is a push-pull self-oscillator made according to a half-bridge circuit. The two arms of the bridge are Q1 and Q2, and the other two arms contain capacitors C1 and C2, so this bridge is called a half bridge.

One of its diagonals is supplied with mains voltage, rectified by a diode bridge, and the other is connected to the load. In this case, this is the primary winding of the output transformer. They are made according to a very similar scheme, but instead of a transformer they include a choke, capacitors and filaments of fluorescent lamps.