Pulse power supply diagram for 30 volts. How to make a pulse power supply with your own hands? Packaging and equipment
How many interesting radio devices are collected by amateurs, but the basis, without which there will be almost no single scheme - a power supply. From what they just do not try to drink novice masters their devices - batteries, Chinese adapters, charging from mobile phones... and often until the assembly of a decent unit simply does not reach hands. Of course, the industry produces sufficiently high-quality and powerful stabilizers of voltage and current, but not everywhere they are sold and not everyone has the opportunity to buy them. It's easier to discharge with your own hands.The proposed diagram of a simple (only 3 transistor) power supply is beneficial to the accuracy of maintaining the output voltage - there is a compensation stabilization, reliability of launch, a wide range of adjustment and cheap deficiencies. PCB in Lay format -.
After proper assembly, it works at once, only we select the stabilion according to the desired value of the maximum output voltage of the BP.
The case makes the fact that at hand. Classic option - metal box from computer BP ATX. I am sure everyone has them a lot, since sometimes they burn, but buy a new easier than to repair.
The transformer is 100 watt, and the board with the details will be found.
The cooler can be left - it will not be superfluous. And so that it does not noise, simply feed it through a current-brewing resistor, which will pick up experimentally.
For the front panel, I did not praise and bought a plastic box - it is very convenient to make holes and rectangular windows for indicators and regulators.
Ampmeret take the shooter - so that the currents are clearly visible, and the voltmeter put the tsley - so more comfortable and more beautiful!
After assembling the adjustable power supply, we check it in operation - it should give almost a complete zero at the lower (minimum) position of the regulator and up to 30V - at the top. By connecting the load of the Ampera floor - we look at the output stress stage. It should also be minimal.
In general, with all its apparent simplicity, this power supply is probably one of the best in its parameters. If necessary, you can add the protection node into it - a couple of extra transistors. How it is done look at the forum. The scheme collected and experienced - Mars.
Discuss a power supply unit 0-30V
Power supply 0-30 volts do it yourself
How many interesting radio devices are collected by radio amateurs, but the basis without which there will be almost no scheme - power Supply. . Hello before assembling a decent power supply simply do not reach hands. Of course, the industry produces sufficiently high-quality and powerful stabilizers of voltage and current, but not everywhere they are sold and not everyone has the opportunity to buy them. It's easier to discharge with your own hands.
Power supply diagram:
The proposed scheme of a simple (only 3 transistor) power supply is favorably different from similar accuracy of maintaining the output voltage - compensation stabilization, launch reliability, a wide adjustment range and cheap deficiencies are applied.
After proper assembly, it works at once, only we select the stabilion according to the desired value of the maximum output voltage of the BP.
The case makes the fact that at hand. Classic option - metal box from computer BP ATX. I am sure everyone has them a lot, since sometimes they burn, but buy a new easier than to repair.
The transformer is 100 watt, and the board with the details will be found.
The cooler can be left - it will not be superfluous. And so that it does not noise, simply feed it through a current-brewing resistor, which will pick up experimentally.
For the front panel, I did not praise and bought a plastic box - it is very convenient to make holes and rectangular windows for indicators and regulators.
Ampmeret take the shooter - so that the currents are clearly visible, and the voltmeter put the tsley - so more comfortable and more beautiful!
After assembling the adjustable power supply, we check it in operation - it should give almost a complete zero at the lower (minimum) position of the regulator and up to 30V - at the top. By connecting the load of the Ampera floor - we look at the output stress stage. It must also be minimal.
In general, with all its apparent simplicity, this power supply is probably one of the best in its parameters. If necessary, you can add the protection node into it - a couple of extra transistors.
Since resumed its amateur activity, I often visited the idea of \u200b\u200bhigh-quality and universal. Available and produced 20 years ago a power supply had only two output voltages - 9 and 12 volts at a current of the order of one ampere. The remaining voltage necessary in practice had to "unscrew" adding different voltage stabilizers, and to obtain voltages above 12 volts - use the transformer and different converters.
Such a situation was tired of the order and began to look after a laboratorian scheme on the Internet for repetition. As it turned out, many of them are the same scheme on operating amplifierx, but in different variations. At the same time, on the forums of discussion of these schemes on the topic of their performance and parameters, the thesis of dissertations was reminded. I did not want to repeat and spend the dubious schemes, and during the next trip to Aliexpress suddenly dropped to the set of a linear power supply structure with quite decent parameters: adjustable voltage from 0 to 30 volts and a current of up to 3 amps. The price of $ 7.5, made the process of independent purchase of components, development and etching board simply meaningless. As a result, I received such a set by mail:
Not looking at the price of the set, the quality of the fee can be called excellent. Included even turned out to be two extra capacitors by 0.1 μF. Bonus - will be useful)). All you need to do is "turning on the attention mode", place the components in its place and solder. Chinese comrades took care to confuse that only a person was able to first learn about the battery and a light bulb - a silk-screen printing with nominations of components is applied on the fee. The final turns out this fee:
Characteristics of the laboratory power supply unit
- input voltage: 24 V AC;
- output voltage: from 0 to 30 V (adjustable);
- output current: 2 mA - 3 A (adjustable);
- pulsation output voltage: less than 0.01%
- cap size 84 x 85 mm;
- short-circuit protection;
- protection for exceeding the established current value.
- On the exceeding current is exceeding the LED.
To obtain a full-fledged block, add only three components - a voltage transformer on the secondary winding of 24 volts at 220 volts at the inlet (an important moment about which is detailed below) and a current of 3.5-4 A, the radiator for the output transistor and a 24 volt cooler To cool the radiator with a large load current. By the way, on the Internet there was a diagram of this power supply:
From the main nodes of the scheme can be allocated:
- diode bridge and filter capacitor;
- regulating node on transistors VT1 and VT2;
- the protection node on the VT3 transistor disables the output until the power amplifiers are normal
- fan power stabilizer on chip 7824;
- on the elements R16, R19, C6, C7, VD3, VD4, VD5, a node of the formation of a negative power supply pole of operational amplifiers is built. The presence of this node causes the power of the entire circuit of the alternating current from the transformer;
- output capacitor C9 and protective diode VD9.
Separately, you need to stop on some components used in the scheme:
- rectaging diodes 1N5408, editable - Maximum rectified current of 3 amps. And at least diodes in the bridge work alternately, it will not be superfluous to replace them with more powerful, such as stem diodes by 5 A;
- the fan power stabilizer on the 7824 chip selected in my opinion is not entirely successful - at hand, many radio amateurs will certainly have a 12 volt fans from computers, but the Culls on the 24rd are much less likely. It did not buy such a thing, deciding to replace 7824 at 7812, but in the process of testing BP abandoned this idea. The fact is that with the input alternating voltage of 24 V, after a diode bridge and the filtering capacitor, we obtain 24 * 1.41 \u003d 33.84 volts. The 7824 chip will perfectly cope with the task of dispersion of superfluous 9, 84 volts, but 7812 accounts for hard, dissipating in heat 21.84 volts.
In addition, the input voltage for chips 7805-7818 is regulated by the manufacturer at 35 volts, for 7824 at 40 volts. Thus, in the case of a simple replacement of 7824 to 7812, the latter will work on the verge. Here is a link to datasheet.
Considering the above, a 12-volt cooler, which was available in stock, connected via a stabilizer 7812, drinking it from the exit of the standard stabilizer 7824. Thus, the cooler power circuit turned out to be a two-stage, but reliable.
The operating amplifiers TL081, according to the datasheet, require two-polar nutrition +/- 18 volts - in general, 36 volts and this is the maximum value. Recommended +/- 15.
And here it begins the most interesting about the variable input voltage of 24 volts! If you take a transformer, which at 220 V at the inlet, gives 24 V at the output, then again after the bridge and the filtering capacitor, we obtain 24 * 1,41 \u003d 33.84 V.
Thus, only 2.16 volts remains until the critical value. With an increase in the voltage in the network up to 230 volts (and it happens in our network), with a filtering capacitor, we already remove 39.4 volts of constant voltage, which will lead to the death of operating amplifiers.
Outputs there are two: either replace the operational amplifiers by others, with a higher allowable supply voltage, or reduce the number of turns in the secondary winding of the transformer. I went on the second path, picking up the number of turns in the secondary winding at 22-23 volts at 220 V at the entrance. At the exit of BP received 27.7 volts, which was quite suitable.
The radiator of the processor has found as a radiator for the transistor D1047. It also fastened the voltage stabilizer 7812. Additionally set the fan rotation control fee. She shared a donor computed PC power supply with me. The thermistor consolidated between the ribs of the radiator.
When current in the load is up to 2.5 A, the fan rotates on average circulation, with a current increase to 3 and for a long time, the fan turns on the hollow power and reduces the temperature of the radiator.
Digital Indicator for Block
To visualize voltage and current readings in the load applied the DSN-VC288 voltammermeter, which possesses the following characteristics:
- measurement range: 0-100 V 0-10A;
- operating current: 20MA;
- measurement accuracy: 1%;
- display: 0.28 "(two colors: blue (voltage), red (current);
- minimum voltage measurement step: 0.1 V;
- minimum current measurement step: 0.01 A;
- working temperature: from -15 to 70 ° C;
- size: 47 x 28 x 16 mm;
- the operating voltage required for the operation of the ampervoltmeter electronics: 4.5 - 30 V.
Given the operating voltage range there are two ways to connect:
- If the voltage measured source operates in the range from 4.5 to 30 voltsthen the connection scheme looks like this:
- If the source of the measured voltage operates in the range of 0-4.5 V or above 30 volts, up to 4.5 volts an ampervoltmeter will not start, and at a voltage of more than 30 volts it will simply fail, in order to avoid what the following scheme should be used:
In the case of this power supply, the voltage to power the ampervoltmeter is from which to choose. In the power supply there are two stabilizers - 7824 and 7812. Up to 7824, the length of the wire was turned into shorter, therefore the device was packed from it, to drop the wire to the outlet of the chip.
About Wires from the kit
- the wires of the three-pin connector are thin and made wire 26AWG - thicker here and do not need. Color insulation is intuitive - red is the power of the module electronics, black is a weight, yellow - measuring wire;
- the wires of the two-accomplice connector are the currents of the current meter and are made with thick wire 18AWG.
When connected and comparing readings with the indications of the multimeter, the discrepancy was 0.2 volts. The manufacturer has provided stress resistance on the board for calibrating the testimony of voltage and current, which is a big plus. In some instances, the readings of the ammeter without load are observed. It turned out that it was possible to solve the problem with a discharge of an ammeter reading, as shown below:
Picture from the Internet, because I apologize for grammatical mistakes in inscriptions. In general, with scheme engineering finished -
The scope of application of pulsed power supplies in everyday life is constantly expanding. Such sources are used to power all modern household and computer equipment, to implement uninterruptible power sources, charger For batteries for various purposes, the implementation of low-voltage lighting systems and for other needs.
In some cases, the purchase of a finished power supply is little acceptable from an economic or technical point of view and assembly of a pulsed source own hands It is optimal output from such a situation. It simplifies such an option and the wide availability of a modern element base at low prices.
The most popular in everyday life is impulse sources with power supply from the standard AC network and a powerful low-voltage output. The block diagram of such a source is shown in the figure.
The network rectifier SV converts the variable voltage of the supply network into constant and smoothing the ripples of the straightened voltage at the output. The high-frequency converter of the RFP transforms the straightened voltage into an alternating or unipolar, having a form of rectangular pulses of the required amplitude.
In the future, such a voltage or directly, or after straightening (HV) enters a smoothing filter, the load is connected to the output. RCP control is carried out by the control system receiving a signal feedback From the load rectifier.
Such a structure of the device may be criticized due to the presence of multiple conversion links, which reduces the source efficiency. However, with the right choice of semiconductor elements and the qualitative calculation and manufacture of motion units, the level of power loss in the diagram is small, which allows to obtain the real efficiency of the efficiency above 90%.Circuits of pulsed power supplies
Decisions of structural blocks include not only the rationale for the choice of scheme implementation options, but also practical recommendations for the choice of the main elements.
To straighten the network single-phase voltage, one of three classic schemes depicted in the figure are used:
- single-alterogeneous;
- zero (two-speech-mode with an average point);
- dVXPOLUPERIOUS MOST.
Each of them is inherent in dignity and disadvantages that determine the scope.
Single-Perside scheme It has simplicity of sales and minimum semiconductor components. The main disabilities of such a rectifier are a significant amount of pulsation of the output voltage (only one half-wave is present in the straightened network voltage) and a small straightening coefficient.
Rectification coefficient Kv.determined by the ratio of the average voltage value at the output of the rectifier UDKvalid value of phase network voltage UF.
For single-alterogeneic scheme KV \u003d 0.45.
For smoothing pulsation at the output of such a rectifier, powerful filters are required.Zero, or two-speech diagram with medium dotAlthough it requires a doubled number of rectifying diodes, however, this deficiency is largely compensated by a lower level of ripples of the straightened voltage and the increase in the magnitude of the rectification coefficient to 0.9.
The main disadvantage of such a scheme for use in domestic conditions is the need to organize an average network voltage point, which implies the presence of a network transformer. Its dimensions and mass are incompatible with the idea of \u200b\u200ba small-sized homemade impulse source.
Two-footer-line bridge scheme Straightening has the same indicators for the level of pulsation and the rectification ratio, which is zero scheme, but does not require network availability. This compensates for I. chief flaw - a double number of rectifier diodes both from the point of view of the efficiency and cost.
For smoothing pulsations of straightened voltage the best solution is the use of a capacitive filter. Its use allows you to raise the magnitude of the straightened voltage to the amplitude value of the network (at UF \u003d 220V UFM \u003d 314B). The disadvantages of such a filter it is customary to consider the large values \u200b\u200bof impulse currents of rectifying elements, but this deficiency is not critical.
The selection of the rectifier diodes is carried out by the magnitude of the average direct current Ia and the maximum reverse voltage U Bm.Taking the value of the pulsation coefficient of the output voltage of KP \u003d 10%, we obtain the average value of the rectified voltage UD \u003d 300B. Taking into account the capacity of the load and efficiency of the RF converter (80% is accepted for the calculation, but in practice it turns out above, it will allow some reserve).
Ia - the average current of the rectifier diode, the power of the load, η - the efficiency of the RF converter.
The maximum reverse voltage of the rectifier element does not exceed the amplitude value of the network voltage (314B), which allows the use of components with a value U BM \u003d 400B with a significant reserve. You can use both discrete diodes and ready-made rectifier bridges from various manufacturers.
To ensure a given (10%) pulsation at the output of the rectifier, the capacitance of the filter capacitor is taken at the rate of 1MKF to 1W output power. Electrolytic capacitors are used with a maximum voltage of at least 350V. Capacities of filters for different power are shown in the table.
High-frequency converter: its functions and schemes
The high-frequency converter is a single or two-stroke key converter (inverter) with a pulse transformer. Options for RF transducers are shown in the figure.
Single scheme. With the minimum number of power elements and simplicity of implementation, has several flaws.
- The transformer in the scheme works on the private hysteresis loop, which requires an increase in its size and overall power;
- To provide power at the output, it is necessary to obtain a significant amplitude of the pulse current flowing through the semiconductor key.
The scheme has found the greatest use in low-power devices, where the effect of these disadvantages is not so significant.
To independently change or install a new meter, no special skills are required. The choice of correct will ensure correct accounting of the current consumption and will increase the safety of the home power grid.
In modern conditions to ensure lighting both indoors and the street, motion sensors are increasingly used. This attaches not only comfort and convenience to our dwellings, but also allows you to save substantially. Discover practical advice By selecting the installation site, the connection schemes can be.
Two-stroke scheme with an average transformer point (Pushpule). Received its second name from the English version (Push-Pull) description of the work. The scheme is free from the disadvantages of the one-bit option, but has its own - the complicated transformer design (the manufacture of identical sections of the primary winding is required) and increased requirements for the maximum voltage of keys. Otherwise, the decision deserves attention and is widely used in impulse power sources made by their own hands and not only.
Two-stroke welded scheme. According to the parameters, the diagram is similar to the diagram with the midpoint, but does not require a complex configuration of the transformer winding. The own disadvantage of the scheme is the need to organize the middle point of the rectifier filter, which entails a fourfold increase in the number of capacitors.
Due to the simplicity of implementation, the scheme is most widely used in pulse power sources with a capacity of up to 3 kW. For large facilities The cost of filter capacitors becomes unacceptably high compared to the semiconductor keys inverter and the bridge scheme is most advantageous.
Two-stroke pavement scheme. By parameters, similar to other two-stroke schemes, but is devoid of the need to create artificial "midpoints". A double number of strength keys becomes a pay for this, which is beneficial with economic and technical points of view to build powerful pulsed sources.
The selection of the keys of the inverter is carried out according to the amplitude of the collector current (drain) I CMA and the maximum voltage collector-emitter uham. For calculation, load power and the transformation coefficient of the pulse transformer are used.However, before you need to calculate the transformer itself. The pulse transformer is performed on the ferrite core, permalloe or twisted in the ring of transformer iron. For power up to units of kW, ferrite cores of ring or W-shaped type are fully suitable. The transformer calculation is based on the required power and frequency of the conversion. To eliminate the appearance of acoustic noise, the conversion frequency is desirable to be taken out of the sound range (made above 20 kHz).
In this case, it must be remembered that with frequencies close to 100 kHz, losses in ferrite magnetic pipelines significantly increase. The transformer calculation itself is not difficult and can easily be found in the literature. Some results for various sources and magnetic pipelines are shown in the table below.
The calculation is manufactured for a frequency of conversion of 50 kHz. It is worth noting that when working at a high frequency, the effect of turning out the current to the surface of the conductor takes place, which leads to a decrease in the efficient winding area. To prevent this kind of trouble and reduce losses in conductors, it is necessary to carry out a multiple cross section. At a frequency of 50 kHz, the permissible diameter of the winding wire does not exceed 0.85 mm.
Knowing the load capacity and transformation coefficient can be calculated in the primary winding of the transformer and the maximum stream of the power key collector. The voltage on the transistor in the closed state is selected higher than the straightened voltage entering the input of the RF transducer with some reserve (U camaes\u003e \u003d 400V). According to these data, the keys are selected. Currently best option is the use of IGBT or MOSFET power transistors.
For the rectifier diodes on the secondary side, it is necessary to observe one rule - their maximum operating frequency must exceed the frequency of the conversion. Otherwise, the efficiency of the output rectifier and the converter will generally decrease significantly.Video about the manufacture of the simplest pulse feeder
Each radio amateler, repairman or simply the master requires a power source to feed its schemes, test them using the power supply, or simply sometimes you need to charge the battery. It happened so that I was fascinated by this topic for some time ago and I also became needed like a similar device. As usual, there were many pages on the Internet on this issue, followed many themes on the forums, but the exact thing that I needed in my presentation was not anywhere - then it was decided to do everything yourself by collecting all the necessary information in parts. In this way, a pulse laboratory power supply was born on the TL494 chip.
What is special - yes, it seems to be a little, but I will explain - to redo the native power supply of the computer all on the same printed circuit board it seems to me not quite along the hair dryer, and not beautiful. With the housing the same story - it simply does not look, although if there are fans of such a style, I have nothing against anything. Therefore, the basis of this design is only the basic details from the native computer Blok. food, but the printed circuit board (more precisely printed circuit boards - There are actually three of them) is done separately and specifically under the case. The case here also consists of two parts - by itself the base of the Kradex Z4A case, as well as the fan (cooler), which you can see in the photo. It is a continuation of the body, but about everything in order.
Power supply diagram:
List of parts you can see at the end of the article. And now you will briefly analyze the diagram of the pulse laboratory power supply. The scheme works on the TL494 chip, there are many analogues, but I recommend using the original chips, they are quite inexpensive, and they work reliably unlike Chinese analogs and fakes. You can also disassemble several old power supplies from computers and get the necessary parts from there, but I recommend using all the same new details and chips - it will increase the chance of success, so to speak. Because of output power Built-in key elements TL494 are not sufficient to control powerful transistors working on the main pulse transformer TR2, the control circuit of the power transistors T3 and T4 is being built using the TR1 control transformer. This control transformer is used from the old computer power supply without making changes to the windings. TR1 control transformer swinging T1 and T2 transistors.
Signals of the control transformer through D8 and D9 diodes come to the base transistors. T3 and T4 transistors are used MJE13009 bipolar grades, you can use transistors to a smaller current - MJE13007, but it is still better to leave for a larger current to increase the reliability and power of the circuit, although it will not save it from a short circuit in high-voltage circuits. Next, these transistors shake the TR2 transformer, which converts the straightened voltage of 310 volts from the VDS1 diode bridge to the required us (in this case, 30 - 31 volts). The transfer data (or winding from zero) of the transformer a little later. The output voltage is removed from the secondary windings of this transformer to which the rectifier and a number of filters are connected so that the voltage is maximum without ripples. Rectifier must be used on Schottki diodes to minimize losses when straightening and exclude a large heating of this element, a dual diode Schottky D15 is used according to the diagram. There is also the greater the permissible current of the diodes, the better. With negligence at the first launch of the circuit, the high probability of spoiling these diodes and power transistors T3 and T4. In the output filters of the scheme it is worth using electrolytic capacitors with low EPS (Low ESR). Chokes L5 and L6 were used from old computers nutrition blocks (although as old - simply faulty, but new and powerful, it seems 550 W). L6 is used without changing the winding, is a top cylinder with a tenth or so turns of thick copper wire. L5 It is necessary to rewind, as several voltage levels are used in the computer - we only need one voltage that we will adjust.
L5 is a yellow ring (not every ring will go, as ferrites with different characteristics can be used, we need to be yellow). It is necessary to wind up approximately 50 turns of the copper wire with a diameter of 1.5 mm. Resistor R34 quenching - It discharges capacitors so that when adjusting it does not occur to a long wait for the voltage reduction when the adjustment knob turns.
The most suspended elements T3 and T4, as well as the D15 are installed on radiators. In this design, they were also taken from old blocks and formatted (cut off and curved under the sizes of the case and the printed circuit board).
The scheme is a pulse and can be made to the household network its own interference, so it is necessary to use the L2 syphanger choke. To filter out the available interference networks use filters using chokes L3 and L4. Thermistor NTC1 will exclude a current jump at the time of turning on the circuit in the outlet, the start of the circuit will be softer.
To control voltage and current, as well as for the operation of the TL494 chip, it is necessary voltage more low levelthan 310 volts, therefore, a separate power circuit is used for this. It is built on a small transformer TR3 BV EI 382 1189. From the secondary winding, the voltage straightens and smoothes the capacitor - simply and angrily. Thus, we obtain 12 volts necessary for the control part of the power supply circuit. Next, 12 volts are stabilized to 5 volts using a linear stabilizer 7805 chip - this voltage is used for the voltage and current indication circuit. Also artificially creates a voltage -5 volt to power the operational amplifier voltage and current indication scheme. In principle, you can use any available voltmeter and ammeter diagram for this power supply and in the absence of the need for voltage stabilization cascade can be excluded. As a rule, measurement and indication schemes are used, built on microcontrollers, which need to feed about 3.3 - 5 volts. The connection of the ammeter and the voltmeter is indicated in the diagram.
On the photo, the printed circuit board with a microcontroller is an ammeter and a voltmeter, to the panel are attached to the bolts, which are screwed into the nuts, securely glued to the plastic super glue. This indicator has a limit on measuring the current to 9.99 A, which is clearly not enough for this power supply. In addition to the indication functions, the current measurement module and voltage is no longer involved relative to the main board of the device. Any measuring module for replacement is functionally suitable.
The voltage and current control circuit is built on four operating amplifiers (LM324 is used - four operating amplifiers in one case). To power this chip, it is worth using a power filter on elements L1 and C1, C2. The scheme setting is the selection of elements marked with an asterisk to specify the control ranges. The adjustment circuit is assembled on a separate printed circuit board. In addition, for more smooth adjustment, you can use several variable resistors connected accordingly.
To set the frequency of the converter, it is necessary to choose the rating of the C3 condenser and the value of the R3 resistor. The diagram shows a small plate with calculated data. Too much frequency can increase losses on power transistors When switching, therefore, it is not too interested in it, optimally, in my opinion, use the frequency of 70-80 kHz, and even less.
Now about the winding or rewind of TR2 transformer. I also used the basis from the old power supplies of the computer. If you do not need a high current and a lot of voltages, you can not rewind such a transformer, and use ready, connecting the windings accordingly. However, if a larger current and voltage is needed, the transformer must be reworked to get a better result. First of all, you have to disassemble the core, which we have. This is the most responsible moment, as Ferrites are quite fragile, and it is not worth breaking them, otherwise everything is on trash. So, in order to disassemble the core, it must be heated, since to glue the halves, the manufacturer usually uses epoxy resin, which is softened when heated. Open sources of fire should not be used. Electric heating equipment is well suitable, in domestic conditions, this is, for example, electric stove. When heated, gently disconnect the half of the core. After cooling, we remove all native windings. Now you need to calculate the required number of turns of the primary and secondary windings of the transformer. To do this, you can use the Excellentit (5000) program in which you specify the parameters of the converter you need and calculate the number of turns relative to the core used. Next, after winding the core, the transformer needs to be brought back, it is also desirable to use high-strength glue or epoxy resin. When buying a new core, the need for gluing may be absent, since often halves the core can be tightened with metal brackets and bolts. Winding need to wove tightly to eliminate acoustic noise when working. At the request of the winding, you can pour some paraffins.
Printing boards were designed for Z4A housing. The hull itself is subjected to small refinement to ensure air circulation for cooling. For this, several holes are drilled on the sides and behind the sides, and the hole for the fan is cut from above. The fan blows down, excess air goes through the holes. You can position the fan and vice versa, so that it sucking the air from the case. In fact, the cooling fan is rare when it is necessary, besides, even at high loads, the elements of the circuit are not very hot.
Facial panels are also prepared. Voltage and current indicators are used using sevegment indicatorsAnd as a light filter for these indicators, a metallized antistatic film is used, like that in which radio elements are packaged with a marking sensitivity to electrostatics. You can also use a translucent film that glue on the window glass, or a tinting film for cars. A set of elements on the front panel in front and rear can be combined according to any taste. In my case, behind the connector for connecting to the outlet, the fuse compartment and switch. Front - current and voltage indicators, current stabilization LEDs (red) and stabilization of voltage (green), knobs of variable resistors for adjusting the current and voltage and quick-pressure connector to which the output voltage is connected.
With the correct assembly, the power supply needs only in the adjustment of regulatory ranges.
Current protection (current stabilization) in the following way: When the set current is exceeded, the TL494 chip is fed a voltage reduction signal - the smaller the voltage, the smaller the current. In this case, a red LED lights up on the front panel, which signals the exceeding current, or about a short circuit. In the normal stabilization mode, the green LED is burning.
The main characteristics of the pulse laboratory supply unit depend mainly on the element base used, in this embodiment the following characteristics are:
- Input voltage - 220 volts of alternating current
- Output voltage - from 0 to 30 volts direct current
- The output current is more than 15 A (actually tested)
- Voltage stabilization mode
- Current Stabilization Mode (Short Circuit Protection)
- Indication of both modes LEDs
- Small dimensions and weight with big power
- Adjusting current and voltage limit
Summing up, it can be noted that the laboratory power supply turned out to be quite high quality and powerful. This allows you to use this option Power supply as for testing some of their schemes, right up to charging car batteries. It is also worth noting that the outlet capacity is quite large, so short circuits are better not allowed, since the discharge of capacitors is likely to withdraw the scheme (the one to which you connect), but without this tank, the output voltage will be worse - will increase Pulsation. This feature is the impulse block, in analog block Nutrition The output capacity does not exceed 10 μF as a rule, due to its circuitry. Thus, we obtain a universal laboratory pulse power supply capable of working in a wide range of loads almost from zero to dozens of amps and volts. The power supply has perfectly proven itself as in the nutrition of small circuits when testing (but here the protection against the CZ will help little due to a large output capacity) with consumption in milliamps and in the application in situations, the code requires a large output power during my meager experience in Electronics fields.
I did this laboratory power supply about 4 years ago, when it was just started to make the first steps in electronics. To date, not a single breakdown, taking into account the fact that he worked often far beyond 10 amps (charging of automotive batteries). When describing due to the long-term production period, something might miss something, add questions, comments in the comments.
Software for calculating the transformer:
I apply to the article printed circuit boards (voltmeter and ammeter not included here - you can apply absolutely any).
List of radio elements
| Designation | A type | Nominal | number | Note | Score | My notebook |
|---|---|---|---|---|---|---|
| IC1 | PWM controller | TL494. | 1 | In notebook | ||
| IC2. | Operational amplifier | LM324 | 1 | In notebook | ||
| VR1. | Linear regulator | L7805AB | 1 | In notebook | ||
| VR2. | Linear regulator | LM7905. | 1 | In notebook | ||
| T1, T2. | Bipolar transistor | C945. | 2 | In notebook | ||
| T3, T4. | Bipolar transistor | MJE13009. | 2 | In notebook | ||
| VDS2. | Diode bridge | MB105 | 1 | In notebook | ||
| VDS1 | Diode bridge | GBU1506. | 1 | In notebook | ||
| D3-D5, D8, D9 | Rectifying diode | 1N4148. | 5 | In notebook | ||
| D6, D7. | Rectifying diode | FR107. | 2 | In notebook | ||
| D10, D11 | Rectifying diode | FR207. | 2 | In notebook | ||
| D12, D13 | Rectifying diode | FR104. | 2 | In notebook | ||
| D15 | Diode Schottki | F20C20. | 1 | In notebook | ||
| L1. | Throttle | 100 μH | 1 | In notebook | ||
| L2. | Syncane choke | 29 mpn | 1 | In notebook | ||
| L3, L4. | Throttle | 10 μH | 2 | In notebook | ||
| L5 | Throttle | 100 μH | 1 | on the yellow ring | In notebook | |
| L6. | Throttle | 8 μH | 1 | In notebook | ||
| TR1. | Pulse transformer | EE16. | 1 | In notebook | ||
| TR2. | Pulse transformer | EE28 - EE33. | 1 | ER35 | In notebook | |
| TR3. | Transformer | BV EI 382 1189 | 1 | In notebook | ||
| F1 | Fuse | 5 A. | 1 | In notebook | ||
| NTC1 | Thermistor. | 5.1 Oh. | 1 | In notebook | ||
| VDR1 | Varistor | 250 B. | 1 | In notebook | ||
| R1, R9, R12, R14 | Resistor | 2.2 com | 4 | In notebook | ||
| R2, R4, R5, R15, R16, R21 | Resistor | 4.7 com | 6 | In notebook | ||
| R3 | Resistor | 5.6 com | 1 | pick up | In notebook | |
| R6, R7 | Resistor | 510 com | 2 | In notebook | ||
| R8. | Resistor | 1 MΩ | 1 | In notebook | ||
| R13 | Resistor | 1.5 com | 1 | In notebook | ||
| R17, R24. | Resistor | 22 com | 2 | In notebook | ||
| R18. | Resistor | 1 com | 1 | In notebook | ||
| R19, \u200b\u200bR20 | Resistor | 22 Oh. | 2 | In notebook | ||
| R22, R23 | Resistor | 1.8 com | 2 | In notebook | ||
| R27, R28. | Resistor | 2.2 Oh. | 2 | In notebook | ||
| R29, R30 | Resistor | 470 com | 2 | 1-2 W. | In notebook | |
| R31 | Resistor | 100 Oh. | 1 | 1-2 W. | In notebook | |
| R32, R33 | Resistor | 15 Ohm. | 2 | In notebook | ||
| R34 | Resistor | 1 com | 1 | 1-2 W. | In notebook | |
| R10, R11 | Variable resistor | 10 com | 2 | you can use 3 or 4 to use | In notebook | |
| R25, R26 | Resistor | 0.1 Oh. | 2 | shunts, power depends on the output power of BP | In notebook | |
| C1, C8, C27, C28, C30, C31 | Capacitor | 0.1 MKF. | 7 | In notebook | ||
| C2, C9, C22, C25, C26, C34, C35 | Electrolytic condenser | 47 μF | 7 | In notebook | ||
| C3. | Capacitor | 1 NF. | 1 | film |