How to make an LED module. Production of circuit boards and assembly of a device for smooth ignition of LEDs Schemes LED for printed circuit boards

LEDs and products based on them are becoming increasingly popular. LED light bulbs and fixtures are systematically replacing traditional light sources from store shelves. Radio amateurs, this semiconductor device also cannot leave indifferent, and more and more often the question arises: how to make an LED with your own hands?

The LED itself is quite complicated to manufacture, and it is impossible to repeat the technological process outside the production conditions. Growing a crystal, packaging, applying a phosphor - all this requires complex expensive equipment. However, the further life path of an LED that has gone out of production can be very diverse. LEDs are used in monitor backlighting, indication, lighting, and many other areas. They open up huge opportunities for both professional developers and simple amateurs to make something with their own hands.

In order for the LED to work, it must be soldered to the board, such a node will already be called an LED module. The module may include one or more light emitting diodes.

Unlike indicator LEDs, which have long solder leads into holes, high-power lighting LEDs are mainly made in surface-mounted packages. Therefore, soldering them to the board with your own hands is much more difficult, and the printed circuit boards for such LEDs themselves come in different types.

Fiberglass can only be used if the power is low, no more than a watt per LED, to avoid overheating. In this case, the space near the diode should be metallized, and sometimes it is “dotted” with vias for the fastest heat removal to the second side of the board. Although the heat sink from such a board turns out to be unimportant, it has a significant advantage - you can easily make it yourself using the good old “printer and iron” technology.

For optimal heat dissipation, a high-power LED is usually mounted on an MCPCB (“Metal Core Printed Circuit Board” - a printed circuit board on an aluminum base).

It is an aluminum plate, which has copper printed conductors on the surface, separated from the base by a thin dielectric oxide film. Such boards usually have a thickness of 1.5-2 mm, they are much more expensive than textolite boards and, as a rule, they can only be obtained in finished form, already diluted for specific types of LEDs. It will not be possible to make such a board with your own hands - you need to have a specialized production. However, recently, almost all domestic manufacturers of printed circuit boards have begun to provide MCPCB manufacturing services, and if there is a strong desire to manufacture your own unique LED module, then today you can implement it. It won't be cheap.

Soldering the LED to the MCPCB board presents certain difficulties:

when you try to solder the diode with a conventional soldering iron or soldering station, the board becomes a significant hindrance - a radiator that removes heat from the contact pad, preventing it from heating up properly, so you have to use a powerful soldering iron;
A powerful LED, in addition to the cathode and anode, usually also has a heat dissipation terminal, which is a flat area located at the bottom of the LED housing, i.e. inaccessible to the soldering iron tip.

A typical board for such LEDs is shown in the figure below.

Because of the bizarre shape, such a board is called a "star". In the center is the seat of the LED, in this case XPE from CREE. The LED looks like this

Soldering the LED to the "star" can be done with a hot air gun, but this must be done with great care so as not to damage the lens. You should also make sure that the air flow does not dislodge the LED. Solder paste should not be abused, if you apply an excess amount, the case can “float” and you will get a skew.

If you need to solder a large number of LEDs, for example, a module in the form of a long ruler, then a hair dryer is definitely not the best option.

There is a more efficient mounting method. An old flat iron can be the perfect tool for "baking" LED modules. It is installed with the sole up and heated to about 230 degrees. Then an aluminum board is carefully installed on it with flux, solder paste and LEDs installed. Visually, it will be possible to see when the board heats up, the solder paste melts and clear solderings form. The main thing is not to overexpose - the LED can be exposed to such temperatures only for a few tens of seconds, otherwise you can disable it or lose a significant proportion of the luminous flux. In this way, you can solder several dozen LEDs at the same time.

Question: "Is it possible to make an LED with your own hands?" among ordinary masters will certainly cause surprise. It would seem, why invent something that has long been invented and is mass-produced? However, there is such a category of people who love to make something unusual. For them, designing an LED is an opportunity to repeat the experiments of O.V. Losev, held about a hundred years ago, and a chance to prove to yourself and your friends the reality of creating an LED at home.

What you need

The main structural material is a piece of silicon carbide. You can’t buy it in a regular store, but if you try, you can find it on the Internet among private ads. In addition to it, you will need a needle from a pin, connecting wires, two furniture nails with a wide hat and an adjustable voltage source (0-10 volts). You will also need solder and a little skill in using a soldering iron. A simple multimeter is suitable for measuring the parameters of a homemade LED.

Preparatory work

The first step is to find an area on the surface of silicon carbide capable of emitting light. To do this, the source material will have to be crushed into several pieces 2-5 mm in size. Then each of them is placed in turn on a metal plate connected to the plus of a power source with a voltage of about 10V. The second electrode is a sharp probe or needle connected to the minus of the power source.

Then, the piece to be examined must be pressed against the plate with tweezers, and with a sharp needle, probe its upper part in search of a luminous area. Thus, the crystal with the highest brightness is selected. It is worth noting that silicon carbide can emit light in the spectrum from orange to green.

LED manufacturing

For ease of installation, it is better to take a carnation 10-15 mm long with a large hat and tin it well. It will serve as the base and heat sink for the crystal. With the help of a soldering iron, the tin on the hat is brought to a liquid state and the prepared carbide instance is slightly sunk with tweezers. Naturally, the radiating section should be directed upwards. After the solder solidifies, you need to make sure that the crystal is securely fixed.

To make a negative electrode, you will need the sharp part of a pin and a single-core copper wire. As can be seen from the photo, both parts are tinned and reliably soldered together. Then a loop is made on the wire to give it the properties of a spring. The free end of the wire is soldered to the head of the second nail. Both studs are attached to the circuit board at a short distance from each other.

At the final stage, power of the corresponding polarity is supplied to the legs of the nails. The electrical circuit is closed with a needle, which is fixed at the point of the crystal with maximum luminescence. By smoothly increasing the supply voltage, you can determine the value at which the brightness ceases to grow intensively. As a result of the measurements, the voltage drop was 9V, and the forward current was 25 mA. When the polarity is reversed, silicon carbide ceases to emit light, which partly explains its semiconductor properties.

I won’t be surprised if experienced radio amateurs express their negative attitude towards the resulting unusual design, reminiscent of a simple LED. However, sometimes collecting such things on your own is interesting and even useful. An example is amateur radio circles for schoolchildren, in which children get acquainted with the properties of different materials, learn to solder and learn the basics of semiconductors.

LED lamp

Represents a small luminous diode element, powered by direct current, mainly 12V. To create lamps, they are assembled several times, depending on the required light intensity.. The advantages of such lighting:

meager electricity consumption;
service life from 100,000 hours;
can work for days without shutting down;
There is a wide range of different models available for sale.

The main disadvantage is the high cost of finished LED lamps. Sellers are not well versed in the issue and can not competently answer your questions. In the very characteristics of the lamp losses due to the passage of light through the scatterer are not taken into account, frosted glass and reflector properties.

The packaging of the luminaire contains calculated data based on the characteristics and number of LED elements. Therefore, in fact the luminous flux of the purchased lamp is significantly lower than required and the lighting is poor. The lamps themselves and the parts for creating circuits cost a penny. Therefore, it is easiest for craftsmen to do everything with their own hands.

Use of LED lights

In houses and apartments, constant lighting of a place is often necessary. It can be stairs and children's rooms, toilets where there are no windows, and a child lives in the house who cannot reach the switch.

Dim light and low energy consumption make it possible to install lighting in entrances and on the porch, in front of the gate and garage doors. Luminaires with a soft glow due to glare damping, used to illuminate desktops in offices and kitchens.

Making an LED lamp with your own hands

Many are tormented by the question of how to make an LED lamp with your own hands and is it possible. There are many schemes for creating LED lighting powered by 220 V AC, they all solve a number of common tasks:

When creating LED lighting with your own hands, you also have to solve problems:

where to put circuits and LEDs;
how to isolate the lighting structure;
correct heat transfer.

Schemes of LED lamps

Aligning variable sweat and creating the necessary power and resistance for LED fixtures is solved in two ways. Schemes can be conditionally divided into:

with diode bridge;
resistor, with an even number of LED elements.

Each option has simple schemes and its own advantages.

Scheme of a converter with a diode bridge

The diode bridge consists of 4 diodes directed in different directions. Its task is to turn a sinusoidal alternating current into a pulsating one. Each half wave passes through two elements, and the minus changes its polarity.

In the circuit, for an LED lamp, a capacitor C10.47x250 v is connected to the positive side of the bridge from the AC source. A resistance of 100 ohms is placed in front of the negative terminal. Behind the bridge, parallel to it, another capacitor is installed - C25x400 v, which smooths out the voltage drop. It is easy to make such a scheme with your own hands, it is enough to have the skills to work with a soldering iron.

LED element

The board with LED elements is used standard, from a failed lamp. It is necessary to check before assembly that all parts are working. For this, a 12 V battery is used, it can be from a car. Non-working elements can be replaced by carefully unsoldering the contacts and putting in new ones. Pay close attention to the location of the anode and cathode legs. They are connected in series.

When replacing 2 - 3 parts, you simply solder them in accordance with the position that the failed elements occupied.

When assembling a new LED lamp with your own hands, you need to remember a simple rule. Lamps are connected 10 in series, then these circuits are connected in parallel. In practice, it looks like this:

Put 10 LEDs in a row and solder the legs of the anode of one with the cathode of the second. It turns out 9 connections and one free tail at the edges.
Solder all chains to the wires. To one cathode ends, to the other anode.

In texts, verbal designation of contacts is often used, icons on diagrams. Reminder for novice electricians:

cathode, positive - "+", joins the minus;
The anode is negative - "-", joins the plus.

When assembling circuits with your own hands, make sure that the soldered ends do not touch others. This will lead to a short circuit and burn out the entire circuit that you managed to make.

Schemes for a softer glow

In order for the LED lamp not to irritate the eyes by blinking, several details must be added to the assembly diagram. In general, the current converter consists of:

diode bridge;
400 nF and 10 uF capacitors;
100 and 230 ohm resistors.

To protect against power surges, a 100 ohm resistor is placed first, and then a 400 nF capacitor is soldered. In the previous version, they are installed at different ends of the entrance. Behind the capacitor after the diode bridge, another 230 ohm resistor is installed. It is followed by a series of LEDs (+).

Resistor circuits

The simplest circuit for those who want to do everything with their own hands consists of two 12 k resistors and two chains with the same number of LED elements, lamps connected in series with different directions are soldered. From the R 1 side, one strip is soldered by the cathode, the second - by the anode. Another layer to R 2 is the other way around.

This creates a softer glow of the lamps, since the LED elements are lit alternately and the pulsation of the flashes is almost imperceptible to the eyes. Such lamps can even be used as local lighting when working at a table, thus replacing an ordinary table lamp.

Experts who have made more than one lamp with their own hands recommend collecting at least 20 LEDs for this circuit. 40 is more commonly used. This provides good lighting and the circuit is easy to assemble. For a larger number, it is difficult to produce high-quality soldering of the circuit without hitting adjacent contacts. Yes, and it is difficult to collect it in the case.

You can make a lamp from 4 or 6 more powerful LEDs. To calculate the schemes, use a special calculator that can be found on the Internet.

When creating various circuits with your own hands from LED devices and others, you can use an online calculator for the correct calculation. It is easy to find on sites that are dedicated to electrical appliances and descriptions of how to make them. Its use will greatly simplify the process of calculating the current strength, resistance and will allow you to check the correct selection of parts.

Housings for LED lamps

For convenient inclusion of a do-it-yourself LED lamp in ordinary lighting devices, use:

socles of conventional incandescent lamps;
housings from energy-saving lamps;
halogen lamps;
homemade fixtures.

Each specialist, making an LED lamp with his own hands, chooses the most suitable option. The base makes it possible to screw the lamp into a conventional cartridge and at the same time provides heat transfer. Overheating, the LED lamp fails faster.

Base with incandescent lamps

Carefully separate the glass flask and remove the spiral. Then a circuit is placed inside the base and lamps are attached to the top of the board. The disadvantage of such a base is in an unsightly appearance and poor insulation.

Energy saving lamp housing

The most convenient and practical option for creating an LED lamp with your own hands. Methods for mounting diodes can be different. First, the burned-out lamp is carefully disassembled. Then the converter board is removed from it. Next, there are options.

It can be placed in the holes of the lid, which are made for glass flasks. This is in the version of the lamp with three arc-shaped light elements. The circuit is located inside the base providing heat transfer. LEDs are inserted into ready-made holes and mounted in them.

The finished board with LEDs can be placed in the base using a simple plastic water bottle cap. You can use a self-made circle and drill holes for the diodes in it. As a result, it is convenient to use and aesthetically pleasing.

Some craftsmen, making their own hands, use the body of a halogen lamp. The inconvenience of this option is the absence of the usual opportunity for a base to screw the lamp into a cartridge. This option is more suitable for creating do-it-yourself indicators and DC lamps.