LED characteristics: current consumption, voltage, power and light output

LED characteristics: current consumption, voltage, power and light output

The days when LEDs were used only as indicators for turning on devices are long gone. Modern LED devices can completely replace incandescent lamps in household, industrial and street lamps. This is facilitated by various characteristics of LEDs, knowing which you can choose the right LED analog. The use of LEDs, taking into account their basic parameters, opens up an abundance of opportunities in the field of lighting.

The basis of the LED is an artificial semiconductor crystal

What are the LEDs

An LED (denoted SD, LED, LED in English) is a device based on an artificial semiconductor crystal. When an electric current is passed through it, the phenomenon of photon emission is created, which leads to a glow. This glow has a very narrow range of the spectrum, and its color depends on the material of the semiconductor.

LEDs may well replace conventional incandescent bulbs

LEDs with red and yellow glow are produced from inorganic semiconductor materials based on gallium arsenide, green and blue are made on the basis of indium gallium nitride. To increase the brightness of the luminous flux, various additives are used or the multilayering method is used, when a layer of pure aluminum nitride is placed between semiconductors. As a result of the formation of several electron-hole (p-n) transitions in one crystal, the brightness of its glow increases.

There are two types of LEDs: for indication and lighting. The former are used to indicate the inclusion of various devices in the network, as well as as sources of decorative illumination. They are colored diodes placed in a translucent housing, each of them has four outputs. Devices emitting infrared light are used in devices for remote control of devices (remote control).

In the field of lighting, LEDs emitting white light are used. LEDs with cold white, neutral white and warm white glow are distinguished by color. There is a classification of LEDs used for lighting according to the installation method. The marking of the SMD LED means that the device consists of an aluminum or copper substrate on which the diode crystal is placed. The substrate itself is located in the housing, the contacts of which are connected to the contacts of the LED.

The use of LED lighting in the kitchen interior

Another type of LED is designated OCB. In such a device, many crystals coated with phosphor are placed on one board. Thanks to this design, a greater brightness of the glow is achieved. This technology is used in the production of LED lamps with a large luminous flux on a relatively small area. In turn, this makes the production of LED lamps the most affordable and inexpensive.

Pay attention! Comparing lamps on SMD and COB LEDs, it can be noted that the former can be repaired by replacing a failed LED. If the lamp on COB LEDs does not work, you will have to change the entire board with diodes.

Characteristics of LEDs

When choosing a suitable LED lamp for lighting, the parameters of the LEDs should be taken into account. These include supply voltage, power, operating current, efficiency (light output), glow temperature (color), radiation angle, dimensions, degradation period. Knowing the basic parameters, it will be possible to easily choose devices for obtaining a particular illumination result.

LED technologies are used in the design of airport and train station displays

The value of the LED consumption current

As a rule, a current of 0.02 A is provided for conventional LEDs. However, there are LEDs designed for 0.08 A. Such LEDs include more powerful devices, in the device of which four crystals are involved. They are located in the same building. Since each of the crystals consumes 0.02A, in total one device will consume 0.08A.

The stability of LED devices depends on the current value. Even a slight increase in the current strength contributes to a decrease in the intensity of radiation (aging) of the crystal and an increase in color temperature. This ultimately leads to the fact that the LEDs begin to cast blue and prematurely fail. And if the current strength indicator increases significantly, the LED immediately burns out.

To limit the current consumption, current stabilizers for LEDs (drivers) are provided in the designs of LED lamps and lamps. They convert the current, bringing it to the desired value of the LEDs. In the case when you need to connect a separate LED to the network, you need to use current-limiting resistors. The calculation of the resistance of the resistor for the LED is carried out taking into account its specific characteristics.

Useful advice! To choose the right resistor, you can use the calculator for calculating the resistor for the LED, located on the Internet.

The LED garland can be used as a room decor

LED voltage

How to find out the voltage of the LEDs? The fact is that the LEDs do not have a power supply voltage parameter as such. Instead, the characteristic of the voltage drop on the LED is used, which means the value of the voltage at the output of the LED when the rated current passes through it. The voltage value indicated on the package reflects just the voltage drop. Knowing this value, it is possible to determine the voltage remaining on the crystal. It is this value that is taken into account when calculating.

Considering the use of various semiconductors for LEDs, the voltage of each of them may be different. How do I find out how many Volts an LED is? You can determine by the color of the glow of the devices. For example, for blue, green and white crystals, the voltage is about 3V, for yellow and red – from 1.8 to 2.4 V.

When using parallel connection of LEDs of identical nominal value with a voltage value of 2V, you may encounter the following: as a result of the spread of parameters, some emitting diodes will fail (burn out), while others will glow very weakly. This will happen due to the fact that with an increase in voltage even by 0.1 V, there is an increase in the current passing through the LED by 1.5 times. Therefore, it is so important to ensure that the current corresponds to the nominal value of the LED.

100W incandescent lamp is equivalent to 12-12.5W LED lamp

Light output, glow angle and LED power

Comparison of the luminous flux of diodes with other light sources is carried out, taking into account the strength of the radiation emitted by them. Devices measuring about 5 mm in diameter give from 1 to 5 lm of light. While the luminous flux of an incandescent lamp in 100W is 1000 lm. But when comparing it, it must be taken into account that a conventional lamp has diffused light, and an LED has directional light. Therefore, it is necessary to take into account the scattering angle of the LEDs.

The scattering angle of different LEDs can range from 20 to 120 degrees. When illuminated, the LEDs give a brighter light in the center and reduce illumination to the edges of the scattering angle. Thus, LEDs better illuminate a specific space, while using less power. However, if it is necessary to increase the area of illumination, scattering lenses are used in the design of the lamp.

How to determine the power of LEDs? To determine the power of the LED lamp required to replace the incandescent lamp, it is necessary to apply a coefficient equal to 8. So, you can replace a conventional lamp with a power of 100W with an LED device with a power of at least 12.5 W (100W /8). For convenience, you can use the data of the table of compliance of the power of incandescent lamps and LED light sources:

When using LEDs for lighting, an efficiency indicator is very important, which is determined by the ratio of luminous flux (lm) to power (W). Comparing these parameters for different light sources, we get that the efficiency of an incandescent lamp is 10-12 lm / W, fluorescent – 35-40 lm / W, LED – 130-140 lm / W.

Color temperature of LED sources

One of the important parameters of LED sources is the glow temperature. The units of measurement of this value are degrees Kelvin (K). It should be noted that all light sources are divided into three classes according to the glow temperature, among which warm white has a color temperature of less than 3300 K, daytime white – from 3300 to 5300 K and cold white over 5300 K.

Pay attention! The comfortable perception of LED radiation by the human eye directly depends on the color temperature of the LED source.

The color temperature is usually indicated on the marking of LED lamps. It is indicated by a four-digit number and the letter K. The choice of LED lamps with a certain color temperature directly depends on the features of its application for lighting. The table below shows the options for using LED sources with different glow temperatures:

The wave nature of color allows you to express the color temperature of LEDs using wavelength. The marking of some LED devices reflects the color temperature precisely in the form of an interval of different wavelengths. The wavelength has the designation λ and is measured in nanometers (nm).

Standard sizes of SMD LEDs and their characteristics

Considering the size of the SMD LEDs, the devices are classified into groups with different characteristics. The most popular LEDs with sizes 3528, 5050, 5730, 2835, 3014 and 5630. The characteristics of SMD LEDs vary depending on the size. So, different types of SMD LEDs differ in brightness, color temperature, power. In the LED marking, the first two digits show the length and width of the device.

SMD 5630 LEDs on LED strip

Main parameters of SMD 2835 LEDs

The main characteristics of SMD LEDs 2835 include an increased radiation area. In comparison with the SMD 3528 device, which has a round working surface, the radiation area of the SMD 2835 has a rectangular shape, which contributes to greater light output at a lower element height (about 0.8 mm). The luminous flux of such a device is 50 lm.

The housing of the SMD 2835 LEDs is made of heat-resistant polymer and can withstand temperatures up to 240 ° C. It should be noted that the degradation of radiation in these elements is less than 5% during 3000 hours of operation. In addition, the device has a sufficiently low thermal resistance of the crystal-substrate transition (4 S / W). The operating current in the maximum value is 0.18 A, the crystal temperature is 130 ° C.

According to the color of the glow, warm white with a glow temperature of 4000 K, daytime white – 4800 K, pure white – from 5000 to 5800 K and cold white with a color temperature of 6500-7500 K. It is worth noting that the maximum value of the luminous flux is for devices with a cold white glow, the minimum is for LEDs of warm white color. The design of the device has increased contact pads, which contributes to better heat dissipation.

Useful advice! The SMD 2835 LEDs can be used for any type of mounting.

Dimensions of the SMD 2835 LED

Characteristics of SMD 5050 LEDs

The design of the SMD 5050 housing contains three LEDs of the same type. LED sources of blue, red and green have technical characteristics similar to SMD 3528 crystals. The value of the operating current of each of the three LEDs is 0.02A, hence the total current value of the entire device is 0.06 A. In order for the LEDs not to fail, it is recommended not to exceed this value.

SMD 5050 LED devices have a forward voltage of 3-3.3V and a light output (network flow) of 18-21 lm. The power of one LED consists of three values of the power of each crystal (0.7 watts) and is 0.21 watts. The color of the glow emitted by the devices can be white in all shades, green, blue, yellow and multicolored.

The close arrangement of LEDs of different colors in the same SMD 5050 housing made it possible to implement multi-color LEDs with separate control of each color. Controllers are used to regulate luminaires using SMD 5050 LEDs, so that the glow color can be smoothly changed from one to another after a given amount of time. Usually such devices have several control modes and can adjust the brightness of the LEDs.

Dimensions of the SMD 5050 LED

Typical characteristics of the SMD 5730 LED

SMD 5730 LEDs are modern representatives of LED devices, the body of which has geometric dimensions of 5.7 x 3 mm. They belong to ultra-bright LEDs, the characteristics of which are stable and qualitatively differ from the parameters of their predecessors. Manufactured using new materials, these LEDs are characterized by increased power and highly efficient light flux. In addition, they can work in conditions of high humidity, are resistant to temperature changes and vibration, and have a long service life.

There are two types of devices: SMD 5730-0.5 with a power of 0.5W and SMD 5730-1 with a power of 1W. A distinctive feature of the devices is the possibility of their functioning on pulsed current. The value of the rated current of SMD 5730-0.5 is 0.15A, with pulse operation, the device can withstand a current of up to 0.18 A. This type of LEDs provides a luminous flux of up to 45 lm.

SMD 5730-1 LEDs operate at a constant current of 0.35 A, with pulse mode – up to 0.8 A. The light output efficiency of such a device can be up to 110 lm. Thanks to the heat-resistant polymer, the device housing can withstand temperatures up to 250 ° C. The scattering angle of both types of SMD 5730 is 120 degrees. The degree of degradation of the luminous flux is less than 1% when working for 3000 hours.

Dimensions of the SMD 5730 LED

Characteristics of Cree LEDs

The company Cree (USA) is engaged in the development and production of ultra-bright and most powerful LEDs. One of the Cree LED groups is represented by a series of Xlamp devices, which are divided into single-chip and multi-chip. One of the features of single-chip sources is the distribution of radiation along the edges of the device. This innovation made it possible to produce lamps with a large glow angle using a minimum number of crystals.

In the XQ-E High Intensity series of LED sources, the glow angle ranges from 100 to 145 degrees. Having small geometric dimensions of 1.6×1.6 mm, the power of ultra–bright LEDs is 3 Volts, and the luminous flux is 330 lm. This is one of the newest developments of the Cree company. All LEDs, the design of which is developed on the basis of a single crystal, have high-quality color reproduction within CRE 70-90.

Related article:

Outdoor LED garlands: frost-resistant and moisture-resistant decorations
How to make or repair an LED garland yourself. Prices and main characteristics of the most popular models.

Cree has released several variants of multi-chip LED devices with the latest power types from 6 to 72 volts. Multi-chip LEDs are divided into three groups, which include devices with high voltage, power up to 4W and above 4W. In sources up to 4W, 6 crystals are assembled in an MX and ML type housing. The scattering angle is 120 degrees. You can buy Cree LEDs of this type with a white warm and cold glow color.

Useful advice! Despite the high reliability and quality of light, you can buy powerful MX and ML series LEDs at a relatively low price.

The group over 4W includes LEDs from several crystals. The largest in the group are devices with a capacity of 25W, presented by the MT-G series. The novelty of the company is the LEDs of the XHP model. One of the large LED devices has a 7×7 mm housing, its power is 12W, light output is 1710 lm. LEDs with high power supply voltage combine small dimensions and high light output.

LED lamps of the XQ-E High Intensity series manufactured by Cree (USA)

LED connection diagrams

There are certain rules for connecting LEDs. Taking into account that the current passing through the device moves only in one direction, for the long-term and stable operation of LED devices, it is important to take into account not only a certain voltage, but also the optimal current value.

Wiring diagram of the LED to the 220V network

Depending on the power source used, there are two types of schemes for connecting LEDs to 220V. In one of the cases, a driver with a limited current is used, in the second – a special power supply that stabilizes the voltage. The first option takes into account the use of a special source with a certain current strength. A resistor is not required in this circuit, and the number of connected LEDs is limited by the power of the driver.

Two types of pictograms are used to indicate the LEDs in the diagram. Above each schematic image of them there are two small parallel arrows pointing upwards. They symbolize the bright glow of the LED device. Before connecting the LED to 220V using the power supply, it is necessary to include a resistor in the circuit. If this condition is not met, it will lead to the fact that the working life of the LED will be significantly reduced or it will simply fail.

Wiring diagram of LEDs to the 220V network using a quenching capacitor C1

If you use a power supply when connecting, then only the voltage will be stable in the circuit. Given the insignificant internal resistance of the LED device, turning it on without a current limiter will cause the device to burn. That is why an appropriate resistor is introduced into the LED switching circuit. It should be noted that resistors come with different nominal values, so they should be calculated correctly.

Useful advice! A negative aspect of the schemes for switching the LED into a 220 Volt network using a resistor is the dissipation of high power when it is necessary to connect a load with increased current consumption. In this case, the resistor is replaced by a quenching capacitor.

How to calculate the resistance for an LED

When calculating the resistance for the LED , the formula is used:

U = IhR,

where U is the voltage, I is the current, R is the resistance (Ohm’s law). Let’s say you need to connect an LED with the following parameters: 3V – voltage and 0.02 A – amperage. So that when connecting the LED to 5 Volts on the power supply, it does not fail, it is necessary to remove the extra 2V (5-3 = 2V). To do this, it is necessary to include a resistor with a certain resistance in the circuit, which is calculated using Ohm’s law:

R = U/I.

Resistors with different resistance values

Thus, the ratio of 2V to 0.02A will be 100 ohms, i.e. this is exactly what a resistor is needed.

It often happens that considering the parameters of the LEDs, the resistance of the resistor has a non-standard value for the device. Such current limiters cannot be found at points of sale, for example, 128 or 112.8 ohms. Then resistors should be used, the resistance of which has the nearest greater value compared to the calculated one. At the same time, the LEDs will not function at full capacity, but only by 90-97%, but this will be unnoticeable to the eye and will have a positive effect on the device’s resource.

There are many variants of LED calculators on the Internet. They take into account the main parameters: voltage drop, rated current, output voltage, number of devices in the circuit. By setting the parameters of LED devices and current sources in the form field, you can find out the corresponding characteristics of the resistors. To determine the resistance of color-coded current limiters, there are also online calculations of resistors for LEDs.

Schemes of parallel and serial connection of LEDs

When assembling structures from several LED devices, schemes for switching LEDs into a 220 Volt network with a serial or parallel connection are used. At the same time, for correct connection, it should be borne in mind that when the LEDs are switched on sequentially, the required voltage is the sum of the voltage drops of each device. While when the LEDs are turned on in parallel, the current strength is added.

Schemes of parallel connection of LEDs. In option 1, a separate resistor is used for each diode circuit, in option 2 — one common for all circuits

If LED devices with different parameters are used in the circuits, then for stable operation it is necessary to calculate the resistor for each LED separately. It should be noted that there are no two identical LEDs. Even devices of the same model have minor differences in parameters. This leads to the fact that when a large number of them are connected to a serial or parallel circuit with a single resistor, they can quickly degrade and fail.

Pay attention! When using a single resistor in a parallel or serial circuit, only LED devices with identical characteristics can be connected.

The discrepancy in the parameters when several LEDs are connected in parallel, for example 4-5 pcs., will not affect the operation of the devices. And if you connect a lot of LEDs to such a scheme, it will be a bad decision. Even if LED sources have a slight variation in characteristics, this will lead to the fact that some devices will emit bright light and burn out quickly, while others will glow weakly.  Therefore, when connecting in parallel, you should always use a separate resistor for each device.

As for the serial connection, there is an economical consumption here, since the entire circuit consumes an amount of current equal to the consumption of one LED. With a parallel circuit, the consumption is the sum of the expenditure of all the LED sources included in the circuit included in the circuit.

The scheme of serial connection of LEDs

How to connect LEDs to 12 Volts

In the design of some devices, resistors are provided at the manufacturing stage, which makes it possible to connect LEDs to 12 volts or 5 Volts. However, such devices can not always be found on sale. Therefore, in the wiring diagram of LEDs to 12 volts, a current limiter is provided. The first step is to find out the characteristics of the connected LEDs.

Such a parameter as a direct voltage drop in typical LED devices is about 2V. The rated current of these LEDs corresponds to 0.02 A. If you need to connect such an LED to 12V, then the “extra” 10V (12 minus 2) it is necessary to extinguish the limiting resistor. With the help of Ohm’s law, you can calculate the resistance for it. We get that 10/0.02 = 500 (ohms). Thus, a resistor with a nominal value of 510 ohms is needed, which is the closest in a number of electronic components E24.

In order for such a scheme to work stably, it is also necessary to calculate the power of the limiter. Using a formula based on which the power is equal to the product of voltage and current, we calculate its value. The voltage of 10V is multiplied by a current of 0.02 A and we get 0.2 Watts. Thus, a resistor is required, the standard power rating of which is 0.25 watts.

Wiring diagram of RGB LED strip to 12V

If two LED devices need to be included in the circuit, then it should be borne in mind that the voltage falling on them will already be 4V. Accordingly, for the resistor, it will remain to extinguish not 10V, but 8V. Therefore, further calculation of the resistance and power of the resistor is done based on this value. The location of the resistor in the circuit can be provided anywhere: from the side of the anode, the cathode, between the LEDs.

How to check the LED with a multimeter

One of the ways to check the working condition of LEDs is testing with a multimeter. With such a device, LEDs of any design can be diagnosed. Before checking the LED with a tester, the switch of the device is set in the “ringing” mode, and the probes are applied to the terminals. When the red probe is closed to the anode, and the black one to the cathode, the crystal should emit light. If the polarity is reversed, the display of the device should display the reading “1”.

Useful advice! Before checking the LED for operability, it is recommended to dim the main lighting, since the current is very low during testing and the LED will emit light so weakly that it may not be noticed in normal lighting.

The scheme of checking the LED with a digital multimeter

LED devices can be tested without using probes. To do this, in the holes located in the lower corner of the device, the anode is inserted into the hole with the symbol “E”, and the cathode is inserted with the pointer “C”. If the LED is in working condition, it should light up. This test method is suitable for LEDs with sufficiently long solder-free contacts. The position of the switch with this method of checking does not matter.

How to check the LEDs with a multimeter without soldering? To do this, it is necessary to solder pieces from a regular paper clip to the tester’s probes. As insulation, a textolite gasket is suitable, which is placed between the wires, after which it is treated with duct tape. The output is a kind of adapter for connecting the probes. The paper clips spring well and are securely fixed in the connectors. In this form, you can connect the probes to the LEDs without soldering them out of the circuit.

What can be made from LEDs with your own hands

Many radio amateurs practice assembling various LED structures with their own hands. Self-assembled products are not inferior in quality, and sometimes even surpass analogues of industrial production. These can be color-musical devices, flashing LED designs, running lights on LEDs with their own hands and much more.

The use of LEDs in the creation of stage costumes

Assembling a current stabilizer for LEDs with your own hands

In order for the LED’s resource not to be exhausted before the due date, it is necessary that the current flowing through it has a stable value. It is known that red, yellow and green LEDs can cope with an increased current load. While blue-green and white LED sources burn out in 2 hours even with a slight overload. Thus, for the normal operation of the LED, it is necessary to solve the issue with its power supply.

If you assemble a chain of LEDs connected in series or in parallel, then you can provide them with identical radiation if the current passing through them will have the same strength. In addition, reverse current pulses can negatively affect the resource of LED sources. To prevent this from happening, it is necessary to include a current stabilizer for LEDs in the circuit.

The qualitative characteristics of LED lamps depend on the driver used – a device that converts the voltage into a stabilized current with a specific value. Many radio amateurs assemble a power supply circuit for LEDs from 220V with their own hands based on the LM317 chip. Elements for such an electronic circuit have a low cost and such a stabilizer is easy to construct.

Wiring diagram of a powerful LED using an integrated voltage stabilizer LM317

When using a current stabilizer on the LM317 for LEDs, the current is regulated within 1A. The LM317L-based rectifier stabilizes the current to 0.1 A. The device circuit uses only one resistor. It is calculated using an online resistance calculator for an LED. Available improvised devices are suitable for power supply: power supplies from a printer, laptop or other consumer electronics. It is not profitable to assemble more complex schemes yourself, since it is easier to purchase them ready-made.

DRL from LEDs with your own hands

The use of daytime running lights (DRL) on cars significantly increases the visibility of the car during daylight hours by other road users. Many motorists practice self-assembly of DRL using LEDs. One of the options is a DRL device of 5-7 LEDs with a power of 1W and 3W for each unit. If you use less powerful LED sources, the luminous flux will not meet the standards for such lights.

Useful advice! When making DRL with your own hands, take into account the requirements of GOST: the luminous flux is 400-800 Cd, the angle of illumination in the horizontal plane is 55 degrees, in the vertical – 25 degrees, the area is 40 cm2.

Daytime running lights improve the visibility of the car on the road

For the base, you can use an aluminum profile board with pads for mounting LEDs. The LEDs are fixed on the board using a heat-conducting adhesive compound. Optics are selected according to the type of LED sources. In this case, lenses with a glow angle of 35 degrees are suitable. The lenses are installed on each LED separately. The wires are output in any convenient direction.

Next, a housing for DRL is made, which serves as a radiator at the same time. To do this, you can use a U-shaped profile. The finished LED module is placed inside the profile, fixing it on screws. All the free space can be filled with a transparent silicone-based sealant, leaving only the lenses on the surface. Such a coating will serve as moisture protection.

The connection of the DRL to the power supply is made with the mandatory use of a resistor, the resistance of which is pre-calculated and checked. The connection methods may be different, given the car model. Connection diagrams can be found on the Internet.

Connection diagram of the DRL with the control unit

How to make the LEDs blink

The most popular flashing LEDs, which you can buy ready-made, are devices regulated by the level of potential. The flashing of the crystal occurs due to a change in the power supply at the terminals of the device. So, a two-color red-green LED device emits light depending on the direction of the current passing through it. The flashing effect in the RGB LED is achieved by connecting three pins for separate control to a specific control system.

But you can also make a regular monochrome LED blink, having a minimum of electronic components in the arsenal. Before you make a flashing LED, you need to choose a working circuit that will be simple and reliable. You can use a flashing LED circuit that will be powered from a source with a voltage of 12V.

The circuit consists of a low-power transistor Q1 (a silicon high-frequency KTZ 315 or its analogues will do), a resistor R1 820-1000 ohms, a 16-volt capacitor C1 with a capacity of 470 UF and an LED source. When the circuit is switched on, the capacitor is charged to 9-10V, after which the transistor opens for a moment and gives the accumulated energy to the LED, which starts flashing. This scheme can be implemented only in the case of power supply from a 12V source.

Flashing LEDs are used, for example, in a Christmas tree garland

It is possible to assemble a more advanced circuit that works by analogy with a transistor multivibrator. The circuit includes KTZ 102 transistors (2 pcs.), resistors R1 and R4 of 300 ohms each to limit the current, resistors R2 and R3 of 27000 ohms each to set the current of the transistor base, 16-volt polar capacitors (2 pcs. with a capacity of 10 UF) and two LED sources. This circuit is powered by a DC voltage source of 5V.

The circuit works on the principle of “Darlington pairs”: capacitors C1 and C2 are alternately charged and discharged, which causes the opening of a particular transistor. When one transistor gives off energy C1, one LED lights up. Then C2 is smoothly charged, and the base current VT1 decreases, which leads to the closure of VT1 and the opening of VT2 and another LED lights up.

Useful advice! If you use a power supply voltage over 5V, you will need to use resistors with a different nominal value to eliminate the failure of the LEDs.

The scheme of flashes on the LED

Assembling color music on LEDs with your own hands

To implement quite complex schemes of color music on LEDs with your own hands, you must first figure out how the simplest scheme of color music works. It consists of one transistor, a resistor and an LED device. Such a circuit can be powered from a source with a nominal value from 6 to 12V. The operation of the circuit is due to cascade amplification with a common emitter (emitter).

The VT1 base receives a signal with varying amplitude and frequency. In the event that the signal fluctuations exceed the specified threshold, the transistor opens and the LED lights up. The disadvantage of this scheme is the dependence of flashing on the degree of the audio signal. Thus, the effect of color music will manifest itself only at a certain degree of sound volume. If the sound is increased. the LED will be on all the time, and when it is reduced, it will flash a little.

To achieve a full-fledged effect, use a color music scheme on LEDs with a breakdown of the sound range into three parts. The circuit with a three-channel sound converter is powered by a 9V voltage source. A huge number of color music schemes can be found on the Internet on various amateur radio forums. These can be schemes of color music using a single-color tape, RGB-LED tape, as well as schemes of smooth switching on and off of LEDs. You can also find schemes of running lights on LEDs on the network.

Scheme for assembling color music with your own hands

The design of the LED voltage indicator with your own hands

The voltage indicator circuit includes a resistor R1 (variable resistance 10kOhm), resistors R1, R2 (1kOhm), two transistors VT1 KT315B, VT2 KT361B, three LEDs – HL1, HL2 (red), HLZ (green). X1, X2 – 6-volt power supplies. In this scheme, it is recommended to use LED devices with a voltage of 1.5 V.

The algorithm of operation of a homemade LED voltage indicator is as follows: when the voltage is applied, the central LED source lights up green. In case of a voltage drop, the red LED located on the left turns on. An increase in voltage causes the red LED located on the right to glow. At the middle position of the resistor, all transistors will be in the closed position, and the voltage will be supplied only to the central green LED.

The opening of the transistor VT1 occurs when the slider of the resistor is moved up, thereby increasing the voltage. In this case, the supply of voltage to HL3 stops, and it is supplied to HL1. When moving the slider down (lowering the voltage), the transistor VT1 closes and VT2 opens, which will give power to the HL2 LED. With a slight delay, LED HL1 will go out, HL3 will flash once and HL2 will light up.

Assembly diagram of the voltage indicator on LEDs with your own hands

Such a scheme can be assembled using radio components from outdated equipment. Some assemble it on a textolite board, observing a scale of 1:1 with the dimensions of the parts so that all the elements can fit on the board.

The limitless potential of LED lighting makes it possible to independently design various lighting devices from LEDs with excellent characteristics and a fairly low cost.