1 . Transistor type KT315 (It doesn't matter if it will be the letters b, c, d, any one will do).
2 . electrolytic capacitor with a voltage of at least 16 volts, and a capacity of 1000 microfarads - 3000 microfarads (The smaller the capacity, the faster the LED flashes).
3 . Resistor 1 kOhm, power as you like.
4 . Light-emitting diode(Any color other than white).
5
. two wires(Preferably stranded).
To begin with, the LED flasher circuit itself. Now let's start making it. It can be made as an option on a printed circuit board, or it can be surface mounted, it looks something like this:
We solder the transistor, then the electrolytic capacitor, in my case it is 2200 microfarads. Do not forget that electrolytes have polarity.
There are situations when you need a beacon circuit that would create really bright and noticeable flashes, for example, on a company car or a camping lamp.
Above is a diagram of such a beacon that flashes, creating a strobe effect.
The circuit is powered by a power source of at least 10 volts. To reduce the operating voltage, you can change the transistors VT1 and VT2 to transistors with the lowest voltage CE junction. And also adjusting the values of the resistors R1 and R2.
Resistors R3 and R4 regulate flashes, if you increase the resistor values to 100 ohms, the LEDs will light up smoothly. Thanks to the 1 ohm resistors, the LEDs flash quickly, in connection with which the strobe effect is created.
Capacitors C1 and C2 regulate the flash frequency of the LEDs VD1 and VD2. Reducing the capacitance of the capacitors can increase the speed of flashes.
It is desirable to put LEDs brighter with greater luminous intensity.
As can be seen from the diagram, the device consists of two similar blocks, the first block consists of resistors R1 and R3, capacitor C1, transistor VT1 and LED VD1. The rest of the details belong to the second block. By composing additional blocks, you can increase the number of beacons.
Pay attention to the bases of transistors VT1 and VT2, they are not connected, this is not a mistake, but indeed the bases of the transistors in the device are not connected!
The device was mounted on a printed circuit board, the board was inserted into the housing from the relay, then it was tested and installed on the Niva service car in place of the standard dimensions, three LEDs were installed in each headlight. The device has been working successfully for the second year already, the components do not heat up, no malfunctions have been recorded.
The device was developed over a year ago, at the request of a friend, based on data taken from open sources on the Internet.
List of radio elements
| Designation | Type | Denomination | Quantity | Note | Shop | My notepad |
|---|---|---|---|---|---|---|
| VT1, VT2 | bipolar transistor | KT315B | 2 | With any letter index | To notepad | |
| C1, C2 | electrolytic capacitor | 1000uF 16V | 2 | To notepad | ||
| R1, R2 | Resistor | 1 kOhm | 2 | To notepad | ||
| R3, R4 | Resistor | 1 ohm | 2 | To notepad | ||
| VD1, VD2 | Light-emitting diode | 2 |
To open the world of radio electronics full of mysteries without having a specialized education, it is recommended to start with the assembly of simple electronic circuits. The level of satisfaction will be higher if the positive result is accompanied by a pleasant visual effect. The ideal option is circuits with one or two blinking LEDs in the load. Below is information that will help in the implementation of the most simple do-it-yourself schemes.
Ready flashing LEDs and circuits using them
Among the variety of ready-made flashing LEDs, products in a 5 mm case are the most common. In addition to ready-made single-color flashing LEDs, there are two-pin instances with two or three crystals of different colors. They have a built-in generator in the same case with crystals, which operates at a certain frequency. It gives out single alternating pulses to each crystal according to a given program. The blinking speed (frequency) depends on the set program. When two crystals are lit at the same time, the blinking LED produces an intermediate color. The second most popular are flashing light emitting diodes controlled by current (potential level). That is, to make an LED of this type blink, you need to change the power at the corresponding pins. For example, the color of the radiation of a two-color red-green LED with two leads depends on the direction of current flow.
The three-color (RGB) flashing LED with four pins has a common anode (cathode) and three pins for controlling each color separately. The flashing effect is achieved by connecting to an appropriate control system.
Making a flasher based on a ready-made flashing LED is quite easy. This will require a CR2032 or CR2025 battery and a 150-240 ohm resistor, which should be soldered to either pin. Observing the polarity of the LED, the contacts are connected to the battery. The LED flasher is ready, you can enjoy the visual effect. If you use a krone battery, based on Ohm's law, you should choose a resistor of greater resistance.
Ordinary LEDs and flashing lights based on them
A novice radio amateur can assemble a flasher on a simple single-color light-emitting diode, having a minimal set of radio elements. To do this, consider several practical schemes that differ in the minimum set of radio components used, simplicity, durability and reliability. 
The first circuit consists of a low-power transistor Q1 (KT315, KT3102 or a similar imported analogue), a 16V polar capacitor C1 with a capacity of 470 uF, a 820-1000 Ohm resistor R1 and an L1 LED like AL307. The entire circuit is powered by a 12V voltage source.
The above circuit works on the principle of avalanche breakdown, so the base of the transistor remains “hanging in the air”, and a positive potential is applied to the emitter. When turned on, the capacitor is charged, up to about 10V, after which the transistor opens for a moment with the return of the accumulated energy to the load, which manifests itself in the form of a blinking LED. The disadvantage of the circuit is the need for a 12V voltage source.
The second circuit is assembled on the principle of a transistor multivibrator and is considered more reliable. To implement it, you will need:
- two transistors KT3102 (or their equivalent);
- two polar capacitors for 16V with a capacity of 10 microfarads;
- two resistors (R1 and R4) of 300 ohms each to limit the load current;
- two resistors (R2 and R3) of 27 kΩ each to set the base current of the transistor;
- two LEDs of any color.
In this case, a constant voltage of 5V is applied to the elements. The circuit works on the principle of alternate charge-discharge of capacitors C1 and C2, which leads to the opening of the corresponding transistor. While VT1 dumps the accumulated energy C1 through an open collector-emitter junction, the first LED is lit. At this time, a smooth charge of C2 occurs, which helps to reduce the base current VT1. At a certain moment, VT1 closes, and VT2 opens and the second LED lights up.
The second scheme has several advantages at once:
- It can operate in a wide voltage range starting from 3V. When applying more than 5V to the input, you will have to recalculate the resistor values so as not to break through the LED and not exceed the maximum current of the transistor base.
- 2-3 LEDs can be connected to the load in parallel or in series by recalculating the resistor values.
- An equal increase in the capacitance of the capacitors leads to an increase in the duration of the glow.
- By changing the capacitance of one capacitor, we get an asymmetric multivibrator, in which the glow time will be different.
In both cases, it is possible to use pnp conduction transistors, but with correction of the wiring diagram.
Sometimes, instead of blinking LEDs, a radio amateur observes a normal glow, that is, both transistors are partially open. In this case, you need to either replace the transistors, or solder resistors R2 and R3 with a lower rating, thereby increasing the base current.
Keep in mind that 3V power will not be enough to light an LED with a high forward voltage value. For example, a white, blue, or green LED will require more voltage.
In addition to the considered circuit diagrams, there are a great many other simple solutions that cause the LED to flash. Novice radio amateurs should pay attention to the inexpensive and widespread NE555 chip, which can also implement this effect. Its versatility will help to collect other interesting schemes.
Application area
Flashing LEDs with a built-in generator have found application in the construction of New Year's garlands. By assembling them in a series circuit and installing resistors with a slight difference in value, they achieve a shift in the blinking of each individual element of the circuit. The result is a beautiful lighting effect that does not require a complex control unit. It is enough just to connect the garland through the diode bridge.
Flashing light-emitting diodes, controlled by current, are used as indicators in electronic engineering, when each color corresponds to a certain state (on / off charge level, etc.). They are also used to assemble electronic displays, advertising signs, children's toys and other products in which multi-colored flashing is of interest to people.
The ability to assemble simple flashing lights will be an incentive to build circuits on more powerful transistors. With a little effort, you can create many interesting effects with the help of flashing LEDs, for example, a traveling wave.
Read also
Flashing beacons are used in electronic house security systems and on cars as indication, signaling and warning devices. Moreover, their appearance and “stuffing” often do not differ at all from flashing beacons (special signals) of emergency and operational services.
There are classic beacons on sale, but their internal “stuffing” is striking in its anachronism: they are made on the basis of powerful lamps with a rotating cartridge (a classic of the genre) or lamps of the IFK-120, IFKM-120 type with a stroboscopic device that provides flashes at regular intervals ( pulse beacons). Meanwhile, in the courtyard of the XXI century, when there is a triumphal procession of very bright (powerful in terms of luminous flux) LEDs.
One of the fundamental points in favor of replacing incandescent and halogen lamps with LEDs, in particular in flashing beacons, is a longer resource (uptime) and lower cost of the latter.
The LED crystal is practically “indestructible”, therefore the resource of the device determines mainly the durability of the optical element. The vast majority of manufacturers use various combinations of epoxy resins for its manufacture, of course, with varying degrees of purification. In particular, because of this, LEDs have a limited resource, after which they become cloudy.
Different manufacturers (we won't advertise them for free) claim the resource of their LEDs from 20 to 100 thousand (!) Hours. I hardly believe in the last figure, because the LED must work continuously for 12 years. During this time, even the paper on which the article is printed will turn yellow.
However, in any case, compared to traditional incandescent lamps (less than 1000 hours) and discharge lamps (up to 5000 hours), LEDs are several orders of magnitude more durable. It is quite obvious that the guarantee of a long resource is to ensure a favorable thermal regime and stable power supply to the LEDs.
The predominance of LEDs with a powerful luminous flux of 20 - 100 lm (lumens) in the latest industrial electronic devices, in which they work instead of incandescent lamps, gives reason for radio amateurs to use such LEDs in their designs. Thus, I bring the reader to the idea of the possibility of replacing various lamps in emergency and special beacons with powerful LEDs. In this case, the current consumption by the device from the power source will decrease and will depend mainly on the LED used. For use in a car (as a special signal, an emergency light indicator, and even an “emergency stop sign” on the roads), the current consumption is unimportant, since the car’s battery (battery) has a fairly large energy capacity (55 or more Ah or more). If the beacon is powered from an independent source, then the current consumption of the equipment installed inside will be of no small importance. By the way, the battery of a car without recharging can be discharged during prolonged operation of the beacon.
So, for example, the “classic” beacon of operational and emergency services (blue, red, orange, respectively) when powered from a 12 V DC source consumes a current of more than 2.2 A, which consists of the consumption of the electric motor (rotating the cartridge) and the lamp itself. During the operation of a flashing pulse beacon, the current consumption decreases to 0.9 A. If, instead of a pulse circuit, an LED is assembled (more on this below), the current consumption will be reduced to 300 mA (depending on the power of the LEDs used). The cost savings are also significant.
Of course, the question of the strength of light (or, better, its intensity) from various flashing devices has not been studied, since the author did not have and does not have special equipment (luxmeter) for such a test. But due to the innovative solutions proposed below, this issue becomes secondary. After all, even relatively weak light pulses (in particular from LEDs) passed through the prism of the inhomogeneous glass of the beacon cap at night are more than sufficient for the beacon to be noticed several hundred meters away. That's the point of early warning, isn't it?
Now consider the electrical circuit of the "lamp substitute" flashing beacon (Fig. 1).
This electrical circuit of the multivibrator can rightly be called simple and affordable. The device was developed on the basis of the popular integrated timer KR1006VI1, which contains two precision comparators, providing a voltage comparison error of no worse than ±1%. The timer has been repeatedly used by radio amateurs to build such popular circuits and devices as time relays, multivibrators, converters, signaling devices, voltage comparison devices, and others.
The device, in addition to the integral timer DA1 (multifunctional microcircuit KR1006VI1), also includes a time-setting oxide capacitor C1, a voltage divider R1R2. C3 output chip DA1 (current up to 250 mA) control pulses are sent to the LEDs HL1-HL3.
The principle of operation of the device
The beacon is switched on using the switch SB1. The principle of operation of the multivibrator is described in detail in the literature.
At the first moment, there is a high voltage level at pin 3 of the DA1 chip - and the LEDs are on. The oxide capacitor C1 begins to charge through the circuit R1R2.
After about one second (the time depends on the resistance of the voltage divider R1R2 and the capacitance of the capacitor C1, the voltage on the plates of this capacitor reaches the value necessary to operate one of the comparators in a single package of the DA1 microcircuit. In this case, the voltage at pin 3 of the DA1 microcircuit is set to zero - and the LEDs This continues cyclically as long as the supply voltage is applied to the device.
In addition to those indicated in the diagram, I recommend using powerful HPWS-T400 LEDs or similar ones with a current consumption of up to 80 mA as HL1-HL3. Only one LED from the LXHL-DL-01, LXHL-FL1C, LXYL-PL-01, LXHL-ML1D, LXHL-PH01,
LXHL-MH1D by Lumileds Lighting (all in orange and red-orange glow).
The supply voltage of the device can be increased to 14.5 V, then it can be connected to the on-board car network even when the engine (or rather, the generator) is running.
Design features
The board with three LEDs is installed in the housing of the flashing beacon instead of the "heavy" standard design (lamps with a rotating cartridge and an electric motor).
In order for the output stage to have even more power, it will be necessary to install a current amplifier on the VT1 transistor at point A (Fig. 1), as shown in Fig. 2.
After such refinement, it is possible to use three parallel-connected LEDs of the types LXHL-PL09, LXHL-LL3C (1400 mA),
UE-HR803RO (700 mA), LY-W57B (400 mA) are all orange. In this case, the total current consumption will increase accordingly.
Flash lamp option
Those who have preserved the details of cameras with built-in flash can go the other way. To do this, the old flash lamp is dismantled and connected to the circuit as shown in Figure 3. Using the presented converter, which is also connected to point A (Figure 1), pulses with an amplitude of 200 V are obtained at the output of the device with a low supply voltage. Supply voltage in this case, unequivocally increase to 12 V.
Flashing beacons are used in electronic house security systems and on cars as indication, signaling and warning devices. Moreover, their appearance and "stuffing" often do not differ at all from flashing beacons (special signals) of emergency and operational services.
There are classic beacons on sale, but their internal "stuffing" is striking in its anachronism: they are made on the basis of powerful lamps with a rotating cartridge (a classic of the genre) or lamps of the IFK-120, IFKM-120 type with a stroboscopic device that provides flashes at regular intervals ( pulse beacons). Meanwhile, in the courtyard of the XXI century, when there is a triumphal procession of very bright (powerful in terms of luminous flux) LEDs.
One of the fundamental points in favor of replacing incandescent and halogen lamps with LEDs, in particular in flashing beacons, is a longer resource (uptime) and lower cost of the latter.
The LED crystal is practically "indestructible", so the life of the device determines mainly the durability of the optical element. The vast majority of manufacturers use various combinations of epoxy resins for its manufacture, of course, with varying degrees of purification. In particular, because of this, LEDs have a limited resource, after which they become cloudy.
Different manufacturers (we won't advertise them for free) claim the resource of their LEDs from 20 to 100 thousand (!) Hours. I hardly believe in the last figure, because the LED must work continuously for 12 years. During this time, even the paper on which the article is printed will turn yellow.
However, in any case, compared to traditional incandescent lamps (less than 1000 hours) and discharge lamps (up to 5000 hours), LEDs are several orders of magnitude more durable. It is quite obvious that the guarantee of a long resource is to ensure a favorable thermal regime and stable power supply to the LEDs.
The predominance of LEDs with a powerful luminous flux of 20 - 100 lm (lumens) in the latest industrial electronic devices, in which they work instead of incandescent lamps, gives grounds for radio amateurs to use such LEDs in their designs. Thus, I bring the reader to the idea of the possibility of replacing various lamps in emergency and special beacons with powerful LEDs. In this case, the current consumption by the device from the power source will decrease and will depend mainly on the LED used. For use in a car (as a special signal, an emergency light indicator and even an "emergency stop sign" on the roads), the current consumption is unimportant, since the battery (battery) of the car has a sufficiently large energy capacity (55 or more Ah or more). If the beacon is powered from an independent source, then the current consumption of the equipment installed inside will be of no small importance. By the way, the battery of a car without recharging can be discharged during prolonged operation of the beacon.
So, for example, the "classic" beacon of operational and emergency services (blue, red, orange - respectively) when powered from a 12 V DC source consumes a current of more than 2.2 A, which consists of the consumption of the electric motor (rotating the cartridge) and the lamp itself. When a flashing pulse beacon is operating, the current consumption decreases to 0.9 A. If, instead of a pulse circuit, an LED is assembled (more on this below), the current consumption will be reduced to 300 mA (depending on the power of the LEDs used). The cost savings are also significant.
Of course, the question of the strength of light (or, better, its intensity) from various flashing devices has not been studied, since the author did not have and does not have special equipment (luxmeter) for such a test. But due to the innovative solutions proposed below, this issue becomes secondary. After all, even relatively weak light pulses (in particular from LEDs) passed through the prism of the inhomogeneous glass of the beacon cap at night are more than sufficient for the beacon to be noticed several hundred meters away. That's the point of early warning, isn't it?
Now consider the electrical circuit of the "lamp substitute" flashing beacon (Fig. 1).
Rice. 1. Schematic diagram of the LED beacon
This electrical circuit of the multivibrator can rightly be called simple and affordable. The device was developed on the basis of the popular integrated timer KR1006VI1, which contains two precision comparators, providing a voltage comparison error of no worse than ±1%. The timer has been repeatedly used by radio amateurs to build such popular circuits and devices as time relays, multivibrators, converters, signaling devices, voltage comparison devices, and others.
The structure of the device, in addition to the integrated timer DA1 (multifunctional microcircuit KR1006VI1), also includes a time-setting oxide capacitor C1, a voltage divider R1R2. C3 output chip DA1 (current up to 250 mA) control pulses are sent to the LEDs HL1-HL3.
The principle of operation of the device
The beacon is switched on using the switch SB1. The principle of operation of the multivibrator is described in detail in the literature.
At the first moment, there is a high voltage level at pin 3 of the DA1 chip - and the LEDs are on. The oxide capacitor C1 begins to charge through the circuit R1R2.
After about one second (the time depends on the resistance of the voltage divider R1R2 and the capacitance of the capacitor C1, the voltage on the plates of this capacitor reaches the value necessary to operate one of the comparators in a single housing of the DA1 microcircuit. In this case, the voltage at pin 3 of the DA1 microcircuit is set to zero - and the LEDs This continues cyclically as long as the supply voltage is applied to the device.
In addition to those indicated in the diagram, I recommend using powerful HPWS-T400 LEDs or similar ones with a current consumption of up to 80 mA as HL1-HL3. Only one LED from the LXHL-DL-01, LXHL-FL1C, LXYL-PL-01, LXHL-ML1D, LXHL-PH01,
LXHL-MH1D by Lumileds Lighting (all in orange and red-orange glow).
The supply voltage of the device can be increased to 14.5 V, then it can be connected to the on-board car network even when the engine (or rather, the generator) is running.
Design features
The board with three LEDs is installed in the housing of the flashing beacon instead of the "heavy" standard design (lamps with a rotating socket and an electric motor).
In order for the output stage to have even more power, it will be necessary to install a current amplifier on the VT1 transistor at point A (Fig. 1), as shown in Fig. 2.
Rice. 2. Wiring diagram for an additional amplifying stage
After such refinement, it is possible to use three parallel-connected LEDs of the types LXHL-PL09, LXHL-LL3C (1400 mA),
UE-HR803RO (700 mA), LY-W57B (400 mA) are all orange. In this case, the total current consumption will increase accordingly.
Flash lamp option
Those who have preserved the details of cameras with built-in flash can go the other way. To do this, the old flash lamp is dismantled and connected to the circuit as shown in Figure 3. Using the presented converter, which is also connected to point A (Figure 1), pulses with an amplitude of 200 V are obtained at the output of the device with a low supply voltage. Supply voltage in this case, unequivocally increase to 12 V.
The output pulse voltage can be increased by including several zener diodes in the circuit, following the example of VT1 (Fig. 3). These are silicon planar zener diodes designed to stabilize the voltage in DC circuits with a minimum value of 1 mA and a power of up to 1 W. Instead of those indicated in the diagram, KS591A zener diodes can be used.
Rice. 3. Flash lamp connection diagram
Elements C1, R3 (Fig. 2) make up a damping RC circuit that dampens high-frequency oscillations.
Now, with the appearance (in time) of pulses at point A (Fig. 2), the flash lamp EL1 will turn on. This design, built into the body of the flashing beacon, will allow it to be used further if the standard beacon is out of order.
Board with LEDs installed in the standard housing of the flashing beacon
Unfortunately, the resource of a flash lamp from a portable camera is limited and is unlikely to exceed 50 hours of operation in a pulsed mode.
See other articles section.