|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
LED flashing beacon. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / LEDs 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 by 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. The above data were established experimentally by the author (in total, six different classic flashing beacons were tested). 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 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. Principle of operation of the device The beacon is turned 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-T1 LEDs or similar ones with a current consumption of up to 3 mA as HL400-HL80. 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.
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.
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.
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. Author: A.Kashkarov
A New Way to Control and Manipulate Optical Signals
05.05.2024 Primium Seneca keyboard
05.05.2024 The world's tallest astronomical observatory opened
04.05.2024
▪ AOC technology will reduce the harm of monitors to vision ▪ Music server on ARM processor ▪ Melting glaciers in the Swiss Alps recognized as unprecedented ▪ Technology for creating artificial joint selfies
▪ section of the site Palindromes. Article selection ▪ article Seduced and abandoned. Popular expression ▪ article How do lobsters grow? Detailed answer ▪ Rutabaga article. Legends, cultivation, methods of application ▪ article Birdsong imitator. Encyclopedia of radio electronics and electrical engineering ▪ article Car socket 220 volts 400 watts. Encyclopedia of radio electronics and electrical engineering
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page