Battery powered lamp. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Lighting

 Comments on the article

Power outages have become a common occurrence in many parts of the country in recent years. The proposed lamp will help not to remain without light in such situations, in which one or two low-power fluorescent lamps are powered by a 12 V car or motorcycle battery. The device consists of widely used parts, its assembly will not take much time.

The basis of the lamp, the scheme of which is shown in Fig. 1, - blocking generator on the transistor VT3. Resistor R7 limits the base current of the transistor. Diode VD1 protects the device from being connected to the battery power supply) in the wrong polarity. The sources of illumination are two fluorescent lamps (LDS) EL1 and EL2 connected in series with a power of 6 W from the Chinese lantern "ROBO". The luminaire has also been tested with single LDS with a power of 6 and 20 watts. According to the ratio of brightness and current consumption, the choice was made in favor of two six-watt ones. The low battery indicator is optional (all the elements included in it can not be installed on the board), but it is very useful especially when using a relatively small capacity battery (for example, a motorcycle battery).

The indicator consists of LED HL1, transistors VT1, VT2, resistors R1-R5, capacitor C1 and is a Schmitt trigger. To achieve a sufficiently small width of the trigger hysteresis loop, the values ​​​​of the resistors R1 and R3 had to be increased, and the positive feedback resistor R5 had to be decreased. Resistor R4 limits the current through the LED HL1. Capacitor C1 - noise suppression.

While the battery is sufficiently charged, the transistor VT1 is open, since the voltage at its base is greater than the opening threshold. Transistor VT2 is closed - its base-emitter section is shunted by an open transistor VT1. LED HL1 off. As the battery discharges, the voltage at the base of the transistor VT1 decreases, the transistor VT1 starts to close. Due to the positive feedback, the process proceeds like an avalanche. As a result, the transistor VT1 closes completely, VT2 opens, the HL1 LED lights up.

In standby mode, the indicator consumes no more than 1 mA, and after operation - approximately 5 mA.

The entire LDS power unit is mounted on a printed circuit board made of one-sided foil-coated fiberglass (Fig. 2). It uses fixed MLT resistors of the power indicated in the diagram. Trimmer resistor R2 - multi-turn SP5-3. Capacitor C2 - K73-9, any small-sized one is suitable as C1.

Transistors VT1, VT2 - series KT315, KT3102 with any letter indices. Diode VD1 must be designed for a current not less than that consumed by the lamp from the battery, and it, in turn, depends on the power of the installed LDS. With one six-watt lamp, a diode from the KD226 series can be used here. LED HL1 - any color of glow, but better than red, the most suitable for signaling a situation requiring intervention.

Of several transistors of the KT815, KT817, KT819 series, tested as VT3, the one indicated on the KT819G diagram ensured reliable switching on of the LDS. In addition, it has a fairly large margin for limiting current and voltage. The latter is especially necessary in case of accidental disconnection of the load from a running generator. For example, the KT815B transistor with a maximum collector-emitter voltage of 25 V worked properly until one of the wires connecting the LDS to winding III of the T1 transformer broke. The transistor was immediately broken.

The magnetic circuit of the transformer T1 - B22 from ferrite 2000NM1. Windings I (9 turns of wire PEV-2 0,45) and I (10 turns of wire PEV-2 0,3) begin to wind simultaneously with two wires turn to turn. After the ninth, the end of the winding I is fixed in the slot of the frame, then the last turn of the winding II is wound up. The frame with the finished windings I and II is carefully impregnated with paraffin and wrapped with thin paper in two layers, ironing each with a hot soldering iron tip. As a result, the paper absorbs excess paraffin and adheres tightly to the wires of the windings, fixing them and providing the necessary insulation. Next, a high-voltage winding III is wound. For one LDS, it should contain 180, for two connected in series, - 240 ... 250 turns of wire PEV-2 0,16. The coils are laid in bulk, trying to distribute them as evenly as possible.

It is necessary to ensure that those of them that are at the beginning and at the end of the winding do not touch each other. For example, it is highly undesirable to place both terminals of winding III in the same frame slot. The coil is once again impregnated with paraffin and inserted into the magnetic circuit, which is assembled with a gap of 0,2 mm between the "cups", using a paper or thin plastic gasket for this. Transformer T1 is attached to the board with a screw made of non-magnetic material, passed through the central hole of the magnetic circuit. This method, in contrast to assembly on glue, provides reliable fixation of the transformer on the board, and, if necessary, quick dismantling.

The lamp is assembled on a wooden (plywood) base measuring 280x75x6 mm. In the upper part of the base, two LDSs are placed parallel to each other, in the lower part - a printed circuit board covered with an aluminum sheet casing. The casing provides holes for the HL1 LED and connecting wires, including two stranded ones with crocodile clips for connecting to the battery. Transistor VT3 is attached to the casing, using the latter as a heat sink. LDS is installed on two wooden bars glued to the base with a section of 15x10 mm. One of them is located at the upper edge of the base, the other is lower, at a distance equal to the length of the LDS without leads (215 mm).

Under the conclusions of the lamps on the bars, contacts made of tin are installed. The contact on the upper bar simultaneously serves as a jumper between two LDS, and the terminals of the winding III of the transformer T1 are connected to the two on the lower bar. LDS is fixed with four screws screwed between their leads. In the contacts, it is necessary to drill holes for the screws in advance, and washers must be placed under the heads of the latter. This mounting method provides a reliable connection between the LDS and the transformer and allows you to replace the lamps without resorting to a soldering iron. For better light output, the base under the lamps is pasted over with a reflective film or foil.

Before turning on the lamp for the first time, it is imperative to check the quality of the connection of the LDS with the winding III of the T1 transformer. A bad contact can lead to a breakdown not only of the VT3 transistor, but also of the transformer. If, after applying the supply voltage, there is not even a slight glow of the LDS, you should swap the conclusions of one of the windings I or II of the transformer T1 completely, VT2 opens, the HL1 LED lights up.

See other articles Section Lighting.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive Tape without glue 06.09.2003 The University of Manchester (England) has created adhesive tape without glue. True, so far only a small piece of one square centimeter has been obtained. The developers took advantage of the recently revealed secret of the gecko. This small lizard runs briskly along vertical surfaces, including glass. It was recently discovered that the legs of the gecko are covered with the finest hairs, which, in contact with any surface, are attracted to it simply due to intermolecular forces. Each hair provides only a very slight attraction, but there are many billions of such hairs. By shifting the sole so that the hairs form an acute angle with the surface, the gecko disengages the foot from the surface. Using nanotechnology methods, the researchers were able to apply hairs 2 microns long and 0,2 microns thick to a flexible polymer film, just like a natural sample. There are about a hundred million of them per square centimeter. It is estimated that if you make a glove with such a coating, a person can hang on the ceiling or wall on one hand wearing such a glove. But the mass production of such a film is not yet planned: the process is too complicated. And it is not clear how long the micro-hairs will last - in a gecko they grow as they are erased.

Other interesting news:

▪ Apple creates 3D interface for iPhone and iPad

▪ NASA intern discovers exoplanet

▪ Spectrometer in your pocket

▪ Uneducated flies live longer

▪ Freeform displays from Sharp

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Parameters of radio components. Article selection

▪ article Crocodile tears. Popular expression

▪ article When Was Aluminum Foil Invented? Detailed answer

▪ article Operator of an automobile, caterpillar or pneumatic wheel crane. Standard instruction on labor protection

▪ article Interference simulator for network filter testing. Encyclopedia of radio electronics and electrical engineering

▪ article Testing food products for acidity. Chemical experience

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024