Voltage polarity converter. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Voltage converters, rectifiers, inverters
Comments on the article
Most modern devices are made using microcircuits. Moreover, the device may contain both digital and analog ICs, for example, operational amplifiers, which require a bipolar voltage source to power them.
When using the device in stationary conditions, problems, as a rule, do not arise due to the fact that there are no strict requirements for the weight of the device and the choice of circuit design for the power source. In field conditions, batteries or accumulators are usually used for power supply, the cost and weight of which can also be significant. In this regard, as well as for reasons of convenience of replacing power sources, various types of polarity converters are used to generate, usually, negative voltage.
Searching for voltage polarity converter circuits, modeling and testing their performance using the Electronics Workbench EDA simulator program led to the simple circuit shown in the figure.
(click to enlarge)
The proposed converter differs from most similar devices in its transformerless circuit, which greatly facilitates its assembly and configuration, and its very small dimensions, especially when using imported capacitors C3 and C4. The author will be grateful for suggestions for upgrading the device.
A "meander" generator is assembled on timer DA1. The generator output is loaded onto a rectifier assembled according to a voltage doubling circuit VD1, VD2, C3, C4. Resistor R1 is the load of the discharge transistor of timer DA1. The shape and magnitude of the output signal voltage depends on its rating. Despite the small value of resistor R1, the average collector current of the transistor is within 140 mA (with an acceptable value of 200 mA). Capacitor C1 and resistor R3 are the frequency-setting elements of the generator. The total current consumption by the unit does not exceed 150mA. At a load of 500 Ohms (R4), the output voltage of the converter is -8.5 V at a load current of 17 mA. The ripple voltage does not exceed 40 mV.
When the value of resistor R1 was increased to 1 kOhm (during modeling using the Electronics Workbench EDA program), a distortion in the shape of the generator output signal and a decrease in the output voltage level were observed.
Adjustment
The output voltage of the converter depends on the capacitance of capacitor C3, as well as on the frequency of the generator, determined by elements R3, C1. The load current is also regulated by changing the value of C3. The level of ripple voltage at the load depends on the capacitance of capacitor C4. Resistor R1 selects the optimal collector current of the discharge transistor. The output frequency can be calculated using the formula:
F = 0.722 R3C1.
The generator can also be assembled using ordinary logic elements. The advantage of the generator on the KR1006VI1 microcircuit. used by the author is a fairly large output power (the open-collector output stage provides an output current of up to 200 mA)
If necessary, by using a more powerful generator and a voltage multiplication circuit, you can obtain a power source with a higher voltage, for example, to power the final stage of a radio transmitting device. I would also like to note that some companies, for example. MAXIM produces integrated polarity and voltage converters.
Literature
- Alekseenko A.G. and others. Application of precision analog microcircuits - M., Radio and communications. 1965
Author: A.Ilyin, St. Petersburg
See other articles Section Voltage converters, rectifiers, inverters.
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 A new way to chemically convert plastic into fuel
22.07.2019
One of the most acute and serious problems in the context of modern ecology on Earth is the problem of excessive amounts of plastic accumulating as waste and poisoning rivers, lakes, seas and large areas of land. According to modern data, already now the volume of this waste plastic reaches 5 billion tons, which is quite a critical indicator. And despite the fact that most experts suggest recycling this plastic, thus saving the earth's ecology from direct danger, there is still a more interesting way of recycling - it was proposed by a team of specialists from Purdue University, and it consists in transformation.
Namely, in the transformation of most types of plastic into the most useful fuel that can be used in a variety of spectrums and tasks. At the same time, it is worth noting that specialists invented and tested a new technological process for such a conversion of plastic into fuel, reminiscent of gasoline and diesel in its characteristics and properties. This technological process concerns the use of polypropylene as the final conversion product.
Polypropylene is a fairly common material, often found in children's toys, medical equipment and environmentally friendly devices, and as such is cheap and easy to change. As a transformational agent, scientists have proposed using so-called supercritical water - which has both the properties of a liquid and the properties of gases - by heating it between 716 and 932 degrees Fahrenheit at an average pressure 2,300 times that of deep sea pressure.
With such a chemical transformation of polypropylene, it becomes possible to convert plastic into fuel - especially since, according to experts, almost any plastic widely used in various fields is suitable for such a procedure. It remains to wait for news regarding the completion of the project.
|
Other interesting news:
▪ China begins research into 5G communications
▪ Drone wolf pack
▪ Scanning photo frame
▪ Alternative to pain medications
▪ The computer game was recognized as a medicine
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site Microphones, radio microphones. Article selection
▪ article Ranevskaya Faina Georgievna. Famous aphorisms
▪ article Are there games that do not require sports equipment? Detailed answer
▪ article Port node. Travel Tips
▪ article Power modules. Encyclopedia of radio electronics and electrical engineering
▪ article Box with a double bottom. Focus Secret
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese