Battery charger with polarity reversal protection. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Battery charger with polarity reversal protection. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Chargers, batteries, galvanic cells

Comments on the article

The universal charger circuit is designed to charge small batteries of all types (Ni-Cd & Ni-Mh). The distinctive features of this circuit are: simplicity, protection against battery reversal, indication of the state of charge, compliance with the rules and technology for charging batteries required by product manufacturers, versatility, which makes it possible to manufacture only one type of printed circuit board and by selecting elements to achieve different values of output voltage and current, high stability of output parameters.

(click to enlarge)

Before starting the manufacture of the device, it is necessary to calculate the voltage at the end of the charge and the charge current. The output voltage value is calculated according to the principle of 1,45 V multiplied by the number of battery cells. The charge current value is defined as 1/10 of the battery capacity in Ah. Such parameters are considered optimal, do not harm the battery, make it possible to carry out up to 700 cycles (charge - discharge) with batteries while maintaining their parameters in the norms declared by manufacturers. True at ambient temperatures up to 25°C. At higher temperatures, certain precautions must be taken to prevent the temperature from exceeding 35°C during charging.

The value of the required charge voltage is set by selecting a tuning resistor R4. It is desirable that the value of the maximum current does not exceed 600 mA. If the charge current value does not exceed 200 mA, there is no need to install the U1 stabilizer on the radiator. LED D5 indicates the presence of the charge current, LED D7 indicates the battery is charged and the charger switches to the mode of maintaining the minimum charge current - excluding self-discharge of the battery. It is advisable to leave the battery in charge for another couple of hours after switching the unit to this mode - to guarantee a fully charged battery. The reverse polarity protection device is assembled on transistors Q3, Q4. Charge indication on transistors Q2, Q4. The transformer must be at least 15-20 W, the output voltage is at least 15-20% higher than the calculated charge voltage.

With the existing ratings, a 30-volt transformer is used in the circuit. As an option, it is recommended to install devices on the front panel of the device: an ammeter and a voltmeter, put resistance R4 in this case of a variable type and also bring it to the front panel of the device. Get a universal charger compact device.

See other articles Section Chargers, batteries, galvanic cells.

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

Toshiba MG10F hard drives 03.10.2023

Manufacturers of traditional hard drives continue to push the envelope, introducing devices with capacities up to 22 terabytes. After Seagate and Western Digital, Toshiba presented its solution in this segment. The new MG10F series of drives not only continues the tradition of the Toshiba MG10 line with 3,5-inch drives, but also raises the capacity bar to 22 terabytes.

Toshiba MG10F are enterprise hard drives of the second level (nearline), offering options from 2 to 22 terabytes, operating at speeds of 7200 rpm and providing a choice between SAS interfaces with a bandwidth of 12 Gbit/s and classic SATA with a bandwidth of 6 Gbit/s. s, starting from 1 terabyte.

When it comes to recording methods, Toshiba takes a few different approaches in this line. For disks up to 10 terabytes inclusive, traditional perpendicular recording (PMR) and an air hermetic block are used. Disks with a capacity of 12-16 terabytes are switching to a helium hermetic block and using platters with the same recording technology. Models with a capacity of 18, 20 and 22 terabytes use recording with microwave support (Flux Control Microwave Assisted Magnetic Recording, FC-MAMR). All drives are designed to operate 24/7 and can withstand loads of up to 550 terabytes per year.

Depending on the disk capacity, the cache memory size can vary: up to 2 terabytes - 128 megabytes, up to 14 terabytes - 256 megabytes, and models with a capacity of 16 to 22 terabytes are equipped with 512 megabytes of DRAM cache. The data transfer speed of the smallest disks (1 and 2 terabytes) reaches 204 megabytes per second, and for the largest version it grows to 284 megabytes per second. This is comparable to the performance of Seagate IronWolf Pro drives of the same capacity (285 megabytes per second), but slightly lower than WD Gold (291 megabytes per second).

Although the use of tile-structured recording (SMR) would increase the maximum capacity of the drives by 15%, Toshiba does not use this technology in this line. While Western Digital offers 26 terabyte drives with SMR technology. Toshiba previously announced a similar model, but it never appeared on the market.

Deliveries of Toshiba MG10F drives with a SAS interface have already begun, and SATA versions will appear later, in the fourth quarter. Encryption options (Self-Encrypting Drive) and secure erasure (Sanitize Instant Erase) are also available.

Other interesting news:

▪ Quantum dots have reduced the size of terahertz devices

▪ New technologies for switched networks

▪ Pocket Photo Printer

▪ Tiny eMMC Embedded Drives from Toshiba

▪ stem cell management

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Firmware. Article selection

▪ article by Alfred Newman. Famous aphorisms

▪ article What is the law of free fall? Detailed answer

▪ article Gelsemium evergreen. Legends, cultivation, methods of application