Stabilizer-charger with adjustable voltage and current. Encyclopedia of radio electronics and electrical engineering

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

 Comments on the article

The device operates in two modes: voltage stabilizer and current stabilizer. Moreover, both modes smoothly transition from one to another at the border of the beginning of voltage stabilization.

The first mode is designed to power radio equipment, DC micromotors, etc. The second mode of the current stabilizer is designed to charge batteries, and a full charge ends in the voltage stabilizer mode.

Stabilizer Features:

1. Current stabilization protects its own output transistors from overload when the supply voltage is turned on and a sharp short-term surge of the charging current of capacitor C2, as well as in the event of an output short circuit, which means that the reliability of operation increases.

2. The simplicity of the circuit (see figure), since the output transistors perform a dual role: they stabilize the current and voltage.

3. In the voltage stabilizer mode in the unit, you can set, if necessary, a current limit to protect the powered equipment from overloads during its operation.

4. In the current stabilizer mode, you do not need to monitor the battery charging process and turn it off so that harmful overcharging does not occur.

The unit itself monitors the process of charging and increasing the voltage on the battery.

When fully charged, the unit smoothly switches to voltage stabilizer mode. The charging current drops to zero. In this state, the battery can remain connected to a working unit without harm for a long time.

5. Constant charging current favorably distinguishes the unit from chargers with resistive current limiting, where the battery charging current gradually decreases as the battery is charged due to the growth of its counter voltage in relation to the voltage of the charger itself.

A smooth decrease in current in a resistive charger will stretch the battery charge over time. Conversely, the proposed block on a stabilized current will provide a faster battery charge.

Main Specifications

The unit is powered by a constant voltage of 25 V and allows you to adjust the constant stabilized voltage at the output from 0,8 to 12 V and the constant stabilized current from 0,4 mA to 2,4 A.

The principle of operation of the device and its components

When a constant voltage is applied to the input of the block, capacitor C1 is charged.

Transistors VT2 and VT1 (if the latter is connected with the SA1 button) charge the capacitor C2 with a stabilized current.

Further, the unit remains in the current stabilizer mode if the voltage at the load does not rise to the stabilization voltage.

If the amount of current is sufficient, the voltage at the load increases to the stabilization value. In this case, the current through the circuit increases: resistors R17, R18 and the input of the transistor VT4. If the patch cord is removed, then the zener diodes are included in the circuit. Transistor VT4 abruptly unlocks and unlocks transistor VT3. The voltage from the output of the latter partially locks the transistors VT2 and VT1. The stabilized current of the latter sharply decreases. The increase in voltage on the load stops, and it stabilizes.

Transistor VT2 is a current stabilizer, it is connected by the base to a stabilized voltage divider: a zener diode VD2-resistor R14. A set of resistors R1 ... R8 in the emitter circuit allows you to set the required stabilization current for the transistor VT2. Transistor VT1 is an emitter follower of current VT2 and, when SA1 is turned on, provides an expansion of the limits of regulation of the stabilized current.

The voltage divider VD1-resistor R12 provides a negative voltage at the emitter of the transistor VT1 and facilitates its locking at low stabilization currents.

The output voltage divider of the block consists of zener diodes, an emitter-base junction of the VT4 transistor and two low resistance resistors. It compares favorably with a divider on resistors in terms of voltage stabilization, as it reacts more sharply with a change in current in its circuit to minor changes in voltage at the output of the device, which increases voltage stabilization through the circuits of transistors VT4-VT1.

Transistor VT3 - germanium with low saturation voltage.

Transistor VT4 - silicon with a small reverse collector current.

Resistor R15 reduces the voltage at the collector VT4 and its heating.

Resistor R17 limits the discharge current of capacitor C2 through the zener diodes and input VT4 when switching the output voltage.

Establishment

With suitable components and proper installation, the unit does not require special adjustment, except for the initial selection of resistors R1, R8 and zener diodes VD5-VD12 to obtain the necessary current and voltage switching stages. For the convenience of using the block, it is necessary to apply the values ​​​​of the received currents near the terminals of the resistors, and apply voltages between the terminals of the zener diodes.

Features of operation

The voltage is set by shorting some or all of the zener diodes. In the latter case, the emitter-base transition voltage of the VT4 transistor is 0,8 V. Smooth adjustment (0,2 V) is performed by resistor R18. The current is set by switching the terminals with a patch cord.

Initially, a voltage is set at the output of the unit, corresponding to the passport value of the connected load. Further, for the operation of the unit in the charger mode, a current is set that is less than or equal to 0,1 of the nameplate capacity of the battery being charged. To operate the unit in the voltage stabilizer mode, a current is set equal to or greater than the current of the load itself. And finally, a constant voltage of 25 V is applied to the input of the block.

Author: V. E. Borzenkov

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:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Sex cells grown from stem cells 17.10.2012 A team of scientists from the University of Kyoto has achieved a sensational success: from the stem cells of an adult mouse, they grew full-fledged germ cells, spermatozoa and eggs. Thus, for the first time, an adult individual was actually grown from induced pluripotent stem cells. The donor mouse became both the father and mother of their children, which is impossible under natural conditions for healthy bisexual mammals. Last year, scientists already announced that they had succeeded in creating spermatozoa from stem cells. Now oocytes (immature eggs) have been created in the same way. In their experiment, the scientists used embryonic stem cells taken from embryos and adult induced pluripotent stem cells reprogrammed from normal body cells. In theory, both types of stem cells are capable of transforming into any other cells, but scientists until now could not repeat the "trick" of nature and create sperm and eggs from stem cells. Japanese scientists have developed a process that solves this problem. To obtain spermatozoa, they grew pluripotent stem cells in a cocktail of proteins and obtained germ cells (the precursors of sex cells), which turned into spermatozoa. With oocytes it is more difficult - here I had to use a mixture of embryonic stem cells and sex precursors. These cells were placed in the ovaries of live mice and after 4 weeks and 4 days they developed into oocytes. The scientists then extracted the resulting oocytes and fertilized them. Subsequently, healthy mice grew from the embryos. Scientists believe that they will be able to understand the molecular mechanisms involved in the formation of germ cells, and subsequently dispense with the intermediate stage of germ cell transplantation, that is, grow full-fledged spermatozoa and eggs directly in vitro. Subsequently, this technology will allow the production of human embryos from cell lines and tissues of any person. This study may help in the treatment of infertility, although the ethical problem posed by this discovery is simply enormous. So far, a woman is needed to bear a child, but now, theoretically, every person can have a child only from their own stem cells, turned into sex cells. That is, only one person can be a biological parent, and not a mother and father couple.

Other interesting news:

▪ Earth is running out of phosphorus

▪ Sony Handycam FDR-AX4E 1K camcorder

▪ Gallium Arsenide Amplifiers MGA-61563 and MGA-62563

▪ Mobile chargers up to 7800 mAh

▪ Weeding video camera

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Power supplies. Article selection

▪ article It was recently, it was a long time ago. Popular expression

▪ article Why can't I create a folder called con in Windows? Detailed answer

▪ article Onboard conductor. Standard instruction on labor protection

▪ article The sun is a pumping station. Encyclopedia of radio electronics and electrical engineering

▪ article Norms of acceptance tests. Load switches. Encyclopedia of radio electronics and electrical engineering

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