Switching voltage stabilizer on KT825. Scheme, description

Free technical library

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

Switching voltage stabilizer on KT825. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Surge Protectors

Comments on the article

Due to the high efficiency, switching voltage stabilizers have recently become more widespread, although they are usually more complicated than traditional ones and contain a larger number of elements. So, for example, a simple switching regulator (Fig. 5.6) with an output voltage lower than the input voltage can be assembled on only three transistors, two of which (VT1, VT2) form a key regulatory element, and the third (VT3) is an error signal amplifier.

Switching voltage stabilizer on KT825

The device operates in self-oscillating mode. The positive feedback voltage from the collector of the transistor VT2 (it is composite) through the capacitor C2 enters the base circuit of the transistor VT1. Transistor VT2 periodically opens up to saturation with current flowing through resistor R2. Since the base current transfer coefficient of this transistor is very large, it saturates at a relatively small base current. This allows you to choose the resistance of the resistor R2 rather large and, therefore, increase the transfer coefficient of the regulating element.

The voltage between the collector and emitter of a saturated) transistor VT1 is less than the opening voltage of transistor VT2 (in a composite transistor, as you know, two p-n junctions are connected in series between the base and emitter terminals), therefore, when the transistor VT1 is open, VT2 is securely closed.

The element of comparison and the amplifier of the error signal is a cascade on the transistor VT3. Its emitter is connected to a reference voltage source - the zener diode VD2, and the base - to the output voltage divider R5 ... R7.

In switching stabilizers, the regulating element operates in the key mode, so the output voltage is regulated by changing the duty cycle of the key. In the device under consideration, the transistor VT2 controls the opening and closing of the transistor VT3 according to the signal of the transistor VT1. At the moments when the transistor VT2 is open, in the inductor L1, due to the flow of load current, electromagnetic energy is stored. After closing the transistor, the stored energy through the diode VD1 is given to the load.

Despite its simplicity, the stabilizer has a fairly high efficiency. Thus, at an input voltage of 24 V, an output voltage of 15 V, and a load current of 1 A, the measured efficiency was 84%.

The inductor L1 is wound on a K26x16x12 ring made of ferrite with a magnetic permeability of 100 wire with a diameter of 0,63 mm and contains 100 turns. The inductance of the inductor at a bias current of 1 A is about 1 mH. The characteristics of the stabilizer are largely determined by the parameters of the transistor VT2 and the diode VD1, the speed of which should be as high as possible. In the stabilizer, transistors KT825G (VT2), KT313B, KT3107B (VT1), KT315B, (VT3), a diode KD213 (VD1) and a zener diode KC168A (VD2) can be used.

Author: Semyan A.P.

See other articles Section Surge Protectors.

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

AIWA TVX-F21D1 - CRT TV with built-in DVD player 19.01.2004

Aiwa introduced the TVX-F21D1. This is a 21" CRT TV with a built in DVD player.

The player supports DVD-Video and MP3 formats recorded on DVD-R, DVD-RW, DVD+R, DVD+RW, CD-R and CD-RW discs. The stereo system of the TV has a 2.1 formula and a built-in subwoofer. Digital amplifier power - 18 W, there are 5 equalizer presets. Used in TVX kinescope F21D1 from SONY - FD Trinitron. 100 Hz progressive scan, screen aspect ratio -16:9. Dimensions: height 653 mm, depth 530 mm, width 496 mm, weight - 29,8 kg.

Sales are scheduled for February 1, 2004, the cost of TVX-F21D1 will be $500.

Other interesting news:

▪ Container for carrying computers

▪ 2nm technology from IBM

▪ Exhibition of domestic robots

▪ Mushkin REACTOR 1 TB SSD

▪ Security Robot

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Electronic directories. Article selection

▪ article Tuesok for berries. Tips for the home master

▪ article Why a ban on marriages between cousins does not make sense? Detailed answer

▪ article by Ferul Lehmann. Legends, cultivation, methods of application

▪ article Capacitance meter - prefix to the tester. Encyclopedia of radio electronics and electrical engineering

▪ article Preparation of casein glue. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

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