Unusual application of the KR142EN19A chip. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur

 Comments on the article

As you know, the KR142EN19A microcircuit is a precision analogue of a zener diode with adjustable stabilization voltage, therefore it is usually used in various power supplies. However, it is also capable of working in other amateur radio designs, which are described in the article.

The possibilities of using this microcircuit in slightly different modes, compared with the main purpose, are due to the fact that it includes such components as a reference voltage source and an operational amplifier with an output stage on a transistor.

Its functional diagram is shown in fig. 1 [1], and the symbol and pinout of the conclusions - respectively in fig. 2a and 2b [2].

A diagram of the simplest amplifying stage that can be performed on the indicated microcircuit is shown in Fig. 3, and its transfer characteristic - in Fig. 4.

If the load resistor R2 is selected with a relatively large resistance (a few kiloohms), the characteristic turns out to be flat due to the fact that the microcircuit nodes consume a current of about 1 mA. In the case of using a resistor with a resistance of less than a kiloohm, the characteristic will become steep and more linear.

When the microcircuit operates in a linear mode, it can be used in a voltage stabilizer (its main purpose), a current stabilizer, various generators and amplifiers. In the non-linear mode, it performs the function of a comparator with a response voltage of about 2,5 V. Moreover, such a comparator has a stable response voltage determined by the reference voltage source.

A few words about the microcircuit itself. Unfortunately, one of its shortcomings, which limits the scope of application, is the small allowable dissipation power. So, with a stabilization voltage of 20 V, the maximum current should not exceed 20 mA. It is not difficult to eliminate this shortcoming by "powering" the microcircuit with the help of a transistor (Fig. 5). The main characteristics will be determined by the microcircuit, and the maximum current and power by the transistor. For the one indicated in the diagram, they are 4 A and 8 W, respectively. If there is a negative voltage on the body of the structure, it is permissible to mount the transistor directly on it.

On fig. 6a shows a diagram of a low-power current stabilizer. It works like this. The load current flows through resistor R1. As soon as the voltage across the resistor exceeds 2,5 V, the current through the chip and resistor R3 will increase. The voltage at the load will decrease to such a value at which the voltage at the control input of the microcircuit will be set to 2,5 V.

The stabilized current is set by the resistor R1, the resistance of which is determined by the formula

R1 \u2,5d 2,5 / ln, where 0,1 is the voltage drop across the resistor, V; lH - current through the load, A, which should not exceed 3 A. Knowing the supply voltage Upit and the specified maximum load current, calculate the resistance of the resistor RXNUMX:

R3 \u2,5d (Upit-XNUMX) / ln.

Moreover, the supply voltage should be chosen so that the required voltage is provided at the load, therefore, such a device is recommended to be used, for example, for charging batteries with a capacity of up to 0,75 Ah.

This formula is needed to determine the minimum resistance of the resistor R3 for the case when Rн = 0 (for example, short circuit). Then stabilization will be, but it is not needed.

Another stabilizer (Fig. 6, b) with a transistor current "amplifier" has much greater opportunities. Here, the resistance of the resistor R1 is determined according to the above formula, and its power is based on the flowing maximum load current, which can reach 4 A with the transistor indicated in the diagram.

The high steepness and satisfactory linearity of the transfer characteristic of the microcircuit makes it possible to make a 3-hour amplifier on its basis, the load of which can be a dynamic head with a resistance of at least 50 ohms (Fig. 7, a). Although it is not very economical, it is very easy to manufacture and provides an output power of up to 150 mW, sufficient for scoring a small room.

In another amplifier (Fig. 7b), which has a gain of about 100 times (40 dB) and can become a preliminary one, resistor R4 is used as a load. The gain here is regulated by a tuned resistor R1, and by selecting the resistor R3 in both amplifiers, the optimal operating point is set, which provides the maximum undistorted output voltage.

The high gain of the KR142EN19A chip allows you to assemble various generators on it. As an example, in fig. 8a shows a diagram of an RC oscillator, the output signal frequency of which is close to 1000 Hz - it is set by the phase-shifting chain C1R3C2R4C4. The R1R2C3R5 feedback circuit provides automatic setting of the DC mode.

On fig. 8b shows a diagram of another 3H generator and at the same time an acoustic signaling device. The frequency-setting element in it is a piezoelectric BQ1 type ZGI (another similar one is suitable). Negative voltage feedback through resistor R1 provides DC mode. Generation occurs at the resonant frequency of the piezoelectric emitter.

It is permissible to perform a sinusoidal-to-rectangular signal converter according to the circuit shown in fig. 9, a. Its sensitivity is set by a tuning resistor R1 from a few millivolts to 2,5 V. The converter is fed with a voltage of 4 ... 30 V, while the amplitude of the output signal can be obtained from 1 V to almost half the supply voltage, and a signal with a frequency of up to 50 kHz can be applied to the input .

On two microcircuits, it will be possible to build a multivibrator (Fig. 9, b), at the output of which a rectangular signal is formed. The oscillation frequency is determined by the capacitance of the capacitor C1, the values ​​​​of the resistors R3, R4 and can lie in a wide range - from fractions of a hertz to tens of kilohertz.

Of course, the possibilities of "non-standard" use of the KR142EN19A chip are not limited to the examples given. In the future, it is supposed to tell readers about other constructions.

Literature

1. Yanushenko E. Chip KR142EN19. - Radio, 1994, No. 4, p. 45, 46.
2. Nechaea I. Voltage stabilizers with a KR142EN19A microcircuit. - Radio, 2000, No. 6, p. 57, 58.

Author: I. Nechaev, Kursk

See other articles Section Beginner radio amateur.

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 Pedestrian crossing lights up 07.11.2001 Belgian inventor Tony Cavaleri proposes to make zebra stripes luminous to improve the safety of pedestrian crossings. Lamps covered with durable glass are embedded in the asphalt. They light up automatically as soon as a person approaches the transition. During the day, the brightness of the light is increased, at night it automatically decreases. In particularly dangerous places, such as schools, the light may flash periodically while people are walking along the luminous stripes. The new system received an award at one of the exhibitions of inventions. Luminous transitions are now being tested in Belgium, France and Holland, the Americans expressed their interest.

Other interesting news:

▪ Oxygen from moon dust

▪ Created an artificial organism with one chromosome

▪ The tallest statue in the world

▪ baby cry translator

▪ Sewerage for energy

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Amateur radio calculations. Article selection

▪ article Betting. Popular expression

▪ article Why do stars emit light? Detailed answer

▪ article Air wheel. Children's Science Lab

▪ article A simple metal detector based on the K155LA3 chip. Encyclopedia of radio electronics and electrical engineering

▪ article Unbreakable handkerchief. Focus Secret

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