Hidden wiring finder on an operational amplifier. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Indicators, detectors

 Comments on the article

In hidden wiring finders, various inductive elements are mainly used as sensors (relay coils with a large number of turns on a steel or ferrite core, coils from high-resistance phones such as TON-1. TON-2 and similar, dynamic microphones MD200. MD201. magnetic heads from tape recorders, etc.). I managed to get the best result when using the old universal head from the Yauza reel-to-reel tape recorder. Such an "unconventional" element as a laryngophone from a tank helmet has also proven itself well (Fig. 1).

The output of the laryngophone has three contacts: the body (screen) and two contacts - "+" and "-". The sensor is connected to the amplifier with polarity (Fig. 2).

The radiation pattern of the resulting device is wide, which allows it to be used when finding hidden wiring in small communication networks (in apartments, private houses). In industrial premises, where all the walls are "entangled" with electric cables, the device will be ineffective. But where there is a single electrical wiring, but it is deeply hidden in concrete or under a thick layer of wooden walls, the device detects it at a distance of up to 80 cm.

As a sound emitter, a DEM-4M telephone primer is used, which provides sufficient sound volume. The power supply of the device is stabilized, 5-volt. Current consumption at maximum amplification is 10...12 mA. A voltage regulator is assembled on the elements R4, VD1, C3, C4. Capacitor C4 filters low-frequency power noise, C3 - high-frequency noise. Resistor R4 provides the operating mode of the Zener diode VD1. The device can be powered by two A316 elements. Then R4, VD1, C3, C4 are not needed. The DA1 supply voltage can be in the range from 1,4 to 5 V, however, at a voltage of more than 3,5 V, the amplifier is prone to self-excitation, and the noise level increases.

The local acoustic effect due to the proximity of the BM1 and HA1, which appears when the supply voltage rises to 5 V, can be removed by adjusting the resistance R9. but this also reduces the overall gain. The input signal amplification is regulated by a variable resistor R5. At frequencies of 1000 ... 5000 Hz, the gain of DA1 is about 100.

All fixed resistors, except R4, are MPT-0.25 (R4 is MLT-0,5). Oxide capacitors - K50-6, the rest - KM-6. Instead of a laryngophone, any dynamic capsule with a resistance of 1 ... 180 Ohm can be used as a BM250 sensor. for example, DEMSh-1A. Pickup HA1 can be replaced by TM-4. VP-1. The device can be placed in any suitable housing. For example, I used a plastic case from a flashlight (Fig. 3).

The location of the wiring is determined by the maximum sound volume in the phone. Naturally, alternating current must flow through the desired wires. The greater the current, the greater the distance and with greater accuracy the wiring is detected.

Literature

1. V. Paley. Hidden wiring finder. - Electrician, 2005. No. 7, p.33.

Author: A.Kashkarov, St. Petersburg

See other articles Section Indicators, detectors.

<< 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 Smartphone with e-ink color screen 06.01.2020 Hisense has introduced its new device - a smartphone with a color display on electronic ink. This is the first smartphone with such a screen (color E Ink screens are already used in e-books, but they have not been used in smartphones before). The production process of E Ink displays for smartphones is ripe for mass production of electronic ink color screens for such gadgets. However, the company claims that the new displays have an improved refresh rate than previous similar screens used on smartphones. At the moment, however, Hisense does not disclose when a serial device with such a display may appear. The first smartphone with an e-ink screen was YotaPhone, introduced in 2012: it received two screens - one regular main display and one e-ink screen on the rear panel.

Other interesting news:

▪ Google Glass glasses will transmit sound through the skull bone

▪ Bicycle wheel purifies the air

▪ Single Board PC LattePanda 3 Delta

▪ Solar cells for laser energy transmission systems

▪ Diamond nanowires are more efficient than Li-Ion batteries

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Videotechnique. Article selection

▪ article What is Hecuba, what is Hecuba to him? Popular expression

▪ article How did the prophecies of Thomas Robert Malthus, a pioneer in the field of demography, come true? Detailed answer

▪ Eye injury article. Health care

▪ metronome article. Encyclopedia of radio electronics and electrical engineering

▪ article Magic closet. 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