We weigh KPI. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur
Comments on the article
This article is an example of how a homemade product that does not suit any parameters can be successfully applied in another area.
I once experimented with a self-made KPI. It was necessary to obtain a maximum capacitance of 30 ... 40 pF with small sizes. The KPE stator consisted of two plates etched on a printed circuit board with dimensions of 20x25 mm, and the rotor was a plate of foil fiberglass with dimensions of 20x50 mm. The capacity of such a KPI was regulated by changing the distance between the stator and the rotor.
The capacitance measurement was carried out with a conventional balance bridge. The initial capacitance between the stator plates was less than 3 pF (one plate was connected to a common wire, the other to the "hot" end of the generator coil). Thus, contact with the moving rotor is not required, but at the cost of halving the capacitance of the KPI. The initial capacitance of the KPI suited me perfectly, but the maximum capacitance was only 10 ... 15 pF, even when the rotor completely lay down on the stators covered with thin paper. Reducing the thickness of the paper spacer allowed a slight increase in the maximum capacity of the KPI, but did not solve the problem. I changed the paper to a thin polyethylene film - the capacitance increased to 18 ... 20 pF, but this was not enough for me.
During measurements, it was found that the polyethylene film is springy. Pressing the rotor against the stator hard enough, I got a maximum capacitance of 80 pF! It turned out that by changing the pressure on the rotor, you can change the capacitance, but this requires a special screw clamp, the board may be deformed when the KPI is rebuilt.
However, laying various objects on the rotor as a clamp, I noticed that each object (its mass) has its own KPI capacity. It is only necessary to achieve the mechanical stability of the structure and create a calibration (conversion) table of the capacity value into the mass of "weighed" objects. Capacitance can be measured with an accurate digital meter.
Another "profession" of the proposed KPI is a pressure sensor. At a certain load on the KPI rotor, a capacitance corresponding to this load is obtained.
In the manufacture of sensor parts, the main attention should be paid to obtaining the same shape and area of both stator laminations. The rotor must overlap them symmetrically, each time coming to the same place, without moving to the sides. Both the stator and the rotor must be free of roughness and burrs. It is best to polish them. To protect against oxidation, it is possible to cover the plates of the capacitor sensor with some "ageless" metal.
Author: V.Besedin, Tyumen
See other articles Section Beginner radio amateur.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
Traffic noise delays the growth of chicks
06.05.2024
The sounds that surround us in modern cities are becoming increasingly piercing. However, few people think about how this noise affects the animal world, especially such delicate creatures as chicks that have not yet hatched from their eggs. Recent research is shedding light on this issue, indicating serious consequences for their development and survival. Scientists have found that exposure of zebra diamondback chicks to traffic noise can cause serious disruption to their development. Experiments have shown that noise pollution can significantly delay their hatching, and those chicks that do emerge face a number of health-promoting problems. The researchers also found that the negative effects of noise pollution extend into the adult birds. Reduced chances of reproduction and decreased fertility indicate the long-term effects that traffic noise has on wildlife. The study results highlight the need ... >>
Wireless speaker Samsung Music Frame HW-LS60D
06.05.2024
In the world of modern audio technology, manufacturers strive not only for impeccable sound quality, but also for combining functionality with aesthetics. One of the latest innovative steps in this direction is the new Samsung Music Frame HW-LS60D wireless speaker system, presented at the 2024 World of Samsung event. The Samsung HW-LS60D is more than just a speaker system, it's the art of frame-style sound. The combination of a 6-speaker system with Dolby Atmos support and a stylish photo frame design makes this product the perfect addition to any interior. The new Samsung Music Frame features advanced technologies including Adaptive Audio that delivers clear dialogue at any volume level, and automatic room optimization for rich audio reproduction. With support for Spotify, Tidal Hi-Fi and Bluetooth 5.2 connections, as well as smart assistant integration, this speaker is ready to satisfy your ... >>
A New Way to Control and Manipulate Optical Signals
05.05.2024
The modern world of science and technology is developing rapidly, and every day new methods and technologies appear that open up new prospects for us in various fields. One such innovation is the development by German scientists of a new way to control optical signals, which could lead to significant progress in the field of photonics. Recent research has allowed German scientists to create a tunable waveplate inside a fused silica waveguide. This method, based on the use of a liquid crystal layer, allows one to effectively change the polarization of light passing through a waveguide. This technological breakthrough opens up new prospects for the development of compact and efficient photonic devices capable of processing large volumes of data. The electro-optical control of polarization provided by the new method could provide the basis for a new class of integrated photonic devices. This opens up great opportunities for ... >>
| Random news from the Archive Sleeping before bed improves memory
06.02.2019
Children are usually rocked before bed so that they fall asleep faster. But, as experiments show, lulling helps to sleep not only for children, but also for adults. Researchers from the Universities of Geneva and Lausanne invited 18 volunteers to spend three nights in the laboratory. On the first night, they simply got used to the new environment, and on the other two, some participants in the experiment began to rock on a special bed before going to bed, while others continued to sleep as usual.
Those who were rocked fell asleep faster, slept longer, their sleep was deeper. And their memory also improved: in the morning, those who were rocked, remembered better the pairs of words that they were asked to learn before going to bed.
Brain activity during sleep was recorded using electroencephalography. It turned out that rhythmic motion sickness helps to synchronize neural activity in thalamocortical neural networks, which are actively involved in the regulation of sleep and the transformation of memory from short-term to long-term.
|
Other interesting news:
▪ CRT TV with built-in DVD recorder from PANASONIC
▪ graphene chip
▪ The robot copies a one-year-old child
▪ Mobile data rate 1 Tbps
▪ Folding electric bike
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ site section Color and music installations. Selection of articles
▪ article Oh! Eh! Will the time come when ... Popular expression
▪ article Which musician was accused of copyright infringement for performing silence? Detailed answer
▪ article Machine operator of a sleeper machine. Standard instruction on labor protection
▪ article Simple alarm clock on PIC16F84. Encyclopedia of radio electronics and electrical engineering
▪ article Protecting the transformer from increased mains voltage. 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
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese