Correspondence school of radio electronics. Correspondence school of radio electronics Topic: Correspondence school of radio electronics
The car was created in order to receive electric charges, and for this they had to learn how to remove them from glass and skin. In those days, this was a difficult task: the skin does not conduct electricity, so it seemed impossible to remove the charge from it. But an unknown inventor thought of making it electrically conductive by impregnating it with zinc amalgam.
This liquid substance, obtained by dissolving zinc in mercury, is inherently prone to decay, so the mercury gradually evaporated. People of that time did not care, because mercury was then considered almost a medicine.
Today we know about the great harm that mercury vapor brings, so leather pads are impregnated with harmless substances.
Electrostatic Friction Machine late XIX century.
At first, the negative charge removed from the pads went to the ball electrode, and in 1766 the German inventor D. Ramsden thought of putting copper rings on both sides of the disk, and the machine became much more efficient.
How to make such a machine? In principle, it is simple, but you should not start by making an exact copy of an old model. The figure shows an amateur version of an electrostatic machine that can be repeated. At? neat and correct execution, it looks like quite "old".
Start manufacturing with the most difficult part - the glass circle. It is very difficult to cut it out of ordinary silicate glass without experience with this material. It is much easier to make it from organic glass, which, by the way, is electrified much more than usual.
Modern amateur electrostatic machine.
You can cut it with a special tool - a ruler with a cutter. To do this, drill a hole in a wooden ruler, insert a bolt with a diameter of 3–4 mm into it and secure it firmly with a nut. After that, on the emery, sharpen the end of the bolt so that you get a cutter. Next, drill a hole in a piece of plexiglass of suitable size, nail it to a sheet of plywood or chipboard and start cutting. In 15-20 minutes your circle will be ready. To speed up the work, the cut line can be watered.
Next, we proceed to the manufacture of pillows. It consists of a piece of leather glued to a thin aluminum plate, which you fold in half after the glue has dried. In this case, we use not simple glue, but electrically conductive.
There are many such adhesives on the market. We recommend inexpensive electrically conductive adhesive T-412, which is used for sticking synthetic carpet. This material is easily electrified, and in dry weather, if you glue the carpet with ordinary glue, you, without suspecting it, can become an electrostatic machine that generates voltages up to 35,000 V.
If you can't get the right glue, make your own with two parts copper powder and one part graphite powder, by weight. Mix them with oil varnish and add turpentine so that you get a mass with a thick cream. Copper powder is made by filing a thick copper wire with a file. Graphite powder - crushed pencil lead.
When you're done, spread the electrically conductive adhesive on the smooth side of the leather, press it against the metal backing, and press dry. After the adhesive has dried, it is useful to measure the transverse resistance of the skin. If it does not exceed 50 MΩ, then your machine will work.
As already mentioned, Ramsden rings serve to remove the negative charge from the disk. They are curved on a round blank with a diameter of 50–70 mm from copper wire with a diameter of 4–6 mm. It must first be straightened by stretching it around a wooden rod, and then polished with a thin sandpaper. The rings are connected to the second discharge ball.
Balls and balls in the manufacture of high-voltage electrical machines is a difficult issue. The industry almost does not produce them, and it is not easy to make them yourself.
Some balls can be found among school kits for electroscopes and electrometers. But balls and balls quite suitable for our purposes can be made from ... children's balls. To do this, choose a children's ball without a seam and paste over it with aluminum foil using the remnants of the same glue. Pierce the balls first to release air from them. From this they will not lose their shape, but through these holes they can then be planted on metal racks.
The spheres obtained in this way are almost equivalent in their electrical parameters to polished metal spheres. M. Plante's machine, with a fast rotation of a disk with a diameter of 300 mm, produces sparks up to 7 cm long (this is approximately the same voltage that made a chain of 700 monks jump). If the speed of rotation of the disk is increased, the length of the sparks will increase, but the disk itself will begin to overheat and warp.
To obtain higher voltages, a Vomelsdorff machine based on other principles is good. We will describe it in one of the subsequent issues of the journal. In the same place we will tell you how to make polished metal balls of any size.
A. VARGIN
CORRESPONDENCE SCHOOL OF RADIO ELECTRONICS
Detector reception in the field
(End. See the beginning in the previous issue.)
For field use, the scheme can be further simplified. In most cases, after careful tuning to the maximum receiving volume, the changes in capacitance and C2 of the capacitor turned out to be minimal, therefore, it is not needed at all. You can tune in to different stations by changing the inductance of the coil. The next simplification: it is unlikely that you will be able to hang a long antenna on a hike, then the capacitor C1 is redundant.
However, the limits for changing the inductance with a ferrite rod are not enough to cover the broadcasting ranges of both medium and long waves (MW and LW). If there is only one powerful radio station in your area, whether it is MW or LW, you can choose the number of turns of the coil so that it is received in the middle position of the ferrite tuning rod. If there is a desire to receive in both bands (for example, distant stations at night), then the coil design must be changed and a switch added (Fig. 1).
The winding is carried out with two wires folded together, forming closely connected coils L1 and L2. It should be wound 100 ... 150 turns. The beginnings of the wires are indicated by dots. The switch connects the coils either in parallel, as shown in the figure, or in series, in which case the total inductance is quadrupled. Conventionally, the first position can be called "SV", and the second - "DV". The switch can be of any type, two-section, two positions.
No less important- antenna and grounding. If you are not far from the transmitting station, say, 30 ... 40 kilometers, then any, but better, insulated wire 2 ... 3 meters long will serve as an antenna. Throw it on a tree branch, a bush, or pick it up on a dry stick, tying a suitable weight to the end of the wire.
In an old Radio Front magazine from the 1920s, an amateur recommended a weight tied to a string. Throwing it over the branches and pulling the string, the weight was lowered to the ground, the antenna wire was tied instead of it and, choosing the string, they raised the wire to the tree. A modern American radio amateur recommends plastic bottles instead of cargo. Pouring water into them, it is easy to choose the optimal weight of the bottle, and throw it like a grenade.
Unfortunately, bright light, even completely devoid of infrared radiation, in itself causes a rapid death of microorganisms.
There is only one way to combat this phenomenon - the use of a sensitive television camera connected to a video projector. But today such systems are too expensive for schools. However, there is hope that soon it will become much cheaper.
A. VARGIN
CORRESPONDENCE SCHOOL OF RADIO ELECTRONICS
Attention to broadcast!
On the night of April 14-15, 1912, a distress signal sounded from the sinking ocean liner Titanic. The enormity of the disaster and the effectiveness of this radio call for help soon became known to the whole world. A simple, easy-to-remember set of telegraph parcels - three dots - dash - three dots - has since bailed out many distressed sailors. To make it easier to hear, a standard transmission frequency is allocated - 500 kHz (wavelength 600 m) and radio silence on this wave twice an hour - from the 15th to the 18th and from the 45th to the 48th minute.
During one of these pauses in April 1972, the radio operator of the American liner Theodore Roosevelt received a distress call from the long-dead Titanic. The requested coastal services did not record such a signal ...
Nevertheless, the radio operator turned to the military archives and found reports confirming his own observations: SOS from the Titanic have been recorded since 1924, with a period of six years. And in April 1996, the Canadian newspaper SUN reported another signal from the Titanic, received by the Canadian ship Quebec.
According to some scientists, the cause of the amazing phenomenon was the phantom of the radio signal, which was formed in the field of space-time, and its next appearance can be expected now in 2008.
Will the forecast come true?
This, if desired and patience, can be checked using your own equipment. An emergency radio receiver operating in the medium wave range can be built according to the schematic diagram shown in Figure 1.
Rice. one
The device is made according to the scheme of direct amplification; its operation, unlike the superheterodyne, is free from false whistles that interfere with tuning. A dual-circuit configurable input on the elements L1, C2, C3.1 and C3.2, C7 and L2 give good selectivity. Sensitivity and selectivity can be greatly increased by skillful operation of the C6 feedback controller. The feedback signal is taken from the resistor R1 at the output of the RF path and fed into the input circuit.
The elements in the DA1 chip package also detect the received signal and amplify it at audio frequencies, which are reproduced by the BF1 phones from the audio player.
The reception volume can be adjusted with a variable resistor R2. Coil L1 is wound on a ferrite rod with a diameter of 10 mm and a length of 200 mm and contains 45 turns of PELSHO 7x0.07 wire. Coil L2 - on the K16x8x4 ring made of 100NN ferrite has 94 turns of the same wire. The feedback coil L3 has about 10 turns of PELSHO-0.2 wire.
Capacitor C4 is formed by twisting short pieces of insulated wire with a diameter of about 0.4 mm, soldered to the petals of the terminals of the KPE SZ block. The magnetic antenna should be located at a distance of about 50 mm from the KPI.
The receiving direction of the WA1 magnetic antenna is useful for determining the azimuth of the alarm transmitter. The WA2 external antenna increases the receiving range. For finer adjustment of the feedback in place C5, you should use a KPV-type capacitor with an air dielectric.
Regulating feedback, do not bring it to generation. Figure 2 will tell you how the pins are located on the DA1 chip of type K174XA10.
Rice. 2
So, on April 14–15, 2008, we are waiting for signals from the Titanic. We choose the time for reception adjusted for our time zone, because the Titanic died south of Labrador. And try to record his call signs on a tape recorder!
I wish you success!
Y. PROKOPTSEV
READING CLUB
Question answer
Can you please tell me why the single European currency was called the "euro"? Were there any other name options?
Alexander Perevozchikov,
Nizhny Tagil
Yes, there were options. So, the euro had a predecessor - the ecu. This is an abbreviation, which, when deciphered and translated, means: “a single European unit”. However, when in 1995 the governments of 12 European countries decided to switch to a common currency, after some discussion, the name euro was adopted. We decided that, firstly, it is already part of the word "Europe" and thus characterizes the ownership of the currency. And secondly, this word sounds almost the same in many languages and is understandable to all people without translation.
Are Russian specialists planning flights to the Moon and landing on its surface in the near future?
Andrey Karavanov,
St. Petersburg
Yes, they do. Moreover, the British company Space Adventures, which works closely with our specialists, has already announced that it is selling two tickets to travel to the Moon for 53 million British pounds each.
Passengers will go to the moon together with a Russian cosmonaut who will fly the ship, which is a modification of the Soyuz. This ship was originally intended to participate in the Soviet lunar program Zvezda.
"A crew of three will fly over the surface of the moon at an altitude of just 65 miles and return to Earth with minimal risk," says company president Eric Anderson. - According to a preliminary agreement with the Russian side, the first such trip may take place in 2010. And in total, according to our data, there are about 1000 people in the world who want to participate in such an expedition "...
To the above, it remains to be added that it was Space Adventures that once offered us the first space tourist, Denis Tito, who was in orbit in 2001. So soon the first “lunatics” tourists will appear on the ISS. They will spend about two weeks in orbit to get used to weightlessness, and then make a six-day trip to the moon and back.
Recently, over Khimki, many people saw strange V-shaped objects in the sky. Some say they were UFO scouts, but I don't believe it. What do you think?
Igor Kvasnikov,
The investigation showed that the role of the UFO in this case was strips of foil connected together with a thin wire. Such simple devices, like simple pieces of steel, are commonly used by military aircraft as passive interference designed to puzzle enemy air defense observers. The only mystery is who and why dropped these strips over the city.
I read that in winter, a hungry wolf's eyes glow in the dark. green light. Why?
Alexander Zaikin,
Orenburg
The eye retina of wolves, cats and some other animals is a kind of reflector reflecting the light of the moon or stars. The fact is that in the dark the pupil of the eye expands to the maximum, and when it is illuminated by a beam of light (otherwise the eye cannot be seen), reflection from the bottom of the retina occurs. As for the belief that the eyes of hungry wolves glow in the dark on their own, scientists do not confirm this fact. The eyes should still reflect at least some light.
Usually they say that about people who are craftsmen. However, at the II Specialized Exhibition of Robotics, "iron workers" - cybers of various designs and purposes - demonstrated outstanding skill and capabilities. Our special correspondent Stanislav ZIGUNENKO got acquainted with them. Here are his impressions.
Who has the longer arm?
They didn’t say about anyone that he had envious eyes, and raking hands. Meanwhile, the champions in this business are robotic manipulators, - V. Ya. Potapov, a representative of the State Scientific Center of the Russian Federation "Institute for High Energy", explained to me. - Look, with its help I can get an object that is a good three meters away from you and me ...
And Vladimir Yakovlevich waved his hand lightly. At the same moment, the manipulator's hand began to move, ending in special grips, and carefully took out a glass test tube from the tripod.
A modern industrial robot no longer surprises anyone.
It looks like a robotic chimney sweep...
A manifestation of machine gallantry: a robotic arm is quite capable of presenting a flower to a lady operator.
However, as Pavlov told me, trained operators are able to use a manipulator to thread a needle. And that's what! A new generation of telemanipulators is being prepared for production, the master and executive parts of which can be separated from each other not by meters, but by many hundreds and even thousands of kilometers. In this case, communication between them is carried out not through kinematics, but with the help of telecontrol, carried out through special communication channels or even via the Internet.
They say that with the help of such manipulators the first experimental surgical operations have already been carried out. And the surgeon can be, for example, in Moscow, and his patient - say, in Antarctica. But regardless of the distance, the movement accuracy will be micron.
In the meantime, copying manipulators are most often used when working with radiation isotopes or especially dangerous chemicals. The operator is separated from them by reliable protection, he observes the operations through special windows or with the help of a telemonitor.
Robot chimney sweep
In cases where even the most flexible manipulator cannot get somewhere, self-propelled cleaning robots are used. One of them, something like an enlarged earthworm, was shown to me by one of its creators, chief designer of the laboratory of robotics and mechatronics of the Institute for Problems in Mechanics of the Russian Academy of Sciences L.N.
Our robot is able to crawl through a pipe that has numerous turns and twists, even at an angle of 90 degrees, - said Leonid Nikitich. - This is largely due to its design. The robot really moves like an earthworm. First, it will push its frontal part forward, fix it on the walls of the pipe, and then pull up the back. And at the ends of it are rotating brushes, with the help of which it cleans pipes.
Petersburg robots are ready to go even under water, even into space...
While the chimney sweep robot receives energy for movement and control commands through the cable that stretches behind it. But in the future, as the creators of this original robot believe, completely independent, autonomous structures will appear, which will be controlled by radio.
From under water to space
This doesn't just happen to people. As you know, Valery Rozhdestvensky, a former submariner from St. Petersburg, later became an astronaut. And this is no coincidence. There are quite a few similarities between the two elements. In both cases, a person often experiences weightlessness, he is surrounded by a rather aggressive, alien environment that does not forgive mistakes.
Therefore, as S.Yu.Stepanov, a representative of the State Scientific Center "Central Research Institute of Robotics and Technical Cybernetics", based in St. Petersburg, told me, both cosmonauts and submariners increasingly use robots to perform the most dangerous operations.
Such robots, in contrast to conventional, ground ones, must have a special design, - Sergey Yuryevich explained. - Firstly, their nodes are made in a modular design. That is, in such a way that each node is structurally complete and can be replaced without any problems. Secondly, each module is placed in a casing that protects the most delicate parts of the structure from harmful effects. environment. And, thirdly, such designs must be ultra-reliable. If they break during operation, you won’t get the hassle of repairing them ...
All these and many other requirements are met by robots created at the Central Research Institute. They have already proven themselves well in a number of special projects, for example, when working in the "dirty" zone of nuclear submarines and at some other facilities.
The hand of the manipulator is controlled by a human hand ...
Rescuers and explosives
Increasingly, robots come to the aid of people in other difficult cases. For example, many have already seen on television more than once how not an explosives engineer, but a robot is heading towards a suspicious object. He drives up, carefully examines the suspicious find from all sides, and the operators, who carefully monitor the activities of the robot with the help of television cameras, decide what to do next.
As Mikhail Germanovich Kanin, the leading designer of the Scientific Institute of Special Machines at the Moscow State Technical University named after N.E. Bauman, multi-purpose robotic complexes MRK-26, MRK-27, MRK-UTK, Varan and others are designed to replace a person when performing work in extreme conditions. The caterpillar chassis, relatively small dimensions and weight allow the robot to penetrate into various nooks and crannies, climb flights of stairs, clearly following all the operator's commands. At the same time, the robot can carry on board up to 8 color video cameras, lighting equipment, has a remotely controlled manipulator that allows you to lift various objects and carry them over a distance of several hundred meters.
At the same time, the design of the robot itself is modular, which makes it possible to combine various sets of equipment on the chassis, quickly make repairs in the event of, say, a mine explosion, and easily clean parts of the structure after working in the radioactive zone.
Such robots have already been tested in the subdivisions of the Ministry of Atomic Energy, the Ministry of Emergency Situations and the Federal Security Service, participated in the liquidation of the accident in the city of Sarov, in demining operations in Chechnya and Moscow. They are mass-produced, and every day there are more and more such human assistants, and they themselves are cheaper.
ELECTRONIC ABC
Thanks to the advances in electronics in the entertainment industry, the new kind slot machines. They are mass-produced by industrial enterprises in the form of a variety of stationary devices for gaming halls of cinemas and recreation parks, desktop structures, and even as set-top boxes for ordinary TVs. Today we will talk about a simple slot machine that makes the game more interesting and exciting and at the same time allows you to objectively judge its course and results.
The essence of the game is as follows: after turning on the "Network" and "Start" toggle switches, the player must switch the switches on the remote control, adhering to the order of the letters in the alphabet. At the same time, the light bulbs that illuminate the letters on the scoreboard will record the progress of the game. Simultaneously with turning on the “Start” toggle switch, the electronic stopwatch is turned on, and the time of the game starts counting on the “Time” counter.
After the entire alphabet is "passed" by the player without errors, the "End of the game" board lights up and the "Time" counter turns off. It should be borne in mind that the slot machine closely “monitors” the observance of the rules of the game (switches must be turned on strictly in the order of the letters in the alphabet). If the player makes a mistake, then the next scoreboard with the letter will not light up - you must turn off the incorrectly turned on switch and turn on another one.
Appearance of the gaming machine is shown in Figure 1. There are 33 round scoreboards on the inclined front panel in an arc. On each board one letter of the Russian alphabet is written, which becomes visible only when the light bulb located under the board lights up. The scoreboard letters are arranged in an arc in alphabetical order from left to right. In the center of the inclined panel there is a "Time" counter and a light board "End of the game".
On the base of the machine there is a control panel with 33 switches, next to each switch there is a plate with a letter. The letters on the remote are in disarray. In the lower right part of the remote control there are switches "Start" and "Network".
The circuit diagram of the machine is shown in Figure 2. Consider the operation of the circuits of the machine. After turning on the “Start” toggle switch S34, the multivibrator power supply circuit is closed on transistors V5-V6. In one of the arms of the multivibrator (the period of its oscillations is 1 s), the relay K1 is connected, the contacts of which K 1.1 with a frequency of 1 Hz will close the power supply circuit of the counter BI "Time". On the scoreboard of the "Time" counter, the time of the game will be counted in seconds. When the contacts of the S33.2 switch are opened, next to which the letter I is fixed, the multivibrator power supply circuit opens and the time count stops. In addition, contacts S33.1 close the power supply circuit of the H34 lamp, which illuminates the “End of the Game” display.
A logical chain of switch contacts S1 - S33 "makes sure" that the player does not make mistakes and turns on the switches according to the order of the letters in the alphabet. For example, the lamp H14 (letter M) will light up when the switch S14.1 is turned on only if the lamp switch H13 (letter H) - S13.2 was previously turned on.
After the end of the game, it is necessary to turn off the "Start" switch, return the letter switch to its original position and set the arrows of the "Time" counter to zero.
Adjustment of the gaming machine is reduced to the selection of the oscillation frequency of the multivibrator (1 Hz), which is set by resistors R2 and R3.
In the slot machine that we have reviewed, “monitoring” of compliance with the rules of the game is passive in nature - in case of an error, the lamp that illuminates the letter does not light up. If the player does not look at the scoreboard at this time, then he may not notice this and continue the game.
The described gaming machine can be improved by introducing an error signaling device into its circuit (Fig. 3).
In the second version of the slot machine, in case of a player’s mistake, the “Error” board flashes and a sound generator signal sounds, which indicate an error until the player corrects it. The logical chain, made up of contacts S1.2-S33.2, has interesting property: if they are included in the specified sequence (S1.2, S2.2, S3.2 ... S31.2, S32.2, S33.2), then this chain does not pass electric current. One has only to make a mistake - violate the order of turning on the toggle switches - as an electric current flows through the chain: the power circuit of the H35 lamp and the sound generator on transistors V7-V9, a symmetrical multivibrator with a single-stage signal amplification, will close. The H35 lamp illuminates the "Error" display, and the dynamic head B2 emits a sound signal with a frequency of about 1 kHz until the erroneously turned on toggle switch is turned off.
The appearance of the second version of the slot machine remains the same, only the “Error” scoreboard and the loudspeaker are added to the inclined panel. The second version of the slot machine (Fig. 3) is connected to points a, b, c, d of the rectifier (Fig. 2). The electronic stopwatch on the multivibrator remains unchanged.
Of course, not only the order of the letters in the alphabet can be used as the sequence that the player must follow during the game. This may be a list of stations from one settlement to another (for example, 33 major stations from Moscow to Vladivostok), the chronological order of any historical dates, and much more. Accordingly, the signs near the switches and the names of the light panels change.
In both versions of the slot machine, the same parts are used: HI-H34 lamps - LN type 3.5 V X 0.28 A; lamp H35 - 36 V X 0.12 A; switches S1-S32 - type TP1-2; S34-S35 - type T1-C; S33 - type TV1-2; diodes VI-V4 - type D226B; transistors V5-V9 - type MP42; dynamic loudspeaker
B 2 - type 0.1 - GD; transformer T2 - any output transformer from transistor radios; capacitors C1-C3 - electrolytic, 200 microfarads, 50 V; counter B1 - type SB - 1 M / 100. The counter is reinforced with inside front panel on the bracket, the meter toggle switch is not used and should be removed. To set zero, there are two heads on the back of the counter, they must be extended with rods that are brought out to the back wall of the case. The core of the network transformer is assembled from Sh32 plates, a package of 20 mm. Winding I contains 2750 turns of PEL-0.15 wire; winding II - 87 turns of PEL-0.35 wire; winding III - 300 turns of PEL-0.35 wire.
B. IGOSHEV,
Senior Lecturer, Department of General Physics, Sverdlovsk Pedagogical Institute
Drawings by Y. CHESNOKOV
