The ladder or ladder diagram language LD (from the English Ladder Diagram) is an easy-to-use, graphical development language. It is based on relay-contact circuits, so the logic elements here are: relay windings, relay contacts, horizontal and vertical jumpers.

A pair of relay contacts or buttons are the main logical variables of the LD language, while the state of the variables is nothing more than the state of the contacts: open or closed. The program itself in this graphic language seems to be an analogue of the relay circuit, which can include many different functional blocks. In general, the syntax of the LD language makes it very easy to build logic circuits for relay technology. As such, the language of relay circuits existed in the time of Thomas Edison, and only in the early 1970s it was adapted for the first PLCs ...

Often, when designing a powerful device on power transistors, or resorting to the use of a powerful rectifier in the circuit, we are faced with a situation when it is necessary to dissipate a lot of thermal power, measured in units, and sometimes tens of watts.

For example, Fairchild Semiconductor's FGA25N120ANTD IGBT transistor, if installed correctly, is theoretically capable of delivering about 300 watts of thermal power through its chassis at a chassis temperature of 25 ° C! And if the temperature of its case is 100 ° C, then the transistor will be able to give 120 watts, which is also quite a lot. But in order for the transistor case to be able to give this heat in principle, it is necessary to provide it with the proper working conditions so that it does not burn out ahead of time. All power switches are issued in such cases which can be easily installed on an external heat sink - a radiator ...

First of all, it is necessary to find out the following details: the expected temperature range of measurements, the required accuracy, whether the sensor will be located inside the medium (if not, a radiation thermometer will be needed), the conditions are assumed normal or aggressive, is the possibility of periodic dismantling of the sensor important, and finally, is it necessary graduation is in degrees or it is acceptable to receive a signal, which will then be converted into a temperature value.

These are not idle questions, answering which the consumer gets the opportunity to choose for himself a more suitable temperature sensor with which his equipment will work in the best way. Of course, one cannot simply and unequivocally answer the question of which temperature sensor is better, the choice remains to be made to the consumer, having previously familiarized himself with the features of each type of sensor ...

PID (from the English P-proportional, I-integral, D-derivative) - a regulator is a device used in control loops equipped with a feedback link. These controllers are used to generate a control signal in automatic systems where it is necessary to achieve high requirements for the quality and accuracy of transients.

The control signal of the PID controller is obtained by adding three components: the first is proportional to the value of the error signal, the second is the integral of the error signal, and the third is its derivative. If any of these three components is not included in the addition process, then the controller will no longer be PID, but simply proportional, proportionally differentiating or proportionally integrating. The output signal gives a proportional component. This signal leads to counteraction to the current deviation of the input quantity ...

In the article "How to control a chandelier in two wires", various schemes were considered that allow switching several groups of lamps. The operation algorithm for all circuits is the same: with a short click of the switch, the first group lights up, with the second second, with the third click both groups at once. To turn off the chandelier, switch the switch, as usual, to the open position. All the circuits considered at different times were developed by ham radio.

In Chinese-made chandeliers, such devices are already installed, and in addition to them there are some additional lighting and even sometimes sound effects. My colleague at work was engaged in the repair of one of these devices: until you are busy repairing production equipment, you can work hard for yourself. And the defect of the mentioned device was like this - no matter how you click the switch, nothing turns on. Still managed to repair the circuit ...

The dynamos in the century before last began to be called direct current generators, the first industrial generators that were later replaced by alternating current generators suitable for conversion by transformers, and extremely convenient for long-distance transmission with little loss.

Today, the word "dynamo", as a rule, means small bicycle generators (for headlights) or hand generators (for tourist flashlights). As for industrial generators, today all this is alternating current generators. Let us, however, recall how the first dynamos developed and improved. The first model of a direct current generator, or unipolar dynamo, was proposed back in 1832 by Michael Faraday, when he only discovered the phenomenon of electromagnetic induction. It was the so-called "Faraday disk" ...

Do you change bulbs too often? Seriously, this question is hardly asked by those who use incandescent lamps in the old fashioned way. Indeed, incandescent lamps cost a penny, and there is no problem in replacing a burnt out bulb with a new one. If a person does not care about the energy saving problem, then everything is in order, he does not experience inconvenience.

But what about those people who have already switched to LED lamps? What if, for example, a zealous owner, deciding to take care of energy conservation, put LED bulbs at home, and they burn out all the time? In this case, you have to forget about saving, because LED lamps are quite expensive, compared with the same incandescent lamps. This is where a person is faced with a real problem. So why not eliminate the cause of regular burnout of LED lamps? Of course, it is worth eliminating it, but first you need to identify this reason. Let's see what are the reasons ...

They are called free energy machines or simply perpetual motion machines ... Ever since the time when mankind put electricity to its service, the tireless minds of inventors have been looking for a brilliant solution - a source of free energy without the need for any kind of fuel. What can I say, historians have always found technical sketches of “perpetual motion machines”.

Here and there, now more often than in ancient times, one can find projects of “perpetual motion machines”. Let’s take a closer look at this problem and see what does exist and what it actually is. Educated people are well aware that the perpetual motion machine cannot work in principle, this does not need to be proved. But since the debate does not subside in any way, this requires attention. The eternal engine, if it were a real device, would violate the laws of thermodynamics, which are actually indestructible ...

In everyday life, we use many electrical mechanisms, the regularity of use of which suggests the automation of the process. For example, controlling outdoor lighting or a well pump. This idea is not new, and there are a lot of devices of this purpose, which have received a common name - a time relay.

The programmable weekly timer electronic TE 15 is a device that can control many household devices. He is a vivid example of the benefits of modern technology. To verify this, just remember what devices had to use before. Previously, a mechanical timer was popular. Built-in power outlet, he could turn on household appliances for a certain time. In fact, it was a countdown timer; accordingly, its scope was limited. One of the works of Chinese industry - "Kitchen timer." In fact, this is a regular outlet with a timer ...

To determine the current value in an electric circuit, special devices are used - ammeters. The ammeter is connected in series to the circuit under study, and, due to the extremely small intrinsic resistance, this measuring device does not make any significant changes to the electrical parameters of the circuit.

The instrument scale is graduated in amperes, kiloamperes, milliamperes, or microamperes. To extend the measurement range, the ammeter can be connected to the circuit through a transformer or parallel to the shunt, when only a small fraction of the measured current passes through the device, and the main circuit current flows through the shunt. Today there are two particularly popular types of ammeters - mechanical ammeters - magnetoelectric and electrodynamic, and electronic - linear and transformer. In a classic magnetoelectric ammeter with an arrow ...

When the light goes out in a house or apartment, not only does the connection with civilization disappear, but the products in the refrigerator begin to deteriorate, especially in the summer, especially in the southern regions. Someone did not have a gas, but an electric stove, not to mention a computer, TV, electric kettle, etc. This was fully felt by those who lived in the 90s. On the territory of Russia and the CIS during that difficult period, here and there, there were regular interruptions in electricity, and it was not uncommon that entire city blocks were saved in the evenings only with wax candles.

And although the dashing 90s are behind, in some places even today there are sometimes interruptions in power supply. This problem, of course, is solved by the use of modern uninterruptible power supplies (UPS) or liquid fuel generators. But not every homeowner can afford high-quality autonomous power supply for an apartment, not to mention a large private house. Let's look at the possibilities for offline ...

In October 1975, California inventor Robert Alexander introduced the public to an advanced drive for a car. According to the inventor, this electric drive was supposed to save car owners from the need to use combustible fuel, from unnecessary noise, and from the need to constantly recharge the batteries.

The experts who arrived at the demonstration were very puzzled, because it seemed that the energy comes from "nothing." However, the car drove easily without fuel at a speed of 36 miles per hour. To experts' doubts, the inventor replied that the car was driving, and she did not care about their arguments. The initial power was provided by a converted electric motor of 7/8 horsepower.The electric motor was redone so that 12 volts were obtained at its output, otherwise the output power would be too large ...