An adapter for connecting a PC computer and controllers with a current loop interface. It does not require scarce parts, it is available for manufacture even at home.

In 1969, the American Electronic Industries Association developed the RS-232C communications interface. Its initial purpose is to provide communication between computers that are remote over a long distance.

An analogue of this interface in Russia is called “Joint S2”. Communication between computers is carried out using modems, but at the same time, devices such as a “mouse,” which was also called “komovskaya,” as well as scanners and printers, were connected to the computers via the RS-232C interface. Of course, all of them should have been able to connect via the RS-232C interface ...

Logic probe scheme for troubleshooting digital circuits, a description of its capabilities and methods of working with a probe.

It is well known that an oscilloscope is needed to repair and establish electronic digital circuits. Of course, now those days are gone when it was necessary to repair large computers in factories. But then there were devices for various purposes on microcontrollers, specialized microcircuits, a large number of devices using digital microcircuits of a small degree of integration (not all enterprises and organizations managed to acquire modern imported equipment).

It is impossible to see the processes occurring in pulsed circuits with a conventional avometer and draw conclusions about the operation of the circuit as a whole. But the oscilloscope is not always at hand. In this case, the described logical probe can be of invaluable help ...

The article describes how, using optocoupler interchanges, to input discrete information with a level of 220 V into the controller, a practical scheme is available for production in any electric laboratory.

In technological processes, it is often necessary to control the position of moving parts of machinery mechanisms. For these purposes, limit switches of various designs and operating principles have been developed and successfully applied.

Often, mechanisms with contact switches are included in automated systems running under control of controllers. In this case, information about the position of the mechanism should be transmitted to the controller that controls the operation of this mechanism.

One of these mechanisms is the most common water valve. Using her example, we will consider how to transfer information about her position to the controller. This is most simply and reliably done using optocoupler isolation. This will be discussed in this article ...

A detailed story about the popular "laser-ironing" technology for the manufacture of printed circuit boards, its features and nuances.

Printed circuit boards in radio engineering have been used for a very long time. At home or in factory electrical laboratories involved in the repair of electrical equipment, such boards had to be painted manually with various varnishes. Tools for drawing were used in a wide variety of ways, from just a sharpened match to needles from a syringe and glass drawing pens.

Now computer technology has penetrated into all spheres of human activity, including amateur radio. Printed circuit boards by hand are now no longer necessary, unless very simple, which can even be cut with a knife. But first things first ...

A story about what a safety transformer is, why it is needed and how it can be manufactured independently.

Many electrical, and more often electronic designs have transformerless power supplies. The power of such power supplies is usually small, but quite sufficient for powering devices such as thyristor power controllers, twilight switches, devices for slowing down incandescent lamps, timers, and many others.

Once assembled, such devices are placed in an insulating plastic case, which excludes human contact with live parts.

An isolation transformer, or as it is sometimes called a safety transformer, will be invaluable in setting up such devices. Such a transformer will not be out of place during the repair of such industrial manufacturing schemes ...

An article about various ways to connect the load to the control unit on microcircuits using relays and thyristors.

All modern equipment, both industrial and domestic, is powered by electricity. At the same time, its entire electrical circuit can be divided into two large parts: control devices (controllers from the English word CONTROL - to control) and actuators.

About twenty years ago, control units were implemented on microcircuits of small and medium degree of integration. These were the series of chips K155, K561, K133, K176 and the like. They are called logical digital circuits, as they perform logical operations on the signals, and the signals themselves are digital (discrete).

The operation algorithm of such control units was carried out due to the corresponding connection of microcircuits, and their number was quite large. Currently, all control units are developed on the basis of different types of microcontrollers ...

The article describes a converter circuit made on a modern element base, containing a minimum number of parts and allowing to obtain significant power in the load.

For many years now, on the pages of radio engineering publications, circuits have been published that make it possible to obtain an alternating voltage of 220V from a car battery to power various equipment in “field” conditions.

The modern elemental base allows us to significantly simplify such schemes. The proposed scheme, in comparison with the just described, contains a minimum number of parts ...

Sometimes, with a reduced voltage in the network or soldering of massive parts, it becomes simply impossible to use a soldering iron. Here the power regulator for a soldering iron can come to the rescue.

There are many guides and articles on how to perform high-quality soldering. In addition to using high-quality fluxes and solders, the quality of soldering largely depends on the temperature of the soldering iron.

There are many schemes for regulating the power of a soldering iron: from the simplest inclusion of a diode in series with a soldering iron to very complex temperature-stabilizing devices. But, unfortunately, all such devices can only work on lowering the power, i.e. power regulation occurs from 0 ... 100% or 50 ... 100% ...