Schemes of homemade measuring instruments

The circuit of the device, developed on the basis of a classic multivibrator, but instead of load resistors, transistors with the opposite main conductivity are included in the collector circuits of the multivibrator.

It's good if your lab has an oscilloscope. Well, if it is not there and it is not possible to buy it for one reason or another, do not worry. In most cases, it can be successfully replaced by a logic probe, which allows you to control the logical levels of signals at the inputs and outputs of digital integrated circuits, determine the presence of pulses in the controlled circuit and reflect the information received in visual (light-color or digital) or audio (tonal signals of various frequencies). ) forms. When setting up and repairing structures based on digital integrated circuits, it is far from always so necessary to know the characteristics of the pulses or the exact values ​​of the voltage levels. Therefore, logic probes make it easy to set up, even if you have an oscilloscope.

A huge selection of different pulse generator circuits is presented. Some of them form a single pulse at the output, the duration of which does not depend on the duration of the triggering (input) pulse. Such generators are used for a wide variety of purposes: simulating the input signals of digital devices, when checking the performance of digital integrated circuits, the need to supply a certain number of pulses to a device with visual control of processes, etc. Others generate sawtooth and rectangular pulses of various frequencies, duty cycles and amplitude

Repair of various units and devices of low-frequency radio-electronic equipment and technology can be greatly simplified if you use a function generator as an assistant, which makes it possible to investigate the amplitude-frequency characteristics of any low-frequency device, transients and nonlinear characteristics of any analog devices, and also has the ability to generate rectangular pulses. form and simplify the process of setting up digital circuits.

When setting up digital devices, one more device is definitely needed - a pulse generator. An industrial generator is a rather expensive device and is rarely on sale, but its analogue, although not so accurate and stable, can be assembled from available radio elements at home

However, the creation of a sound generator that produces a sinusoidal signal is not an easy and rather painstaking task, especially in terms of adjustment. The fact is that any generator contains at least two elements: an amplifier and a frequency-dependent circuit that determines the frequency of oscillations. Usually it is connected between the output and input of the amplifier, creating a positive feedback (POS). In the case of an RF generator, everything is simple - a single-transistor amplifier and an oscillatory circuit that determines the frequency are enough. For the audio frequency range, it is difficult to wind the coil, and its quality factor turns out to be low. Therefore, in the audio frequency range, RC elements are used - resistors and capacitors. They filter the fundamental harmonic of the oscillations rather poorly, and therefore the sinusoidal signal turns out to be distorted, for example, limited in peaks. To eliminate distortion, amplitude stabilization circuits are used to maintain a low level of the generated signal when distortion is still invisible. It is the creation of a good stabilizing circuit that does not distort the sinusoidal signal that causes the main difficulties.

Often, having assembled the structure, the radio amateur sees that the device is not working. After all, a person does not have sense organs that allow him to see an electric current, an electromagnetic field, or processes occurring in electronic circuits. Radio measuring instruments help to do this - the eyes and ears of a radio amateur.

Therefore, some means of testing and checking telephones and loudspeakers, audio frequency amplifiers, various sound recording and sound reproducing devices are needed. Such a tool is amateur radio circuits for audio frequency signal generators, or, more simply, a sound generator. Traditionally, it produces a continuous sinusoidal signal, the frequency and amplitude of which can be changed. This allows you to check all ULF stages, find faults, determine the gain, take amplitude-frequency characteristics (AFC) and much more.

A simple amateur radio home-made prefix is ​​considered that turns your multimeter into a universal device for checking zener diodes and dinistors. PCB drawings available

Wiring diagrams for beginners, for amateurs and professionals

Welcome to the Radio Circuits section! This is a separate section of the Radio Amateurs Site, which was created specifically for those who are friends with a soldering iron, used to doing everything themselves with their own hands, and it is dedicated exclusively to electrical circuits.

Here you will find schematic diagrams of various topics such as for self-assembly by novice radio amateurs, and for more experienced radio amateurs, for those to whom the word RADIO has long been not just a hobby but a profession.

In addition to circuits for self-assembly, we also have a fairly large (and constantly updated!) Base of electrical circuits for various industrial electronics and household appliances - circuits for TVs, monitors, radio tape recorders, amplifiers, measuring instruments, washing machines, microwave ovens and so on.

Especially for workers in the field of repair, we have a section on the site "Datasheets", where you can find reference information on various radio elements.

And if you need any scheme and have a desire for it download, then we're all here free, no registration, no SMS, no file hosting and other surprises

If you have questions or did not find what you were looking for, come to our FORUM, we will think together!

To facilitate the search for the necessary information, the section is divided into categories.

Schemes for beginners This section contains simple circuits for beginner radio amateurs. All schemes are extremely simple, have a description and are intended for self-assembly. materials in the category	Light and music lighting devices x effects: flashing lights, color music, strobe lights, garland switching machines and so on. Of course, all the schemes can be assembled independently materials in the category	Power Supply Diagrams Any electronic equipment needs power. This category is dedicated to power sources. materials in the category
Electronics in everyday life This category contains diagrams of devices for domestic use: rodent repellers, various alarms, ionizers, and so on... In general, everything that can be useful for the home	Antennas and Radios Antennas (including home-made ones), antenna components, as well as radio receiver circuits for self-assembly	Spy things This section contains diagrams of various "spy" devices - radio bugs, silencers and telephone taps, radio bug detectors
Auto-Moto-Velo electronics Schematic diagrams of various auxiliary devices to cars: chargers, direction indicators, headlight control and so on	Measuring instruments Electrical circuit diagrams of measuring instruments: both homemade and industrial production materials in the category	Domestic technology of the 20th century A selection of electrical circuit diagrams for household radio equipment produced in the USSR materials in the category
Schemes of LCD TVs (LCD) Electrical schematic diagrams of LCD TVs (LCD) materials in the category	Schemes of programmers Schemes of various programmers materials in the category	Audio Schemes of devices related to sound: transistor and microcircuit amplifiers, preliminary and tube amplifiers, sound conversion devices materials in the category
Monitor schemes Schematic diagrams of various monitors: both old kinescope and modern LCD materials in the category	Schemes of car radios and other auto-audio equipment A selection of car audio circuits: car radios, amplifying devices and car TVs

Do-it-yourself motion sensor connection diagram

It happens that you need to install lighting in the country, or in the house, which will be triggered when moving or a person or someone else.

The motion sensor, which was ordered by me from Aliexpress, works well with this function. The link to which will be below. By connecting light through the motion sensor, when a person passes through his field of vision, the light turns on, burns for 1 minute. and turns off again.

In this article I tell you how to connect such a sensor if it does not have 3 contacts, but 4 like this one.

Do-it-yourself power supply from an energy-saving light bulb

When to get 12 volts for LED strip, or for some other purpose, there is an option to make such a power supply with your own hands.

DIY fan speed controller

This regulator allows smooth adjustment variable resistor fan speed.

The floor fan speed controller circuit came out the simplest. To fit into the case from an old Nokia phone charger. There also climbed the terminals from a conventional electrical outlet.

The installation is quite tight, but this was due to the size of the case.

DIY lighting for plants

DIY lighting for plants

There is a problem with the lack of lighting. plants, flowers or seedlings, and there is a need for artificial light for them, and this is the light we can provide DIY LEDs.

DIY brightness control

DIY brightness control

It all started with the fact that after I installed halogen lamps at home for lighting. When turned on, they often burned out. Sometimes even 1 bulb a day. Therefore, I decided to make a smooth turn-on of lighting based on a dimmer with my own hands, and I am attaching a dimmer circuit.

Do-it-yourself refrigerator thermostat

Do-it-yourself refrigerator thermostat

It all started with the fact that after returning from work and opening the refrigerator found it warm. Turning the thermostat knob did not help - the cold did not appear. Therefore, I decided not to buy a new unit, which is also rare, but to make an electronic thermostat on the ATtiny85 myself. With the original thermostat, the difference is that the temperature sensor is on the shelf, and not hidden in the wall. In addition, 2 LEDs appeared - they signal that the unit is on or the temperature is above the upper threshold.

DIY soil moisture sensor

DIY soil moisture sensor

This device can be used for automatic watering in greenhouses, flower greenhouses, flower beds and indoor plants. Below is a diagram by which you can make the simplest sensor (detector) of soil moisture (or dryness) with your own hands. When the soil dries out, voltage is applied, with a current of up to 90mA, which is quite enough, turn on the relay.

It is also suitable for automatically turning on drip irrigation to avoid excess moisture.

Fluorescent lamp power circuit

Power supply circuit for a fluorescent lamp.

Often, when energy-saving lamps fail, the power circuit burns out in it, and not the lamp itself. As is known, LDS with burned-out filaments, it is necessary to feed the mains with rectified current using a starterless starting device. In this case, the filaments of the lamp are shunted with a jumper and to which a high voltage is applied to turn on the lamp. There is an instantaneous cold ignition of the lamp, a sharp increase in voltage on it, when starting without preheating the electrodes. In this article, we will look at do-it-yourself LDS lamp start.

USB keyboard for tablet

USB keyboard for tablet

Somehow, suddenly, he took something and decided to buy a new keyboard for his PC. The desire for novelty is unstoppable. Changed the background color from white to black, and the color of the letters from red - black to white. A week later, the desire for novelty naturally went away like water in the sand (an old friend is better than two new ones) and the new thing was sent to the closet for storage - until better times. And now they came for her, did not even imagine that it would happen so quickly. And therefore the name would be even better suited not which is, but how to connect usb keyboard to tablet

Do-it-yourself clock on IN-14 lamps

Do-it-yourself clock on IN-14 lamps

I have long wanted to post an article on the manufacture do-it-yourself clocks on IN-14 lamps, or as they say, a steampunk watch.

I will try step by step and dwelling on the key points to state only the most important. The clock indication is clearly visible both day and night, and they themselves look very nice, especially in a good wooden case. In general, let's get started.

Nowadays, there is a huge selection of tools and devices for practicing radio electronics: soldering stations, stabilized laboratory power supplies, engraving kits (for drilling boards and processing structural materials), a tool for stripping and processing wires and cables, and so on. And all this equipment costs a lot of money. A reasonable question arises - will a novice radio amateur be able to purchase all this arsenal of equipment? The answer is obvious, especially for some people who are fond of electronics on occasion (for a single production of some useful devices for domestic purposes), the purchase of such a quantity of tools is not required. The way out of this situation is quite simple - to make the necessary tool with your own hands. These homemade products will serve as a temporary (and for some, permanent) alternative to factory equipment.
So let's get started. The basis of our device is a network step-down transformer from any outdated radio-electronic device (TV, tape recorder, stationary radio, etc.). A power cord, fuse box and power switch may also come in handy.

Next, you need to supply our power supply with an adjustable voltage regulator. Since the design is designed to be repeated by beginner radio amateurs, the most rational, in my opinion, will be the use of an integrated stabilizer on an LM317T (K142EN12A) chip. Based on this microcircuit, we will assemble an adjustable voltage regulator from 1.2 to 30 volts with a full load current of up to 1.5 amperes and protection against overcurrent and overtemperature. Schematic diagram of the stabilizer is shown in the figure.

You can assemble the stabilizer circuit on a piece of non-foiled glass fiber (or electric cardboard) by surface mounting or on a breadboard - the circuit is so simple that it does not even require a printed circuit board.

A voltmeter can be connected to the output of the stabilizer (in parallel with the terminals) to control and adjust the output voltage, and (in series with the positive terminal) a milliammeter to control the current consumption of an amateur radio homemade product connected to the stabilizer.

Another thing necessary in the arsenal of a novice radio amateur is a microelectric drill. As you know, in the arsenal of any (beginner or experienced) do-it-yourselfer there is a "warehouse" of obsolete or faulty equipment. Well, if in such a "warehouse" there is a children's machine with an electric drive, the micromotor from which will serve as an electric motor for our microdrill. It is only necessary to measure the diameter of the motor shaft and purchase a chuck with a set of collet clamps (for drills of different diameters) for this micromotor in the nearest radio shop. The resulting microdrill can be connected to our power supply. By adjusting the voltage, you can adjust the number of revolutions of the drill.

The next necessary thing is a low-voltage soldering iron with galvanic isolation from the mains (for soldering field-effect transistors and microcircuits that are afraid of static discharge). There are low-voltage soldering irons for 6, 12, 24, 48 volts on sale, and if the transformer that we chose for our product is from an old tube TV, then we can be considered very lucky - we have a ready-made winding for powering a low-voltage electric soldering iron (you should use filament windings (6 volts) of the transformer to power the soldering iron). The use of a transformer from a tube TV gives one more plus to our circuit - we can also equip our device with a tool for stripping the ends of the wire.

The basis of this device is two contact blocks, between which a nichrome wire and a button are fixed, with normally open contacts. The technical design of this device can be seen from the figure. It is connected to the same filament winding of the transformer. When you press the button, nichrome warms up (everyone probably remembers what a burner is) and burns the wire insulation in the right place.

The case for this power supply can be found ready-made or assembled by yourself. If you make it out of metal and provide ventilation holes only on the bottom and sides, then you can place racks for a soldering iron and a wire stripping tool on top. Switching of all this economy can be carried out using a package switch, a system of toggle switches or connectors - there are no limits for imagination here.

However, this unit can be upgraded to suit your needs - supplemented, for example, with a battery charger or an electric spark engraver, etc. This device served me for many years and still serves (though now in the country) for the manufacture and testing of various electronic and electrical homemade products. Author - Electrodych.