Electronic phase meter. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Measuring technology

 Comments on the article

The phase meter is designed to measure the phase shift angles between two periodically changing electrical oscillations and can be used in amateur radio practice in the development, adjustment and operation of electronic and electrical apparatus and devices. The proposed electronic phase meter simultaneously provides information about the sign and magnitude of the phase shift angle, which makes it more visual. In the device, it was possible to significantly simplify the nodes for selecting the magnitude and sign of the angle and to combine the functions of individual elements.

Main technical characteristics:

• Range of measured phase shift angles, el. deg......0...180
• Operating frequency range, Hz.......10...104
• Input voltage range, V.......0,01...50
• Range of measured currents, A......0,01...2
• Measurement error, %, no more.......2

The schematic diagram of the electronic phase meter is shown in fig. one.

Ris.1

Input voltages Uin1 and Uin2 of arbitrary shape (for example, sinusoidal) from the measured circuits through the dividers R1VD1VD2 and R2VD3VD4 are fed to the input of the shapers DA1 and DA2 (voltage comparators) and are converted into unipolar rectangular pulses with fairly steep rises and falls. The width of the pulses corresponds to the duration of the half-cycle of the input signal, which is illustrated by the timing diagrams shown in Fig.2.

Ris.2

The dynamic D-trigger (DD1) selects the sign of the phase shift angle, i.e., at the moment of formation of the pulse front of the second measuring channel used in this circuit as a synchronizing (clocking) signal, the leading or lagging nature of the signal of the first measuring channel, the output of which is connected to the information input of the D-flip-flop. In this case, the synchronizing pulse, with its front, transfers the D-flip-flop to a state determined by the voltage level at its information input at a given time. Therefore, if the input voltage Uin1 is in phase with the voltage Uin2, then the direct output of the D-flip-flop (pin 9 DD1.1) is set to a voltage corresponding to a logical unit, and the inverse output is set to a logical zero.

The phase shift angle meter is implemented on the basis of a coincidence element (DD2.2), one of the inputs of which is connected directly to the output of the DA2 shaper, and the second is connected through the DD2.1 inverter with the measuring channel shaper DA1. The width of the generated pulse at the output of such an element is proportional to the angle of mutual overlap of the input pulses, i.e., the phase shift angle between the voltages Uin1 and Uin2, which is confirmed by the timing diagrams in Fig. 2. Combining information about the magnitude and sign of the angle in the scheme under consideration is carried out by introducing into its composition one more coincidence element (DD2.3), which performs the same functions of measuring the magnitude of the angle as described above. However, each of these 3I-NOT elements (DD2.2 and DD2.3) is connected by one of its inputs, respectively, to the direct and inverse outputs of the D-flip-flop, as a result of which the latter determines at the output of which of the coincidence elements a pulse is emitted, in width equal to the phase shift angle.

The PA1 measuring device is connected between the outputs of the coincidence elements DD2.2 and DD2.3, thus forming a differential circuit, as a result of which its arrow will deviate in the direction determined by the sign of the angle, and by an angle corresponding to the phase shift angle between the voltages Uin1 and Uin2. Capacitor C1, connected in parallel with the PA1 indicator, is designed to reduce the pulsation of the arrow when measuring at low frequencies.

The construction of the input circuits of the phase meter allows you to measure the phase angle not only between two voltages, but also between current and voltage or between two currents, for which the input dividers are equipped with appropriate leads.

The electronic phase meter is made as a separate unit. The front panel displays the input terminals of the measuring channels, a microammeter, the scale of which is calibrated in el. deg., and a power switch. The elements of the device are mounted on a printed circuit board made of one-sided foil fiberglass 1,5 mm thick and fixed directly on the measuring clamps of the microammeter. The connections of the printed circuit board with the input terminals of the device are made with a shielded wire, which is caused by ensuring its noise immunity.

The device uses resistors MLT and SP3-16 (R5), capacitor C1 - type MBM, and as an indicator PA1 - microammeter type M906 with a two-sided scale of 50-0-50 μA.

Instead of those indicated in the device, microcircuits of other series of a similar functional purpose can be used with an appropriate choice of their supply voltage. Unipolar pulse shapers DA1 and DA2 can be made not only on the basis of K554CA3 or 521CA3 functional microcircuits, but also on operational amplifiers or transistor stages operating in the key mode and providing the required steepness of the generated pulse fronts. Diodes VD1 - VD4 are selected from the conditions of the flow of a long-term measured current through them. If the phase meter is designed to measure the phase shift between two voltages only, then these diodes can be replaced by any others without presenting requirements for current and reverse voltage.

The device is powered from a single source of unipolar stabilized voltage (Fig. 3).

Ris.3

The expansion of the measurement limits for the voltage of the input signal can be carried out by proportionally changing the parameters of the resistors R1 and R2. If there is no need to measure the sign of the phase angle, then the dynamic D-trigger can be excluded from the circuit, and the phase angle difference signal extraction unit (Fig. 4) can be connected directly to the outputs of comparators DA1 and DA2. In this device, the DD1.4 element implements a differential switching circuit for the PA1 indicator and provides compensation for the logic zero voltage.

Ris.4

As an indicator of the controlled parameter PA1, an electronic oscilloscope or a digital voltmeter can be used, this will significantly improve the accuracy of reproduction of the measured value.

The electronic phase meter has a linear scale, which makes it easy to calibrate. To do this, two linear voltages of a three-phase network should be taken as calibration voltages (the phase angle of the linear voltages is 120 el. deg.). In the process of calibration, it is necessary to match the calibration voltages with the permissible level of input voltages. The value of deviations of the indicator needle and the required scale mark is carried out by resistor R5.

See other articles Section Measuring technology.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

The world's tallest astronomical observatory opened 04.05.2024

Exploring space and its mysteries is a task that attracts the attention of astronomers from all over the world. In the fresh air of the high mountains, far from city light pollution, the stars and planets reveal their secrets with greater clarity. A new page is opening in the history of astronomy with the opening of the world's highest astronomical observatory - the Atacama Observatory of the University of Tokyo. The Atacama Observatory, located at an altitude of 5640 meters above sea level, opens up new opportunities for astronomers in the study of space. This site has become the highest location for a ground-based telescope, providing researchers with a unique tool for studying infrared waves in the Universe. Although the high altitude location provides clearer skies and less interference from the atmosphere, building an observatory on a high mountain poses enormous difficulties and challenges. However, despite the difficulties, the new observatory opens up broad research prospects for astronomers. ... >>

Controlling objects using air currents 04.05.2024

The development of robotics continues to open up new prospects for us in the field of automation and control of various objects. Recently, Finnish scientists presented an innovative approach to controlling humanoid robots using air currents. This method promises to revolutionize the way objects are manipulated and open new horizons in the field of robotics. The idea of ​​controlling objects using air currents is not new, but until recently, implementing such concepts remained a challenge. Finnish researchers have developed an innovative method that allows robots to manipulate objects using special air jets as "air fingers". The air flow control algorithm, developed by a team of specialists, is based on a thorough study of the movement of objects in the air flow. The air jet control system, carried out using special motors, allows you to direct objects without resorting to physical ... >>

Purebred dogs get sick no more often than purebred dogs 03.05.2024

Caring for the health of our pets is an important aspect of the life of every dog ​​owner. However, there is a common assumption that purebred dogs are more susceptible to diseases compared to mixed dogs. New research led by researchers at the Texas School of Veterinary Medicine and Biomedical Sciences brings new perspective to this question. A study conducted by the Dog Aging Project (DAP) of more than 27 companion dogs found that purebred and mixed dogs were generally equally likely to experience various diseases. Although some breeds may be more susceptible to certain diseases, the overall diagnosis rate is virtually the same between both groups. The Dog Aging Project's chief veterinarian, Dr. Keith Creevy, notes that there are several well-known diseases that are more common in certain breeds of dogs, which supports the notion that purebred dogs are more susceptible to disease. ... >>

Random news from the Archive Artificial glacier against global warming 03.05.2017 American scientists have proposed to fight global warming by growing artificial glaciers and thus stop negative trends in the environment. During the construction of a man-made glacier, artificial snow will be used. According to scientists, to protect the artificial block from exposure to sunlight, you need a layer of several centimeters of such snow. The glacier is expected to grow within 20 years and reach a height of about 800 meters. In case of successful implementation of this project, such glaciers are planned to be grown all over the world. At the same time, the bright dreams of American scientists are not shared by some economists who believe that the project will cost a fabulous amount. But apparently such a payment will have to be made to humanity for climate change on Earth.

Other interesting news:

▪ GaN-on-silicon LEDs

▪ Data transfer speed record over LiFi

▪ Durable memory polymer

▪ Low Noise LDO LDLN030

▪ LG Signature OLED M Wireless TV

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Electric meters. Article selection

▪ article Carthage must be destroyed. Popular expression

▪ Article What determines hair color? Detailed answer

▪ article Guarantees of the worker's right to labor protection. Prohibition of forced labor

▪ article Inverter source of welding current. Encyclopedia of radio electronics and electrical engineering

▪ article Recharging the battery 7D-0,125D from the network charger. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024