Voltage - With this term, we are quite often faced in everyday life. Sometimes we need to measure the voltage in the network to understand why any device works unsatisfactory or incandescent lamp burns quite dimly. For this kind of measurements, voltmeters are used. The voltmeter connects to the measured device only in parallel, why is it so?
As known electrical voltage - This is the ratio of work perfect electric field By moving the charge A, to the value of the charge Q, U \u003d A / Q. It also characterizes the electrical field that occurs when the electric current is passed.
In the system of international designations, C is denoted as u and measured in volts (1 V \u003d 1 J / CL). In order to measure the voltage on the device, you must connect a voltmeter to it in parallel.
In order to reduce the current consumed by a voltmeter and a loss with a parallel inclusion electrical Energy Inside the device, the inner measuring resistance is selected as much as possible. If you turn on the voltmeter in the chain sequentially, then in connection with the large internal resistance, we actually obtain the chain break. That is, losses when measuring the voltage will be too large, which is unacceptable, as well as measurements will be incorrect. Therefore, the voltmeter is connected only in parallel:
If a constant voltage is measured from 1 to 1000 μV can use , But the cup uses digital voltmeters. Values \u200b\u200bfrom dozens Milvololt to hundreds of volts are measured by the instruments of such systems as: electromagnetic, electrodynamic, magnetoelectric. Also, they do not bomb and electronic analog and digital voltmeters. Also, when measuring, additional resistance can use:
Where RV is an internal voltmeter resistance, RDOB1 ... 3 - additional resistance, UMV - the maximum that can measure the voltmeter itself, and U1 ... 3 - which it can measure with additional resistances.
The resistance of the addition resistors is determined by the formula:
Where M is a large-scale coefficient.
If the constant voltages are measured in a few kilovolt, then in most cases electrostatic voltmeters use, less often use measuring devices of other systems connected via divisor:
Where resistors R 1, R 2 are resistors that perform the role of the divider, R ism. - The measuring resistance from which the voltage is removed.
If voltage variables are measured to units of volts, then use analog, rectifier and digital devices. From units to hundreds of volts and frequency range Up to several tens of kilohertz use rectifying systems, electromagnetic, electrodynamic instruments. If the frequency reaches several tens of megahertz, then, in this case, the voltage is measured by thermoelectric and electrostatic devices.
In the acting values, usually grads the scale of devices for measuring values alternating current. Therefore, when measuring, it is necessary to take into account this (if it is necessary to measure amplitude and mean values, they are usually recalculated according to the corresponding formulas).
When measuring in AC networks, voltage above 1000 V can be used both dividers and voltage transformers or measuring transformers. More often use transformers, since the transformer not only lowers the voltage value, but potentially separates the measuring chain from the power. Measurements can be carried out with the same instruments as in the above cases. The inclusion scheme is shown below:
Where FU1, FU2 is fuses protecting the measuring chain from a short circuit.
Appearance of single-phase transformer:
As we can see, when measuring various types of voltages can be used as a different kind of devices (digital, analog, etc.) and devices (dividers, transformers). When measuring, it is important to take into account each method of measurement, to obtain as an exact result as possible, as well as the correct measurement work.
Like any physical value, the voltage can be measured, a voltmeter is used for this. But to get reliable data, it must be connected correctly.
Operating principle
All devices that are measured in electrical networks are divided into two groups: electromechanical and electronic.
Electromechanical devices
These are the arrow devices. The arrow in them is fixed on the frame to which the wire is wound. This coil is on the same axis with a permanent magnet in the instruments used in the network. direct current, or with another coil - in alternating voltage devices.
Reference. AC device in a constant network will not work, but a device for measuring constant voltageIf you enable it through the diode bridge, you can connect to the AC network with the accuracy loss.
When current over the winding current, an electromagnetic field interacts with a magnet or other winding is indispensable, and the frame turns. The rotation of the coil with the arrow prevents the spring, so the angle of rotation of the frame corresponds to the current through it and the potential on the terminals.
To reduce the oscillations of the arrow, the damper is installed electromagnetic plate from an aluminum plate or pneumatic, from piston and cylinder.
To increase the accuracy, the arrow is equipped with respects, eliminating the effect of gravity, and the mechanism itself is performed from alloy steel to reduce wear.
Electronic devices
In electronic devices, a sensitive element is an electronic board that converts the input signal in the instrument reading. Power Such a device can receive from a measured voltage or other source - internal batteries or external power supply.
Electronic voltmeters have two types:
- Analog. They contain the input signal converter to an angle of rotation of the arrow, indicating the scale of the measured voltage on the scale. Lack of analog schemes - in the need to recalculate the testimony of the scale when changing the measurement limit;
- Digital. In such devices, there is a digital display and a converter that displays the input signal in digital form. When the device is connected to a DC network, the polarity of the connection is shown on the scoreboard. These designs differ compactness, and the accuracy of such a device depends on the quality of the built-in controller.
Voltmeter connection
The voltage on the power supply or the chain element is measured by the machine that is connected parallel to the device.
The coil of the device has low resistance, and with direct inclusion in the network current will be large. To reduce current consumption and influence on electric network The chain consistently with the device includes additional resistance.
Important! When you turn on the voltmeter sequentially with the load, it will show the power supply voltage with the error due to the load resistance. The ammeter is consistently connected.
Poutline voltage
Methods for measuring constant voltage depend on its value:
- up to 1 millivolt - digital and analog apparatus with a built-in amplifier;
- up to 1000 volts use conventional devices of various systems;
- over 1 kV measurement is made by electrostatic devices designed to work in high-voltage networks or conventional included in the divider.
Increasing the measurement limit is made on the inclusion sequentially with the device of the addition resistance of the RDB. To increase the limit in n.once general resistance should also be increased in n. Once and, given the resistance of the RPR device, RDB \u003d RPR * ( n.-one). Scale readings are also multiplied by n..
AC voltage
Methods and types of devices for measuring in AC networks depend on the voltage and network frequency:
- up to 1 volt - digital and analog devices with amplifiers;
- up to 1kv and frequency up to tens kHz - rectifier systems, electromagnetic, electrodynamic devices;
- at frequency up to tens of megahertz - thermoelectric and electrostatic devices.
Important! AC voltmeter shows the active voltage value. With a sinusoidal form, its value in √3 (1.7) is less than amplitude.
Expansion of measurement limits are made on the separation or autotransformer, as well as the use of additional resistance. Its value is calculated similarly to measurements in the DC network.
When using a separation transformer, the instrument readings are multiplied by the transformation coefficient n.\u003d U1 / U2.
The voltmeter connection must be made according to specific schemes. This is done so that the instrument readings correspond to network parameters.
Video
For successful control over the battery status, it is important to know how to connect a voltmeter in the machine and how to decrypt its readings. Since the appearance of cars equipped with an on-board computer, the need for a separate voltmeter is moving to the background, because it does not provide full monitoring of all electrical nodes of the machine. The relevance of the device is also determined by the need for constant monitoring of the battery charge, which is especially important in winter. In case of a sharp drop in the voltmeter readings, it is possible to take appropriate countermeasures and avoid an unexpected engine stop.
Voltmeter -, useful device for cars that do not have an on-board computer. Using it, you can monitor the battery charge status.
Principle of operation of the voltmeter in the car
The voltmeter is a fairly simple device for the inner structure, the main purpose of which is, measuring the voltage in the network. The principle of the voltmeter is to interact with each other electromagnetic coil and a permanent magnet or two electromagnets. The current passing through the coil, rejects the voltmeter arrow is the stronger than the voltage value.
In modern devices, the readings are transformed into a digital display, which is well noticeable even at night in an unlit vehicle cabin. The accuracy of such sensors is much higher than the analog "arrogant" models, and depends on the discreteness of the main component, analog-to-digital converter. Input voltage, entering wires, is converted to digital signalwhich then turns from binary code In numeric value and displayed on the backlit scoreboard.
Selection of Voltmeter model
Digital voltmeter scheme.
The modern market of devices for cars offers a wide selection of voltmeter models. Such types of devices are most popular:
- analog "arrogant" voltmeters - installed mainly on domestic cars, connecting to the dashboard instead of hours,
- digital sensors connected to the cigarette lighter socket
- digital voltmeters mounted in the dashboard.
Most often used the last two types of devices, as they combine modern appearance, accuracy of readings and ease of installation.
Maximum relevant reality Measurement results provide voltmeters connected directly to the dashboard. Although their installation is sometimes associated with some difficulties, but by setting them, you can get constant monitoring of the state of the battery, which is especially important with a large number of connected nodes. Voltmeter car
The cost of the digital voltmeter is quite low and ranges in the range of 120-150 rubles in the event of an order through online stores. It has a standard rectangular shape, thanks to which it will harmoniously fit into the interior of any car. Illuminated color -, white, yellow, blue, green, red. Sometimes there is a problem with the high brightness of the screen, which acts as a distracting factor and interferes with focus on the road, but such a deficiency is rapidly solved using a tinting film.
Settings Installation
Digital voltmeter characteristics table.
If with digital voltmeters that feed from the cigarette lighter, there are no problems during installation, the models installed directly into the dashboard often force drivers to think over the order of their connection.
Most voltmeters presented in the market have two or three wires for connecting to the network, although there are models and with four contacts. Wires have standard color labeling:
- the red wire corresponds to the "plus",
- black wire is connected to "minus",
- the white wire is responsible for managing the backlight intensity, turn on and off the device.
In some cases, an unforeseen problem occurs with such a voltmeter connection: it shines dull either in general refuses to work. The reason can be an alternative marking of wires, in which the white wire is responsible for "minus", and black -, for controlling the device.
The voltage sensor is set to a regular place of hours, but in some cases it is impossible to find a free space for the voltmeter, you have to do a hole for it directly in the dashboard.
A great place to connect the device -, the dashboard plug on the left side of the steering wheel. It has a small size, it is easy to remove and secure for processing.
Figure 1. Voltmeter connection circuit with a pulsed stabilizer.
The voltmeter case has a relief surface: the frame around the display will perform above the surface of the car panel. Thanks to this, the device will not fall inside the planting socket, and will also hide the irregularities of the edges of the hole.
Inexpensive voltmeter models may not have a separate wire for power, the connection of such a device is carried out by three contacts on the sensor housing (Fig. 1). In this case, the voltmeter connection is made using a 4-core wire from a computer drive (Fig. 2). The wide IDE format connector is cut off, and the remaining wiring is fixed using soldering to car wiring contacts. 4-pin contact provides a good connection and makes it possible, if necessary, promptly and without much effort to replace the voltmeter when breakdown.
Regardless of the characteristics of the voltmeter structure, the car's wiring diagram is studied in detail, according to which the device is determined. It will not be superfluous to be attentive to read the instructions for the device, since methods for its connection may differ.
Interpretation of the instrument readings
Installation of a voltmeter -, it is only the first step to obtain control over the battery state and the electrical system of the car. Full information can be obtained only by defining the main values \u200b\u200bof the instrument indicators.
The standard value of the battery voltage on passenger cars is 12 V. The voltage indicators of the on-board network will be slightly different, making up 13.7-14 V. If the values \u200b\u200bon the voltmeter are reduced relative to the specified parameters, this may mean a breakdown of the voltage controller or malfunction in the generator.
The decline in the voltage can also be associated with the discharge rechargeable battery. Especially often it happens in winter: in the cold, discharge occurs faster, and the presence of a heater adds a load on the network.
Figure 2. Voltmeter connection diagram to chain.
If the voltmeter is connected directly to the battery terminals, then on its numeric values, you can easily find out the battery charge level. Indicators in the range of 12.6-12.9 V indicate that your battery is fully charged. As they discharge, the voltage gradually falls. At a value of 12.3-12.6 in charge, it drops to 75%, at 12.1-12.3, the battery is defused approximately half. With a gradual decrease in the voltage to 11.8-12.1 in the battery, it is considered empty on 3/4, and at 11.5-11.8 in the brought the car you will not succeed.
For getting full information There will be no superfluous on the network of the network directly on the battery terminals, after which it is compared to the onboard voltmeter. If, when you turn on heating, left-beam or other loads, the voltage will differ more than 0.4 V, then this may indicate an unstabilized on-board network. In this case, it is necessary to check the mode of the generator and the voltage relay in the right time.
Conclusion on the topic
To the question of how to connect the voltmeter in the car, should be approached with full responsibility.
This simple device will allow you to keep the rechargeable battery under close attention, thereby ensuring additional tool control over electrical system Your car.
A variety of modern voltmeter models, their availability for any driver and simplicity of installation make it possible to equip the machine of any model to equip this device.
voltmeter automotive
We collect a loud audio system in the car. Part 1. Power.
Description:
I tell in detail how loud music in the car will be collected. In this part I will talk about the preparation of the car immediately before installing the music. In this part we are engaged in voltmeters, wiring in a car, and all that is associated with a reliable electrician.
Tracks:
Ceanty-Easy.
ERIO-Monolith.
Foreword & Matters - Journey
MDC-HOME.
Vassh-Wet Walls
How to install a voltmeter in the car
Description:
I will tell you how to install a portable voltmeter in a car
Self-dealers, designing, developing and implementing the most different schemes charger or power supplies, constantly faced with an important factor - visual control over the output voltage and current consumed. It is very often stretched by an aliexpress help hand, promptly delivering Chinese digital measuring instruments. In particular: a digital ampervoltmeter - the device is very simple, affordable and displays quite accurate information data.
But newcomers commissioning (connection to the ampervoltmeter scheme) may turn out to be a problematic task, since the measuring instructor comes without documentation and connect the wire quickly marked with each shoulder.
The image of one of the most popular voltammeter homemade groups is lined below.
this is an ampervoltmeter per 100 volts / 10 amp, it comes with an integrated shunt. Many radio amateurs such measuring instruments are often acquired for their homemade. Digital device can be powered by both separate sources,
so from one operated and measured voltage source. But here is hidden a small nuance, it is necessary to observe the condition - the voltage of the power supply used was within 4.5-30 V.
Homemade workers who are not entirely clear: thick black wiring plug into a minus power supply, thick red wiring - on the plus power supply (the testimony of the voltmeter scale will appear),
thick blue postings connect to the load, the second end of the load comes to the plus of the power supply (the readings of the ammeter scale will appear).
For successful control over the battery status, it is important to know how to connect a voltmeter in the machine and how to decrypt its readings. Since the appearance of cars equipped with an on-board computer, the need for a separate voltmeter is moving to the background, because it does not provide full monitoring of all electrical nodes of the machine. The relevance of the device is also determined by the need for constant monitoring of the battery charge, which is especially important in winter. In case of a sharp drop in the voltmeter readings, it is possible to take appropriate countermeasures and avoid an unexpected engine stop.
Voltmeter is a useful device for cars that do not have on-board computer. Using it, you can monitor the battery charge status.
Principle of operation of the voltmeter in the car
The voltmeter is quite simple to the inner structure, the main purpose of which is the voltage measurement on the network. The principle of the voltmeter is to interact with each other electromagnetic coil and a permanent magnet or two electromagnets. The current passing through the coil, rejects the voltmeter arrow is the stronger than the voltage value.
In modern devices, the readings are transformed into a digital display, which is well noticeable even at night in an unlit vehicle cabin. The accuracy of such sensors is much higher than the analog "arrogant" models, and depends on the discreteness of the main component of the part - analog-to-digital converter. The input voltage, entering the wires, is converted into a digital signal, which is then converted from a binary code into a numeric value and is displayed on the backlit scoreboard.
Selection of Voltmeter model
The modern market of devices for cars offers a wide selection of voltmeter models. Such types of devices are most popular:
- analog "arrogant" voltmeters - installed mainly on domestic cars, connecting to the dashboard instead of hours;
- digital sensors connected to the cigarette lighter socket;
- digital voltmeters mounted in the dashboard.
Most often used the last two types of instruments, as they combine modern appearance, accuracy of readings and ease of installation.
Maximum relevant reality Measurement results provide voltmeters connected directly to the dashboard. Although their installation is sometimes associated with some difficulties, but by installing them, you can get constant control of the battery status, which is especially important with a large number of connected nodes.
The cost of the digital voltmeter is quite low and ranges in the range of 120-150 rubles in the event of an order through online stores. It has a standard rectangular shape, thanks to which it will harmoniously fit into the interior of any car. Illuminated color - white, yellow, blue, green, red. Sometimes there is a problem with the high brightness of the screen, which acts as a distracting factor and interferes with focus on the road, but such a deficiency is rapidly solved using a tinting film.
Settings Installation
If with digital voltmeters that feed from the cigarette lighter, there are no problems during installation, the models installed directly into the dashboard often force drivers to think over the order of their connection.
Most voltmeters presented in the market have two or three wires for connecting to the network, although there are models and with four contacts. Wires have standard color labeling:
- the red wire corresponds to the "plus";
- the black wire is connected to "minus";
- the white wire is responsible for managing the backlight intensity, turn on and off the device.
In some cases, an unforeseen problem occurs with such a voltmeter connection: it shines dull either in general refuses to work. The reason can be an alternative marking of wires in which the white wire is responsible for "minus", and black - for controlling the device.
The voltage sensor is set to a regular place of hours, but in some cases it is impossible to find a free space for the voltmeter, you have to do a hole for it directly in the dashboard.
A great place to connect the device - the dashboard plug on the left side of the steering wheel. It has a small size, it is easy to remove and secure for processing.
Figure 1. Voltmeter connection circuit with a pulsed stabilizer.
The voltmeter case has a relief surface: the frame around the display will perform above the surface of the car panel. Thanks to this, the device will not fall inside the planting socket, and will also hide the irregularities of the edges of the hole.
Inexpensive voltmeter models may not have a separate wire for power, the connection of such a device is carried out by three contacts on the sensor housing (Fig. 1). In this case, the voltmeter connection is made using a 4-core wire from a computer drive (Fig. 2). The wide IDE format connector is cut off, and the remaining wiring is fixed using soldering to car wiring contacts. 4-pin contact provides a good connection and makes it possible, if necessary, promptly and without much effort to replace the voltmeter when breakdown.
Regardless of the characteristics of the voltmeter structure, the car's wiring diagram is studied in detail, according to which the device is determined. It will not be superfluous to be attentive to read the instructions for the device, since methods for its connection may differ.
Interpretation of the instrument readings
Installation of a voltmeter is only the first step to obtain control over the state of the battery and the electrical system of the car. Full information can be obtained only by defining the main values \u200b\u200bof the instrument indicators.
The standard value of the battery voltage on passenger cars is 12 V. The voltage indicators of the on-board network will be slightly different, making up 13.7-14 V. If the values \u200b\u200bon the voltmeter are reduced relative to the specified parameters, this may mean a breakdown of the voltage controller or malfunction in the generator.
The decline in the voltage can also be associated with the discharge of the battery. Especially often it happens in winter: in the cold, discharge occurs faster, and the presence of a heater adds a load on the network.
Figure 2. Voltmeter connection diagram to chain.
If the voltmeter is connected directly to the battery terminals, then on its numeric values, you can easily find out the battery charge level. Indicators in the range of 12.6-12.9 V indicate that your battery is fully charged. As they discharge, the voltage gradually falls. At a value of 12.3-12.6 in charge, it drops to 75%, at 12.1-12.3, the battery is defused approximately half. With a gradual decrease in the voltage to 11.8-12.1 in the battery, it is considered empty on 3/4, and at 11.5-11.8 in the brought the car you will not succeed.
To obtain full information about the status of the network, it will not be superfluous to measure the voltage directly on the terminals of the battery, then compare it with the indicators of the onboard voltmeter. If, when you turn on heating, left-beam or other loads, the voltage will differ more than 0.4 V, then this may indicate an unstabilized on-board network. In this case, it is necessary to check the mode of the generator and the voltage relay in the right time.
Conclusion on the topic
To the question of how to connect the voltmeter in the car, should be approached with full responsibility.
This simple device will allow you to keep the rechargeable battery under close attention, thereby ensuring an additional control tool for the electrical system of your car.