AC ammeter: types of devices and wiring diagram

Various measuring devices are used to control the parameters of the electrical network. An AC ammeter is a special device that allows you to find out the amperage.

For correct measurements and accurate readings, it must have a very low resistance and be connected in series.

Features of various designs

There are various ammeter circuits, depending on the conditions of use and the measured values. The types of such devices are as follows:

1. Direct current dial ammeter. It is used to measure low values ​​of the chain. The principle of this electrical device is based on the interaction of a magnet with a coil. It has excellent sensitivity and a convenient scale, but unfortunately is not suitable for AC circuits. The disadvantages of this device are also its complexity and high cost.
2. An alternating current ammeter is an electromagnetic system that allows operation in networks with a frequency of about 50 hertz. The arrows of the device are connected to one or more cores. Due to the versatility of the device, it is also possible to work with direct current. The disadvantage is the large resistance index, which affects the accuracy. In addition, the non-linear measuring scale makes it difficult to read the readings.
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3. The ferrodynamic device is highly accurate. Due to the fact that the operation of the device is based on a closed ferromagnetic wire, it is practically unaffected by external magnetic fields. The scale is non-linear.
4. Thermoelectric ammeter is used to measure high frequency alternating current. It consists of a conductor and a thermocouple. It is based on the principle of metal expansion when heated.
5. The electrodynamic pointer meter is not widespread. It is overly sensitive to external magnetic fields. If you do not provide reliable shielding, the results are very distorted. The advantage of this device is its very high accuracy, which allows it to be used as a controller for other ammeters. Also, the advantages of the device include its versatility.
6. The digital model is popular for its versatility and convenience. It does not have a scale, and the measurement results can be seen digitally on the scoreboard. It is often used in a domestic environment and is part of a multimeter. Recently, the digital device has noticeably supplanted instruments with an arrow head.

Connecting the ammeter to the network

All current measuring devices are connected to the network only in series.

Due to the very low resistance of the ammeter, connecting it in parallel will lead to an imminent short circuit and damage to the device.

For correct measurement and to avoid breakage you must adhere to several rules:

• find out what is the current in the network (alternating or direct);
• the arrow of the device should be located on the scale beyond its middle;
• polarity must be observed;
• the measured current should not be more than the maximum possible;
• compliance of the environment with certain requirements;
• lack of vibration.

Digital ammeters are immune to vibration and external magnetic fields. Polarity is optional.

When it is necessary to measure a large current strength, it is necessary to resort to shunts. For this, a small section of the circuit is taken, from which resistors are connected in parallel. An ammeter is connected to them. From the results obtained using calculations, the correct indicator is found.

Often, to connect the device to the network, they use transformer. This is done in cases where the current is greater than the measuring capability of the ammeter.

The clamp meter measures amperage without being plugged into an electrical circuit. Alternating current, flowing through the wires, forms a magnetic field around them. A non-contact ammeter is brought to the conductor, measures the field strength and gives the result in amperes. Although this device is not very accurate, it is quite suitable for everyday life. Its main advantages are convenience and safety.

Scope of application and advice on selection

Various types of ammeters are widely used in many areas of human activity. The industries in which this device is used are:

• energy;
• electrical engineering;
• radio electronics;
• construction;
• transport;
• Scientific research.

In everyday life and everyday life, an ammeter is needed for independent minor repairs of electrical appliances. Car enthusiasts use it in the process of monitoring the battery charge.

Along with digital instruments, dial gauges are used. Their main advantage is the absence of batteries.

If there is a need to urgently measure an alternating current, and only a direct current ammeter is at hand, then you can rectify the current using a diode bridge and connect the device to it. A few tips before buying a device:

• if increased accuracy is required, a device with a resistance of less than 0.5 Ohm is better;
• anti-corrosion coating of contacts will extend their service life;
• the sealed body prevents moisture from entering the working mechanism and increases wear resistance and accuracy;
• for convenience, a digital meter is most suitable.

Observing these simple rules, you can avoid buying a low-quality device and buy exactly what you need. A correctly chosen device will become an irreplaceable assistant in your work and will serve for many years.