Even people far from technology often have to meet with such a common electrical device as a measuring shunt. And many of them do not understand at all what this element is, used in special equipment. Therefore, most users want to know what it is, how it works and how it works in measuring circuits (photo below).
What does shunt mean in general?
First, you need to decide on this concept itself, which, according to official sources, is interpreted as a "branch" designed to start a part of the flow of something bypassing the main section. As applied to measuring circuits, a shunt is a branch of an electrical circuit that takes on a part of the total current flowing through it.
At its core, a shunt element is nothing more than a device that allows you to organize current division in circuits for measuring constant electrical quantities (photo below).
The main chain here is a measuring device with an indicator arrow calculated for a certain deflection angle. The value of the current component flowing through it usually does not exceed 50-250 microamperes. In this case, the device is calibrated in terms of current in amperes acting in the entire chain.
Where are they used and what are they made of
The main field of application of current shunts is measuring equipment used for taking readings in DC and AC circuits.
Note: In the latter case, the alternating current is rectified by diodes built into the circuit and supplied to the measuring head in the desired polarity.
According to current standards, shunts for currents up to 30 Amperes are built directly into the device case. If it is necessary to measure current values of a larger value, they are made in the form of an external assembly. Such products are already calibrated, that is, they are designed for certain currents and voltages, which allows them to be used at various measurement ranges.
The accuracy of the selection of the value of the shunting element is influenced by many factors, including the structural features of the material used for its manufacture. Therefore, one of the most important characteristics of any shunt is the accuracy class corresponding to values from the following series: 0.02; 0,05; 0,1; 0.2 and 0.5. This indicator represents the permissible deviation of the nominal resistance in percent.
In most cases, the shunting element is manufactured as:
- a simple thick plate (shunt with resistance calculated for a fraction of Ohm);
- coils of wire with a selected cross-section, also having a low resistance;
- a typical resistor designed for Ohm units.
As a rule, manganin or copper is used as a material for the manufacture of shunts (photo below).