It is also known from the general school physics course that an electric circuit is characterized by a number of parameters. Among them, the voltage value, also known as potential, the value and type of current flowing through the conductor, the power consumed by the load from the network, the resistance value (in Ohms) and some others.
Specialized devices were created to measure each of them. For current, these are ammeters, for voltage - voltmeters, ohmmeters for resistance, etc. However, what to do if it becomes necessary to measure not one parameter, but several at once? Carry all existing devices with you? In this case, there is no need to talk about mobility and convenience. To solve this problem, universal solutions were created: devices that functionally combine several others at once. For example, by switching a special toggle switch to the first position, you can measure the voltage, while in the second position, the internal logic is activated, which allows you to determine the resistance. Comfortable! Such instruments are known as multimeters. That is, "multi" - a lot, but "meters" - to measure. The second name, which is not entirely correct, is testers. Modern digital multimeters allow you to measure many parameters: fromsimple resistance of a circuit section to ambient temperature.
Modifications
Despite the wide variety of these devices, they are all divided into two main classes: analog and digital multimeters. For most users, the latter are more convenient, although the former have a number of advantages, however, specific ones.
Graduated scale and arrow
Analogue models are almost out of production, as demand for them turned out to be negligible compared to the alternative (digital DT multimeter is now incredibly popular). However, new similar solutions can still be found on the markets, so we will briefly consider them. Analog devices are very easy to distinguish from others: on the case there is a ratchet switch designed to select the measurement mode, as well as a rather large panel with a scale on which division marks are applied (similar to a ruler). When the probes are connected to the circuit, a current arises in the internal coils, magnetic fields are created and their interaction causes the pointing arrow to deviate by a certain angle. It remains only to calculate the division price and find out the value of the measured parameter. In this regard, digital multimeters are more preferable, since an error is excluded when recalculating the scale graduation under the limit set by the ratchet.
Number display
Digital multimeters look almost the same as analog multimeters, except thatthe switch block has been replaced by a compact screen that displays the measurement results. Internal changes, of course, are much more significant. The printed circuit board contains a microcircuit that performs complete processing of the signal coming from the probes. Often, several additional elements are used - resistors, capacitors and coils. Among the distinguishing features of these solutions, it is worth noting a slight measurement error - a high accuracy class inherent even in budget models, for example, such as a digital multimeter 838.
Summing up
For a person who occasionally needs to measure some parameters of the electrical circuit at home or, for example, in the on-board system of a car, an inexpensive digital tester is the best choice. It is enough to understand the rules for using a ratchet and understand the principle of choosing the measurement limits.
