The upper limit of the lower sub-range in which the device can measure alternating current (see "Type of current").
The operating ranges of modern multimeters and other measuring instruments are usually divided into subranges. This is done for accuracy and convenience in measurements: the lower the subrange, the smaller values it covers, the higher the measurement accuracy at low current values. The minimum alternating current describes exactly the lower range, designed for the weakest current values: for example, if the characteristics in this paragraph indicate 500 μA, this means that the lower subrange allows you to measure currents from 0 to 500 μA.
It is worth choosing according to this indicator taking into account the specifics of the planned application: for example, a device with low rates can be useful for delicate work, such as repairing computers or mobile phones, but especially high current sensitivity is not required for servicing household electrical networks.
The type of battery used in the device. Note that the term “battery” in this case refers to all types of autonomous power sources - both rechargeable and disposable. These include:
AAA,
AA,
C,
“Krona”,
A23,
CR2032, etc.
- AA. Classic AA batteries, one of the most popular sizes these days. Available both in the form of disposable cells and in the form of rechargeable batteries; sold almost everywhere. The number of such batteries required to power a multimeter can be from 1 to 8, depending on the features of the device.
- AAA. “Mini-finger” or “little finger” batteries, similar to the AA batteries described above, but having reduced dimensions (and, accordingly, less power and capacity). However, given that many multimeters are also quite compact and their power consumption is low, this option is found in measuring instruments even more often than AA. The number of such elements in this case is usually from 1 to 4.
- “6LR61”. The batteries have a characteristic rectangular shape with a voltage of 9 V and a pair of contacts on one of the ends. High voltage contributes to the accuracy of measurements and allows even quite “gluttonous” models to use only one battery; so this option is quite popular in multimeters. Note that most often “Kronas”
...are produced in the form of disposable cells, but if desired, you can also find batteries of this size.
- 6LR61 and AAA. Powered simultaneously from the two types of batteries described above. As a rule, each of these power sources is responsible for its own part of the functionality (for example, AAA for resistance measurements, Krona for testing transistors), and in the absence of one of the sources, only the capabilities directly related to it are unavailable. However, in general, such a combination is not particularly convenient and practical, which is why it is rare.
— Krona and AA. An option completely similar to the “6LR61 + AAA” described above - except that in this case, instead of “pinky” batteries, AA batteries are used. Also not popular.
— C. Cylindrical 1.5-volt elements. Available in two types - accumulators and batteries; similar in length to AA (50 mm), but almost twice as thick - 26 mm instead of 14 mm. As a result, they provide higher capacity and power supply, but due to their large size they are used mainly in advanced desktop devices. Moreover, many of these devices have an insulation test function, and the number of C batteries in them can be from 8 to 12 - this is necessary to create the high voltages used for such testing.
- A23. Cylindrical cells characterized by high voltage - 12 V, despite the fact that the size of such batteries is only 29 mm in length and 10 mm in size. Most often they are disposable batteries. In general, they are poorly distributed, which is why they are used relatively rarely in measuring instruments.
— LR44 / SR44. Miniature 1.5-volt batteries in the form of “tablets” with a size of 11.6 mm and a thickness of 5.4 mm. They are made only for disposable use; At the same time, simple and inexpensive alkaline batteries are marked with the “LR44” index, and more expensive and advanced silver-oxide batteries with the “SR44” index. In multimeters, as a rule, you can use both one and the other. In any case, due to their small size, the power and capacity of all such batteries is small, so they are used mainly in miniature devices - not designed for serious tasks and not having enough space in the case for more solid batteries.
- CR2032. Miniature button batteries with a voltage of 3 V, having a size of 20 mm and a thickness of 3.2 mm. Like LR44 / SR44, they are found mainly in small devices - incl. very miniature, made in the form factor of a pen or even a key fob; however, due to their larger sizes, they provide more advanced power characteristics, which is why they are noticeably more common. CR2032 elements are made only disposable.
— 18650. Removable lithium-ion batteries are cylindrical, 65 mm long and 18 mm in size. With an operating voltage of 3.7 V, they can also have a fairly high capacity. However, for a number of reasons, this option is not popular - it can be found in some advanced devices.
— Branded battery. Batteries created specifically for specific devices (or series of devices) and not related to standard sizes; often made non-removable. Such batteries can have more advanced characteristics than replaceable batteries, and they eliminate additional expenses - you do not need to regularly buy batteries (or a separate battery with a charger), it is enough to charge the existing power source from time to time. On the other hand, when the charge is depleted, such a battery cannot be quickly replaced with a fresh one - the only option is charging, and this requires an outlet and takes time, sometimes quite considerable. As a result, this method of nutrition has not become particularly widespread.
