To measure the physical value directly, enter the meter in the interaction with the object, which is represented by this value.A method for providing such interaction is dependent on what is being measured.For example, an ammeter is included in the open circuit, the voltmeter - parallel to the load, and to measure the length of the object is clamped between the jaws calipers.
Select measuring device in such a way that it has minimal impact on the measured value.In particular, the internal resistance of the voltmeter must be much greater load resistance - and at the ammeter - on the contrary, it is much less.The thermometer should have a considerably lower mass than the object whose temperature is being measured.When measuring the length of the caliper can not exert exces
sive pressure on the object, or the size of the measured change significantly.Subject to this requirement, the change in the value under the influence of the measuring device can be neglected.
When measuring very high values, use tools that allow file for the device is not full-size, but only parts of it.These are, in particular, the shunt ammeters, voltmeters dividers.If the value is, on the contrary, it is too small, use amplifiers with known gain.When changing the mechanical values ​​of divisors such analogs and amplifiers are, in particular, crosslinks.
to use indirect measurement devices to convert non-electrical quantities in power.The latter include voltage, resistance, current, frequency.To the transmitter for indirect force measurement gages are, mechatronic, mechanical resonant frequency of the resonance system, depending on the effort.Indirect temperature measurement is made using probes, thermistors, and even conventional diodes.Illumination is measured using solar cells with external and internal photoelectric effect.
Measure the quantity of electricity produced by means of the inverter.Multiplying it by the calibration factor, calculate the measured non-electrical quantities.If the transmitter has a non-linear characteristic, instead, use the calibration factor table or nomogram.