The type of the detector defines how it was already specified, belonging of of alternating current to voltmeters of amplitude, mean square or srednevypryamlenny tension. According to it detectors as follows: in the Ux parameter ~ ^ to which there corresponds current or tension in an output chain of the detector: peak detector, detectors of mean square and srednevypryamlenny values of tension; according to the scheme of an entrance: detectors with the opened and closed entrance on constant tension;
Measuring potentiometers can be used and for measurement of tension. However the compensating tension needs to be regulated in this case not only on the module, but also on a phase. Therefore such have more difficult scheme, than potentiometers of a direct current, and on accuracy considerably concede to them because of absence on alternating current of a model measure similar according to the characteristics of NE. In practice of electroradio measurements they are forced completely out by electronic compensation voltmeters.
Lack of the considered scheme — need of installation by It manually. Therefore in the majority of voltmeters the scheme of SP is, providing automatic compensation of Ux and Ek. voltmeters are direct-reading devices and are more convenient in operation.
At high frequencies the entrance resistance of the voltmeter decreases, and entrance capacity and inductance of conductors form a consecutive contour which at a resonant frequency has almost zero resistance. For neutralization of these effects of PI it structurally as a portable sampler with VDN in the form of a nozzle.
Electronic analog voltmeters are the first of the electronic measuring devices considered it is aware. Among them meet both voltmeters of a direct, and comparison voltmeters. Let's consider the principle of work, block diagrams and the main functional knots of analog voltmeters of direct transformation and comparison.
At the second stage measure Ex (Ux) value. For this purpose the switch in situation 2, and by change of resistance of a potentiometer of R the zero indication again And. At Ip = const to it corresponds to Ex (Ux) = IpR, i.e. required Ex value (U^} ^.R and can be counted on R scale.
Let's consider circuit solutions of the main functional knots, metrological characteristics of analog voltmeters. The majority of these knots are applied and in other types of electronic measuring devices.
to resistance and measuring transformers of tension, still we will dress in the way of expansion of limits of measurement of voltmeters. is applied this way in electronic voltmeters and other radio measuring devices.