Peculiarity of frequency balancing of quadrature circuits
- 14 Downloads
The input impedance of an amplifier does not affect the transformation of the measured quantity to frequency or period. A change of Zin involves only a change of sensitivity of transformation.
Condition (3) can be realized not only for complete identity of the switches, if one selects small resistances in series with the switches and large resistances parallel to the switches. In this case the effect on the function of transformation of the instability of the resistances of the switches is minimized and the effect of the resistance of the wires connecting the quadrature circuit with the switches and amplifier is eliminated.
An experimental check of the effect of the resistances of the switches confirmed the conclusion obtained.
KeywordsPhysical Chemistry Analytical Chemistry Measured Quantity Input Impedance Small Resistance
- 1.V. Yu. Kneller and L. N. Sokolov, Izmeritel'. Tekh., No. 6 (1963).Google Scholar
- 2.K. B. Karandeev and G. A. Shtamberger, Generalized Theory of AC Bridge Circuits [in Russian], Izd. SO AN SSSR, Novosibirsk (1961).Google Scholar
- 3.V. O. Arutyunov, Phase-Constant Measuring Circuits and Their Use [in Russian], Standartgiz, Moscow (1963).Google Scholar
- 4.M. M. Fetisov, Izmeritel'. Tekh., No. 1 (1964).Google Scholar