A non-contact capacitance type liquid level transducer for a conducting liquid consists of a short circuited non-inductive coil wound on a uniform cylinder made of insulating material like glass, PVC, nylon, teflon etc. The cylinder is connected with a storage tank through a metallic connector and the capacitance between upper short circuited end of the coil and metallic connector varies linearly with liquid level measured from datum level. The capacitance at datum level depends on atmospheric condition and the fringe effect of other conductors. So the transducers require frequent recalibration depending on atmospheric and environmental conditions. In the present paper, this non-contact capacitive sensor has been further modified in order to minimize this defect of non-contact capacitive sensor. Moreover, all the conventional capacitance type level sensors are associated with a perpendicular plate capacitance between liquid and electrode which varies with the length of the electrode. In the present paper, the effect of this perpendicular capacitor on liquid level measured has been studied and its effect is minimized. The proposed modified transducer has been designed and developed and its theory of operation has been derived. The performance of the developed transducer has been experimentally studied and the experimental results are reported in the paper. A good linear performance characteristic of the transducer with very minimum parasitic capacitance effect has been observed.
In high tension power measurement, potential transformer (PT) and current transformer (CT) are used in order to reduce high tension voltage and current, respectively. But both PT and CT suffer from ratio error and phase angle error, which may produce severe error in power measurement. In the present paper, modified designs of PT and CT are combined to develop an electronic power measurement circuit in order to reduce the measurement errors. The modified PT and CT have reduced phase angle error and ratio error. In the power measurement circuit, the instantaneous product of the outputs of these PT and CT is determined by using a simple light emitting diode (LED)-light dependent register (LDR) or LED-LDR-based product circuit. The operation of the proto type power measurement unit designed in the present work has been experimentally tested and the measured outputs are compared with the readings of laboratory standard wattmeter. The experimental results are reported in the paper. Very good linear characteristics are observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.