Hiranmoy Mandal

Bio: Hiranmoy Mandal is an academic researcher from Academy of Technology. The author has contributed to research in topics: Transducer & Capacitance. The author has an hindex of 3, co-authored 7 publications receiving 60 citations.

Study of a Modified Capacitance-Type Level Transducer for Any Type of Liquid

Abstract: The conventional capacitance-type liquid level sensor consists of an insulated solid metallic rod electrode immersed in the liquid contained in a metallic storage tank, or two such identical electrodes in a nonmetallic storage tank. Such metallic rods may suffer from the self-inductance effect which varies nonlinearly with the level. In this paper, we present a modified capacitance-type level sensor in which effect of self-inductance of the metallic rod has been eliminated. The theoretical equations describing the operation of the sensor are derived. The sensor is designed and tested experimentally and is found to follow the theoretical equations. The experimental results are also presented. A very good linearity of the sensor is observed.

Study of a Modified LVDT Type Displacement Transducer With Unlimited Range

Abstract: The conventional LVDT is generally used as displacement transducer but has some limitations such as small linear range, measurement errors due to stray capacitance effect, electromagnetic interference effect, and core loss effect. In this paper, a modified LVDT type displacement transducer has been proposed in order to overcome these limitations of conventional LVDT. The proposed LVDT will consist of only two identical coils instead of three coils of conventional LVDT. This design does not require any excitation coil. In this design, two identical coils wound on a former made of ferromagnetic material act as displacement sensing inductive coils with specially designed movable core. The design has been analyzed under three cases. It has been shown that the range of the displacement transducer is about 50% of the overall length of the sensor under two cases like conventional LVDT and is about 100% of the overall length of the sensor under the third case. So in this paper, a displacement transducer has been designed and tested experimentally considering only the third case with unlimited range equal to the entire length of the sensor. The transducer consists of an op-amp-based differential inductance measuring circuit and an output instrumentation amplifier. The performance equations of this sensor under three cases and of the transducer under third case are derived in the paper. The experimental results reported in the paper are found to follow the derived equations with very good linearity and repeatability.

A Temperature Compensated Non-Contact Pressure Transducer Using Hall Sensor and Bourdon Tube

Abstract: This paper describes the design of a simple non-contact-type pressure transducer using a Bourdon tube and a Hall sensor where the effect of atmospheric temperature is compensated. In this design, a pressure sensing Hall IC is fixed with the nonmagnetic aluminum casing of a Bourdon gauge in front of a tiny disc-type permanent magnet rigidly attached with the free tip of the Bourdon tube. With the increase of pressure of the fluid inside the Bourdon tube, the free end along with the magnet moves toward the Hall sensor, and the magnetic field intensity due to the magnet on the Hall sensor increases with an increase of pressure. Due to this magnetic field, the outputs of the Hall sensor and the transducer circuit consisting of a differential amplifier and an instrumentation amplifier increase with the increase of pressure of the fluid inside the Bourdon tube. The transducer circuit consists of a unity gain differential amplifier circuit where the output of a second identical temperature sensing Hall IC is subtracted from the pressure sensing Hall IC output in order to compensate the effect of ambient temperature in the proposed transducer. The theoretical equations describing the operation of the transducer are derived in this paper. The static characteristic curves of a prototype design of the transducer are determined experimentally. The experimental results are reported in this paper. The characteristics curves are found to follow the theoretical equations with good repeatability and are free from ambient temperature effect.

An improved technique of capacitance measurement of solar cells

Abstract: It is very much important to design an efficient and reliable power conditioner with detailed study on measurement of AC parameter of solar cell (especially the cell capacitance). In this paper, we measured the capacitance of GaAs/Ge and Silicon (BSFR) solar cells under dark condition over a wide range of bias voltages using low level sine wave signal of desired amplitude. The approach of sinusoidal wave method offers the accurate and most economic way of studying the capacitance of semiconductor devices. Here frequency domain techniques have been used. It is shown that for GaAs/Ge solar cell, it exhibits only transition capacitance while Silicon (BSFR) solar cell exhibited both transition and diffusion capacitances.

Study of a Noncontact Flow Transducer Using Semicylindrical Capacitive Sensor

Abstract: The fluid flow rate through a pipeline is a very important process variable in any process plant that is required to be measured accurately. In this article, a new noncontact semicylindrical capacitive flow sensing technique has been developed and studied. The proposed capacitive sensor consists of two semicylindrical curved copper plates mounted on the outside surface of an insulating pipeline near the turbulence region produced at the junction of a larger diameter pipe and a smaller diameter pipe. Here the insulating pipeline section between the copper plates along with the flowing fluid acts as a composite dielectric material of the sensing capacitor. The semicylindrical curved copper plates along with two lead wires are rigidly mounted without any air gap on the larger diameter pipe using a thin layer of araldite. A mathematical relation between the sensor capacitance and flow rate is derived in this article. This capacitance is found to vary nonlinearly with flow rate and is measured using an op-amp-based DeSauty bridge-type transducer circuit where a similar capacitor with the same fluid at zero flow is used as a dummy capacitor. A prototype unit of the proposed transducer is designed, developed and tested experimentally. The static characteristic curves drawn from the experimental results are found to follow the derived mathematical equation to a very good extent with good repeatability.

Digital light processing 3D printing of conductive complex structures

Abstract: 3D printing has gained significant research interest recently for directly manufacturing 3D components and structures for use in a variety of applications. In this paper, a digital light processing (DLP®) based 3D printing technique was explored to manufacture electrically conductive objects of polymer nanocomposites. Here, the ink was made of a mixture of photocurable resin with multi-walled carbon nanotubes (MWCNTs). The concentrations of MWCNT as well as the printing parameters were investigated to yield optimal conductivity and printing quality. We found that 0.3 wt% loading of MWCNT in the resin matrix can provide the maximum electrical conductivity of 0.027S/m under the resin viscosity limit that allows high printing quality. With electric conductivity, the printed MWCNT nanocomposites can be used as smart materials and structures with strain sensitivity and shape memory effect. We demonstrate that the printed conductive complex structures as hollow capacitive sensor, electrically activated shape memory composites, stretchable circuits, showing the versatility of DLP® 3D printing for conductive complex structures. In addition, mechanical tests showed that the addition of MWCNT could slightly increase the modulus and ultimate tensile stress while decreasing slightly the ultimate stretch, indicating that the new functionality is not obtained at the price of sacrificing mechanical properties.

Review of high sensitivity fibre-optic pressure sensors for low pressure sensing

Abstract: Fibre Bragg grating (FBG) pressure sensors show a great potential in replacing conventional electrical pressure sensors due to their numerous advantages. However, increasing their pressure sensitivity performance for low hydrostatic pressure measurement is still a challenge. This paper reviewed recent pressure sensitivity enhancement methods that could be divided into two groups, namely intrinsic and extrinsic. For the intrinsic enhancement method, this paper reviewed polymer FBGs, special fibre sensors, interferometric sensors, and special grating sensors. For the extrinsic enhancement method, polymer-based pressure transducers, diaphragm-based pressure transducers, and other structure-based pressure transducers were reviewed in detail.

A Review on Capacitive-Type Sensor for Measurement of Height of Liquid Level

Abstract: The capacitive sensors are used in a variety of industrial and automotive application. A capacitive sensor converts a change in position, or properties of dielectric material into an electrical sig...