Performance evaluation of 2.4kVA grid-tie inverter

This paper is focused on experimenting the overall performance of a 2.4kVA direct solar power supply system. The overall aim is to implement a solar power supply system without a battery back-up in order to minimize cost. The objectives include measuring the performance of grid-tie inverter, determine its period of operation under load conditions, to make the use of batteries optional in solar power supply system and minimize initial cost of installation. Various tests (variable load, fixed load and no-load) were carried out for the purpose of analysis. A dual trace digital storage oscilloscope was used to monitor the output waveform of the inverter to observe possible harmonic distortion on the waveform. The inverter takes its input power directly from the solar modules (panels) through the maximum power point tracker (MPPT) charge controller. Each category of test was conducted for at least three days of different weather conditions, to determine how variation in the sun’s intensity (irradiance) affects the operation of the inverter and its output power. Test results show that the inverter performs its function during the day apart from the early hours in the morning and later in the evening of each day, and the loads were powered successfully during the period of test. The output waveform as observed from the oscilloscope is not purely sinusoidal; it is rather a modified sine wave.

METHOD FOR MEASURING THE PRESSURE OF A SHOCK-ACOUSTIC WAVE OF AN ELECTRIC EXPLOSION OF A CONDUCTOR IN A DISCHARGE CHAMBER WITH A CONDENSED ENVIRONMENT

An electric explosion of conductors, as well as an electric discharge as a whole, is a poorly studied unique phenomenon that is widely used both in basic scientific research and in various technological processes, which determines the relevance of further studies of ongoing processes. In this paper, we consider the methods and carry out calibration procedures to determine the value of the conversion coefficient for a piezoelectric pressure transducer with a reactive acoustic waveguide made of non-Newtonian fluid material. Designs of calibration plants are shown, the principle of which is based on the method of falling load and the interaction of parallel currents. The results of recording and measuring the pressure of a shock acoustic wave (SAW) generated by an electric explosion of a metal conductor of a ring-shaped geometry in a closed space of conical geometry with a condensed (aqueous) medium are presented. The discharge current and the voltage drop across the exploding flat ring foil (EEFRF) were recorded by the Rogowski belt and voltage divider, respectively. The pressure pulse of the acoustic shock wave was recorded by a piezoelectric pressure transducer. The electrical signals were recorded with a GDS-810 S digital two-beam storage oscilloscope. The amplitude value of pressure was estimated by plastic deformation of the plate sensor in the form of a round thin plate with clamped edges.

A Method for Measuring LC Resonance Frequency by Impulse Response

LC circuit resonance frequency measurement often requires the use of professional analysis instruments such as LCR meters, vector network analyzers, but currently such instruments on the market are expensive, and it is difficult for non-professional institute personnel to access. Here comes unnecessary trouble. In view of this situation, a test method for measuring the resonance frequency using only a digital storage oscilloscope is proposed. Using the impulse signal to obtain the system response, the response waveform period can be observed through the oscilloscope.

Digital Circuit for Seamless Resampling ADC Output Streams

Fine resolution selection of the sample rate is not available in digital storage oscilloscopes (DSOs), so the user has to rely on offline processing to cope with such need. The paper first discusses digital signal processing based methods that allow changing the sampling rate by means of digital resampling approaches. Then, it proposes a digital circuit that, if included in the acquisition channel of a digital storage oscilloscope, between the internal analog-to-digital converter (ADC) and the acquisition memory, allows the user to select any sampling rate lower than the maximum one with fine resolution. The circuit relies both on the use of a short digital filter with dynamically generated coefficients and on a suitable memory management strategy. The output samples produced by the digital circuit are characterized by a sampling rate that can be incoherent with the clock frequency regulating the memory access. Both a field programmable gate array (FPGA) implementation and an application specific integrated circuit (ASIC) design of the proposed circuit are evaluated.

Detection of Skin Cancer using Optical Method

Skin is the one of the most important organ present in our body that does some of the important functions like protection, temperature regulation etc. Due to some conditions, skin is affected by many abnormalities. The abnormalities may be smaller or larger, which depends on the damage caused to the skin. Some abnormalities of skin are irritations, allergic reactions, swelling etc. One of the most major problems that affect the skin completely is of skin cancer. Skin cancer is the most common type of cancer that affects the 40% of people in all over world. It may be caused due to several factors like genetic, working in hazardous chemical areas, exposure to sun, repeated X-ray exposures etc. All of these factors affects the skin and causes skin cancer. Skin biopsy is a major technique used at present to detect all types of skin cancers. As this biopsy method is invasive, and takes more time to check the cancer tissue, we are using this optical method for detection of skin cancer. Optical imaging is the upcoming technology that plays the major role in all fields. In this method Near Infra-Red (NIR) light source is passed into the affected skin region. The transimpedance amplifier is used to amplify the output from photodiodes. Then the output from the photodiodes is connected to the Digital Storage Oscilloscope (DSO) in which the waveform shows the variations due to skin cancer.

Multichannel Photon Counting Lidar Measurements Using USB-based Digital Storage Oscilloscope

We present a simple method of making multichannel photon counting measurements of weak lidar signal from large ranges, using commonly available USB-based digital storage oscilloscopes. The single photon pulses from compact photomultiplier tubes are amplified and stretched so that the pulses are large and broad enough to be sampled efficiently by the USB oscilloscopes. A software interface written in Labview is then used to count the number of photon pulses in each of the prescribed time bins to form the histogram of LIDAR signal. This method presents a flexible alternative to the modular multichannel scalers and facilitate the development of sensitive lidar systems.