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Different types of driver circuits for the temperature-invariant brightness of light emitting diodes and the RF performance of Schottky barrier diodes, p–i–n diodes and p–n junction diodes are presented. The sensitivities of the proposed driver circuits with ambient temperature, bias voltage and other component variations are presented. Novel techniques are proposed and demonstrated to compensate the performance variation of diode-based circuits due to the temperature sensitivity of the components of driver circuits. The proposed driver circuits eliminate the requirement of conventional temperature compensation techniques with temperature sensors. The driver circuits respond directly to the junction temperature of the diodes itself; thus, there will be no compensation error due to the temperature gradient or self-heating of the diodes. This technique is very simple, accurate and easy to implement. [ABSTRACT FROM AUTHOR]

This paper offers a fresh look into the temperature behaviour and compensation of Schottky barrier diode's radio frequency (RF) resistance. RF resistance of a Schottky diode varies with temperature at conventional fixed current bias as well as fixed voltage bias condition. Here we have proposed “optimum load-line biasing technique” to achieve temperature invariant RF performance of the Schottky diode based RF circuits. Mathematically we have shown and verified by measurements that the proposed technique provides temperature insensitive RF performance over a very wide range of operating temperature. Thus, without any separate temperature sensor and compensation circuits, as used in conventional temperature-compensation schemes, it is possible to achieve temperature invariant RF performance of the Schottky diode based RF circuits. [ABSTRACT FROM AUTHOR]

The conventional current transformers (CTs) in the form of a bar primary and secondary winding on a highly permeable ring core suffer from ratio error and phase angle errors, which are primarily due to the no-load current of the transformer. A modified design of a CT has been described. In this design, a feedback technique has been used in order to reduce the no-load current to a negligibly small value so that the said error may be minimal. Using this technique, a CT has been designed and fabricated with the commercially available material. The performance of the transformer has been tested experimentally and the output and input AC waves have been observed in a storage cathode ray oscilloscope (CRO) and the experimental results are reported. [ABSTRACT FROM AUTHOR]

This brief offers a fresh insight into the behavior of PIN diodes over temperature. A simple but accurate biasing and control circuit for attenuators and other PIN diode applications is described. The circuit can easily be optimized for a high attenuation setting accuracy over a wide temperature range without using any temperature sensor or compensation circuit. [ABSTRACT FROM AUTHOR]

The design, development and test results of a predistortion type lineariser based on Schottky and pin diodes are presented. The lineariser is capable of providing different combinations of amplitude and phase characteristic for use with different power amplifiers. Integrated with a 60 W Ku-band travelling wave tube amplifier it improves the two-tone third-order intermodulation distortion by 1.9 dB at 0 dB power input back off (IBO) and 16 dB at 7 dB IBO. [ABSTRACT FROM AUTHOR]

This paper presents the design, simulation and test results of a novel photonic band-gap (PBG) structure for filter application. The proposed PBG structure is a 50Ω meander microstrip line with a single rectangular ground-etched pattern instead of conventional periodic ground-etched pattern. The simulated results, verified by the test results, demonstrate that this proposed structure provides less ripple in the lower pass-band with an increased rejection bandwidth of about 20%, as compared to a conventional PBG filter with same fill-factor. This single etched ground pattern enables easier fabrication and packaging, as compared to conventional multiple ground-etched patterns. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 188–190, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21302 [ABSTRACT FROM AUTHOR]

A thyristor driven pump is operated by varying the DC input signal in the firing circuit of thyristor drive. This operation suffers from difficulties due to the nonlinear relation between thyristor output and DC input. In the present paper, an opto-isolator based linearization technique of a typical thyristor driven pump has been proposed. The design, fabrication and the necessary circuit diagram along with theoretical explanations of the resultant output has been described. The operation of the linearized thyristor driven pump has been studied experimentally and the experimental data before and after linearization are reported. The characteristic graphs are found to have very good linearity., (Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.)

In the present paper, design of a flow control loop using a thyristor driven pump as final control element has been described. In this technique, the load current of a thyristor driven pump motor has been utilized as a mass flow sensing parameter of a fluid passing through a pipeline. This thyristor driven pump has been utilized as a final control element of a flow control loop and the speed of the pump has been selected as the manipulated variable. The non-linearity between the thyristor input signal and pump output has been eliminated by using a modified PID control technique with inverse derivative control action. Thus without using any conventional flow meter and control valve only the thyristor driven pump has been utilized both as the final control element and flow indicating device by using the proposed technique. The whole system has been designed, fabricated and tested by using tap water as the flowing liquid through a pipe line. The experimental results along with the theoretical analysis are compared and reported in the paper., (Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.)