Rise time

About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.

Objective functions modification of GA optimized PID controller for brushed DC motor

Abstract: PID Optimization by Genetic Algorithm or any intelligent optimization method is widely being used recently. The main issue is to select a suitable objective function based on error criteria. Original error criteria that is widely being used such as ITAE, ISE, ITSE and IAE is insufficient in enhancing some of the performance parameter. Parameter such as settling time, rise time, percentage of overshoot, and steady state error is included in the objective function. Weightage is added into these parameters based on users’ performance requirement. Based on the results, modified error criteria show improvement in all performance parameter after being modified. All of the error criteria produce 0% overshoot, 29.51%-39.44% shorter rise time, 21.11%-42.98% better settling time, 10% to 53.76% reduction in steady state error. The performance of modified objective function in minimizing the error signal is reduced. It can be concluded that modification of objective function by adding performance parameter into consideration could improve the performance of rise time, settling time, overshoot percentage, and steady state error

Note: An avalanche transistor-based nanosecond pulse generator with 25 MHz repetition rate.

Abstract: We have developed an avalanche transistor-based pulse generator for driving the photocathode of an image intensifier, which comprises a mainly capacitive load on the order of 100 pF. The circuit produces flat-top pulses with a rise time of 2 ns, a FWHM of 10 ns, and an amplitude of tens of V at a high repetition rate in the range of tens of MHz. The generator is built of identical avalanche transistor sections connected in parallel and triggered in a sequence, synchronized to a reference rf signal. The described circuit and mode of operation overcome the power dissipation limit of avalanche transistor generators and enable a significant increase of pulse repetition rates. Our approach is naturally suited for synchronized imaging applications at low light levels.

Simple nanosecond capacitive voltage divider

Abstract: The construction of a simple and inexpensive capacitive voltage probe by using coaxial cable is described. The probe has been tested to a frequency response of better than 30 MHz for sinusoidal voltage input and a rise time of <20 ns for single‐pulse input. The probe is ideal for applications in small experiments involving low‐energy and high‐voltage capacitor discharge of nanosecond rise time.

Fiber-Optic Current Sensor Based on FBG and Optimized Magnetostrictive Composite

Abstract: In this letter, we present a compact, open-loop fiber-optic current sensor (FOCS) based on fiber Bragg gratings (FBG) and magnetostrictive composites of Terfenol-D (TD) optimized for enhanced sensitivity and linearity using small concentrations of this alloy. Using magnetic field concentration techniques and orientation of magnetic domains of the composites, a prototype of the proposed FOCS was built with different doping concentrations of TD (10%, 20%, and 40%) and characterized with currents of 15–700 Arms. The proposed FOCS showed a linear response for currents of up to 450 Arms with a linearity error of ±0.55%, a sensitivity of $201~\mu \text{V}$ /A, and 4.8 degrees of phase shift between output and input signals, which are competitive features compared to previous works, since it employs very small amounts of TD (1.5 g max.). The developed prototype also presented a fast response-time to a current transient and a rise time of 1.5 ms, allowing for the proposed FOCS to be applied not only for current sensing, but also to fault detection and monitoring in transmission and distribution lines.

A compact nanosecond pulse generator for DBD tube characterization.

Abstract: High voltage pulses of very short duration and fast rise time are required for generating uniform and diffuse plasma under various operating conditions. Dielectric Barrier Discharge (DBD) has been generated by high voltage pulses of short duration and fast rise time to produce diffuse plasma in the discharge gap. The high voltage pulse power generators have been chosen according to the requirement for the DBD applications. In this paper, a compact solid-state unipolar pulse generator has been constructed for characterization of DBD plasma. This pulsar is designed to provide repetitive pulses of 315 ns pulse width, pulse amplitude up to 5 kV, and frequency variation up to 10 kHz. The amplitude of the output pulse depends on the dc input voltage. The output frequency has been varied by changing the trigger pulse frequency. The pulsar is capable of generating pulses of positive or negative polarity by changing the polarity of pulse transformer's secondary. Uniform and stable homogeneous dielectric barrier discharge plasma has been produced successfully in a xenon DBD tube at 400-mbar pressure using the developed high voltage pulse generator.