Rise time

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

A General Purpose Linear Amplifier

Abstract: An amplifier that is suitable for use in a variety of nuclear‐particle counting experiments is described. The high and low frequency response of the amplifier can be varied by means of a three‐position switch. In the wide‐band position the transient response to a step function is a voltage pulse with a rise time of 0.15 μsec. and a total duration of less than 0.5 μsec. In the narrow‐band position a signal of 3 microvolts produces a voltage pulse at the output equal to r.m.s. noise. A pulse‐height selector is included for measuring pulses up to 100‐volts amplitude.

Airborne sound insulation of thick walls

Abstract: Approximate analytical solutions are presented for the transmission of airborne sound through a plate between two rooms. The rooms are placed above each other and are of different size. The area of the plate is larger than the area of either room. Simple formulas are derived from the Euler–Bernoulli plate theory for the transmission due to the forced as well as the resonant field of the plate. The most interesting result concerns the forced response at coincidence, which is shown to be heavily dependent on the size of the excited area. A “rise length” on the analogy of the rise time in a single-degree-of-freedom system is introduced. Within the rise length, which is often very large, the displacement is proportional to the trace length on the plate of the exciting sound ray. The mean transmission factor due to the forced response at frequencies above the critical frequency is for this reason dependent on the source room area, but not on the loss factor. The coupling between a diffuse sound field and the free waves is, on the other hand, loss factor dependent, but the dependence of the coupling on the angle of incidence is shown to be quite different from that in the corresponding case of an infinite plate.

Lead acid battery rejuvenator and charger

Abstract: An electrical power source, either AC or DC, lead acid battery rejuvenator and charger circuit switchable between rejuvenator and charger modes of operation. For the rejuvenator mode of operation a rejuvenator pulse signal generating circuit supplies voltage in the form of fast rise voltage pulses peaking at a voltage necessary to cause battery plate saturation that is 1:1 to 1:3 times the theoretical battery cell voltage. This is accomplished by use of very short duration pulses in the order of 5 micro seconds or less time width wise with extremely fast rise time in the order of 5 mega volts per second rise time with these pulses occurring in approximately the 2,000 to 10,000 times per second frequency range. The transfer of electrons between metal electrode and ions in battery lead acid solution is not instantaneous, and that therefore with the fast rise time pulse rising to 1:1 to 1:3 times battery cell voltage the instantaneous voltage is distributed over entire battery plate surfaces and lead sulphate deposits that have occurred on battery plate surfaces will be released, either going back into the solution or broken up.

Mid-infrared time-resolved photoconduction in black phosphorus

Abstract: Black phosphorus has attracted interest as a material for use in optoelectronic devices due to many favorable properties such as a high carrier mobility, field-effect, and a direct bandgap that can range from 0.3 eV in its bulk crystalline form to 1.7–2.0 eV for a single atomic layer. The low bandgap energy for multilayer black phosphorus consisting of more than approximately five atomic layers allows for direct transition photoabsorption that enables detection of light out to mid-infrared frequencies. In this work, we characterize the room temperature optical response of a black phosphorus photoconductive detector at wavelengths ranging from 1.56 to 3.75 μm. Pulsed autocorrelation measurements in the near-infrared regime reveal a strong, sub-linear photocurrent nonlinearity with a response time of 1 ns, indicating that gigahertz electrical bandwidth is feasible. Time resolved photoconduction measurements covering near- and mid-infrared frequencies show a fast 65 ps rise time, followed by a carrier relaxation with a time scale that matches the intrinsic limit determined by autocorrelation. The sublinear photoresponse is shown to be caused by a reduction in the carrier relaxation time as more energy is absorbed in the black phosphorus flake and is well described by a carrier recombination model that is nonlinear with excess carrier density. The device exhibits a measured noise-equivalent power of 530 pW Hz−1/2, which is the value expected for Johnson noise limited performance. The fast and sensitive room temperature photoresponse demonstrates that black phosphorus is a promising new material for mid-infrared optoelectronics.

Hydrogen Sensor Based on Palladium Coated Side-Polished Single-Mode Fiber

Abstract: This paper reports a fiber-optic hydrogen sensor based on a side-polished single-mode fiber coated with a palladium (Pd) thin film whose optical characteristics change as it absorbs hydrogen. The optical transmission loss of the sensor depends on the hydrogen gas concentration through the complex electric permittivity of the Pd film. An optimal design for the sensor has been pursued to obtain both high sensitivity and short response time. When exposed to 4% hydrogen gas, the optimal change output power obtained in this experiment was 1.2 dB (32%) with a rise time of 100 s.