Tum-on time

From Equation (8.5), the rise (or tum-on) time is more difficult to solve because it depends on the applied voltage and the initial rabbing angle. When the mbbing angle d> = 0, the LC directors are perpendicular to the electric field and the Freedeticksz transition exists. Under these circumstances, the tum-on time can be solved [18] ... 

SCR Cathode Gate Anode Small gate pulse (current) Slow to medium tum-on time ( 5 ds) Anode current goes below holding Delay time before forward voltage can be applied (10-200 Its) Very high power Needs additional circuit to turn off On voltage =2.5 V... 

Schematic stmcture (a), luminance (b) and tum-on time (c) data for LEDs using cyano-P(PV) s. After Reference [763], reproduced with permission.

The preceding discussion and results apply to the case where an extraordinary wave laser is obliquely incident on the (homeotropic) sample (i.e., (3 0). For the case where a laser is perpendicularly incident on the sample (i.e., its optical electric field is normal to the director axis), there will be a critical optical field >, the so-called Freedericksz transition field [see Eq. (8.54)], below which molecular reorientation will not take place. Second, the tum-on time of the molecular reorientation depends on the field strength above Ep (i.e., on op-. ). For small E op the tum-on time can approach many minutes Studies with nanosecond and picosecond lasers" have shown that under this perpendicularly incident (i.e., (3=0) geometry, it is very difficult to induce molecular reorientation through the mechanism discussed previously. 

The combination of fast transitions (tum-on time) and the DC bus voltages of 460 "VAC (input) controllers results in the high dV/dt levels as seen in Fig. E-28. What is typically referred to as dV/dt is the time derivative of the voltage, or the slope of the voltage versus time curve. 

Figure 4. Ionization yield as a function of laser intensity for a radiation pulse with a linear tum-on of 1007 //. The field frequency is an = 10 a.u.. These yields are computed at t = 11007 //. The line represents the results for the time-dapendent Schrodinger equation treatment while the dots are the results of the Klein-Gordon equation treatment,...

Injection-type laser diodes based on GalnN active layers have now been demonstrated by a number of different groups [2,25-30], The threshold current densities range from 1.5 kA/cm2 [31] to about 50 kA/cm2 [26], From measurements of the tum-on delay time Nakamura et al [32] have also estimated the threshold carrier density to be about 1 - 2 x 1019 cm 3. 

The course of MDMA s history has recapitulated to a considerable degree that of LSD. The "tum-on" this time began among chemists and psychiatrists after a preliminary announcement from the team of Shulgin and Nichols in 1978 in a volume titled The Psychopharmacology of Hallucinogens. There followed a chain-reaction of growth in its distribution, which, in this instance, even manifested in a Tupperware party like pyramid scheme for sales. 

Note Here we seem to be indirectly suggesting that the drive resistance is the same for tum-on and turn-off. That need not be so. All the equations we will present can easily take any existing difference in the turn-on and turn-off drive resistances into account. So in general, we will have different crossover times for the turn-on and turn-off transitions. Also note, that in general, within a certain crossover interval (tum-on or turn-off), the actual time it takes for the voltage to transit need not be the same as the time the current takes (unlike the case of a resistive load). 

Note Since the pedestal of the common mode noise envelope is independent of the rise and fall times, does that mean that it doesn t matter how fast we tum-on and turn-off the mosfet Yes it doesn t. But read the similar note previously given for the DM filter design section, (see page 430). 

Let US consider an isolated pair of reactants A and B whose positions in space are r and re at time t. For simplicity, these reactants will be taken as uncharged and there is no potential of mean force consideration to be included either. Such factors may always be included later. The probability that species A is in the small volume cIta at r and species B is in the small volume drg at rg at time t is n rp, r, t) dr drs- Both species can diffuse independently of one another. They can even diffuse through each other, in principle, though in practice this is improbable because A and B will react before they b in to pass through each other. This can always be prevented by including a hard core repulsive term in the interaction evergy, U, which tums-on just inside the reaction distance, R. The probability density rs, t) can change with time due to diffusion of either A or B or both species. The rate of loss of A from is and, similarly, the loss of B from tg is D V n. In these terms, the subscript A and B refer to the co-ordinates of A or B, respectively, and the diffusion coefficients of A and B are, respectively, I>a The dif-... 

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