Power gain

Figure 6.30 (a) Output power versus input power for a single cell in CB mode operated in ciass C mode at 425 MHz, puise width 100 fis, duty cycie 10%, and = 80 V. (b) Coiiector efficiency and power gain versus output power for conditions stated in part (a). 

These results are highly encouraging as they demonstrate the high power capability of the SiC RF-BJT devices along with acceptable power gain and efficiency. From thermal simulations, it is estimated that the junction temperature may reach a peak value of 171 C for pulse widths of 250 jus and 6% duty cycle without any external cooling. Since SiC junctions can easily sustain a temperature of 250 C, there is room to increase the pulse width even further. 

The late portion of the EDR can be described in terms of the frequency response envelope G(a) and the reverberation time Tr (co), both functions of frequency [Jot, 1992b], G(co) is calculated by extrapolating the exponential decay backwards to time 0 to obtain a conceptual EDR(0, co) of the late reverberation. For diffuse reverberation, which decays exponentially, G(co) = EDR(0, co). In this case, the frequency response envelope G(co) specifies the power gain of the room, and the reverberation time Tr (CO) specifies the energy decay rate. The smoothing of these functions is determined by the frequency resolution of the time-frequency distribution used. 

Again if this power gain is equated to the loss of energy of electrons in elastic collisions with the gas molecules, as would occur in the steady state, then... 

According to the power balance, Eq. (38), the mean power gain from the electric field is compensated for by the mean power loss in collisions, and this happens for any given gas and its specific atomic or molecular data and for any reduced field strength E/N. An analogous compensation occurs in the momentum balance, Eq. (39), between the mean momentum gain from the field and the mean momentum loss in collisions. 

Let us now analyze the channels by which the power gain from the electric field is dissipated by the various collision processes during the course of relaxation and the manner in which these channels determine the quite different relaxation times found in the neon plasma at the two field strengths. These losses are illustrated in Fig. 11 for the same plasma conditions as those considered in Fig. 9. 

Fig. 11. Temporal evolution of the mean power gain P /n, the mean power losses P /n and P "ln in elastic and inelastic collisions, and the power loss P /n in all collisions.

This interpretation of the electron response to the field disturbances is largely confirmed by the temporal course of the power gain from the field jn and power losses P" /n, and P /n in elastic, inelastic, and all collisions given in Fig. 18. For example, if the field pulse starts and ends with the low field (left), at the beginning of the pulse and in the later relaxation phase the power gain is almost compensated for by the power loss in elastic collisions, and this leads to the large relaxation time at these periods. However, around the pulse maximum, the power... 

Fig. 18. Temporal evolution of the power gain and losses in both field disturbances.

Passive components contribute no power gain (or amplification) to an electrical circuit or system. They cannot perform control action and do not require any input other than a signal to perform their functions. 

This corresponds to a power 4 X 10 WHz at 290 K which produces an rms noise voltage (AkTBR) across any resistor combination of value R. The p — p fluetuation is 4-5 times greater than this value. Practical circuit devices such as amplifiers increase this apparent noise power by their power gain plus... 

Can rectifiers and strands of conducting polymers be grafted together to form a molecular amplifier with power gain ... 

It appears that the use of drag-reducing additives in hydraulic machines and hydraulic power stations is quite feasible. The additional investment is negligible- The power gain may be several hundred kW per kg of polymer at very low injection rates, hence, it may be economical at peak demands. 

In order to remove the limitation in the input power caused by excessive heating/melting of the anode in the SWT geometry, the rotating anode tube was developed. By employing a cylindrical anode head that rotates rapidly through the electron beam, an output power gain by a factor of 5-10 relative to... 

---