If the switching frequency is given as 16.7 kHz, VIN =15v, and the output is 5v as in section 1, draw the waveform of Vs2 and indicate the duty ratio D. Vout = DVIN. If the output needs to increase, will D increase or decrease? Note that the waveform of Vs2 is a square wave that contains the DC output Vout as well as harmonics. The lowest harmonic has the frequency of 16.7 kHz (from Fourier series expansion), which is also the switching frequency. Also, note that LC in the above converter circuit consists of a second order low pass filter with a corner frequency of LaTeX: \omega_c=1/\sqrt[]{LC}ω c = 1 / L C. To significantly reduce the harmonics, LaTeX: \omega_cω c must be much less than the switching frequency. Why? Assume LaTeX: \omega_cω c =0.1*switching frequency, calculate L and C (assume one and calculate the other).

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w