A switch-mode dc-dc converter is operating at a switching frequency of 20 kHz, and Vd ¼ 150 V. The average current being drawn by the dc motor is 8.0 A. In the equivalent circuit of the dc motor, Ea ¼ 100 V, Ra ¼ 0:25 Ω, and La ¼ 4 mH, all in series.
(a) Plot the output current and calculate the peak-to-peak ripple and
(b) plot the dc-side current.

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater