Let’s explore the accuracy of a simple piecewise-linear model:

(a) find the parameters (vd0, rd) of a piecewise-linear model of a diode for which the measured voltage across its terminals vd is 0.7 v when a current of id = 1 ma is flowing. assume vt = 50 mv. the piecewise-linear model is to intersect the measured diode exponential curve at 1 ma and 10 ma.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.