Below is a topology for a typical variation of the Colpitts oscillator. Assume you want this oscillator to run at a center frequency of 7.5 MHz where C1 can be used for fine tuning. You have available the following standard +/- 10% tolerance capacitor values that you could use for C3 and C4. Which value should you pick? a. 270 pF
b. 330 pF
c. 390 pF
d. 470 pf
e. 560 pf
f. 680 pf
g. 820 pF
h. 910 pF
i. 1000 pF
j. 1200 pF

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.