An inductive load is connected to a AC voltage source of 220 Volts (RMS) and 50 Hz. It is known that the average power is 1.1 kW and the power factor is . If the power factor is to be improved to 0.866 by including a capacitor in paralle with the load, what is the its capacitance?
Solution:
Given the power factor
, the phase angle of the inductive
impedance is
. Also, given the average power
Find the DC operating point of the transistor circuit given below, where , , , , and . If you find the DC operating point is not in the middle of the linear region of the output characteristic plot, modify so that the DC operating point is in the middle of the linear region (to maximize the dynamic range of the AC output).
Solution:
Find the load line: When , , when ,
Now we modify to move Q-point to the middel point where .
The circuit shown below is called Darlington transistor amplifier which is composed of two transistors and with their collectors connected and the emitter of connected to the base of . Assume and both transistors have .
Solution: