Figures (a) and (b) below show two systems that might be used to control the temperature of a room. Explain how each operates. Reference voltage (a) Differential amplifier Electrical power [4 Electronic switch Set point Relay Heater Heater Resistance to voltage converter Electrical power Microcontroller Thermistor Thermistor

A three-phase six-pulse rectifier shown in Figure Q1b is used to power a highly inductive load. The AC input voltage VL is 415 Vand frequency is 50 Hz. The semiconductor switch triggering angle is 45° and the (b) load current is 11 A. Calculate: (i) The output voltage (in Volt). (ii) The output power (in Watt). (iii) The firing angle a that provides output voltage equal to 255 V. (assume load current is constant and supply inductance is 4.5 mH/phase). (iv) The commutation angle u for the case in part (iii). (v) The RMS value of fundamental component in the input current (in Ampere). (vi) The 5th and 7th harmonic currents (in Ampere). io = I, la Vab IT3 Highly inductive Vo + load Vhc ip3 ADI IDI D2 Figure Q1b Three-phase rectifier.