1. Single-phase AC Circuits [40 marks] (a) The admittances of two circuits connected in parallel are 0.0283 2 45° S and

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1 Single Phase Ac Circuits 40 Marks A The Admittances Of Two Circuits Connected In Parallel Are 0 0283 2 45 S And 1 (41.42 KiB) Viewed 26 times

1. Single-phase AC Circuits [40 marks] (a) The admittances of two circuits connected in parallel are 0.0283 2 45° S and 0.1052 -73.4 S respectively. Calculate the input impedance of the combined circuits. [10 marks] (b) A circuit has an applied voltage of 110 2 30° V and draws a current of 12 2 -15°A. Calculate the real power and the reactive volt-amperes. State whether the reactive voltamperes are leading or lagging. [10 marks] (c) A 20:1 step-down transformer is supplied by 230 V, 50 Hz and pulls 0.3 Arms magnetizing current. Calculate the primary current and input power factor when the secondary is loaded by a 230 W load. [10 marks) (d) A 20 resistor, a 0.1 H coil with a resistance of 5, and a 120 uF capacitor are connected in parallel to a 230 V, 50 Hz ac source, as shown below; I T: Ts 20 2 0.1 H 120 uF 522 i) Calculate the currents drawn by each parallel branch T., Tzand Tz. Calculate the total current i drawn from the ac source. (10 marks) Page 2 of 4