Ques:what is duty cycle?
Ans: The duty cycle is the fraction of time that a system is in an "active" state.

duty cycle

where

τ is the duration that the function is active high(normally when the signal is greater than zero);

Τ is the period of the function.

Ques:What is multiplexing?
Ans:multiplexing (also known as muxing) is a process where multiple analog message signals or digital data streams are combined into one signal over a shared medium.For exam, several phone calls may be transferred using one wire.

Ques:Why OC test is conducted on low voltage side?
ANS:The test is to determine the shunt branch parameters of the equivalent ckt of the transformer. One of the winding is connected to the rated voltage and other winding is kept open circuited. The test can be done from HV side too but the losses the power consumption and the risks will be much higher!

Ques:Difference between Neutral and Ground wires?
ANS:Ground wire:Ground or earth in a mains (AC power) electrical wiring system is a conductor that provides a low impedance path to the earth to prevent hazardous voltages from appearing on equipment.Ground wires generally do not carry currents.
Neutral Wire:The neutral is the return for the live feed from your circuit and is bonded at the main panel to the grounding conductor so that any stray currents caused by equipment faults will go back to the utility transformer.It generally carries current in its normal operation.

Household Wiring

Ques.Show the normal colour codes for power conductors?
ANS:-FOR
Live wire-RED;BROWN.
Neutral wire-BLUE;BLACK.
Ground wire-GREEN;YELLOW.