Questions and answers
Explain your block diagram.
Go from source to load: supply, conversion or control stage, sensing, controller and output.
What are the ratings of your main components?
State voltage, current and power ratings of the transformer, battery, panel, MOSFETs or relays and how you chose them.
Why did you use this converter topology?
Relate buck, boost or inverter choice to input and output voltage and efficiency.
What is power factor and why improve it?
It is the cosine of the angle between voltage and current. A low power factor increases current, losses and tariff penalties.
How does your protection scheme work?
Explain what is sensed, the threshold and how the relay or breaker isolates the fault.
What is the difference between a relay and a contactor?
Relays switch low currents for control; contactors switch higher power circuits.
How did you size the solar panel and battery?
Show the load calculation in watt-hours, autonomy, depth of discharge and panel wattage.
What is MPPT?
Maximum power point tracking adjusts the operating point of a solar panel so that it delivers maximum power under changing sunlight.
Which microcontroller did you use and what does it control?
Name it, the sensors it reads and the outputs it drives.
What is the function of the optocoupler or driver circuit?
It isolates the control circuit from the power circuit and provides the gate drive needed.
What readings did you take?
Present a table of voltage, current, power or efficiency under at least three conditions.
What safety precautions are built in?
Fuses, MCBs, earthing, isolation and enclosure.
What are the losses in your system?
Switching, conduction, copper and iron losses as applicable.
What is the future scope?
For example IoT monitoring, higher ratings or grid synchronisation.
FAQs
Will I be asked to draw the circuit?
Often, yes. Practise drawing the block diagram and the main power circuit from memory.
Last reviewed: 2026-10-11. Always follow the format your own department gives you.