This circuit is just a simple demonstration of how an uninterruptible power source works.
Since batteries that can be charged aren't available in EC... I've used actual DC voltage source instead.
Also rectifier and inverter blocks and static switches are avoided for simplicity by using actual DC source as main line power
In normal conditions the green LED indicates that the critical load (lamp here) is receiving power from the main line.
Flip the switch which would resemble a power outage as the main line would be cut off.
The critical load would be supplied power from the "battery" without any delay (well,theoretically)
The red led would indicate the user that the load is running on battery voltage.
