Electricity — remember the wheel?
Do you remember the water-wheel diagram? ↗
What two crucial things did we learn from it?
1
CLOSE — A circuit must be closed, returning to its power source.
2
FLOW — In our DC circuits, current flows in one direction.
CONCLUSION
A circuit has a power source, a consumer, and a return path. It MUST reconnect to its power source — in our DC circuits, to − (GND).
* AC/DC — not just Rock’n’Roll.
AC = Alternating Current — from the wall socket. DC = Direct Current — from a battery.