Thank youOriginal Magsafe chargers only deliver low voltage, before the proper MacBook connection is detected; aprox 6V for Magsafe 1 and 3V for Magsafe 2.
The charger is really smart, it has 32 bits embedded processor.
Meanwhile a fake charger delivers always the full voltage.
It can kill the SMC, if is connected a bit angled.
The 1-wire line is protected inside the MacBook, but sometime this protection is not enough.
You should now understand the price difference of the chargers.
If mentioned processor detects an input leakage, or short circuit, it will disable charger output completely (0V).
If charger detects proper MacBook, then full voltage is delivered.
Since then, SMC is powered on and will check the Magsafe charger specifications; gets that info from its 1-wire memory.
Once both charger and MacBook complete the power recognizing protocol, machine can start power on sequence (controlled by SMC and PCH).
The forum goal is to help in repair processes.
Explaining in details what you've asked about, enters into personal training area.