Why do MOBILE BATTERIES have THREE terminals? A simple Explanation.

Donate: BTC:384FUkevJsceKXQFnUpKtdRiNAHtRTn7SD ETH: 0x20ac0fc9e6c1f1d0e15f20e9fb09fdadd1f2f5cd In this video I am conducting a simple experiment that demonstrates the purpose of the 3rd terminal in cell phone Li-Ion batteries. 0:00 The rule of two wires in electronics. 0:43 How is mobile phone powered? 1:55 The purpose of the 3rd terminal. 3:08 Change of resistance. 3:50 Powering the phone from an external supply. 4:43 Why are 3rd party batteries dangerous?