Showing posts with label BSI pin. Show all posts
Showing posts with label BSI pin. Show all posts

Sunday, June 19, 2011

Whats that middle pin?

The popular Nokia BL5C battery(pic here) has 3 pins.One -ve,one +ve .. and the other one?
Mobile servicemen call it the "BSI" pin.BSI? They say its short for 'Battery Size Indicator'.Hmm,ok.Turns out,its a fixed resistor behind it,between the BSI pin and ground.The phone measures the resistance of the BSI - GND pins, and can determine what kind of battery is in.

The BSI GND Resistance for a normal BL5C comes out to 82.5k,and on a 4C to around 74.6k.Interesting.