I was wondering how waterproof wristbands are charging. I suppose is a common technique that all vendors are using. For example my wristband has two exposed leads as it seems below.
The charger has similar leads that fits to the wristband and a micro usb for current input. When i am trying to measure the voltage on the two exposed leads i am not getting anything, as expected because the device is waterproof, but these leads are charging the wristband.
Does anyone know how this charging method work?
How these leads are going "active" when the charger is attached?