The Qi Coil is generally found in the center of most smartphone models and behind the trigger button on the Auto Sense Wireless Charger.
Please also take note of the following:
1. For all Apple & Samsung devices, please bring down the bottom foot- this will align your device with the "sweet spot" and allow for a seamless charge.
2. Apple devices have a charging radius of 3mm. If the unit falls out of the charging radius the device will not charge
3. Apple & Samsung when in use will utilize standard charge to prevent the smartphone from overheating. Therefore, if you are using a GPS or listening to music while charging your device then you will obtain a minimal charging