Circuit and method for heating a battery. The power adapter includes a transformer having a primary winding for storing energy when a main switch coupled therewith is turned on and transferring the stored energy to the secondary side of the transformer when the main switch is turned off. The first luminescent material includes a relatively inefficient phosphor having a peak emission wavelength longer than 620 nm and includes substantially no phosphor having a peak emission wavelength shorter than 620 nm. A metrology tool is directed to measure the defect characteristic at each of the measurement site in the second subset responsive to the size of the second subset being greater than zero. A temperature sensor is encased in the cylindrical housing. The welding connection has a maximum extension perpendicular to an area of the electrode at which the noble metal element is fastened, and the welding connection has a maximum width at the area.