A semiconductor ceramic composition with small resistivity at room temperature and large temperature coefficient of resistance is provided; the composition is represented by formula,mO3 \u2003\u2003, and the mole ratio m of Ba site to Ti site satisfy the following in equations,0. One embodiment includes an elongated base, which may be disposable, and has a sufficient length to be disposed in an operative position behind the user’s ear. In certain example embodiments, the thicknesses of the silicon nitride based overcoat and the tin oxide based layer are balanced. In one embodiment, the method can include mapping which power supply units correspond to various power supply grids. After attaining the phase lock, the analog loop is used to maintain the phase lock across frequency and phase variation due to changes in temperature and supply.