Electronic circuits and methods are provided for various applications including signal amplification. Preferred bi-tapered fibers of the invention have a high modulus of elasticity in the range of 5-250 Gigapascal and are preferably modulated in both tapering dimensions. Similarly a CDMA SMS message may be stored in a SIMUSIM module using similar techniques. A magnet faces the salient pole radially and is rotated with the hub. The switch to high power supply enables normal operation of the host device. Further, at least one adjustment factor relating to the position of the electronic compass is defined and may be stored in a memory.