Abstract: A power transmission device of the non-contact feeding device includes the transmission coil that supplies power to a power receiving device, a power supply circuit that supplies AC power obtained by boosting or stepping down the input voltage to the transmission coil, a voltage detection circuit that measures the voltage input to the power supply circuit, and a control circuit that controls a degree of boosting or step-down with respect to the input voltage by the power supply circuit according to the input voltage measured. The power receiving device includes a resonance circuit including a receiving coil that receives the power from the power transmission device and a resonance capacitor that resonates with the receiving coil according to the power from the power transmission device and a rectifier circuit that rectifies the power output from the resonance circuit.

Abstract: Disclosed is an electronic magnetic compass which is to be mounted on a small ship and which is reduced in cost and improved in performance. The electronic magnetic compass is provided with an angle sensor interlocked with a compass card so as to produce a code signal at every predetermined angle, a code converter for converting the code signal into a compass indication angle, and a signal conversion circuit for producing a deviation signal indicating a deviation between an azimuth angle signal and an indication angle signal. The compass azimuth measurement is performed with a simple configuration of an open loop system, so that the structure of an encoder for the angle sensor is so simple that the cost can be reduced so much. The azimuth angle signal and the indication angle signal can be automatically calibrated so that the measurement accuracy can be improved.