Abstract: A secondary battery charging system includes a secondary battery charging device and a power generation device that generates a charging current. The secondary battery charging device controls the charging a secondary battery, which has a protection timer that counts a first elapsed time from a start of charging. The secondary battery charging device includes a charging switch that controls a supply of the charging current, a time management timer portion that counts a second elapsed time starting from a point at which the charging switch becomes conductive and performs a charging stop determination and that counts a third elapsed time starting from a point at which the charging switch is cut off and performs a charging start determination, and a charging control portion that causes the charging switch to be conductive or cut off based on results of the charging stop determination and the charging start determination.

Abstract: A secondary battery charging system includes a secondary battery charging device and a power generation device that generates a charging current. The secondary battery charging device controls the charging a secondary battery, which has a protection timer that counts a first elapsed time from a start of charging. The secondary battery charging device includes a charging switch that controls a supply of the charging current, a time management timer portion that counts a second elapsed time starting from a point at which the charging switch becomes conductive and performs a charging stop determination and that counts a third elapsed time starting from a point at which the charging switch is cut off and performs a charging start determination, and a charging control portion that causes the charging switch to be conductive or cut off based on results of the charging stop determination and the charging start determination.

Abstract: A tuner mounting mounts a tuner to a musical instrument to indicate a tuning state of the musical instrument. The tuner mounting device has a hook-and-loop fastener that connects to a main body of the tuner and is configured to wrap directly around at least a part of the instrument so that end portions of the hook-and-loop fastener are removably connected to one another to directly mount the tuner main body to the part of the instrument.

Abstract: Provide a tuner mounting device which does not scratch an instrument and which provides a satisfactory sensitivity to a vibration generated from the instrument. A mounting base portion for fixing a tuner main body to a part of the instrument is fixed to the instrument on a constant basis by a hook-and-loop fastener, with a structure to be fitted into the mounting base portion being provided on a lower surface of a tuner main body containing a vibration sensor for detecting vibration generated through operation of the instrument. The mounting base portion has a power source portion and a power supply contact, with the structure having an electrical contact corresponding to the power supply contact provided on the mounting base portion.

Abstract: A tuning device provided with an A/D conversion circuit receiving a battery voltage as an input and an averaging circuit averaging values obtained through A/D conversion and converting it into display data for display of an averaged voltage value. Therefore, an operator can be informed of the current residual electric energy of a battery even when a reference sound is being produced, and thereby correct operation can be verified.