An information transmitter includes a transmitting coil configured to receive a coil voltage to generate a magnetic field; and a signal generator configured to receive a direct current (DC) voltage and operating switches to apply the coil voltage to the transmitting coil, for a first time constant in a first current path, wherein the coil voltage includes a first value, and for a second time constant in a second current path, wherein the coil voltage includes a second value smaller than the first value, and wherein the first time constant and second time constant are different from each other.