Dispersion of water drops by induction heating using MOS-FET inverter

A single-ended MOS-FET RF inverter connected to the load consisting of a capacitor and a planar coil, which are connected in parallel, is described to remove water drops from the surface of a small mirror. Two types of planar coils have been used, of which one is made of a copper wire, and another is made of a patterned printed circuit board resembling a swirl. Induction heating is accomplished on a sheet of iron by an RF current flowing through the planar coil. The surface temperature of the mirror attached to the iron sheet was 44.6/spl deg/C on the planar coil made of a copper wire when the power of the MOS-FET RF inverter operating at a resonating frequency of 26.0 kHz was supplied from a DC power supply at an output power of 55.2 W. The surface temperature was 45.3/spl deg/C on the planar coil made of a patterned printed circuit board when the power of the inverter operating at a resonating frequency of 33.2 kHz was supplied from a DC power supply at an output power of 63.6 W. These temperatures are high enough to remove water drops from the surface of the mirror.