| 摘要 |
PURPOSE:To enable an efficient and uniform heating of water of specified volume as much as possible by a method wherein an electric heating part is provided at least a part of a container storing a specified volume of liquid through a thin insulator and a semiconductor device is installed at the electric heating part. CONSTITUTION:As an input comparative voltage for a differential amplifier 10, the same voltage as the output of the amplifier 8 corresponding to the hot water setting temperature at the heating part is set in advance by a variable resistor 12. When the hot water temperature at the heating part is decreased less than the predetermined value, the output of the differential amplifier 10 becoms a positive value, this value of voltage is amplified with the amplifiers of Tr1 and Tr2 and then a relay for the power supply switch is turned ON. It is possible to design that in case than a gate voltage of an electrostatic induction transistor is varied by a system in which the output from the differential amplifier 10 is fed to the resistor of R1 in series with or in parallel to it and when the hot water temperature is increased more than the desired temperature, the electrostatic induction transistor is turned off and thus the oscillator 4 is terminated. |
