摘要 |
An electromagnetic induction heating cooker compatible with both 100 V and 220 V inputs. A parallel circuit of a 100 V select switch and a transistor is connected between an output terminal of a bridge diode and a choke coil. The output terminals of the bridge diode and the choke coil are respectively connected to a pair of resistors in series whose values are set so that the same voltages are applied to a non-inverting and inverting input terminals of a comparator when the ratio of the output voltage of the bridge diode to that of the choke coil is 2.2:1. An oscillator, a drive, and a 220 V select switch are connected in series between an output of the comparator and the base of the transistor.
|