| 摘要 |
In an electric tool, in order to carry out a phase control or an antiphase control using a transistor with the cost lower and structure simpler, and to suppress an electromagnetic noise, constant voltage generating means of the electric tool includes a series circuit of a resistor 91 and a diode 93 and a parallel circuit of a capacitor 95 and a Zener diode 97, one end of the resistor 91 is connected to a node between an AC power supply 1 and an AC motor 3, a cathode of the diode 93 is connected to one end of the capacitor 95 and a cathode of the Zener diode 97, and the other end of the capacitor 95 and an anode of the Zener diode 97 are connected to sources of transistors 51, 52. One ends of resistors 53, 54 are connected to gates of the transistor 51, 52, and a voltage at the other ends of the resistor 53, 54 are switched between a voltage at a node between the series circuit and the parallel circuit and a voltage of the source of the transistors 51, 52 so that the transistors 51, 52 are turned ON or OFF. |
