| 摘要 |
PURPOSE:To prevent the lag time of the operation of a thyristor from fluctuating due to that of power or the change in temperature, by providing a Zener diode which is connected at the primary side of a pulse transformer and has a Zener voltage of about 3 to 5V and a negative temperature coefficient. CONSTITUTION:Resistances 30, 32 and that of the primary winding of a pulse transformer 7 are set so that the potential on a point A is higher than a Zener voltage when the voltage of a battery is 6V or more. As a result, the voltage generated by the pulse transformer 7 is made constant to eliminate the fluctuation of lag time which would occur from that of the power source. Since a Zener diode 31 has a negative temperature coefficient, the Zener voltage drops as the temperature rises. Even if a thyristor 4 is triggered due to the rise in the gate sensitivity of the thyristor which is caused by the rise in the temperature, the voltage generated by the pulse transformer 7 decreases to prevent the fluctuation of the lag time. |
