| 摘要 |
PURPOSE:To improve the reliability by providing a series circuit comprising a resistor and a switching element between the 1st tap of the secondary winding of a transistor and a base of a load transistor (TR) so as to prevent malfuncton or damage of the load TR. CONSTITUTION:The series circuit 17 comprising a resistor 15 and a TR 16 is provided between the 1st tap Ta of the secondary winding 2b of the pulse transformer 2 and the base B of the load TR 6. Thus, even when a TR having a current amplification factor of 20-30 is used for the TR 16, the resistance of the resistor 14 is selected to 20-30 times the resistance of the resistor 15, a current flowing to a loop consisting of the 2nd tap Tb, resistor 14, collector- emitter of TR 12 is very small when the TR 3 is turned off and is nearly neglible, then the discharge current of a capacitor 10 is small, and the decrease in the voltage across the capacitor 10 is suppredded while the TR 3 is turned off, the turning off of the TR 12 is prevented and the TR 6 is kept to the reverse bias state surely. |
