| 摘要 |
PURPOSE:To obtain a stable vertical sawtooth waveform which does not vary in DC level even when the ripple of a power supply line increases and to nearly eliminate a vertical flicker on a screen due to the ripple, by interposing a circuit with a sufficiently large time constant in a bias circuit. CONSTITUTION:The bias circuit for the base of a transistor TRQ2 has the sufficiently large time constant by a resistance R3 and a capacitor C1 and even when the voltage of a power source VCC fluctuates, the base potential of the TRQ2 is almost fixed and a TRQ1 has almost no variation in collector potential. The circuit consisting of a TRQ3, diodes D4-D6, and resistances R5 and R6 charges the capacitor C1 speedily through the TRQ3 when a power supply switch is turned on. Said bias circuit turns off the TRQ3 in a stationary state by setting the emitter potential of the TRQ3 a little bit lower than the potential at the connection point of the resistances R3 and R4, and also charges the capacitor C1 slowly when the power supply switch is turned on, so secondary operation such as lateral starting on the screen is prevented. |
