| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of parts of an amplifier circuit for obtaining a sawtooth wave and a triangular wave. SOLUTION: A time-constant capacitor C is connected between an emitter-follower output resistor Ra and a time-constant resistor R to generate Miller effect that seemingly makes the time-constant capacitance C multiplied by an amplification degree (G/0.99-1). A voltage obtained thereof is amplified by an operational amplifier by being multiplied by A=G/0.99-1, and a triangular-wave voltage is obtained. When the charging of the time-constant capacitor C of the NPN transistor emitter follower from an astable multivibrator circuit, which is located in the front stage of the NPN transistor emitter follower circuit, finishes and the discharging starts, a connected diode turns to be in the forward direction. The capacitor C therefore discharges through the collector resister of the transistor not making the amplification in the astable multivibrator, and the latter half part of the voltage waveform latter from the top of the triangular voltage suddenly goes down, resulting to yield a sawtooth wave voltage. COPYRIGHT: (C)2008,JPO&INPIT
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