| 摘要 |
PURPOSE:To attain stable operation of a prescaler by adopting the circuit constitution that a tuning voltage terminal and a prescaler IC connected to an unregulated power supply in a television receiver and a video tape recorder are connected by a resistor so as to apply a current to a prescaler section from both terminals at the same time. CONSTITUTION:A current flowing ratio I1/I2 to the prescaler section 3 from a regulated power supply 1 and the unregulated power supply is decided by a prescaler stability operating condition and resistors R1, R2 are decided by prescaler section consumption current I1+I2. In using a various kind of IC, e.g., a high sensitivity IC or an IC having different operating specification depending on a manufacture, a current from the tuner voltage terminal 2 connected to the stabilized power supply in the current supply to the prescaler section 3 in this electronic tuner is utilized. Further, the cost reduction in the set and the light weight of a transformer are attained.
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