| 摘要 |
<p>TAPE PLAYER PREAMPLIFIER CIRCUIT A preamplifier circuit for a tape player includes a voltage-follower transistor which is operable when turned on to establish the output bias voltage of the preamplifier circuit at substantially a reference voltage. In turn, a voltage divider network develops the reference voltage coincident with energization of the tape transport mechanism. Due to the inertia of the tape transport mechanism, the speed of the tape remains below that necessary for undistorted operation during a start-up time period immediately following energization of the tape transport mechanism. An RC network is responsive to development of the reference voltage to provide a time delay such that the voltagefollower transistor is prevented from turning on until after expiration of the start-up time period. Thus, the output bias voltage of the preamplifier circuit is not established until the tape speed is sufficient to permit undistorted operation.</p> |
