| 摘要 |
<p>The projector comprises a rectifier, a drive motor and an audio transmitter. The latter contains a sound head, an audio amplifier, and a selector switch for connecting a microphone, a tape recorder or a record disc player. The selector switch is incorporated in the control circuit of a gate switching stage. This stage is decoupled from the audio signal circuit and is connected between the audio amplifier and the sound head, or the audio connecting socket. The gate switching stage is insensitive to the mains frequency interface voltages and is mounted in close proximity to the audio amplifier and the audio connecting socket.</p> |
