MFJ-299 has a high quality compressor amplifier with high, medium, and low selection switches.

MFJ-299 有有高度，媒体和低的选择开关的一个高的质量压缩物喇叭筒。

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It is only when the correct voltages are applied to the A/C amplifier from the key inputs that the primary output (the A/C compressor relay) will be energised.

只有A/C扩大器上的电压是来自输入端的正确电压时，初级输出（即A/C压缩机继电器）才会被激活开启。

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Once the circuit is broken the amplifier detects the voltage change in this circuit and de-energises the magnetic clutch relay, turning the compressor off.

一旦线路断开，扩大器探测到线路上的压强变化，就会停止电磁离合继电器运行，关闭压缩机。

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