MFJ-299 has a high quality compressoramplifier 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。
2
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。
3
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.