说明：  经过四天的努力，终于把数控电源整出来了，呵呵 ！外加负载测试，输出电流可以达到500mA，这主要是由LM317决定的，它的输入与输出电压的压差是1.25-37V，而我们用的是12V的变压器，因此满量程时，带负载的能力受到一定的限制，要提高在12V的带负载能力可以用15V或更高一点的变压器。设计电路时，这一点是值得注意的。
(After four days of efforts, finally the whole CNC power out, huh, huh! Plus load testing, the output current can reach 500mA, which is mainly determined by the LM317, and its input and output voltage of the pressure difference is 1.25-37V, and we are using a 12V transformer, so when the full-scale, with load capacity subject to certain restrictions, it is necessary to improve in 12V with load capacity can be 15V or higher point of the transformer. Circuit design, it is worth noting.)