目前,各厂矿的电话交换机大多数都采用蓄电池组供电,尽管电源质量较好,但其维修使用较麻烦,而且至少需两组电池经常转换其充、放电状态。近年来,使用容量较大、稳定度较高的直流稳压电源为各种类型的电话交换机做工作电源之用,但使用中也存在一些问题:一般晶体管直流稳压保护功能不完善,容易引起损坏机台设备的事故,同时仍需要有一组至 At present, most factories and mines’ telephone exchangers are powered by battery packs. Although the power supply is of good quality, their maintenance is cumbersome, and at least two sets of batteries are often required to switch their charge and discharge states. In recent years, the use of larger capacity, higher stability of the DC power supply for all types of telephone exchanges to do the work of the power supply, but there are also some problems in the use of: General transistor DC voltage protection is imperfect, easily lead to Damage to the machine equipment accident, but still need to have a group to