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现在的电话机都具有重发前次电话号码或储存常用号码的功能。要具备这些功能,除了机内发码集成块具有相应空间的存储器(号码从几个到几十个,位长从几位到几十位)外,还必须具备记忆维持电路。记忆维持电路的作用就是在话机处于挂机状态下,给发码集成块提供记忆维持电源,使通过话机键盘输入的存储号码,在挂机时不致于丢失。 一、常见的记忆维持电路有以下三种 1.电容器储能记忆维持电路 电容器储能记忆维持电路如图1所示。电容器C并联在发
Today’s telephones all have the ability to resend the last phone number or store a common number. To have these functions, in addition to the internal code-chip integration block with the corresponding space memory (number from a few to dozens of bit length from a few to tens of bits), you must also have a memory to maintain the circuit. Memory maintenance circuit is the role of the phone is on-hook state, to send code block to provide memory to maintain power supply, so that the phone keypad to enter the storage number, while on-hook will not be lost. First, the common memory to maintain the circuit has the following three 1. Capacitor storage memory to maintain the circuit Capacitor energy storage to maintain the circuit shown in Figure 1. Capacitor C is connected in parallel