论文部分内容阅读
上海航天热工仪表厂生产的HW8501型无绳电话机对手机充电是采用了限流式充电电路(见图1),充电电流随着电池电压逐渐上升而减少,当电池充满时,充电电流维持在二十几毫安,此电话作为办公使用,手机电池处于正常充、放电使用状态,而对于使用率较少的家庭来说,手机充电电池总处于过充状态,再由人工控制充电时间,充电量也难以掌握,长期过充、过放都极易损坏镍镉电池,很难保证手机的正常使用。图2为改进的镍镉电池自动充电电路。时基555作为比较器工作,其基准电压由稳定管D_3提供2.6V电压,W_1调定电压下限值3.8V加到IC_1的第②脚,W_2调定电压上限值4.2V加到IC_1的第⑥脚。当电池电压不足时,IC_1的第②脚
The HW8501 cordless phone manufactured by Shanghai Aerospace Thermometer Factory uses a current-limited charging circuit (see Figure 1). The charging current decreases as the battery voltage gradually increases. When the battery is fully charged, the charging current is maintained at Twenty a few milliamperes, the phone as a office use, cell phone batteries in the normal charge, discharge the use of the state, and for less used families, the phone is always overcharged battery state, and then manually control the charging time, charging The amount is also difficult to grasp, long-term overcharge, over discharge are easily damaged nickel-cadmium batteries, it is difficult to ensure the normal use of the phone. Figure 2 shows an improved nickel-cadmium battery automatic charging circuit. The time base 555 operates as a comparator whose reference voltage is supplied by the stabilizing tube D_3 at 2.6V, the lower limit value of the setting voltage of W_1 at 3.8V is added to the second leg of IC_1, the upper limit voltage of 4.2V is set at 4.2V to IC_1 The ⑥ foot. When the battery voltage is low, the first leg of IC_1