| 摘要 |
A recharger applies a high frequency (about 100 kHz) preferably square wave pulsed d.c. current to a primary or secondary cell (BT1) to be recharged. An oscillator (26) supplies square waves to a current buffer (20), which draws current at terminal (16) when the input is on to cause the battery (BT1) to be recharged via resistor R2. A load (R20) is connected across the battery (BT1) by transistor (Q1) during the charging pulses, and the voltage on the battery terminals (21, 22) is allowed to float between charging pulses. Comparators (28, 29) prevent charging when the battery voltage is below 1 V or above 1.6 V, respectively corresponding to unchargeable and fully charged conditions of a primary cell battery (BT1). This can be changed to 0 V and 3.6 V for secondary e.g. NiCad, cells. Switch S3 allows for the charging current to be varied depending on battery size. The circuit is arranged such that the falling edges of the charging current pulses produce a short spiked reverse pulse. The above features may be used with a pulsed charging current in general, in place of the high frequency current.
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