Under constant-voltage charging, the current drawn from discharged to fully charged state_____________?
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Answer: A. decreases
Explanation
Under constant-voltage charging, the applied voltage remains fixed while the battery terminal voltage increases. This rising internal voltage acts as a back-EMF that opposes the fixed charging source voltage. Consequently, the potential difference driving current into the battery decreases, causing the charging current to drop. Constant-voltage chargers maintain a steady potential difference across the battery terminals throughout the entire cycle. As a lead-acid battery accepts charge, its internal chemical state changes and its terminal voltage naturally rises. Ohm's law dictates that current flow is proportional to the voltage difference divided by internal resistance.
Current increases would occur if the charger voltage were continuously raised relative to the battery terminal voltage. Remaining constant contradicts the fundamental electrical behavior of circuits operating under fixed voltage conditions. None of the above is incorrect because current clearly decreases as the battery approaches a fully charged state.
- Subject
- Engineering
- Category
- Electrical Engineering
- Topic
- —
- Difficulty
- medium
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