3-cell battery holder

A 3-cell battery holder is a compact housing designed to secure three individual battery cells, typically arranged in a side-by-side or "flat" configuration. These holders are widely used in projects requiring a specific voltage range, such as $3.6\text{V}$ to $4.5\text{V}$, which is common for many microcontrollers and LED applications. Series Output: The voltages of the three cells are added together. Alkaline Cells (1.5V each): Total output of 4.5V. NiMH Rechargeable (1.2V each): Total output of 3.6V. Lithium-Ion (3.7V each, e.g., 18650): Total output of 11.1V. Wiring: Usually features a standard 2-wire output (Red for positive, Black for negative). Some advanced models include a third "center-tap" wire for specialized circuit balancing.