PAGE 124 OF 150 · POWER SUPPLIES & BATTERIES
Lithium Coin Cells
Coin cells have limited current capability.
LED SYMBOLTriangle points from anode to cathode; the arrows show light leaving the part.
About CR2032
The CR2032 is a 3 V lithium coin cell, 20 mm across and 3.2 mm thick, with a capacity of roughly 220 mAh. It suits small circuits but can supply only a few milliamps continuously.
- Use red, yellow or orange LEDs, whose forward voltage is low.
- Keep the current at a few milliamps or use short flashes.
- Rechargeable lookalikes such as LIR2032 give 3.6 V.
Safety
Swallowed coin cells are dangerous, especially for children. Keep them away from young children and dispose of used ones safely.
REMEMBER
Coin cells suit tiny, brief, low-current loads.Try it yourself
Sketch the circuit on paper first, calculate the values, then build it on a solderless breadboard using a low-voltage supply. Measure with a multimeter before you make anything permanent.
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