CR2032 · 3 VStainless can (+ terminal) · Ø 20 × 3.2 mmNegative cap (−, bottom face) · the gasket at the edge separates the two poles

Shiny metal flat disc, “+” and “CR2032” text on the wide face
20 mm diameter × 3.2 mm thick

Power supply

Coin cell (CR2032)

In simple terms

What is this?

A tiny flat battery the size of a coin.

What is it for?

It keeps clocks and backup memory that draw very little current running for a long time.

Where do you see it?

Car key, wristwatch and computer motherboard.

How do you spot it?

A flat round button; there is a plus sign and some text on its wide face.

Caution:

Very dangerous if swallowed, keep it away from children; do not try to charge it.

Technical definition

A flat, non-rechargeable battery using lithium-manganese dioxide chemistry. The 20 in the name gives the diameter (mm) and the 32 the thickness (3.2 mm). Because its internal resistance is high, it can only supply very small currents for a long time.

Voltage3 V

Capacitance≈220–240 mAh

Size20 × 3.2 mm

Schematic symbol Same in IEC and ANSI

IEC 60617: the drawing style used in Türkiye and Europe.

Pins 2

1Plus (+)Wide face with the markings, and the edge+

2Minus (−)Small face underneath−

Features typical

Nominal voltage: 3 V
Capacitance: ≈220–240 mAh
Continuous current: A few mA
Cutoff voltage: 2.0 V
Chemistry: Li-MnO₂
Charge: Not rechargeable
Example part: CR2032

Common mistakes

Drawing high currentBecause of its high internal resistance, the voltage sags when it supplies a lot of current, and the battery drains fast. It is not suitable for motors and bright LEDs.

Leaving it within reach of childrenSwallowing it causes serious internal burns. Keep it away from small children.

Holding it with metal tweezersIf metal tweezers touch both faces at the same time, they short the battery. Use plastic tweezers or hold it by the edge.

Test with a multimeter

Test whether this part is good with the multimeter on the measurement screen.

Take a measurement

Where it is used

Motherboard clockRTC module backupCar key and small remoteScale and small sensor