3V

3V is a designation for a voltage equal to three volts in the International System of Units. In electronics, 3V is used as a nominal supply voltage for small devices and as a standard for battery and power rails. The term is commonly encountered in battery labeling and circuit schematics.

The most common 3V sources are primary lithium coin cells, often called CR-series. Common models include CR2032, CR2025, and CR1632, all with nominal voltage around 3.0 V when new. They are non-rechargeable and are used in watches, calculators, remote controls, motherboards for real-time clocks, and some memory backup applications. Discharge reduces voltage gradually; devices specify a minimum operating voltage, typically around 2.0–2.5 V.

3V in electronics design: Modern low-power electronics often run on 3V supply rails, or on dual rails like 3.3V and 1.8V. A 3V supply can come from two lithium cells in series, a Li-ion cell with a regulator, or a dedicated 3V power rail. Designers consider regulator dropout, efficiency, and safety margins. Some sensitivity to voltage means that 3V logic levels exist, distinct from higher voltage families such as 5V logic.

Other uses: 3V may appear in product labels or model numbers indicating voltages, but it does not designate a unique standard outside electronics. In some science fiction or branding, 3V may appear as a name without technical meaning.