30V

Thirty volts, denoted 30 V, is the unit of electric potential difference in the International System of Units. It represents the energy per unit charge that would be transferred between two points in an electric circuit. By Ohm's law, the current that flows through a component depends on its resistance, with I = V/R. For example, at 30 V, a 1-ohm resistor would draw about 30 A (in ideal conditions), illustrating that voltage alone does not determine safety; current does.

In practical use, 30 V is a common low-to-moderate voltage in electronics and instrumentation. Adjustable bench power supplies frequently offer outputs up to 30 V DC, while many automotive, industrial, and consumer devices operate in the 24–30 V range. Components such as LED drivers, motor controllers, and certain battery packs may be rated for a maximum of 30 V. In some contexts, 30 V appears as the rating for low-voltage lighting and test equipment.

Safety: While 30 V is below many high-voltage levels, it can still cause dangerous currents, especially if the skin is wet or the current path includes critical organs. Always follow local safety standards, use insulated tools, and employ proper fusing and enclosures. Disconnect power before servicing circuits.

Measurement: A digital multimeter can measure DC 30 V. To test live circuits, use the meter according to the manufacturer’s instructions, ensuring correct selection of DC voltage range and proper probe placement.

Origin: The volt is named after Alessandro Volta; 30 V is simply a specified potential difference expressed in that unit.