negativevoltage

Negative voltage refers to a voltage value with a sign opposite to a chosen reference potential, typically ground. In electronics, voltage is a potential difference between two points, and its sign depends on how the points are labeled. If a node has a potential of -5 volts relative to ground, that node is described as having a negative voltage with respect to ground.

Sign conventions determine how negative values arise. If you define V as the potential at point A minus the potential at point B (V = VA − VB), a negative result means that A sits at a lower potential than B. The same physical situation can be described with a positive value if you swap the reference labels.

Negative voltage is produced by power supplies and circuit techniques that create a rail below ground. Common sources include dual-rail power supplies (providing both +V and −V), charge pumps and inverters, rectifiers, and DC-DC converters. These arrangements enable op-amps and other analog circuits to swing signals around ground or to bias components in a desired way.

Measurement involves a voltmeter or oscilloscope with a defined reference point. The reading’s sign depends on which lead is designated as the positive terminal. Safety considerations focus on the voltage magnitude and isolation rather than polarity alone; components must be rated for the expected negative potential relative to the reference.

Applications include biasing and signal processing in dual-supply amplifiers, RS-232 communications, sensor interfaces, and any circuit requiring a reference below ground. Negative voltage is a fundamental concept in circuit design, not an intrinsic property of energy, and its use depends on chosen references and ratings.