Vminus

Vminus is a designation found in electrical and electronic schematics and documentation that commonly refers to the negative input, or inverting input, of an operational amplifier (op-amp) or comparator. In many circuit diagrams the inverting input is labeled V- or Vminus to distinguish it from the non-inverting input, which is labeled V+ (or Vplus). The term can also appear in SPICE models and other circuit simulations where nodes are given descriptive names.

In addition to identifying the inverting input, Vminus can also denote the negative supply rail in some contexts, where a circuit uses dual supplies such as V+ (positive supply) and V- (negative supply). The exact meaning depends on the circuit and documentation: some authors use V- to label a node at the negative input, while others use V- specifically for the supply rail. Because naming conventions vary by manufacturer, CAD tool, and region, it is important to review accompanying notes or a schematic legend to determine whether Vminus refers to the inverting input node or the negative supply line.

Usage and conventions vary. In many educational and industrial diagrams, Vminus is explicitly paired with Vplus for the input pair and is distinct from supply rails labeled Vcc, Vdd, Vee, or Vss. Understanding the context within the schematic is essential to correctly interpreting Vminus.