microamperes

The microampere (µA) is a unit of electrical current equal to one millionth of an ampere. The symbol µA is standard, though in plain text you may see uA. By definition, 1 µA = 10^-6 A; equivalently, 1 A = 1,000,000 µA, and 1 mA = 1,000 µA, while 1 nA = 0.001 µA.

Microamperes are convenient for describing small currents in electronics, sensors, and bioelectrical measurements. In low-power circuits, devices such as microcontrollers and sensors may draw a few µA in standby, with active operation rising to hundreds of µA or more. In integrated circuits, bias and leakage currents often lie in the µA to nA range, and in MEMS sensors currents vary from tens to hundreds of µA depending on modality and operating mode.

Measurement of microamperes is typically performed with multimeters set to the µA range, or with more sensitive instruments such as picoammeters for higher precision. Accuracy depends on the instrument’s burden voltage and range, as well as the circuit design.

Examples of contexts involving microamperes include small photodiode or gas sensor circuits that generate currents in the µA range, low-power sensor interfaces that draw a few µA in idle, and analog ICs where certain bias currents are specified in µA. Larger currents in the same systems are usually expressed in milliamperes or higher, while even smaller currents are in nanoamperes or picoamperes.

See also: milliampere, nanoampere, picoampere, ampere.