DCfält

DCfält is a term used to describe a constant field generated by direct current (DC). In physics and engineering it can refer to a constant electric field or a constant magnetic field, in contrast to time-varying fields produced by alternating current (AC).

An electric DC field arises from a static voltage difference and is often treated as time-invariant. In a uniform DC electric field, the field strength is E = V/d, where V is the potential difference and d the separation of conductors. In electrostatics the field is conservative, and the potential difference equals the negative line integral of E. Inside an ideal conductor, charges rearrange to cancel the field, while real materials may sustain a small field that drives a steady current. A DC field in dielectrics can produce polarization, and at sufficiently high voltages can cause dielectric breakdown.

A magnetic DC field is produced by steady currents or by permanent magnets and is also time-invariant. It is described by the magnetic flux density B, with units of tesla. DC magnetic fields are commonly approximated in laboratory setups such as Helmholtz coils to create uniform fields for experiments, calibration, or imaging contexts like MRI. In magnetic materials, a constant field tends to align magnetic moments and influence spin states.

Applications of DCfält include powering electronic devices, characterizing material responses to steady fields, and serving as stable references in sensors and precision instrumentation. Measurement of these fields uses instruments such as voltmeters in conjunction with field probes, gaussmeters, or teslameters, depending on whether the focus is electric or magnetic fields.