Emiteerija

Emiteerija is a term used in Estonian and other contexts to denote a source that emits something, such as electrical charge, light, or particles. In electronics and solid‑state physics, it is most often encountered as the emitter of a transistor or other device that injects carriers or radiation into another region.

In the context of bipolar junction transistors (BJTs), the emiteerija refers to the emitter region or terminal. The emitter is typically heavily doped relative to the base to provide high injection efficiency, allowing majority carriers to be injected into the base. In forward-active operation, the emitter-base junction is forward biased while the base-collector junction is reverse biased. The emitter current is the sum of carriers injected from the emitter and those arriving at the emitter from the base, and it largely governs the transistor’s current gain. A common circuit configuration is the emitter follower (common-collector), in which the emitter voltage closely follows the base voltage minus the base-emitter drop.

Beyond transistors, emiteerija can describe any source of emission in optics and photonics, such as light-emitting diodes, lasers, or incandescent sources. In these contexts, the emitter determines spectral output, intensity, and efficiency. In vacuum electronics, thermionic and field-emission sources function as emitters of electrons for electron guns and related devices, while photocathodes serve as light-activated emitters.

Overall, emiteerija denotes the component or region that provides the emission, with its specific role and characteristics varying across electronic, optical, and vacuum technologies.