Pófalowy

Półfalowy is an adjective in Polish used to describe something related to a half wavelength or half a cycle. The standard form is półfalowy; forms without the diacritic, such as pófalowy, are generally considered incorrect in formal writing. The term is common in physics, electronics, and optics, where it appears in phrases such as prostownik półfalowy and retarder półfalowy.

In electronics, a half-wave rectifier (prostownik półfalowy) uses a single diode to convert alternating current into pulsating direct current by conducting only during one half of the input cycle. The output is a pulsating sine wave with ripple. The theoretical maximum efficiency for a resistive load is about 40.6%. Practical values depend on filtering, transformer design, and diode losses. Because of the limited DC output and higher ripple, half-wave rectifiers are inexpensive and simple but have largely been supplanted by full-wave rectification in most power supplies, though they still appear in simple detectors or specialized circuits.

In optics, a half-wave plate (retarder półfalowy) is a birefringent element that introduces a phase retardation of one half-wavelength (π radians) between two orthogonal polarization components. It rotates linear polarization by twice the angle between the incident polarization and the plate’s optical axis. Half-wave plates are widely used for polarization control, modulators, and fiber-optic applications; they are often discussed alongside quarter-wave (ćwierćfala) retarders.

Etymology and usage: the term combines fala (wave) with the prefix pół- (half) and appears in various technical contexts to denote half-wavelength phenomena or devices.