75-ohm coaxial terminators are passive components designed to terminate 75-ohm coaxial cables, providing impedance matching to prevent signal reflections that can degrade transmission quality. These terminators are essential in systems where 75-ohm impedance is standard, such as video networks, cable TV, satellite communications, and broadcast equipment.

The core function of a 75-ohm terminator is to absorb incident RF signals at the end of a cable, converting the signal energy into heat instead of reflecting it back. This eliminates standing waves, which cause signal loss, distortion, or interference in the system. A well-matched terminator ensures that the voltage standing wave ratio (VSWR) remains below 1.2:1, minimizing signal degradation even over long cable runs.

75-ohm terminators are constructed with a resistive element (typically a carbon or metal-film resistor) rated for the system’s power level—ranging from 0.5 watts for low-power video systems to 50 watts for broadcast transmitters. The resistor is enclosed in a metal housing that matches the coaxial terminal type (e.g., BNC, F-type, or SMA), ensuring mechanical compatibility with the cable’s connector. Some terminators include a weatherproof seal or rubber O-ring, making them suitable for outdoor use in satellite dishes or outdoor cable runs.

Applications of 75-ohm terminators are widespread in video systems: they terminate unused ports on splitters, amplifiers, or patch panels in CCTV networks to prevent signal leakage. In cable TV distribution, they terminate the end of drop cables to maintain impedance consistency across the network. Broadcast studios use high-precision 75-ohm terminators to calibrate test equipment, ensuring accurate signal measurements. For digital video systems (e.g., SDI or HDMI over coaxial), these terminators are critical for maintaining signal integrity, as digital signals are more sensitive to reflections than analog ones.

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