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Dimming fluorescent ballasts and dimming LED drivers often use 0–10 V control signals to control dimming functions. In many cases, the dimming range of the power supply or ballast is limited. If the light output can only be dimmed from 100% down to 10%, there must be a switch or relay available to kill power to the system and turn the light ...
Phase-fired control (PFC), also called phase cutting or phase-angle control, is a method for power limiting, applied to AC voltages. [1] It works by modulating a thyristor , SCR , triac , thyratron , or other such gated diode -like devices into and out of conduction at a predetermined phase angle of the applied waveform.
Flickering of all dimmer-controlled lighting, arising from external sources coupled via a shared utility transformer. Power-line flicker is a visible change in brightness of a lamp due to rapid fluctuations in the voltage of the power supply.
Solid-state, or semiconductor, dimmers were introduced to solve some of these problems. Semiconductor dimmers switch on at an adjustable time (phase angle) after the start of each alternating-current half-cycle, thereby altering the voltage waveform applied to lamps and so changing its RMS effective value. Because they switch instead of ...
The term brownout comes from the dimming experienced by incandescent lighting when the voltage sags. Brownouts can cause poor performance of equipment or even incorrect operation. A blackout is the total loss of power to a wider area and of long duration. [1] It is the most severe form of power outage that can occur.
In a cathode-ray tube television, the reduced output voltage will make the screen image smaller, dimmer and fuzzier. A linear DC regulated supply will maintain the output voltage unless the brownout is severe and the input voltage drops below the drop out voltage for the regulator, at which point the output voltage will fall and high levels of ...
The light may dim briefly as the motor starts. When the armature is not turning (called locked rotor) there is no back-EMF and the motor's current draw is quite high. If the motor's starting current is high enough, it will pull the line voltage down enough to cause noticeable dimming of the light.
Schematic of an inverter using a vibrator as a chopper.. In electronics, a chopper circuit is any of numerous types of electronic switching devices and circuits used in power control and signal applications.