AC Power

AC power is supplied by an alternating electrical system: the voltage changes polarity periodically. Lighting equipment commonly identifies its accepted mains input with an AC voltage range and a frequency in hertz.

Voltage and frequency

A marking such as 100–240 V AC, 50/60 Hz describes the supply conditions accepted by that input. The voltage number is normally an RMS value. Frequency and voltage are separate specifications, and a different plug adapter does not convert either one.

Practical example

An LED fixture may receive AC at its power supply and use regulated DC internally. Its mains-input current is therefore not the same as its LED current or DC-head connection current. Read the specification for the correct side of the system.

Power calculations and camera behaviour

Real AC input power depends on voltage, current and power factor. Startup inrush is a separate characteristic. An AC input also does not determine camera flicker by itself: the lamp, ballast or driver and selected operating mode affect the light-output waveform. Test the fixture at the intended frame rate and shutter setting.

Equipment examples

The Aputure LS 600x Pro uses a powered LED system, while the ARRI True Blue T2 uses a tungsten lamp. Their input and dimming requirements differ.

Related terms

DC Power · Voltage · Amperage · Power Factor · Flicker

References

Fluke: voltage, AC and DC · Fluke: electric current · MEAN WELL: power-supply operation and inrush

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