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This circuit is called a leading-edge dimmer or forward phase dimming. Waveform of the output voltage of a thyristor dimmer set for 60 volts RMS output, with 120 V input. The red trace shows the output device switching on about 5.5 ms after the input (blue) voltage crosses zero.
[4] Stalling is caused by flow separation which, in turn, is caused by the air flowing against a rising pressure. Whitford [5] describes three types of stall: trailing-edge, leading-edge and thin-aerofoil, each with distinctive Cl~alpha features. For the trailing-edge stall, separation begins at small angles of attack near the trailing edge of ...
Leading edge modulation (top plot) uses a reverse sawtooth wave to generate the PWM. The PWM's leading edge is held at the leading edge of the window and the trailing edge is modulated. Trailing edge modulation (middle plot) uses a normal sawtooth wave to generate the PWM. The PWM's trailing edge is fixed and the leading edge is modulated.
A rising edge (or positive edge) is the low-to-high transition. [1] A falling edge (or negative edge) is the high-to-low transition. [1] In the case of a pulse, which consists of two edges: The leading edge (or front edge) is the first edge of the pulse. The trailing edge (or back edge) is the second edge of the pulse.
The top of all sails is called the head, the leading edge is called the luff, the trailing edge is the leech, and the bottom edge is the foot. Head – The head is the upper edge of the sail, and is attached at the throat and peak to a gaff, yard, or sprit. [7] For a triangular sail the head refers to the topmost corner.
The angle between the upper and lower surfaces at the trailing edge is called the trailing edge angle. If the trailing edge angle is zero it is described as a cusped trailing edge. [5] In two-dimensional flow around a uniform wing of infinite span, the slope of the lift curve is determined primarily by the trailing edge angle. The slope is ...
Aerofoil nomenclature showing chord line Chord line of a turbine aerofoil section. Chords on a swept-wing. In aeronautics, the chord is an imaginary straight line segment joining the leading edge and trailing edge of an aerofoil cross section parallel to the direction of the airflow.
Two effects are responsible for this: the waveform of the voltage emitted by a standard phase-control dimmer interacts badly with many ballasts, and it becomes difficult to sustain an arc in the fluorescent tube at low power levels. Dimming installations require a compatible dimming ballast.