Search results
Results from the WOW.Com Content Network
Half-wave rectification requires a single diode in a single-phase supply, or three in a three-phase supply. Rectifiers yield a unidirectional but pulsating direct current; half-wave rectifiers produce far more ripple than full-wave rectifiers, and much more filtering is needed to eliminate harmonics of the AC frequency from the output.
Figure 2.Greinacher circuit. The Greinacher voltage doubler is a significant improvement over the Villard circuit for a small cost in additional components. The ripple is much reduced, nominally zero under open-circuit load conditions, but when current is being drawn depends on the resistance of the load and the value of the capacitors used.
Between the circuit's input and output is a diode that performs half-wave rectification, allowing substantial current flow only when the input voltage is around a diode drop higher than the output terminal. The output is connected to a capacitor of value and resistor of value in parallel to ground. The capacitor is charged as the input voltage ...
The 866 is a mercury vapor half-wave rectifier intended for high-voltage applications. The voltage drop is approximately 15 volts up to 150 Hz. To avoid unwanted shorts the tube must be operated in a vertical position and the filament preheated for at least 30 seconds before applying the plate voltage.
Pulsed DC is commonly produced from AC (alternating current) by a half-wave rectifier or a full-wave rectifier. Full wave rectified ac is more commonly known as Rectified AC. PDC has some characteristics of both alternating current (AC) and direct current (DC) waveforms.
When the AC voltage is applied, the rectified line voltage is applied across C1 and C2, as they are both charged via D3 and R1, until C1 and C2 are each charged up to approximately half of the peak line voltage. When the line voltage falls below the peak, into the "valley" phase, Vout begins to fall toward half of the peak line voltage.
A common arrangement is to allow the rectifier to work into a large smoothing capacitor which acts as a reservoir. After a peak in output voltage the capacitor supplies the current to the load and continues to do so until the capacitor voltage has fallen to the value of the now rising next half-cycle of rectified voltage.
Whereas normal semiconductor diodes have a roughly fixed voltage drop of around 0.5 to 1 volts, active rectifiers behave as resistances, and can have arbitrarily low voltage drop. Historically, vibrator -driven switches or motor-driven commutators have also been used for mechanical rectifiers and synchronous rectification.