Reservoir capacitor: Difference between revisions
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A '''reservoir capacitor''' is a [[capacitor]] that is used to smooth the pulsating DC from an AC [[rectifier]]. |
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The pulsating DC from an AC [[rectifier]] (either half-wave or full-wave) usually needs to be smoothed before use. This can be done using a Reservoir [[capacitor]]. |
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[[Image:Reservoircapdiagram.gif]] |
[[Image:Reservoircapdiagram.gif]] |
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==Performance with low impedance source== |
== Performance with low impedance source == |
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[[Image:Reservoircapidealised.gif]] |
[[Image:Reservoircapidealised.gif]] |
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The above diagram shows reservoir performance from a near zero impedance source, such as a mains supply. As the rectifier voltage increases, it charges the capacitor and also supplies current to the load. At the end of the quarter cycle the capacitor is charged to its peak value Vm of the rectifier voltage. Following this the rectifier voltage starts to decrease as it enters the next quarter cycle. This initiates the discharge of the capacitor through the load. |
The above diagram shows reservoir performance from a near zero [[impedance]] source, such as a mains supply. As the rectifier [[voltage]] increases, it charges the capacitor and also supplies [[current]] to the load. At the end of the quarter cycle, the capacitor is charged to its peak value Vm of the rectifier voltage. Following this, the rectifier voltage starts to decrease as it enters the next quarter cycle. This initiates the discharge of the capacitor through the load. |
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==Performance with significant impedance source== |
== Performance with significant impedance source == |
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These circuits are very frequently fed from |
These circuits are very frequently fed from [[transformer]]s, and have significant [[resistance]]. Transformer resistance modifies the reservoir capacitor waveform, changes the peak voltage, and introduces regulation issues. |
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==See also== |
==See also== |
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* [[ |
* [[Diode]] |
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* [[Diode bridge]] |
* [[Diode bridge]] |
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Revision as of 07:33, 15 July 2008
A reservoir capacitor is a capacitor that is used to smooth the pulsating DC from an AC rectifier.
Performance with low impedance source
The above diagram shows reservoir performance from a near zero impedance source, such as a mains supply. As the rectifier voltage increases, it charges the capacitor and also supplies current to the load. At the end of the quarter cycle, the capacitor is charged to its peak value Vm of the rectifier voltage. Following this, the rectifier voltage starts to decrease as it enters the next quarter cycle. This initiates the discharge of the capacitor through the load.
Performance with significant impedance source
These circuits are very frequently fed from transformers, and have significant resistance. Transformer resistance modifies the reservoir capacitor waveform, changes the peak voltage, and introduces regulation issues.