Differences

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--- other:electronics:rectifier-circuit [2024/06/04 15:50] – [Calculation of ripple voltage] oscar
+++ other:electronics:rectifier-circuit [2024/06/14 12:34] (current) – [Transformer Selection] oscar
@@ Line 26: / Line 26: @@
   * ''** V//rms// = V//p// / √(2) **''
   * ''** V//rms// = V//pp// / (2 * √(2)) **''
-  * ''** V//pp// = √(2) * V//rms// **''
+  * ''** V//pp// = 2*√(2) * V//rms// **''
 ==== Triangle ====
@@ Line 63: / Line 63: @@
 We can improve the average DC output of the rectifier while at the same time reducing the AC variation of the rectified output by using smoothing capacitors to filter the output waveform. Smoothing or reservoir capacitors connected in parallel with the load across the output of the full wave bridge rectifier circuit increases the average DC output level even higher as the capacitor acts like a storage device.
-The ripple voltage can be calculated with the following formulas:
+For a full wave rectifier the ripple voltage can be calculated with the following formulas:
   * ''** V//r// = V//p// / ( f//r// * R//load// * C ) **''
@@ Line 73: / Line 73: @@
   * f//r// is the frequency of the ripple. Due to the rectifier this value is twice the frequency of the transformer. 50 Hz for half-wave rectification and 100 Hz for full-wave rectification.
   * C is the capacitance of the smoothing capacitor
+==== Calculation of ripple Factor ====
+For a full wave rectifier with filter the ripple factor can be calculated with the following formula:
+  * ''** Ripple factor =  1 / ( 4√3fCR ) **''
 Calculate the ripple factor of the output waveform as the ratio of the ripple voltage or current (also known as the RMS voltage) to the DC voltage.
@@ Line 78: / Line 82: @@
   * ''** Ripple factor =  √ ( ( I//rms// / I//dc// )² - 1 ) **''
+==== DC output Voltage ====
+**Please note:** the calculations below only work if the RC time is >> (x10) then the period T.
+E.g. in case of 100 hz (T=10ms) the RC should be in the range of 0,1 (100 ms) = 100 Ohm * 1000uF.
+{{ :other:electronics:rectifier-ripple.jpg?600 |}}
+For a full wave rectifier with filter the output voltage can be calculated with the following formula:
+  * ''** V//dc// =  V//p// - ( I//dc// / 4fC ) **''
+Substituting I//dc// with V//dc// / R this becomes:
+  * ''** V//dc// =  V//p// * 4fRC ) / ( 1 + 4fRC ) **''
+===== Transformer Selection =====
+Based on the above formulas, the table below calculates the required tranformer voltage to achieve a specific DC voltage.
+^Preferred Vdc^Stabilizer drop (V)^Vp^Rectifier Drop (V)^Trafo Vpp^Trafo RMS^
+| |  -3  | |  -1,4  | | |
+|  5  |  8  |  8,0  |  9,4  |  18,9  |  6,7  |
+|  9  |  12  |  12,1  |  13,5  |  26,9  |  9,5  |
+|  12  |  15  |  15,1  |  16,5  |  33,0  |  11,7  |
+|  15  |  18  |  18,1  |  19,5  |  39,0  |  13,8  |
+|  16  |  19  |  19,1  |  20,5  |  41,0  |  14,5  |
+|  18  |  21  |  21,1  |  22,5  |  45,0  |  15,9  |
+|  20  |  23  |  23,1  |  24,5  |  49,0  |  17,3  |
+|  24  |  27  |  27,1  |  28,5  |  57,1  |  20,2  |
 ===== Links =====
   * https://en.wikipedia.org/wiki/Rectifier
@@ Line 85: / Line 112: @@
   * https://www.studocu.com/en-za/document/central-university-of-technology/electronic-fundamentals-i/unit5-power-supply-design-3/14924637
   * https://gtuttle.net/circuits/topics/rectifiers.pdf
+  * https://www.physicsforums.com/threads/calculating-the-dc-value-of-the-output-voltage-for-a-full-wave-rectifier.1003323/
   * https://www.electronics-tutorials.ws/diode/diode_6.html
   * https://resource.download.wjec.co.uk/vtc/2016-17/16-17_1-9/gce-electronics-book-chapter-7.pdf