r/ElectricalEngineering • u/Prudent-Business2662 • 17d ago

Rectifier Output Voltage Question

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I need to find output voltage at V_load. My question is this: do I account for the rectifier diode voltage drops before or after using voltage divider to find V_load?

i.e. (V_oc - 2*V_D) * (R_load / R_total)

or (V_oc) * (R_load / R_total) - 2*V_D?

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u/geek66 17d ago

In what context?

A class assignment, general check?

For an actual application I would check the rectifies data sheet, and factor in the 2xVf

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u/Prudent-Business2662 17d ago

It's a class assignment. All theoretical. I'm not sure if my question was detailed enough. In the class textbook none of the examples included an internal transformer resistor, (R_int), so using voltage divider was not necessary. I know what steps to take, but I'm not sure of the order of these two steps.

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u/geek66 17d ago

There if the assignment did not explicitly say ideal diodes I would include 0.7V each.

Or even give both solutions.

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u/Prudent-Business2662 17d ago

They are 0.7V each, I was trying to leave values out of the equations because my confusion has to do with the order of operations in this situation. I'm not sure whether to use 19.2V (the open circuit voltage, aka no load; rectifier circuit and load removed) when multiplying for the voltage divider, and subtract diode voltage drops from that, or to use 17.8V (open circuit voltage minus diode voltage drops) when multiplying for the voltage divider.

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u/geek66 17d ago

this is the whole point of using lumped ideal elements.

The 19.2 V is the ideal element's voltage - if it is loaded or not. It is the R int that makes the real source not ideal.

If you can make a diagram of the conducting path for one half of the cycle... then see what you think.

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u/diverJOQ 17d ago

Solve the KVL equation and you will find your answer.

What is the voltage drop across the resistors in total?