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Full Wave Rectifier

Nael

Oct 12, 2016
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Hello guys,

I have question, I attach schematic of a full wave rectifier (each half wave schem).

Notice the current flow arrow. That confuses me really.

Would anyone explain the current flow and direction from the transformer to the load and going back! Try make it in simple words, such as Transformer to diode to etc.

Thank you,
 

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Harald Kapp

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Notice the current flow arrow. That confuses me really.
The arrow indicates the electron flow, whereas the so called "technical direction of current" (which is commonly used) is from plus to minus.
The current as shown in the original diagram would have a negative sign.
I indicated the current flow during the two half waves of the sine in red whereas the blue lines indicate where no current can flow due to the diodes blocking.
 

Nael

Oct 12, 2016
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The arrow indicates the electron flow, whereas the so called "technical direction of current" (which is commonly used) is from plus to minus.
The current as shown in the original diagram would have a negative sign.
I indicated the current flow during the two half waves of the sine in red whereas the blue lines indicate where no current can flow due to the diodes blocking.

Are you supposed to attach any photo!! I don't see where is the blue and red indication you talk about!
 

Bluejets

Oct 5, 2014
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During the first half cycle, current flows upwards in the transformer, through diode D1, through inductor LF and down through load RL, through the ground connection and back through the transformer centre tap.
On the second or negative half cycle, current flows down through the transformer, through D2 , up through inductor LF once again and down through the load RL , back once again to the centre tap.
Hence the current flow through the load is always in the same direction.
 

Audioguru

Sep 24, 2016
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The drawing shows voltage polarities. Electrons flow from negative to positive.
A diode conducts when its anode is positive and its cathode is negative. When the polarity across the diode is reversed then it does not conduct.
 

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Nael

Oct 12, 2016
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During the first half cycle, current flows upwards in the transformer, through diode D1, through inductor LF and down through load RL, through the ground connection and back through the transformer centre tap.
On the second or negative half cycle, current flows down through the transformer, through D2 , up through inductor LF once again and down through the load RL , back once again to the centre tap.
Hence the current flow through the load is always in the same direction.

Thank you, but if the current goes through inductor to Load, why the current flow shows otherwise (opposite) on schematic!!
 

Nael

Oct 12, 2016
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The drawing shows voltage polarities. Electrons flow from negative to positive.
A diode conducts when its anode is positive and its cathode is negative. When the polarity across the diode is reversed then it does not conduct.

Thank you really for taking time on schematic, my question, isn't the flow supposed to go from inductor to load! why the electrons flow the opposite way on schematic!!
 

davenn

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Thank you really for taking time on schematic, my question, isn't the flow supposed to go from inductor to load! why the electrons flow the opposite way on schematic!!


don't get stressed out about the difference between conventional current flow ( + to -) and electron flow (- to +)
it's not going to make any difference which you use in most circuits, including the one you are looking at
 

Nael

Oct 12, 2016
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don't get stressed out about the difference between conventional current flow ( + to -) and electron flow (- to +)
it's not going to make any difference which you use in most circuits, including the one you are looking at

Exactly that's what drives me crazy, one schematic I read is in conventional flow and the other is (-to+) don't know how to trace anymore lol
 

Bluejets

Oct 5, 2014
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Don't fuss over it, just accept it.
Wait until you start with transistor theory and the movement of electrons one way or holes in the opposite direction.
 

Ratch

Mar 10, 2013
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Hello guys,

I have question, I attach schematic of a full wave rectifier (each half wave schem).

Notice the current flow arrow. That confuses me really.

Would anyone explain the current flow and direction from the transformer to the load and going back! Try make it in simple words, such as Transformer to diode to etc.

Thank you,

Another example of how technical slang can confuse and bemuse folks. Current flow means "charge flow flow", which is redundant and ridiculous. Current already means charge flow, so you don't have to say it twice. You should instead say current exists, or current is present, or just plainly say current.

You will really meet yourself coming and going if you worry about the polarity of the charge carriers. Don't do that. Always use the mathematical convention, which is that current leaves the positive terminal of a voltage/current source and enters the negative terminal of the same source. Do all your calculations using that rule. Then, if you really need to know the direction of the charge carriers, reverse the calculated direction for negative carriers and keep the direction for positive carriers. Some conduction paths, like electrolytic reactions have negative electrons going one way and positive ions going the opposite direction. Diodes have electrons and holes going the opposite directions. Just use the mathematical convention and you won't get wrapped around the axle. Notice also that ammeters and semiconductor products like diodes are marked according to the mathematical convention.

The current direction of the attachment you presented is wrong. If you inserted a ammeter in series with the load resistor, it will indicate that the mathematical current direction is from top to bottom. No wonder you are confused.

Ratch
 

Audioguru

Sep 24, 2016
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Exactly that's what drives me crazy, one schematic I read is in conventional flow and the other is (-to+) don't know how to trace anymore lol
That is why I never look at "direction of current flow". Instead I simply look at the polarities.

A diode has an arrow, a transistor emitter also has an arrow. The arrow is pointing at the negative wire when the diode or base-emitter junction conducts with forward current (a zener diode is used with reverse polarity).
 

Harald Kapp

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Are you supposed to attach any photo!! I don't see where is the blue and red indication you talk about!
I'm sorry, the image got lost in translation :D
Here you are, see attachment
 

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