Grounded and not grounded full wave Rectfiers

[PrescottDan]

I see this in schematics often when they use two different full wave rectifiers on separate coils from the AC power transformer. I don't understand why they use a full wave rectifier that is grounded by the rectifier diodes or they ground it from a center tap on the transformer. Take a look at the drawing

What is the difference between these two types of full wave rectifiers and when do you use one or other other? for what type of circuits?

Do you use one rectifier for DC circuits and the other for Logic circuits?

 

[gstekboy]

First rectifier circuit have only single output line (For AC there must be potential difference to flow the current), so ground is necessary.
Second rectifier circuit have two output line, one output at a time function as ground or change potential.

 

[dimmich]

Maybe you have not noticed (and maybe noticed) - these schemes are completely identical, the only difference is, one conductor is connected to ground, or not. Just different pictures, and the diodes are connected between themselves are equally.

The first scheme is typically used when a single supply when minus power scheme must be common wire.

The second can be used the same way, if the scheme did not use the symbol notation common wire, but this common wire drafted as a separate conductor. Still the second scheme can be used in circuits with bipolar power, then the transformer must have an average output that is connected to the common wire circuit, and two outputs of the diode bridge will leave positive and negative power supply circuit.

 

[PrescottDan]

They are both full wave rectifiers?

One is a single ended full wave rectifier having one output? and the other is a Bi-polar full wave rectifier having 2 outputs?

 

[chuckey]

YES, each AC input goes to a anode and a cathode, each positive output comes from two cathodes and the negative output comes from two anodes. In the first diagram the the negative output is earthed.
Frank

 

[dimmich]

I would not say that, as you say. On both schemes - identical diode bridge, it is full wave rectifier. A method of using and connecting determines whether he will be a rectifier with one output, or will be bi-polar full wave rectifier having two outputs. If you finish a second scheme, add a transformer with center tap, then we can talk about the second circuit with a diode bridge as a bi-polar rectifier with two terminals.

Such as a resistor: can shunting, or can pull the voltage. In the diagram the same resistor drawn equally. But different methods of using a resistor name differently: shunt or pullup.