On Sunday, March 26, 2023 at 8:56:55 PM UTC-4, Commander Kinsey wrote:
> I have a centre tapped transformer I wanted to get the most power out of. Thinking a traditional full wave rectifier (just a diode on each side, calling the centre tap 0V at the output) is only running current through one half of the secondary at a time, which is inefficient (think of P=i^2R), I thought about putting a bridge rectifier on each half, then connecting the result in parallel. I made the following diagram by adjusting someone else's, so it may look a bit odd.
>
> https://i.imgur.com/d2TfZYO.jpg
>
> I'm a bit confused here because you can trace the current flow and show the output has both 24V (if the current goes through the "wrong" bridge on the way back) and 12V at the same time, which isn't possible. Can someone explain what would happen in this circuit?
>
> Any way to make this work? I want current flowing through both halves of the secondary all the time. But I want half the full secondary's voltage.

I don't expect you will see this post, because I think you have blocked google groups. But this circuit will not work as you expect. Rather than trace current, try figuring out the voltages. That might be more clear.

You have two input terminals labeled "12", so it's hard to differentiate them verbally. So I'm calling the top one 12up and the bottom one 12dn. Actually, they don't need to be considered. The contradiction in your circuit can be seen just by considering the 0 terminal. When 12up is positive, the 0 terminal is connected to the lower end of the load through the upper bridge, with current flowing from the load to the 0 terminal. At the same time, the 12dn terminal is negative wrt to the 0 terminal which is connected to the load upper terminal through the lower diode bridge.

What, what, what??? The same terminal is connected to both ends of the load at the same time??? How can that be?

To understand your circuit better, try connecting a load on the output of each bridge. No common connections, other than the inputs. Now consider the voltages on each load and the voltages between the two loads.

There are two problems with your idea. One is that you can use two diode bridges in this way, you can't. The other is the need. Your two diode circuit with the center tap transformer shown, will give a 12V output. You can use the full transformer with a SINGLE diode bridge and use the entire secondary winding at the same time... but you will get 24V output. If you want 12V output with a bridge, you need a

On Sunday, March 26, 2023 at 10:06:19 PM UTC-4, Ricky wrote:
> On Sunday, March 26, 2023 at 8:56:55 PM UTC-4, Commander Kinsey wrote:
> > I have a centre tapped transformer I wanted to get the most power out of. Thinking a traditional full wave rectifier (just a diode on each side, calling the centre tap 0V at the output) is only running current through one half of the secondary at a time, which is inefficient (think of P=i^2R), I thought about putting a bridge rectifier on each half, then connecting the result in parallel. I made the following diagram by adjusting someone else's, so it may look a bit odd.
> >
> > https://i.imgur.com/d2TfZYO.jpg
> >
> > I'm a bit confused here because you can trace the current flow and show the output has both 24V (if the current goes through the "wrong" bridge on the way back) and 12V at the same time, which isn't possible. Can someone explain what would happen in this circuit?
> >
> > Any way to make this work? I want current flowing through both halves of the secondary all the time. But I want half the full secondary's voltage.
> I don't expect you will see this post, because I think you have blocked google groups. But this circuit will not work as you expect. Rather than trace current, try figuring out the voltages. That might be more clear.
>
> You have two input terminals labeled "12", so it's hard to differentiate them verbally. So I'm calling the top one 12up and the bottom one 12dn. Actually, they don't need to be considered. The contradiction in your circuit can be seen just by considering the 0 terminal. When 12up is positive, the 0 terminal is connected to the lower end of the load through the upper bridge, with current flowing from the load to the 0 terminal. At the same time, the 12dn terminal is negative wrt to the 0 terminal which is connected to the load upper terminal through the lower diode bridge.
>
> What, what, what??? The same terminal is connected to both ends of the load at the same time??? How can that be?
>
> To understand your circuit better, try connecting a load on the output of each bridge. No common connections, other than the inputs. Now consider the voltages on each load and the voltages between the two loads.
>
> There are two problems with your idea. One is that you can use two diode bridges in this way, you can't. The other is the need. Your two diode circuit with the center tap transformer shown, will give a 12V output. You can use the full transformer with a SINGLE diode bridge and use the entire secondary winding at the same time... but you will get 24V output. If you want 12V output with a bridge, you need a

12V transformer.

--

Rick C.

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