I am wondering if there is a difference between a transformer with two secondaries being wired in series, compared to transformer that is center tapped. Can you use the common wires that are tied together in the first example and all that the same as center tapped? I asked because the design of the power supply allows for either non center tapped or center tapped.
rayma,
I accidentally solved the trouble. In the end, this power supply could accept either a CT or not. I chose just to wire the secondaries in series and it works fine.
I accidentally solved the trouble. In the end, this power supply could accept either a CT or not. I chose just to wire the secondaries in series and it works fine.
Yes, if there are three holes for the leads, then two of the leads must go into the middle (CT) hole.
But you have to be sure of which two leads. A wrong choice would mean poor operation and noise.
Fortunately, you were lucky, since the odds were 50/50.
But you have to be sure of which two leads. A wrong choice would mean poor operation and noise.
Fortunately, you were lucky, since the odds were 50/50.
But only if the two windings have the proper relative phase, as shown here:
https://forumelectrical.com/working-principles-of-center-tapped-transformers-an-overview/
https://forumelectrical.com/working-principles-of-center-tapped-transformers-an-overview/
rayma,
That is a good article. One that doesn't go too deep but still gets the basic point across. The transformer that I am working has two secondaries, but in this case, I chose to use them in series so that the final DC voltage was higher (200v). It is good to know that the secondaries can be used as a center tapped transformer if they are connected to each other properly.
That is a good article. One that doesn't go too deep but still gets the basic point across. The transformer that I am working has two secondaries, but in this case, I chose to use them in series so that the final DC voltage was higher (200v). It is good to know that the secondaries can be used as a center tapped transformer if they are connected to each other properly.
Yes, after the tube era most transformer mfrs have gone to two identical secondaries for flexibility and reduced inventory.
It would be nice if all of them used a standardized color coding for the leads, though.
Some use the same color for both leads of a winding, even though the data sheet mentions their series/parallel connection.
It would be nice if all of them used a standardized color coding for the leads, though.
Some use the same color for both leads of a winding, even though the data sheet mentions their series/parallel connection.
I am more comfortable these days with dual secondaries. I'm sure that many transformers out there still have multiple taps such as those needed for a heater or something. When I look at the prices of those sort of transformers, I find more practicability using a set of two transformers. Then, the choice of the type of transformer muddies the field once again for me. I suppose that a split winding for the high voltage and a toroid transformer for the heater would be a good bet. The idea being about reducing RFI with the split winding and having greater efficiency with the toroid. Just thinking out loud.
Sure. Just as you need to put batteries into your flashlight plus to minus. Don't expect much light output if you shove them in randomly. 🙂
Tom
I can't say that I have. I did once accidentally touch the terminals on a 9 V battery to the battery clip in my first DMM with reverse polarity. It was then I learned the importance of turning the stuff off when changing the batteries. That little 'oops' fried all the ICs in the meter. Which sucked as I was about 12 years old at the time and didn't exactly have lots of money to buy replacement ICs. I did eventually fix it, though. And I put a diode in series with the battery leads to ensure that this mistake could not have the same result in the future.
Tom
Tom
Some of the 9 volt battery clips are rotten. They sometimes need adjustment to hold the battery with less than an ape like grip.
There are a couple amplifier topologies that need isolated windings, ie two independent DC supplies.
One is the "circlotron" that drives each audio half wave through the two power supplies. Usually a third (fifth) supply is used for the driver stages.
Another is the QSC topology where each channel requires a separate single voltage because the output comes from the supply capacitor center, providing inherent DC output protection.
In the case of regulated supplies, two windings and two rectifiers; capacitors, allows the use of a positive regulator on the negative supply.
Two bridge rectifies is not required for a split supply, but care must be taken to avoid any transformer current through a signal ground path.
One is the "circlotron" that drives each audio half wave through the two power supplies. Usually a third (fifth) supply is used for the driver stages.
Another is the QSC topology where each channel requires a separate single voltage because the output comes from the supply capacitor center, providing inherent DC output protection.
In the case of regulated supplies, two windings and two rectifiers; capacitors, allows the use of a positive regulator on the negative supply.
Two bridge rectifies is not required for a split supply, but care must be taken to avoid any transformer current through a signal ground path.
All true, but OP basically asks if a transformer with two (presumably identical) secondary windings can be used instead of a transformer with a single, centre-tapped winding. Which it can.
Tom
Tom