Power Supply Design #3 the Toroidal Transformer 

Hi ! first of all thank you sincerely for all your very kind and very valuable video lessons. I am a beginner and slow at learning things but i am finding them very clear and useful. Second i have a question. Sometime i need on the output a 3 terminals arrangement like V-0-V . (For instance in one occasion to power a preamp i needed a transformer outputting 15VAC-0-15VAC) Looking at the video i am not sure how to connect the black, red, orange and yellow wires to achieve a V-0-V output. Maybe connecting red and orange terminals together ? thank you very much again. Kind regards, gino

Man I really find value in your videos, thank you for the hard work you put into them.

That Oscilloscope display the difference between current in rush peak with and without a thermistor was worth 1000 words that was very clear now I have a visual and I’ll try to repeat your experiment with my transformers and my test equipment that I’m learning how to use. 👍

You convinced me to buy thermistors. I have looked at switch bounce before with dc, usually lasts about 8 ms.

Great video, I've been trying to learn as much as possible about NTC thermistors so that I can select a properly sized on for a project. You're videos started showing up in the search results and have been really helpful. I also learned a lot about that Siglent scope watching this video. I actually just bought the same scope a couple of weeks ago and am still getting familiar with it.

Great Eddie! Excellent showing how the current spikes with and without the thermistor.

Hi EDDIE, thank you for the information, Good video.

Thanks good video. Very informative. I wasn’t sure how to wire one of these up now I do.

I'm rebuilding a powered subwoofer but stick, seeing this video gave me insightful information. I have a toroidal transformer that the system came with but as far as a power, stuck. The fuse rated on the label says T1A/250v? But very helpful thanks

Awesome. Learned much. You took out the thermistor and said the in-rush current was 70 amps. It looked like the scope said 150A? Peak to Peak?

Hi Eddie, Good information. Looking at your schematic drawing. You have brown connected to neutral and blue connected to live. Also the fuse is in the neutral side, UK colours are brown is live, blue is neutral and green yellow is protective earth. I always reference the dots as the neutral line. Adam

I like those Wago connectors. Just started using them in house wiring, especially when connecting stranded to solid wires, which doesn't work very well with wire nuts.

Great video. Could you please tell me in what series are you talking about VA W. What you started to explain at 15:52. As I didn't catch it at next series. Thank you.

Thanks for the video and the description: I do have one question; I noticed that the schematic shows the switch, fuse and thermistor all on the hot wire, but when wired up, the thermistor is on the neutral side by itself. Does it matter, or should they all be on the host side?

WOULD IT BE A GOOD IDEA TO USE A 60HZ LINE FILTER BETWEEN THE PLUG AND,TRANSFORMER?

Hi eddie.I have 1000Va torodial for Tda8954.Does it need some y or x capacitors on primary side?

Great video:-) Am I right in that you in last video about inrush current could have used two or more wires to overcome the maximum of 65 amp on your clamp? I mean have used two wires mut only clamped around one of them to get maybe 42 amp = 84 in total inrush? You talk about the Toroid transformer, but I have heard that O-core has less flux and are better in about all and the R-core is even better still?

If I have a 220v ac in 60v ac out what current limiter would I need like the one you show hooked up?

Hi there, How do you connect channel 2 to measure the current?

My 25V caps in Firstwatt F5 amplifier has started to swell, even with the thermistor. I have had a few (slow) fuses blown, so I am going to upgrade the protection to something more sofisticated than a thermistor. I noticed a buzzing sound in the speakers after a few months, but continued to use it for five years, with $2000 speaker drivers, no less. It could be because I turned on-off-on to quickly with a warm thermistor that never got the time to cool down. The buzzing sound could also be because of the rats nest of cables I have in there. Or that I biased it the amplifier way too hot. I can hold my finger on the heatsink for 1 second but not more, and I should have biased it so that I can touch the heatsinks without burning my hand. So with all that heat the mosfets might be slightly damaged. Anyway, looking for inspiration to build a much better PSU now. I read that those thermistors are live and can actually shock you, and should be fastened properly when in use. A logical solution would be to shrink tube the thermistors, but that is not a good idea because they need to cool down so you don't wear out your caps and other components with that 70 amps. Really cool of you to show us why a thermistor (or better) is necessary. I always thought I had an idea of what happens, but in this video I can actually see it happening.

Hey, why this power supplies are better than a conventional one and can this improve a video source?

The toroid isn't solid actually it's made from just one thin laminated plate wound very tight into a coil which is needed for the eddy currents, this type is only used for 50 and 60 Hz toroid transformers

12:58 min, Is that meter true R.M.S. ?

What size thermistor would be needed for a 230 volts torroid transformer?

Safety tip: Dont wear metal jewelry when building power supplies. And that tape looks very dodgy.