joaquins said:Also notice that some tube outputs have DC across the secondary and this transformer is probably not prepared handle it.
joaquins said:42x42x15x6?? In what multiverse are you living dude! I usually guess the bigger core that could fit inside the box, but might not even be an EI core in which case you just have to guess. If you do know the type of core you could make a better guess.
JS
PRR said:> your connection schematic show 3.5:0.5.
Argh. I can not count.
Check my math:
PRR said:> I can't simulate paralell connections in most cases i have error.
Put 1 Ohm or so in series with each winding.
If there is *any* difference in turns, large current will flow in parallel windings.
SPICE default transformer has ZERO ohm windings. It will not even start the computation because "obviously" it can give INFINITE current, which would blow-up the computations. It won't even try.
In real life, turn counts are (often!) very closely matched, and all windings have real resistance. A "100r" winding may be 5 Ohms or so. So adding explicit resistance is legitimate and more realistic. And it solves SPICE's "problem".
However if you just want voltage ratio, there is no need to parallel 0.5 and 0.5 windings. The answer will be the same voltage ratio. (However SPICE may complain about the "un-used" winding; put 1Meg from both ends to ground so it has something to figure.) In real life, if you have identical windings it may usually be a bit better to parallel them for lower total parasitic resistance.
If you AC couple it it's all right, no DC. If you connect directly from the cathode to ground it will have DC current and for that usually gapped transformers are used, to minimize the THD at low freq. Most transformers aren't gapped, as they don't need to handle DC and the gap brings other problems, that's why I said probably this transformer isn't prepared.ln76d said:Why "this transformer is probably not prepared handle it" ?
In standard connection there shouldn't be DC across secondary but i want to connect it to small voltage node at cathode.
I was asking cause you quoted too many dimensions for the transformer...Dude
It's EI core, i don't now why but i assumed that it would be obvious it's EI. Overall dimensions of it are 42X42X15mm.
Sorry, i have sometimes problem with terminology in english, like in case of transformer specific parts.
I can't only determine center column size (hope you understnd what am writing about )
As also i'm sick and have fever
Maybe drawing would be better for dimensions?
joaquins said:If you AC couple it it's all right, no DC. If you connect directly from the cathode to ground it will have DC current and for that usually gapped transformers are used, to minimize the THD at low freq. Most transformers aren't gapped, as they don't need to handle DC and the gap brings other problems, that's why I said probably this transformer isn't prepared. I was asking cause you quoted too many dimensions for the transformer...
The center column area is (or should be) twice the area of the side one, in this case I guess the one you measured 6x15mm so the area of the core should be around 180mm^2. Knowing that and the material you have most data about the core, in some cases you may need the average length. The material of the core might be hard to identify.
JS
gyraf said:On a side note - if it's an output transformer (as indicated in first post), don't expect it to work well for very-low details like microphone in- or output. You need mumetal or amorf for this, not sufficient to have the right ratios.
Jakob E.
Enter your email address to join: