Transformer searches

[twist2b]

Searching for transformers is hard.
https://stevehv.4hv.org/FBD/FBschematic.JPG
The transformer here... I can't find anything that matches it :'(


I don't fully understand transformers, and wondering if anyone could head me in teh right direction.

Thanks,
Craig.

 

[mneary]

I assume you're talking about the CDT 10:20:20 transformer. Apparently he discusses the transformer construction at SSTC 1 - self-resonant half bridge . Is this what you're looking for?

 

[twist2b]

Oh I could not find that. Thats very nice...
But I am having trouble becuase....
The voltage is 25.2 which ends up being like 30 something due to having the rectifier and voltage regulator.
And the second one should only have about 8.6V (I think, I did the math a while ago) to turn out to be 12V

Though the thing is, the 12V has to be right, but the other line can be between 25-40V and still be fine.
SO the thing is, I guess 10:20:20 will work...... Its just slightly strange to me still... I just have to think

 

[kchriste]

It's an oddly drawn circuit. The "D4" bridge could be eliminated entirely. The negative supply of the 12V (Pin2 of the 7812) should be connected to the negative supply of the oscillator (pin 1 of the 555) as well. The artist should have used dots to indicate phasing on the CDT transformer.

 

[mneary]

It is oddly drawn, and I agree that the negative side of the 7812 should be connected to the negative side of the 555 section. However the D4 bridge has an output of about 16-17VDC which is a good input for the 7812. The D3 bridge has an output of 32-34VDC which apparently is the expected input for the Tesla primary. (34V is a bit much for a 7812).

You should not connect the negative of the D3 bridge to the negative of the D4 bridge. They are different.

 

[Hero999]

Why on earth are there two brodge rectifiers?

Only one is needed.

 

[Mike_2545]

Why on earth are there two brodge rectifiers?

Only one is needed.

Is it because they are different phase of the frequency?