Choke question

[nkg]

Can a choke designed for LC power supply filter be used for CLC filter.
nigel

[dhaen]

Why not? But it seems wasteful.

What IS nice is to use the input capacitor value to "fine-tune" the output voltage.

[nkg]

Thanks John
Yes I've only just realised how wasteful I took my daughter to singapore for a week as she finished her degree and bought some tango opts and choke and some other components I had asked for a 5mH 250mH choke he only 300mH choke and just going over the spec sheet and realised its for LC filter,I dont speak chinese and his english wasn't that good so that could be a reasonable excuse. Could you please explain the fine tune I'm still on the steep learning curve.
Thanks Nigel

[dhaen]

Nigel,

Well an LC filter gives just over 0.9x the AC input voltage as DC out, and the CLC gives about 1.4x.
So no input cap gives 0.9 and a big cap gives 1.4.... You can choose a cap value to deliver any voltage in between. It really becomes a hybrid.

If you don't already have it, download PSUD2 free at:
Duncans amp pages
Set it up as a CLC filter and start reducing the input cap and see what happens....

The nice thing is that your choke will never buzz for any value of input C, unlike a choke designed for CLC

[nkg]

Thanks again John
I'm one of those with an apple so I will have to do the calculations with a calculator.But I'm happy that it will never buzz is this due to the higer current rating or more iron required to keep it from saturating or some other factor else as its quite heavy.
Nigel

[dhaen]

I'm one of those with an apple

Me too but I run it in Virtual PC on my G4 and Parallels on my iMac and MacBook.
If you have an IntelMac, you can download a free trial of Parallels Desktop for mac http://www.parallels.com/en/products/workstation/mac/

There is also Crossover Office for Mac from Codeweavers, who also offer a 60 day trial (beta) Th app's not listed but I might just try it....

[nkg]

I'll try the download my I mac is an intel and thanks again for your patience.
Nigel

[dhaen]

Nigel,

I should mention that you will need an operating system to install in your Parallels Virtual Machine. PSUD2 works on all Windows, I think, but for simplicity of installation, one that boots from the installation CD is necessary. I believe that means no earlier than Win98 version B.

Of course I forgot about Apple's free Bootcamp But you need XP....

Oh BTW I have checked PSUD2 running in Crossover Office Version 6.0b3a (6.0.0b3a) and there is a problem. It is not possible to tick the results boxes. So no-go.

[bembel]

Hi all,
Can someone (maybe John) explain the basic difference between CLC & LC chockes ?
What's the way to identify a salvaged one ? Also is there a method to figure out current rating of a salvaged chocke ?
... and finally, can you explain why the LC chocke won't buzz in a CLC circuit ?

thanks again

[dhaen]

Can someone (maybe John) explain the basic difference between CLC & LC chockes ?

Ok, I'll try. I'm happy to hear corrections and additions...


Chokes for LC use have a gap similar to that of a Single-Ended output transformer to allow significant DC before saturation.

An added benefit is that the inductance changes with current and so it can be used to provide crude regulation over a small range of current demand.


More later... supper's ready....