## Search found 105 matches

Thu Feb 19, 2009 8:56 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Well, is it not the task of the Voltage Regulator to eliminate these farther ripples?
That is true, it is not up to the voltage regulator to get rid off the ripple but to keep the voltage level at same level. Does it keep it then within peaks? Just kidding.
Thu Feb 19, 2009 8:51 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Thank you Bigglez. With Hz now correct it comes to 8,500uF and I think I've seen it somewhere.
Thanks.
Thu Feb 19, 2009 7:11 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Well, is it not the task of the Voltage Regulator to eliminate these farther ripples? Bigglez, you say that the first formula is correct but there is no such Cap available in that size!? As it was stated earlier it is to drive LEDs and they are capable of handling min and max voltage and so the 1V r...
Thu Feb 19, 2009 6:08 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

I came up with 16700uF for the Cap!? Is that correct? Vr = 1 / C f That's: C = 1 / 1V x 60Hz = 16.7mF? Something is not right!
Another formula:
Vr = (0.0024s) x Iload / Cf That's: Cf = (0.0024 x .7) / 1V = 1,700uF? This is more like it should be but is it correct?
Thanks.
Wed Feb 18, 2009 2:33 pm
Forum: General Discussion
Topic: caps in line
Replies: 4
Views: 1201

### Re: caps in line

It is a computer power supply and there are chokes and voltage regulators and a transformer but the cap negative is connected to 117V wire line and then there are a couple of diodes. The main rectification is after a transformer. I'll unsolder some of the parts and see the values of the regulators.
Wed Feb 18, 2009 10:17 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

edited
Sorry, I got carried away on this one. If it says 36V how it can support 40V? I guess only expert can know!
Now, where do you get these type of Transformers.
Thanks.
Wed Feb 18, 2009 10:05 am
Forum: General Discussion
Topic: caps in line
Replies: 4
Views: 1201

### caps in line

If there is a cap, 470uF, 200V, in line where 117V is coming into the power supply, what is it there for?
Thanks.
Wed Feb 18, 2009 6:01 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

You guys you're experts who knows all the tricks and ideas. The black box, 40V, 700mA, just does not fall into that category especially if I can manage the design of the load and cannot make up the supply part, just toooo simple! The complex part is this power management for the black box, well, com...
Tue Feb 17, 2009 10:56 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Hello Bob, no, it is not homework, at my age I could care less about education, waste of time and money! It is a bit of my idea that I would like to build (design and build) and see if that could work and maybe turn it into something … !? Very likely I might not succeed in what I am trying to accomp...
Tue Feb 17, 2009 5:51 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

You guys! If you read my post you would find that I need 40Vdc! That is the requirement that I need to follow!
Hopefully that helps.
A 48V secondary, is that RMS value, and so the peak is then 67V, and so should the filter cap based on the peak value? That is after the D bridge?
Thanks.
Mon Feb 16, 2009 8:28 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

That is the role of the NCP3065 to provide the required current at that volage. The voltage does not change since the load is driven by the current. The voltage is just to turn it on to deliver the I.
Mon Feb 16, 2009 7:31 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

How do I insert an image if I cannot attach anything?
Mon Feb 16, 2009 5:31 am
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

It is fixed! You might read that through out the post. No changes in the voltage. It would be called a leanear or steady load, correct?
Thanks.
Sun Feb 15, 2009 8:38 pm
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Well, the load requires 39.6V and 700mA! To drive the output I need to use NCP3065 IC. This chip takes 40V input max. LM317 can handle max load 37.5V with input rated at 40V and so I cannot use it!? And that is why I have to use this LM5118 that can handle the V and the I as well, it’s just complica...
Sun Feb 15, 2009 6:20 pm
Forum: General Discussion
Topic: transformers, current, voltage?
Replies: 53
Views: 11469

### Re: transformers, current, voltage?

Like you said, I need to drive it with correct voltage and so I thought I could use LM317 but it is too much voltage for this IC and so I got to use LM5118 which is much more complex then the LM317. Is there other way to drop down to 40V via LM317 regulator? The transformer delivers 48V and across t...