Designing a Circuit to Give Specific Voltages with Specific Input Voltages

Hey,

Start with the text book. Foreign concept? Maybe your instructor could help you find it.

I'd quote from the FAQ's, but it would be wasted.

Let's start with "elementary electrical design". Can you Google?

Ok yeah, I googled "elementary electrical design"....Now what?

• "Do your own homework. CR4 is not a homework cheat site. While some here might relish the opportunity to sharpen up old rusty skills by working the homework problem, consider this and consider it well. If you cheat on your homework by using someone else's answers, you are only cheating yourself, because the purpose of any homework or other college assignments is to help you learn - by practice, repetition, and self-discovery. (thanks STL Engineer)"

I hope you can understand this. If you can't, I'll be happy to provide clarification that even someone of your meager intelligence limited intellect skill level might comprehend.

I don't see what this has to do with my original question about the circuit design...Maybe if you keep providing me with some more of your brilliant insight on circuits, I'll be able to figure it out. Thanks!

In the simplest terms I can muster, do your own homework. Or, get your mother to do it for you.

I'm done, you're no challenge.

Ok...then please stop responding to my thread. If there is anyone else on this forum that can help me cheat on my homework by answering the original question, that would be fantastic. Thanks in advance

www.cheatingonmyhomework.com

You were doing well up until this last comment. Your approach at the beginning of the thread, asking for guidance, was a valid approach and would have garnered all sorts of discourse on this issue for you that would have been of some assistance.

The comments about doing your own homework from Lyn (while perhaps a tad bit cranky) are the result of many many students showing up here asking for the answers to what are usually easy questions.

Then low and behold, you blow it big time... adding the word "cheating" to your request for assistance drops you down, at least in my book and I am sure in the book of many of the contributors here, to the level of the students that show up and basically state "I do not know what to do, where to go to get it, don't really want to, can you do it for me so I can loaf or practice alternate sexual relations with a canine (a polite way of saying "F**king the Dog".

You had better learn now that thriving and excelling in the engineering fields, no matter the discipline, requires hard word, persistence and a level of ethics that to many young people today do not seem to grasp nor are inclined to understand the myriad number of reasons for.

If "cheating" on anything sits well with you, a rethink of career paths may be in order. Perhaps that of a politician or a gray area tax lawyer or accountant may be in order (with apologies to any real lawyers or accountants reading this - notice the word "gray").

The practice of engineering, again no matter which discipline is, as I so often tell people, "binary" in nature. A thing is either right or wrong. I leave it to you to decide what side of the line "cheating" falls into.

North of 60,

Thanks for the rational response.

Cranky, hell, I'm downright mean when I see people taking the path of least resistance to solve the IMMEDIATE problem, while not attempting to prepare for future dilemmas that they may encounter when they are away from the keyboard and access to intelligent people such as yourself and others here.

Children are now allowed to use calculators in grade school. How long will it be before the most basic concept of manual addition and subtraction are lost forever to the keypad, and the internet.

The information available today is unlimited, but the Fatss8's of the world should grasp the basic concepts before moving on to the next challenge in life. Such as getting a job and making a living.

Cheers.

I'm pretty sure Fatss8 used the word cheat in an ironic sense, in response to the flood of remarks. Presumably he was looking for starting advice, as he said, " lead me in the direction to getting started," from which point he would do the learning and engineering-homework thing.

I'm a big believer in engineering students spending time at manufacturer's websites and reading datasheets and app notes, then undertaking a real design, on paper at least. But it's nice to get some starting advice about where to go and what to look for.

Ok thanks a lot for the info man...I'm not too familiar with zener circuits but I've been coming across that a lot so now I know to look into that more. I'll let you guys know if I have anymore questions or if I figure it out. Thanks.

"out of mischief"

Takes me back to when an innocent doorbell had all the bits for electrocuting (mildly, well, non-fatally) ones fellow students <sigh>

Presumably you're allowed to use standard off-the-shelf power ICs, right? OK, the problem is starting from a low voltage, 1V (or for extra credit, even less?). Check out Linear Technology's LTC3108, which is meant for the new field of energy harvesting. These will work down to 20 milli-volts. :-)

As a second suggestion, once you have a higher voltage to work with, say 5V, you can use that to power various conventional smps controller ICs to drive logic-level MOSFETs that drive a step-up transformer to easily get your 20 volts from 1V, 0.5V or whatever, just so long as it's a low-impedance source.

In the case of 1V, it might be a nearly-dead battery, but in the case of lower voltages it might be a TEC thermopile. You could easily deliver tens of watts from a sufficiently-large TEC, such as a surplus part taken from a 12V picnic cooler or a larger Coleman PowerChill fridge (eBay links), and a heat source.

TECs work from temperature differences, so they need a heatsink and fan on one side. You can get the whole setup ready to go, here's one for $30 on eBay.