maxcosity

It's a 12v regulator which is used to protect your computer and LCD's power supplies.

http://www.stuffandting.com/carputer/?menu=ting





I don't know what all those symbols are and I don't know how it all hooks up (what the electricity flow is).

I know what resistors are but I don't know what the rest are.

I can probably find this stuff pretty easily in an electrical supply store -- I just need to know what to ask for.

Do I just solder this stuff onto the breadboard and hook it up and that is it?

Please help and don't just go telling me to buy some EE books and figure it out on my own (even though I probably should).

Thanks,
Kevin

MP3Car.com

 

MikeHunt79

I think we were all at this stage sometime or other. Here goes:

0v is connected to your carsground. The rest is already labeled. As long as your stuff is connected the same way as the schematic, it should work

the --||-- things are capacitors
the --|>|-- things are diodes
the big square thing in the middle is a semiconductor
I`m sure if you show the guy in the shop the schematic, he'll help.

Yep, that's the idea.

buy some EE books and figure it out on my own... j/k. One last tip, when putting everything on the breadboard, decide where everything is gonna go before soldering.... and good luck

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My Setup

maxcosity

Sweet, you rock man! Thanks a lot!!

So let me get some more things straightened out here..

It looks like everything is in parallel except the semiconductor. There is a diode in parallel to the semiconductor (but that diode isn't labelled so I would imagine it is the same diode as used further down the diagram)..

How do I know which way the diode goes? If memory serves me, one "leg" of the diode is longer, right? Is that the negative end?

Are the capacitors bidirectional, or do they have to go a certain way (and are they marked) ??

What is the difference between the two diodes shown. One looks like it has a switch or something above it.

What is tantalum (next to the 10microFarad capacitors)?

What is the semiconductor used for? I know what the caps are for and I think the diodes are to limit power going through the circuit, right?

Lastly, would larger capacitors be better? With the capacitors shown, how much power could this supply (and for how long) once the caps are charged? I am thinking if they are larger, they would hold more juice and if I momentarily turned off the ingition (or started my car which does similar things), it wouldn't turn off the computer...

Thanks,
Kevin

MikeHunt79

It's probably just normal diode, so just get one thats rated high enough and you should be ok. I`d check the datasheet for the semiconductor just to be sure.

Usually there is a stripe on on end of the diode. I think this is the negative end.

If they are'nt marked, like the middle ones, then yes, they are bidirectional. The one on the right is directional tho, I think that you will need an electrolytic capacitor for that.

I have a feeling the diode on the left is a zener diode. I`m not 100% sure about that tho, it's been a while sonce i've done this sort of thing.

Tantalum is the name of the chemical the dialectric of the capacitor id made from (i think). You don`t need to let that worry you. Just ask for a tantalum capacitor and you should be fine. You can also get electrolytic capacitors, ceramic capacitors and a few others I think. They all have different properties.

The semiconductor is the "brains" of the circuit, the rest of the component are just there to help the semiconductor do it's job, so to speak. If you try and dig up the datasheet for this semiconductor (LT1084...), then it would help a great deal. It tells you what pin does what, so you'd know what way round to connect it chip.

I`m not sure if having larger capacitor would work. By the looks of that schematic they are used for smoothing. Again. the datasheet should give more definate solutions to your questions.
You want to look into a tank circuit if you wanted the computer to carry on working when starting the engine.

Anyway, I gotta go to bed now, it's 4 in the morning! Maybe theres someone on here that's already tried this circuit out, they should know more than me about this...

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My Setup

eugenen

Be carefull with the lm1084, a lot of the similar three terminal regulators have the pins laid out in the same way as the schematic with the input on the left, ground in the middle and output on the right, the lm1084 regulators do not. Also be sure to isolate the lm1084 from the heatsink as the tab on the lm1084 is not ground like most others. If your not sure look for the transistor mounting kit that has a little plastic washer that goes in the hole, and the pad that sits behind it to insulate it from the heatsink.

mp3hombre

Buy some EE books and figure it out on your own...


The diode on top protects the voltage regulator. If for any reason the 4700 uF capacitor "dumps" the voltage back into the regulator's output the diode will "steer" this voltage to the regulator's input instead.

The 1.5KE24A is a surge protection diode.

The tantalum capacitors are high precision components and as far as I know they are polarised (unidirectional). So make sure you connect them the right way. They have a plus sign mark somewhere.

unrealer33

Would this regulator be needed for comp. PSU ---> inverter combo? or do they have their own regulators?

maxcosity

Where can I get the 1.5KE24A diode? Do you know what the other diode would be? the same?

Radio Shack didn't have it.. :-(

Thanks!!
Kevin

mp3hombre

DigiKey might have the 1.5KE24A, the other diode is a 1N4002.

PotzUK

http://www.zorg.org/projects/carpc.shtml

Looks very similar, but has the parts labelled better

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Tony P
My Carputer Project

GingerPrince

That's where I got the basic idea from, and added some bits based on other info trawled from the web. He's added the diode since I last saw that website though.

Basically I added the 10uF at each side of the reg, which according to the specs is required for stability, and I added the transient supressor. All fairly standard stuff working from the spec sheet of the 1084.

Yes I used the plastic ring/mica insulator for the regulator to heatsink.

Cheers muchly,



Sy

MobileSuit

Where do you buy the parts to make this? Can I walk into radio shack and show the guy this picture and he'll get the parts?

frodobaggins

If they have them, yes, if not hit up http://www.digikey.com


But my experience with rat shack suggests that they probably know less than you

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Aaron Cake

I'm surprised that no one has mentioned that making this circuit is essentially pointless. That regulator requires a 1.2 volt overhead to put out a steady 12V. That's great when the car is running, but if he engine is not running, the battery alone will not provide the 13.2 volts needed to run the regulator.

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chiark

Well, depends on what's important to you: life of your PC, or ability to run when the engine's off...

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