How to wire a regulator?

backdrift · Post by **backdrift** » Sun Dec 26, 2004 5:49 pm

i really need help, i have a regulator to use on my xmod and i have no idea how ti rig it, its 35v max, 5v to board.. now how do i use it? it has 3 pins.. please help!

sg219 · Post by **sg219** » Sun Dec 26, 2004 5:58 pm

First off...Why didn't you bother to read your post before hitting submit? It reads like a 3 yr. old typed it. ...and.... Why didn't you post this in the Xmod section?

Anyway...I'd move it, but I don't have that option here.

I'm with you on this one dude.

I've been all over the forums to find out info on installing a 5v regulator, but haven't come up with anything. I read about people installing them, but never get a How-To in the posts.

Good luck. Maybe someone will show up and know how.

betty.k · Post by **betty.k** » Sun Dec 26, 2004 6:32 pm

i'd like to know about this one too, i got one from a busted dvd player. i think it has 3 pins from memory, we should get a pic up so ph2t or whoever can say "pin 1.... pin 2 ......"

backdrift · Post by **backdrift** » Sun Dec 26, 2004 7:18 pm

it didnt actuly sound like a 3yr old typed it, one did

. Well thanks anyways i hope codesuide or ph2t see's this thread!!

sg219 · Post by **sg219** » Sun Dec 26, 2004 7:19 pm

Here is a pic....

The link to info....

http://www.radioshack.com/product.asp?c ... d=276-1770

Type: 7805
• Case style: TO-220
• Output Voltage: +5VDC @ 1A
• Maximum Input Voltage: 35VDC
• May require heatsink in some applications

backdrift · Post by **backdrift** » Sun Dec 26, 2004 7:35 pm

thats the one i bought, i just need to know how to wire it

edit; and u can right click on the image and clikc copy link location and you would get this; http://www.radioshack.com/images/Produc ... 6-1770.jpg

cj · Post by cj » Sun Dec 26, 2004 11:59 pm

Here you go.

http://www.fairchildsemi.com/ds/KA/KA7805A.pdf

it's from Fairchild semiconductor but the wiring of all 7805's in the 220 case you have there is the same.

per the picture pin 1 is input, pin 2 and tab are ground, pin 3 is the output.

The PDF also has some typical schematics for use.

backdrift · Post by **backdrift** » Mon Dec 27, 2004 8:24 am

hmm that dosent really make much sense to me

.. can some one translate that to what i connect to each pin, please!

codesuidae · Post by **codesuidae** » Wed Dec 29, 2004 11:39 am

cj's post pretty much covers everything you need to know to install a regulator. The question I have is what do you need the 5v supply for?

I don't do XMods much, so I don't know what exactly you are trying to accomplish. If I had to guess I 'd say you are trying to run a mosfet board at a high voltage and the electronics at 5v?

stagg · Post by **stagg** » Wed Dec 29, 2004 12:19 pm

IE motor at 25 volts and the board at 5 cuz thats the normal amount so it wont fry

LBRC · Post by **LBRC** » Mon Jan 03, 2005 11:19 am

The problem with trying to tell someone how to install a regulator is that they have to understand a few basics because it’s not simply installing three wires.

Ok, so 5 volts to the board is easy, input to red +, output to circuit board instead of red, ground to ground. Now the board has 5 volts. But the only reason you’d do this is if you are using external FETs and if those FETs are running off of a higher voltage and your input to them is coming from the circuit board at the regulated 5 volts your FETs are going to get hot and die, do you understand unless you are using oversized FETs that can dissipate a hole lot of heat your FETs are going to die, dead, toast.

It’s a matter of biasing and potential and I don’t really have the skill or time to explain it correctly but here’s the short version; you have to match the FET input to it’s Vcc. There are several options, like using an optoisolator, or removing R31 and R33 from the circuit board and putting equivalent resistors between the + source and positive gain on your external FETs, but the value is no longer 475 ohm it depends on your input voltage.

If you didn’t understand what I just tried to say you need more help than I can give.

backdrift · Post by **backdrift** » Mon Jan 03, 2005 2:16 pm

still need more

ok i can do my own fets and such.. i just need to know where to connect what to what, thats the point im not good with..

betty.k · Post by **betty.k** » Mon Jan 03, 2005 10:59 pm

LBRC wrote:Ok, so 5 volts to the board is easy, input to red +, output to circuit board instead of red, ground to ground. Now the board has 5 volts.

what's so fucking hard about that?

backdrift · Post by **backdrift** » Tue Jan 04, 2005 7:44 pm

thats not what i want to do.. i want all the voltage to the motor, with out a external FET board.. or with one, i'd like to know each way actully..
all i need is 5v to board, and say Xv to motor, X is the battery voltage

stagg · Post by **stagg** » Tue Jan 04, 2005 7:59 pm

I dont think you can do it with just 3 pins, if it was that simple people wouldnt sell them for only about 40 bucks.