go_away

Author Topic: Voltage Regulator...?  (Read 3088 times)

0 Members and 1 Guest are viewing this topic.

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Voltage Regulator...?
« on: August 24, 2007, 02:05:24 PM »
I purchased 10 voltage regulators, they are "UA7812KC" 12V 1.5A, and come in a TO-3 casing with two pins coming out. The problem is, I don't know how to use them. I'm guessing the casing acts as the ground.... But which pin is in, and which pin is out?

I tried guessing, but when hooking this to my power supply and measuring the output voltage, I either get the same voltage as the input, or (reversing the pins), no output at all. I can't seem to find a real datasheet for this with a pinout, and a sample circuit on how this is supposed to be used.

Any help would be appreciated....

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #1 on: August 24, 2007, 02:10:48 PM »
two pins? Only two pins?
A Vreg has 3 pins... if it doesnt then its either not a real vreg or its broken...

The middle of the three pins is ground. Looking at it from the front, left of the GND pin is the input, and right of the GND pin is output.

also: Datasheet

-Hope this helped...
« Last Edit: August 24, 2007, 02:12:14 PM by HDL_CinC_Dragon »
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #2 on: August 24, 2007, 02:17:14 PM »
two pins? Only two pins?
A Vreg has 3 pins... if it doesnt then its either not a real vreg or its broken...

The middle of the three pins is ground. Looking at it from the front, left of the GND pin is the input, and right of the GND pin is output.

also: Datasheet

-Hope this helped...


That's not the right part, your datasheet is for the UA7812CKC, mine is an UA7812KC... And it comes in a TO-3 package, not TO220. Yes, it does have two pins, and no, it's not broken. The casing is the third "pin".

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #3 on: August 24, 2007, 02:49:41 PM »
Is it actually possible that my voltage regulator can't output 12V from input voltages less than 12V?

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #4 on: August 24, 2007, 02:51:15 PM »
ok then. The casing is ground, im sure you knew that though...
If your looking at it from the front, probably the left pin would be the input, and then right pin should be the output since that is the standard layout for vregs...

try running like 15 volts through it using that setup and measure using your multimeter between that right pin and GND and you should see 12v...

-EDIT-
But make sure you dont exceed 1.5A!
« Last Edit: August 24, 2007, 02:54:25 PM by HDL_CinC_Dragon »
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #5 on: August 24, 2007, 02:53:46 PM »
If you use voltages less than 12 volts, it cannot output more than what is put in.

Vregs are only used to drop voltage from higher voltages. They usually require even more voltage input then theyre rated to output or they wont work properly...

try the setup I suggested in my previous post and you should be good to go
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #6 on: August 24, 2007, 03:06:40 PM »
The problem is my battery supplies 12V. Do you know where I could get a transformer to convert that into say, 24V?

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #7 on: August 24, 2007, 03:14:51 PM »
hmmm im not 100% sure ATM :-\

Im assuming thats 12v at 18A?
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #8 on: August 24, 2007, 03:21:24 PM »
Definitely need to handle at least 15A. But I suppose multiple transformers could be used in parallel.

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #9 on: August 24, 2007, 03:23:54 PM »
No i mean your powersource, whats its amperage :P

When convert 12v to 24v your going to lose a lot of amperage...
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #10 on: August 24, 2007, 03:31:45 PM »
It's a 35Ah gel battery, meant for wheelchairs.

Maybe I should be clearer on what I intend to do.... I would like to build a module that takes input from my 12V battery and delivers regulated 12V and 5V... On the order of 10-15A. I'm planning on building one myself because I couldn't find what I wanted.
« Last Edit: August 24, 2007, 03:40:16 PM by Nyx »

Offline HDL_CinC_Dragon

  • Supreme Robot
  • *****
  • Posts: 1,261
  • Helpful? 5
Re: Voltage Regulator...?
« Reply #11 on: August 24, 2007, 03:41:20 PM »
ohhh ok

Well I have some concerns about that then
1) 35A is a lot of amperage, I dont think your going to find a cheap vreg that can handle that
2) converting 12v to 24v and then using a vreg to get 12v again means 12v being converted to heat which equals a LOTTTT of heat which would probably melt anything that gets within like 3 inches of it not mention itself.


Ummm based on that, I think we should go in a different direction. What do you plan on using it for? Perhaps you can use a microcontroller and mosfets to control relays to use the 12v 35A for whatever you need it for (heavy duty motors?)
United States Marine Corps
Infantry
Returns to society: 2014JAN11

Offline NyxTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: Voltage Regulator...?
« Reply #12 on: August 24, 2007, 03:49:50 PM »
I guess I'm probably going to end up having to use unregulated 12V for the motors, and regulated 5V for the more sophisticated circuits and servos.

But anyways, having many amps isn't going to be a problem... I can just run the voltage regulators in parallel.

 


Get Your Ad Here

data_list