Go to Post I swear, at IRI, Gary and I only talked about coming up with a plan to do away with Billfred, we didn't actually do anything... yet... - MissInformation [more]
Home
Go Back   Chief Delphi > Technical > Electrical
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
 
 
Thread Tools Rate Thread Display Modes
Prev Previous Post   Next Post Next
  #15   Spotlight this post!  
Unread 30-07-2005, 02:32
Manoel's Avatar
Manoel Manoel is offline
Registered User
FRC #0383 (Brazilian Machine)
Team Role: Mentor
 
Join Date: Jun 2001
Rookie Year: 2000
Location: Porto Alegre, RS, Brazil
Posts: 608
Manoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond reputeManoel has a reputation beyond repute
Send a message via ICQ to Manoel Send a message via MSN to Manoel
Re: the best power regulator

Quote:
Originally Posted by Joe Ross
As far as heatsinks, it depends on how much current you plan to draw and the package of the regulator. Looking at the national datasheet, at 25 degrees C, the TO-220 can dissipate about 2 watts, although for safety, lets use 1 watt. The equation for power dissipation can be approximated by Pdis~=(Vin-Vout)*Iin. Since Vin is 12v and vout is 5v, you can solve for Iin of 1/7 of an amp. Since that's Iin, your output current (Iout) could actually be 350ma. I have a feeling that's more then enough for your application.
Joe,

Voltage regulators are not transformers, unfortunately. The regulation is obtained by means of power dissipation, as you pointed out. I agree I_{in} (is this LaTeX? ) is 1/7 of an amp, but Iout must be essentially the same, minus some small leakage to ground. To make 1/7 of an amp at the input become 350 mA at the output you considered that the input power is equal to the output power, as in an ideal transformer (Vin*Iin = Vout*Iout), but that contradicts your first statement about power dissipation and thus, Iout is not 350 mA.
1/7 of an amp is approximately 142 mA, which is still a good number for sparksandtabs's use (digital logic circuits).
__________________
Manoel Flores da Cunha
Mentor
Brazilian Machine
Team # 383
 


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
portable controls w/o using tether halomaster69 Control System 22 16-10-2005 02:18
Operator Interface power ISSUE kacz100 Technical Discussion 11 27-02-2004 13:46
URGENT!! Need OI power brick specs for 7AM demo tomorrow!!! kmcclary Electrical 8 10-10-2002 10:56
power of globe motor with gear box? Ken Leung Motors 5 21-11-2001 13:43
Max mechanical power of motors, how is it useful? Ken Leung Motors 1 09-11-2001 14:15


All times are GMT -5. The time now is 20:46.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi