the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

12v regulator


Post ReplyPost New Topic
< Prev Topic Next Topic >
sarbein 
Member - Posts: 6
Member spacespace
Joined: Novemberá16, 2006
Location: Greece
Posted: Novemberá16, 2006 at 1:26 PM / IP Logged  
hi all,
when i start my car the starter needs a lot of current to operate.So for 3-4 seconds,until the car starts normally,the voltage drops down to 0V and rises up to 12V very quickly because of inductive phenomenon.
I want to construct a voltage regulator 12v or 12,8v maximum input, to 12v output with 2A circuit current maximum.The circuit in normal operation demands 100mA.So ideal stable output is 12v/100mA!
This circuit will provide a small GPS modem..
if someone has a schematic circuit would help me a lot!!
thanks in advance..
kgerry 
Platinum - Posts: 3,455
Platinum spaceThis member consistently provides reliable informationspace
Joined: Februaryá07, 2004
Location: Saskatchewan, Canada
Posted: Novemberá16, 2006 at 2:15 PM / IP Logged  

go to an electronics wholesaler and ask for a 12 volt + v reg...

but keep in mind that a regulator regulates it's supply voltage... so if supply drops out so will it's regulated output.....

you may want to look at a gel cell battery or alarm backup battery ......

Kevin Gerry
Certified Electronics Technician
MECP First Class Installer
Owner/Installer
Classic Car Audio
since 1979
sarbein 
Member - Posts: 6
Member spacespace
Joined: Novemberá16, 2006
Location: Greece
Posted: Novemberá16, 2006 at 2:41 PM / IP Logged  
thanks kgerry!!
sarbein 
Member - Posts: 6
Member spacespace
Joined: Novemberá16, 2006
Location: Greece
Posted: Novemberá16, 2006 at 4:03 PM / IP Logged  
Just a moment kgerry
I agree that a regulator regulates it's supply voltage,but when the suplly drops out,this msec,can i use a capacitor with a large discharge constant in order to keep my output voltage to 12v?
Then the spike of 12V comes again and recharge my capacitor..this repeats 2-3sec until my car starts operating normally..
If i make a mistake please correct me.
KPierson 
Platinum - Posts: 3,527
Platinum spaceThis member consistently provides reliable informationspace
Joined: Aprilá14, 2005
Location: Ohio, United States
Posted: Novemberá16, 2006 at 5:18 PM / IP Logged  

You're going to need a pretty large cap to supply a 100mA device at 12vdc for 4 seconds.

I'm not sure why you need the voltage regulator at all though.  Most voltage regulators will need ~+2vdc above their output to actually work correctly, meaning you will need about 14vdc constantly to provide a solid 12vdc out.

I like the idea of using a small back up battery system.

Kevin Pierson
Ween 
Platinum - Posts: 1,354
Platinum spacespace
Joined: Augustá01, 2004
Location: Illinois, United States
Posted: Novemberá17, 2006 at 10:30 AM / IP Logged  

hi,

just use a diode (1N4001 or similar) on the power lead and a large value capacitor across the power leads of the device.  used to have to do that with some older radar detectors to have them power up properly.  i'd start with 10000 microfarads and go from there...shouldn't take up much space.

hope this helps

mark

master5 
Silver - Posts: 1,123
Silver spacespace
Joined: Octoberá10, 2006
Location: United States
Posted: Novemberá17, 2006 at 11:25 AM / IP Logged  

What kind of vehicle is this? Perhaps you need a better battery or starter?

If this vehicle requires that much current to start and nothing is defective I would think the best way around is a small back up battery, isolated during crank. I would not trust a cap to perform this function although it might work as well. But the current demands for the small GPS modem seems like a prime candidate for a b/u battery in this case.

I don't believe a regulator will do much if the voltage is actually dropping down to zero as you state, that is not really it's purpose.

master5 
Silver - Posts: 1,123
Silver spacespace
Joined: Octoberá10, 2006
Location: United States
Posted: Novemberá17, 2006 at 11:30 AM / IP Logged  

Oh wait...you didn't mention, where are you measuring this "zero" volts? You might just need to connect the GPS to an ignition wire. If you have it on an ACC wire it will read zero during crank. That is normal. This may not be the problem but  trying to check out all possibilities.

"normally,the voltage drops down to 0V and rises up to 12V very quickly because of inductive phenomenon"

I don't think this has anything to do with inductance, but if everything else is normal it is current draw issues.

Good Luck

sarbein 
Member - Posts: 6
Member spacespace
Joined: Novemberá16, 2006
Location: Greece
Posted: Novemberá18, 2006 at 3:59 AM / IP Logged  
Thanks master5 for your reply!!!
I will try to use a detector (diode-capacitor)as ween said.
The problem is that i don't want to use a battery.Otherwise i wouldn't have problem because battery would save me during crank..
I hope that the combination 1n4001 and 10000ýF will work properly!!!
Thank you ALL!!!12v regulator -- posted image.
master5 
Silver - Posts: 1,123
Silver spacespace
Joined: Octoberá10, 2006
Location: United States
Posted: Novemberá18, 2006 at 12:23 PM / IP Logged  

Ok, keep us posted.

Best of luck.

Page of 2

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Saturday, October 1, 2022 • Copyright © 1999-2022 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer