how can i protect against overvoltage on 12Vdc

Thread Starter

bobrock

Joined Nov 30, 2004
3
I am tryin to find out how i can protect my LCD monitors in the car from an overvoltage . max voltage is 12V and im sure its 13.5 or so when charging.
will a rectifier work ??? or a regulator of some type?? :blink:
 

mozikluv

Joined Jan 22, 2004
1,437
hi,

usually the LM7812 will do the trick, but if you very particular that the voltge does not exceed 12v, this regulator has an output tolerance of +/-5%. so chances are it would still exceed the 12v, but i don't think the 0.6v extra would affect your gadget. :)
 

IanP

Joined Nov 18, 2004
5
Originally posted by mozikluv@Dec 1 2004, 10:25 AM
hi,

usually the LM7812 will do the trick, but if you very particular that the voltge does not exceed 12v, this regulator has an output tolerance of +/-5%. so chances are it would still exceed the 12v, but i don't think the 0.6v extra would affect your gadget. :)
[post=3879]Quoted post[/post]​
The 7812 regulator is not very good for this.
For it to give you 12V you need another 3V.
You should rather use low dropout regulator LT1086-12 (V0ut=Vin+0.5) or switchng regulator such as LMLM2575-12.
 

IanP

Joined Nov 18, 2004
5
The 7812 regulator is not very good for this.
For it to give you 12V you need another 3V.
You should rather use low dropout regulator LT1086-12 (Vin=Vout+0.5) or switchng regulator such as LM2575-12.
 

ram

Joined Dec 3, 2004
1
Originally posted by mozikluv@Nov 30 2004, 09:25 PM
hi,

usually the LM7812 will do the trick, but if you very particular that the voltge does not exceed 12v, this regulator has an output tolerance of +/-5%. so chances are it would still exceed the 12v, but i don't think the 0.6v extra would affect your gadget. :)
[post=3879]Quoted post[/post]​








































you can use a32-tnt relay oto protect from over voltage more than 0.12 volts
 
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