Dropping the voltage

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=89463
Printed Date: May 29, 2024 at 1:46 AM

Topic: Dropping the voltage

Posted By: debeerd
Subject: Dropping the voltage
Date Posted: January 24, 2007 at 8:52 AM

What is the easiest and cheapest way to drop from 12V to +-7V ?

Thanks

Replies:

Posted By: master5
Date Posted: January 24, 2007 at 10:07 AM

An adjustable 12v power converter..any radio shack/bestbuy/CC etc. should stocks these pretty cheap. They are typically on a cigarette lighter type plug but you can solder wires to it if you wish to hardwire and hide it..cake.

You could build one yourself if so inclined but to help you I would also need to know the current demands of what you are hooking up..might be as simple as a resistor depending.

Good Luck

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Posted By: i am an idiot
Date Posted: January 25, 2007 at 6:40 AM

Are you trying to convert 12v to +7 and -7? or is the +- a typo?

Posted By: debeerd
Date Posted: January 26, 2007 at 3:22 AM

typo, my bad.

It is for the hal sensor in a cars distributor. Current draw should be like almost nothing.

It runs on 7v, so it just need to come down from 12v.

Thanks.

Posted By: i am an idiot
Date Posted: January 26, 2007 at 6:51 AM

A resistor is not the way you need to go. If you can not find an adaptor as Master referred to with a 7 volt out, you can build a regulator with only a few components probably available locally in larger cities. An npn transistor, a 7.2 volt zener diode and a resistor. If you can't find an adaptor let me know will send wiring info for the circuit.

Posted By: debeerd
Date Posted: January 26, 2007 at 5:01 PM

Cannot get the adapters in my town, will have to try in the bigger places.

Can you supply me with the circuit please ?

I can get electronic components needed to make one.

Just give me the list and diagram and I'll be able to sort it from there.

Thanks

Posted By: i am an idiot
Date Posted: January 27, 2007 at 12:49 PM

posted_image

Posted By: i am an idiot
Date Posted: January 27, 2007 at 12:50 PM

the 2n6488 is an NTE 331 the zener diode is an NTE 5072A

Posted By: Mad Scientists
Date Posted: January 27, 2007 at 3:36 PM

The easist thing would be to use an adjustable voltage regulator..

https://www.nteinc.com/specs/900to999/pdf/nte956.pdf

But.. I have to ask, what are you trying to do with the hall effect switch?

Jim

Posted By: debeerd
Date Posted: January 29, 2007 at 2:52 PM

Great, thanks.

It is for use in the car itself.

Not using the TP100 anymore which was also supplying the 7V to the hal sensor.

Posted By: debeerd
Date Posted: March 01, 2007 at 4:07 AM

What is the 'Load 70' on the diagram ?

Do I get the 7v from where the 'A' is ?

Thanks