9 volt to 12 volt jump

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=81759
Printed Date: May 09, 2025 at 1:14 PM

Topic: 9 volt to 12 volt jump

Posted By: fozzz
Subject: 9 volt to 12 volt jump
Date Posted: August 18, 2006 at 6:23 PM

I have a low amperage 9volt signal that i need boosted to a 12 volt signal. I have some standard relays but there isnt enough voltage/amperage to turn it on. Can I use a transistor to bump the voltage/ampreage up?

The real trick is that I cannot have this transistor turn on until the signal reaches 9 volts. When the signal is at rest, it sits at around 5.5 or 6 volts. C

Can this be done??

Please help me!

Replies:

Posted By: techguy688
Date Posted: August 18, 2006 at 8:10 PM

use a 9vdc relay. 9 vdc on the coil.
12 vdc across the common and NO or NC

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Just because you've done something for a long time doesn't mean you're any good at it.
Cable Ties Rock!

Posted By: fozzz
Date Posted: August 19, 2006 at 9:14 AM

Are 9volt relays common? My local dealer only has 12 volt ones. I also looked in radioshack. Same result.

Posted By: hotwaterwizard
Date Posted: August 19, 2006 at 11:00 PM

Mouser has them. Cheap too!

https://www.mouser.com/search/ProductDetail.aspx?R=FTR-P4CN009W1virtualkey52910000

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: Mad Scientists
Date Posted: August 20, 2006 at 5:43 PM

Because of your at rest voltage I'd recommend a comparator circuit.. something like this..

https://home.cogeco.ca/~rpaisley4/Comparators.html

I'd think that a nine volt relay would maybe/maybe not trigger on 5-6 volts.

Jim

Posted By: hotwaterwizard
Date Posted: August 20, 2006 at 8:03 PM

There is a circuit on this page that may help you out.

Lowest cost for 5V only supply with higher voltage relay coil

https://www.piclist.com/techref/io/relays.htm

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: hotwaterwizard
Date Posted: August 20, 2006 at 8:38 PM

You could play with the Resistor on this circuit to activate at 9v just put a Variable Resistor instead of the resistor.

Put your 9v on the red arrow and tie the grounds together.

posted_image

Here is the Modified Circuit.

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !