# Hello, I want to reduce 12 volts to 7 volts, how many ohms do I need using a resistor?

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#### johansasa

Jun 19, 2024
8
Hello, I want to reduce 12 volts to 7 volts, how many ohms do I need using a resistor?

Feb 19, 2021
826
How much current do you need ? Does the load vary in current draw ?
What is accuracy of 7V you need ? What is range of 12V input ?

These are all specifications you need to do a proper design.

#### bertus

Moderator
Nov 8, 2019
3,407
Hello,

Is it a fixed load, or can it vary like an amplifier.
You can use a voltage regulator to have a steady voltage.

Bertus

#### Delta Prime

Jul 29, 2020
2,257
Using only one resistor in series with your load, that is your load must be used as the other resistance in order to divide the voltage by the ratio of the ohmic value of the now two resistors.
You wish to make a voltage divider, that takes two resistors. Your load must be purely resistive & your 12 volt source must
not change, meaning no batteries.

#### Bluejets

Oct 5, 2014
7,126
Hello, I want to reduce 12 volts to 7 volts, how many ohms do I need using a resistor?
Save youself a lot of bother and use a \$2 buck ( down) converter.

#### AnalogKid

Jun 10, 2015
2,929
This question is so blazingly incompetent, it smells like a troll.

ak

#### Delta Prime

Jul 29, 2020
2,257
This question is so blazingly incompetent
Well.... Maybe that's why, it makes sense to me,

#### Delta Prime

Jul 29, 2020
2,257
@johansasa
Is this another sensor for audible, visual, alarm?
Would your brother happen to have a Binaural Cochlear Implant hearing prosthetic? If so we can use that to our advantage for targeting the prosthetics audible frequency sensitivity
With a audible alarm within that frequency sensitivity range of the prosthetic.

#### AnalogKid

Jun 10, 2015
2,929
Hello, I want to reduce 12 volts to 7 volts, how many ohms do I need using a resistor?
3.

#### johansasa

Jun 19, 2024
8
I connect a resistor to both sides, but no current flows. If I remove the resistor it gets current. Why is this happening?

I connected a 3 ohm resistor, the current does not go away, if I remove it, it goes away. This is the power unit.

My purpose is not to ask troll questions, but to reduce the voltage of the power unit. I could not achieve 7 volts. Its value does not change. When I connect a resistor, it cuts off.
It's not worth it for something like this, a 7 volt one is on sale, I'll buy it from there, but thank you very much anyway.

Feb 19, 2021
826
Post #2 has a number of pertinent questions.....

#### crutschow

May 7, 2021
864
You seem to have a minimal understanding of circuits, and don't answer our questions, so how can we answer yours?

#### davenn

Moderator
Sep 5, 2009
14,313

@johansasa if you want the thread reopened, message me and show me that you are ready to answer the Q's that have been asked of you

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