You are here:

# Physics/coils

Question
QUESTION: If a coil constructed with insulated copper wire, of many
'turns', has an electrical input of just 1 volt at '0' amps,
can 12 volts at 5 amps be extracted?
BILL.

ANSWER: No, zero amps in means zero amps out.  And you can't get more power out than you put in to a transformer.  A simple coil only has one set of contacts, so you can't extract anything from that in the first place.  But 12 Volts and 5 Amps is 60 Watts (assuming RMS values for AC, since DC won't work in a transformer.  1 Volt at '0' Amps for an input is 0 Watts.  0 < 60 you can't get more power out than you put in.

---------- FOLLOW-UP ----------

QUESTION: Thanks Steve,
In that case, let me put the value of the amps at 1 amp.
Can it work now?
BILL.

ANSWER: No, you're still trying to get 60 Watts out of 1 Watt.  That doesn't work, and the math is backwards.  And I still don't know what your second coil is, you have to have two coils to change voltage/current.  This process is extremely well understood and effective, with efficiency in the  upper 90-something percent range, but not above 100% ever.  :)

---------- FOLLOW-UP ----------

QUESTION: Steve,
I'm at a loss at you asking me what the 2nd coil is!   What 2nd coil?
Can you tell me then, how to generate the 5 amps I require?
BILL.

Voltages exist between two points, like the beginning and end of a coil of wire.  That's two points.  You can put a voltage across that and cause a current to flow.  You can't have two different voltages between the same two points.  One coil, one voltage, one current.  In order to transform electrical signals like you mention into different voltages and currents, you have two coils coupled through the magnetic field between them.  This is a transformer.  Wikipedia is relatively thorough:  http://en.wikipedia.org/wiki/Transformer  If you don't trust wikipedia, try hyperphysics:  http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/transf.html

Physics

Volunteer

#### Dr. Stephen O. Nelson

##### Expertise

I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

##### Experience

I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Education/Credentials
Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.