# How to amplify voltage?

Discussion in 'Electronic Basics' started by zalzon, Sep 7, 2004.

1. ### zalzonGuest

I have 5V DC, 0.5mA, how do I amplify this voltage to 20V DC or
whatever voltage level I want?

Is this something that is easy or hard to do?

I should be easy enough to reduce voltage from 20V to 5V. Just put a
resistor in the path of the current. But how to do the reverse? Step
up the voltage....

I'm thinking coils like a transformer or something. Am I on the right
path?

2. ### Tom BiasiGuest

You are on the right track. Investigate what a transformer does and what
causes it to do it.
See if you can discover what happens on the input to get a certain output.
You will probably see some new terms and be introduced to some new concepts

BTW: When you use a resistor as you describe you didn't reduce the voltage,
you just let some of it reside in a different place.
Tom

3. ### John PopelishGuest

Apply the signal to an opamp with the appropriate feedback network and
a supply voltage higher than the desired output voltage.

4. ### AndybGuest

I got this: http://www.national.com/appinfo/power/files/f5.pdf

Andyb

5. ### andyGuest

If you're talking about a supply voltage, a switching regulator would do
it. They use an inductor (like a transformer but only one coil). It works
by switching a current through the inductor to ground, which stores
magnetic energy in the inductor, then cutting the current path to ground
which forces it to flow into a higher voltage circuit and transfer the
inductor's energy to a capacitor. (Inductors don't 'like' sudden changes
in current the same way that capacitors don't 'like' changes in voltage,
so if the path the current was flowing along is removed, it will look for
a another route).

6. ### MarlboroGuest

Yes, and remember that you can't take out more than what you put in,
is that the thumb rule? I means POWER_out <= POWER_in, the equal sign
"almost" never happen.

7. ### Geir KlemetsenGuest

Like to see any example when the power_out = power_in.

8. ### Travis HayesGuest

Power_out is ALWAYS equal to the power_in. The power out is just in a
different form. In the case of electronics circuits, there is usually an
increase in thermal energy for the drop in electrical energy. Mechanical
motion and emitted photons are other forms that power converted from
electrical energy can take.

9. ### MarlboroGuest

I doubt about that, where all matter came from?
Will this explan the big bang?

10. ### Travis HayesGuest

If you're implying that all matter came from energy initially, then
where did all that energy come from?
Not unless it was running on a microcontroller... No, this is just
according to the classic laws of thermodynamics. Matter and energy are
neither created nor destroyed, just changing forms. If you have a resevoir
of water and run it over a water wheel into a pond, there will be exactly as
much water afterwards as before, but some of it will have evaporated, some
of it will have soaked into the water wheel, some has spilled out of the
wheel onto the ground, but it's all there.
All of the potential energy that the water had in the upper resevoir is
still there, too. Some of it is did work on the water wheel, some of it was
changed into thermal energy because of friction on the wheel, some of it was
converted to sound energy in the air that you heard as splashing, but the
total amount of energy didn't change.
The same thing happens with the electrons (and their energy) in a
circuit. All of the electrons went somewhere. All of the energy went
somewhere.
Once you start getting into nuclear reactions, then you can indeed see
some matter and energy change places.

-Cheers,

Travis

11. ### MarlboroGuest

Well, that's ABSOLUTELY an ASSUMPTION, and you MAYBE ABSOLUTELY
correct when saying "Power_out is ALWAYS equal to the power_in".

Cheer,

12. ### MarlboroGuest

surely you've heard of antimatter and dark energy?

13. ### Geir KlemetsenGuest

After reading the tread, now I understand what Travis Hayes men with
"Power_out". For him it's the electrical power_out + thermal power_out. When
I'm talking about electrical circuits/devices, power_out is only the
electrical power_out. Especially voltage converters, amplifiers, an that
kind of things.

14. ### Guest

On Mon, 13 Sep 2004 00:47:48 +0200, "Geir Klemetsen"

step up dc voltage with a dc..to dc..converter..I frequently use a
5vdc to 12 v dc converter in my circuits..i think you can find a
range to suite your needs in a power components catalog..or on the
internet..