Basic electronics

[Richard Harris]

Hi,

Current is directly proportional to Voltage.
E=I

There for I=E, E=9V, I=9A ?

If this is so, how come you can get a 4.8 V battery in 720 mA and in
1200 mA ?

Would this 4.8 battery allow you to connect to a device that required a
4.8A load?

Thanks.

 

[Andrew Holme]

Richard Harris wrote:

Hi,

Current is directly proportional to Voltage.
E=I

There for I=E, E=9V, I=9A ?

Proportional does not mean equal. Resistance is the constant of
proportionality:

E = IR or I =E/R

If this is so, how come you can get a 4.8 V battery in 720 mA and
in 1200 mA ?

Are you quoting maximum current (mA) or capacity in milliamp-hours (mAh)
there?

Would this 4.8 battery allow you to connect to a device that
required a
4.8A load?

Possibly, yes. What sort of battery is it? Can you post a link to the
spec?

The capacity (= stored charge = current * time) determines how long it will
last.

 

[Peter Bennett]

On Mon, 17 Jan 2005 17:03:10 +0000 (UTC), "Richard Harris"
<richard_harris_2@hotmail.com> wrote:

Hi,

Current is directly proportional to Voltage.
in a resistive circuit.

E=I

No - E = I/R

There for I=E, E=9V, I=9A ?

No. The current depends on the resistance, as well as the voltage.

If this is so, how come you can get a 4.8 V battery in 720 mA and in
1200 mA ?

I suspect that your 4.8 V batteries have a _capacity_ of 720 mA-hours
or 1200 mA-hours. That is, they could theoretically deliver 720 mA
(or 1200 mA) for an hour before becoming fully discharged.

Would this 4.8 battery allow you to connect to a device that required a
4.8A load?

Yes - but it won't run it for long.

Thanks.

--
Peter Bennett VE7CEI
email: peterbb4 (at) interchange.ubc.ca
GPS and NMEA info and programs: http://vancouver-webpages.com/peter/index.html
Newsgroup new user info: http://vancouver-webpages.com/nnq

 

[Bob Myers]

"Peter Bennett" <peterbb@nowhere.invalid> wrote in message
news:ke7ou01ftb7klufq7sg54jdd3gcsscre48@4ax.com...

On Mon, 17 Jan 2005 17:03:10 +0000 (UTC), "Richard Harris"
richard_harris_2@hotmail.com> wrote:

Hi,

Current is directly proportional to Voltage.
in a resistive circuit.

E=I

No - E = I/R

Ummmmm...Peter?.....

Bob M.

 

[jim w]

Bob Myers wrote:

"Peter Bennett" <peterbb@nowhere.invalid> wrote in message
news:ke7ou01ftb7klufq7sg54jdd3gcsscre48@4ax.com...

On Mon, 17 Jan 2005 17:03:10 +0000 (UTC), "Richard Harris"
richard_harris_2@hotmail.com> wrote:


Hi,

Current is directly proportional to Voltage.

in a resistive circuit.


E=I

No - E = I/R


Ummmmm...Peter?.....

Bob M.


Obviously, he meant conductance, not resistance, in that post. ;-)