Lorraine
Guest
Mon May 23, 2005 6:29 am
Hi,
Supposed you have a dc source of 1 ampere and you short
it... from I=V/R, R=0, what then is the current produced??
Also suppose the voltage is 10 volts, and I want the
maximum current, from I=V/R. What is the least ohms
value can I use, 10 ohms? 1 ohm? Suppose the maximum
current of the source is 1 ampere. What value of current
would I get when I use a 1 ohm resistor in the 10
volt circuit? The I=v/r gives out I=10/1ohm= 10 Ampere
which doesn't make sense. What is the rule of units
used? Thanks.
Lorraine
P.S. May I know what are other electronic newsgroups
with lots of participants, tnx.
Lorraine
Guest
Mon May 23, 2005 12:28 pm
Mark VB wrote:
Quote:
Lorraine wrote:
Hi,
Supposed you have a dc source of 1 ampere and you short
it... from I=V/R, R=0, what then is the current produced??
R will never become 0, but for instance 1*10^-15. With 10 volts,
I=10/(1*10^-15)=1*10^16. However, if your dc source is
current-limited
at 1 amp., drawn current will be 1 amp while the voltage is lowered
to
1*10^-15, so V/R will become 1
Also suppose the voltage is 10 volts, and I want the
maximum current, from I=V/R. What is the least ohms
value can I use, 10 ohms? 1 ohm? Suppose the maximum
current of the source is 1 ampere. What value of current
would I get when I use a 1 ohm resistor in the 10
volt circuit? The I=v/r gives out I=10/1ohm= 10 Ampere
which doesn't make sense. What is the rule of units
used? Thanks.
I=V/R <=> R=V/I <=> R=10/1 <=> R=10 Ohms
Lorraine
P.S. May I know what are other electronic newsgroups
with lots of participants, tnx.
I see. So there is a lower limit to the resistor used
to make constant volage. For example. Voltage
is constant at 10 volts if the resistor varies from
10 ohm to 1 Gigaohm in a 1A source. Right? And if
the resistor gets lower than 10 ohm, the voltage
gets down. Now are there applications in which they
intentional make the resistance go down the
critical value to make the voltage lower??
Also why is that in larger load, the current is lesser
in value. How come the electrons don't just get
stuck up at the entry point to the load? How did
the battery knows how much current to send to
the given load? What's the feedback mechanism?
Lorr
