#1

I need a bit of help with a question from my Engineering coursework...

Is the

For example...

My

What would cause this?

I know it's a bit sad, but I've never had any experience with current/circuits and really have no idea on the principles behind the math and how they correlate into real-life situations.

EDIT:

The chart shows...

Vs (volts) = 7

Power (watts) = .9

Measured Current

Calculated Current

Is the

*calculated*current (Icalc) always less than the*measured*current (Icalc)?For example...

My

*measured*current was .22A, while my*calculated*current was .1697A .What would cause this?

I know it's a bit sad, but I've never had any experience with current/circuits and really have no idea on the principles behind the math and how they correlate into real-life situations.

EDIT:

The chart shows...

Vs (volts) = 7

Power (watts) = .9

Measured Current

*I*(amps) = .22Calculated Current

*I*(amps) = .1697*Last edited by dudey5691 at Sep 16, 2009,*

#2

I'm lost...

#3

I would have expected the measured current to be less than the calculated current due to physical imperfections in the components, which leads to higher resistance and less current.

However, I have only had basic level electronics so I don't really know.

However, I have only had basic level electronics so I don't really know.

#4

yeah im with tremolo. but yeah im just in some beginer classes in highschool.

#5

http://wiki.answers.com/Q/Why_is_calculated_current_different_from_measured_current_in_a_circuit

Looks like measured should be lower than calculated.

Are you sure you're calculating it properly?

EDIT :

What's your resistance? Current (I) is Voltage over Resistance (in Ohms). You didn't give the ohms, do you have that number?

Looks like measured should be lower than calculated.

Are you sure you're calculating it properly?

EDIT :

What's your resistance? Current (I) is Voltage over Resistance (in Ohms). You didn't give the ohms, do you have that number?

*Last edited by dark&broken at Sep 16, 2009,*

#6

Typically the measured is less then the calculated.

#7

http://wiki.answers.com/Q/Why_is_calculated_current_different_from_measured_current_in_a_circuit

Looks like measured should be lower than calculated.

Are you sure you're calculating it properly?

EDIT :

What's your resistance? Current (I) is Voltage over Resistance (in Ohms). You didn't give the ohms, do you have that number?

Unrelated. P=IV, where P = power in watts, I = current in amps, and V = voltage. According to that, the calculated seems to be wrong.

#8

Unrelated. P=IV, where P = power in watts, I = current in amps, and V = voltage. According to that, the calculated seems to be wrong.

Ah ok, I knew there were other equations, but I haven't done anything with this since high-school, and I'm now in 2nd year uni, so it's been a while. I was just going by what google had to say.

#9

Alright, after discussing things with an online colleague...

I should have mentioned that we used some quadratic equation that is meant to find theoretical current... RI^2 - VI + P = 0

Our TA said pick the solution closest to the measured, so I chose that... There is, however, a solution that is higher.

BUT, in the case of the .22A-current... the calculated Current would be .5303, which is apparently an irrealistic drop in current.

Any ideas?

It's a parallel circuit with one 10- and 20-ohm resistors, with a multimeter and watt-meter in the circuit.

I'd post a picture, but cannot right now.

I should have mentioned that we used some quadratic equation that is meant to find theoretical current... RI^2 - VI + P = 0

Our TA said pick the solution closest to the measured, so I chose that... There is, however, a solution that is higher.

BUT, in the case of the .22A-current... the calculated Current would be .5303, which is apparently an irrealistic drop in current.

Any ideas?

It's a parallel circuit with one 10- and 20-ohm resistors, with a multimeter and watt-meter in the circuit.

I'd post a picture, but cannot right now.

#10

Is the .3A difference realistic, considering the circuit is parallel, has two different rated resistors, and had two pieces of equipment running through it?

*Not a bump, a more specified question to end thread.

*Not a bump, a more specified question to end thread.