Get the Voltage from the I(A)-Time diagram

In summary, the conversation discusses how to find the energy of a battery and capacitor based on current and time. It is mentioned that without knowing the voltage, it is not possible to determine the energy. There is a mention of using a graph to determine the net charge and using the equation Q=C*V to find the associated change in voltage. The conversation also explores different types of batteries and references an article for further reading. It is also noted that I*R is not the battery voltage, but rather the voltage drop or battery losses, and the delivery energy can be calculated using the formula ʃV*I*dt.
  • #1
papm
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The area under the diagramm is the capacity.Q=I(A)*t(s)
How can I can get the Voltage so tha I get the energy of the battery and capacitor?
 
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  • #2
Welcome to PF.
I assume you are talking about the discharge of a chemical battery.
papm said:
How can I can get the Voltage so tha I get the energy of the battery and capacitor?
Because only current and time are specified, it is not possible to know the voltage of the battery.
Does the word "capacitor" you use actually refer to the capacity of the battery in kW*hours, or do you have a capacitor in the circuit.
 
  • #3
Thank you for the reply
I have a chemical battery and a capacitor (over 45(A)).
Can I find the energy of them?
Can I assume V=I*R with R=1ohm?
Because I(A) get straight to 45(A) and we don't have a curve.
 
  • #4
papm said:
Can I assume V=I*R with R=1ohm?
Where does the idea of 1 ohm come from, why not 1 milliohm, or 1k ?
 
  • #5
Baluncore said:
Where does the idea of 1 ohm come from, why not 1 milliohm, or 1k ?
Don't know I just assumed to find out the energy.
Maybe becouse we get the I=45(A) immediately?
 
  • #6
We need more information.
You need to find the voltage from other references or make a measurement.
 
  • #7
This exercise was on last exams.
The only information was the diagramm that is from a electric car with a battery and and a capacitor for acceleration. There is no more information.
 
  • #8
That diagram will contain the detail.
 
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  • #9
papm said:
Because I(A) get straight to 45(A) and we don't have a curve.
That's 50A isn't it? That graph can tell you the net charge into/out of the capacitor. Then use Q = C.V to determine the associated change in voltage, but you do need to know C.

There'll be a graph describing the battery, and you use that to determine the battery voltage.
 
  • #10
This is cycle of a functioning electric vehicle [as translated from Greek]
Let's say this is total discharge battery= 117.6 Ah .A usual battery of 12V 120 Ah could present this discharge process. However a 24 V battery could present the same.
It could be one like this:12V/120Ah/115F51 JIS Car batteries, Sealed lead acid batteries -in my opinion.
 
  • #12
By the way, I*R it is not the battery voltage-except in short-circuit case-but it is the voltage drop through the battery and so I^2*R it is not the delivery power but the battery losses.
The delivery energy it is ʃV*I*dt .Since in the discharge time interval [up to- let's say 1.8 V from 2.2 V rated] you may consider the delivered voltage as constant and equal to the rated and then the delivered energy will be Vrated*Q.
 

Related to Get the Voltage from the I(A)-Time diagram

1. What is the purpose of the I(A)-Time diagram?

The I(A)-Time diagram is a graphical representation of the current (I) in a circuit over time. It is used to analyze the behavior of electrical components and determine the voltage across them.

2. How do you read the I(A)-Time diagram?

The horizontal axis represents time, while the vertical axis represents current. The line on the graph shows the change in current over time. The voltage can be calculated by multiplying the current at a specific point on the graph by the resistance of the circuit.

3. What is the relationship between current and voltage in an I(A)-Time diagram?

According to Ohm's Law, there is a direct relationship between current and voltage in a circuit. As the current increases, the voltage also increases, and vice versa. This relationship can be seen on the I(A)-Time diagram.

4. How can the I(A)-Time diagram be used in circuit analysis?

The I(A)-Time diagram is a useful tool for analyzing the behavior of electrical components in a circuit. By studying the changes in current over time, one can determine the voltage across different components and identify any potential issues or malfunctions in the circuit.

5. Are there any limitations to the I(A)-Time diagram?

While the I(A)-Time diagram is a useful tool, it does have some limitations. It assumes that the resistance in the circuit is constant, which may not always be the case. Additionally, it does not take into account any external factors that may affect the circuit, such as temperature or fluctuations in power supply.

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