Calculating Power Dissipation in a Circuit

In summary, the question of whether to account for internal resistance when calculating power dissipation from a non-ideal battery depends on the specific question being asked. If the question asks for the power supplied by the battery, then only the power dissipated by the load should be considered. However, if the question is about the total power expended or developed by the battery, then the internal dissipation should be included. The internal dissipation of power in a battery is the reason for its heat and is not available to the circuit, which is only the product of load current and voltage.
  • #1
JSGandora
95
0
If I ran over a problem asking for power supplied by a non-ideal battery, or a battery with an internal resistance. Do I account for the internal resistance when I calculate the power dissipation? Or do I just account for the loads (finding the total resistance excluding the internal resistance of the battery and then multiplying it by the current squared to get the power) excluding the internal resistance?
 
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  • #2
Surely that depends on the question?

The power dissipated in the internal series resistance is the reason batteries become warm/hot when you draw power from them.
But this power is unavailable to the circuit. The power in the circuit is the product of the load current and the voltage across the load.
 
  • #3
Oh, I see now. Thanks for your clear response!
 
  • #4
go well
 
  • #5
Hmm? What do you mean by "go well"?

Also, just to make sure, if the questions stated "What is the power supplied by battery D?", then we only account for the power dissipated by the load, correct?
 
  • #6
Go well is an English phrase wishing you good fortune in the future.

I would take the question
"What is the power supplied by battery D?"

To mean the power drawn by the load.

I think the key word is 'supplied'
The internal dissipation wasted in heating the battery is not supplied to anything.

I would expect a question including the internally dissipated power to read something like

'Find the total power expended by the battery' or 'Find the total power developed by the battery'.
 
  • #7
Thank you, it's very clear to me now. Go well to you too!
 

FAQ: Calculating Power Dissipation in a Circuit

How do you calculate power dissipation in a circuit?

To calculate power dissipation in a circuit, you need to know the voltage and current values. The formula for power dissipation is P = VI, where P is power in watts, V is voltage in volts, and I is current in amps.

What is the unit of power dissipation?

The unit of power dissipation is watts (W). This unit represents the rate at which energy is being transferred or used.

What factors affect power dissipation in a circuit?

The amount of power dissipated in a circuit is affected by the resistance of the components, the voltage applied, and the current flowing through the circuit. The higher the resistance, voltage, or current, the higher the power dissipation.

How can you reduce power dissipation in a circuit?

To reduce power dissipation in a circuit, you can use components with lower resistance, decrease the voltage applied, or decrease the current flowing through the circuit. You can also use more efficient components or implement energy-saving techniques in the design of the circuit.

Why is it important to calculate power dissipation in a circuit?

Calculating power dissipation in a circuit is important because it helps to ensure that the components are not being overheated, which can lead to damage or malfunction. It also helps in designing more efficient and cost-effective circuits by determining the optimal values for voltage and current.

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