Is the r in your diagrams a representation of the internal resistance? If so, it is (b).laser said:
Yesharuspex said:
How would you envisage measuring the value ξ in diagram b? You'd have to put the probes 'somewhere' in amongst the electrolyte and electrodes. emf is a value of potential difference when no current.is being taken. Internal resistance is just a mental construct which gives a value to the amount of energy dissipated inside the battery for each unit of charge that passes through. We don't know where the loss occurs and nor do we find that the value of r is the same for all currents. r is a handy value to tell us things like how 'good' a battery is and what sort of load it will support.laser said:
We measure current in series, voltage in parallel.Orodruin said:
Yeah, I think that was just a typo in his reply, based on his "opposite" comment (which is correct). I've sent Oro a PM to clarify.DaveE said:
Internal resistance refers to the opposition to the flow of electric current within the battery itself. It is caused by factors such as the chemical properties of the electrolyte, the physical structure of the electrodes, and the temperature of the battery. Internal resistance can lead to energy loss in the form of heat and affects the overall performance of the battery.
Yes, the voltage across a battery can change when current flows due to internal resistance. The actual voltage measured at the terminals of a battery under load (when current is drawn) is lower than its open-circuit voltage (when no current is flowing). This drop in voltage is a result of the internal resistance of the battery, which causes a voltage drop proportional to the current flowing through it.
The voltage across a battery can be calculated using the formula: V = E - I * r, where V is the terminal voltage, E is the electromotive force (EMF) or open-circuit voltage of the battery, I is the current flowing through the circuit, and r is the internal resistance of the battery. This equation shows that the terminal voltage decreases as the current increases due to the voltage drop across the internal resistance.
Internal resistance is important because it affects the efficiency, performance, and lifespan of a battery. High internal resistance can lead to significant energy losses, reduced capacity, and increased heat generation during operation. In applications where high current is required, such as in electric vehicles, minimizing internal resistance is crucial for achieving optimal performance and efficiency.
Yes, internal resistance can be measured using various methods. One common approach is to apply a known load to the battery and measure the voltage drop across the terminals while the load is active. By using the formula for voltage drop (V = I * r), the internal resistance can be calculated. Additionally, specialized equipment like an impedance analyzer can provide more precise measurements of internal resistance across different frequencies.