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[skoko]

Umm.. internal resistance? Well.. That is (bad english incoming) electrical value that any battery or power source possess.. Imagine it like small , very small resistor inside battery.

like this ... .


internal resistance is responsible for power drops inside power source... and when you add all EMF-s from any circuit , you will be short for power drop on source (in Kirchhoff's law).. so EVERY battery has internal resistance which is responsible for certain power loss (it small power loss, but it exists) I hope that is internal resistance you were thinking about.

Example : (found on net)


A battery of emf 12 volts and internal resistance 0.5 ohms is connected to a 10 ohm resistor. What is the current and what is the terminal voltage of the battery under load??



Step 2: Work out the total resistance

R tot = R1 + R2 = 10 ohms + 0.5 ohms = 10.5 ohms

Step 3: Now work out the current:

I = V/R = 12 ? 10.5 = 1.14 A
Step 4: work out the voltage across the internal resistor (lost voltage):

v = Ir = 1.14 amps ? 0.5 ohms = 0.57 volts
Step 5: work out the terminal voltage:

Terminal voltage = emf - lost voltage = 12 - 0.57 = 11.43 volts
We can of course work out the terminal voltage by working the voltage across the 10 ohm resistor, assuming there are no losses.

P.S. Well i am rather good with electrical stuff and mathematics (but forgot differential equations of higher orders and similar things) and you can PM me with that kind of problems here on forums , and maybe i can help you !

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