Batteries have resistance.
- Resistance comes from electrons collliding with atoms and losing energy.
- In a battery, chemical energy is used to make electrons move. When they move, they collide with atoms inside the battery.
- This resistance is internal resistance!
- Internal resistance is what makes cells warm up.
- The amount of electrical energy the battery produces per unit charge is called the electromotive force (e.m.f)
- The p.d. across the resistance of the components in the circuit is called the terminal p.d.
- If there was no internal resistance, the terminal p.d. would be the same as the e.m.f. However, in real power supplies there is ALWAYS energy lost overcoming internal resistance.
- Energy wasted overcoming internal resistance is called lost volts.
Many calculations about e.m.f and internal resistance.
One equation interpereted…