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1 Introduction

Figure 1.43: Resisters control the amount of current flowing through a circuit. a) Classification of resistor

types; b) Components of a resistor (here: carbon film resistor).

When talking about energy storage, batteries are important (Figure 1.46). They are made

from electrodes (anode and cathode) in contact with an electrolyte, together called an

“electrochemical cell”. In the battery, an oxidation reaction occurs that generates elec-

trons and thus a current. In rechargeable cells, the oxidation is reversible. A commonly-