Electrode reaction cannot be reversed, and the identities of the anode and cathode are therefore fixed. The anode is always the negative electrode. The cell can be discharged but not recharged. A secondary cell, for example a rechargeable battery, is a cell in which the chemical reactions are reversible. When the cell is being charged, the anode becomes the positive (+) and the cathode the negative (−) electrode. This is also the case in an electrolytic cell. When the cell is being discharged, it behaves like a primary cell, with the anode as the negative and the cathode as the positive
Aluminum electrolytic capacitor as "Z". In this sense the impedance is a measure of the capacitor's ability to pass alternating currents. Impedance can be calculated using the idealized components of a capacitor's series-equivalent circuit, including an ideal capacitor formula_4, a resistor formula_5, and an inductance formula_6. In this case the impedance at the angular frequency formula_7 is therefore given by the geometric (complex) addition of ESR, by a capacitive reactance (Capacitance) and by an inductive reactance (Inductance) Then formula_10 is given by Aluminum electrolytic capacitor Aluminum electrolytic capacitors are polarized electrolytic capacitors whose anode electrode (+) is made of a pure aluminum foil