Electrode electrode. In a vacuum tube or a semiconductor having polarity (diodes, electrolytic capacitors) the anode is the positive (+) electrode and the cathode the negative (−). The electrons enter the device through the cathode and exit the device through the anode. Many devices have other electrodes to control operation, e.g., base, gate, control grid. In a three-electrode cell, a counter electrode, also called an auxiliary electrode, is used only to make a connection to the electrolyte so that a current can be applied to the working electrode. The counter electrode is usually made of an inert material, such as a
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