The Electrolytic capacitor here mainly refers to the Aluminum Electrolytic Capacitor, and its basic electrical parameters include the following five points:
1, the capacitance value
The capacitance of an Electrolytic Capacitor depends on the impedance exhibited when operating at an alternating voltage. Therefore, the capacitance value, that is, the value of the AC capacitor, varies with the operating frequency, voltage, and measurement method. In the standard JISC 5102, the capacitance of the aluminum electrolytic capacitor is measured under the conditions of a frequency of 120 Hz, a maximum AC voltage of 0.5 Vrms, and a DC bias voltage of 1.5 to 2.0 V. It can be asserted that the capacity of the aluminum electrolytic capacitor decreases as the frequency increases.
2, loss tangent tan δ
In the equivalent circuit of the capacitor, the ratio of the series equivalent resistance ESR to the capacitance of 1/ωC is called Tan δ, where the ESR is the value calculated at 120 Hz. Obviously, Tan δ becomes larger as the measurement frequency increases, and increases as the measurement temperature decreases.
3, impedance Z
At a specific frequency, the resistance that blocks the passage of the alternating current is the so-called impedance (Z). It is closely related to the capacitance value and inductance value in the capacitor equivalent circuit, and is also related to ESR.
Where X C = 1 / ωC = 1 / 2πfC
X L = ωL = 2πfL
The capacitive reactance (X C ) of the capacitor gradually decreases with increasing frequency in the low frequency range, and the frequency continues to increase to the value of the reactance (X L ) to the ESR when the intermediate frequency range is reached. Inductive reactance (X L ) when the frequency reaches the high frequency range
