The capacitance formula is C=Q\/U.
plane-parallel capacitor
Special formula: electric field strength between plates
E = U \/ d。
Capacitor capacitance determination C=εS\/4πkd.
The calculation formula related to capacitance
1, a capacitor, if with 1 library of electricity when the potential difference between the two stages
Is 1 volt, the capacitance of this capacitor is 1 method, that is: C=Q\/U.
2, but the size of the capacitor is not determined by Q (with electricity) or U (voltage), that is: C=εS\/4πkd. Where ε is a constant, S is the opposite area of the capacitor plate, d is the distance of the capacitor plate, and k is the electrostatic constant
. The common parallel plate capacitor has a capacitance of C=εS\/d. ε is the permittivity of the dielectric between plates
S is the plate area and d is the distance between plates.
3, the capacitor potential energy calculation formula: E=CU^2\/2=QU\/2.
4, multi-capacitor parallel calculation formula: C=C1 C2 C3... Cn multi-capacitor series calculation formula: 1\/C=1\/C1 1\/C2... 1\/Cn.
5, capacitors for high frequency alternating current
The hindering effect is reduced, that is, tolerance resistance
Small, on the contrary, the capacitors produce large capacitors for low frequency alternating current; For the same frequency of AC electricity. The larger the capacity of the capacitor, the smaller the capacitive reactance, and the smaller the capacity, the greater the capacitive reactance.
6, series voltage division ratio: the larger the capacitor, the smaller the voltage. Parallel shunt ratio: the larger the capacitor, the larger the current.
7, when t= RC, capacitance voltage =0.63E; When t= 2RC, the capacitance voltage is 0.86E; When t= 3RC, capacitance voltage =0.95E; When t= 4RC, capacitance voltage =0.98E; When t= 5RC, capacitance voltage =0.99E; T units S units R units ohm
C unit F.
8, T time voltage: Vt=V0 (V1-V0)*[1-exp(-t\/RC)].
9, charge and discharge time: T=RC*Ln[(V1-V0)\/(v1-vt)].