You will need
  • Capacitance meter
Large capacitors capacity is usually indicated in plain text: 0,25 µf or uF 15. In this case, the method of its determination is trivial.
For the smaller condensers (including SMD) capacitance is indicated by two or three digits. In the first case, it is marked in picofarads. In the second case the first two digits stand for capacitance, and the third in what units it is expressed:1 - tens of picofarads;
2 - hundreds of picofarads;
3 - nanofarad;
4 - tens of nanofarads;
5 - tenths of a microfarad.
There is also a notation of the capacity using the combination of Latin letters and numbers. The letters represent the following numbers:A - 10;
B - 11;
C - 12;
D - 13;
E - 15;
F - 16;
G - 18;
H - 20;
J - 22;
K - 24;
L - 27;
M - 30;
N - 33;
P - 36;
Q - 39;
R - 43;
S - 47;
T - 51;
U - 56;
V - 62;
W - 68;
X - 75;
Y - 82;
Z - 91.The resulting number should be multiplied by the number 10, previously raised to the power equal to the number following the letters. The result is expressed in picofarads.
There are capacitors, the capacity of which is not marked at all. You must have met them, particularly in the starters of fluorescent lamps. In this case, to measure the capacity only by a special device. They are digital and overhead.In any case, if the capacitor is soldered to a device, it should be switched off, discharged the filter capacitors and the capacitor, the capacitance of which is measured, and then desoldering it. Then it must be connected to the device.Digital meter first, choose the rough limit, then switch it until then, until it shows overload. After that, the switch is transferred to one limit back and read the testimony, and the switch position determines what units they are expressed.On the bridge the meter, sequentially switching the limits on each of them scroll the slider from one end of the scale to another until the sound from the speaker will not disappear. Having achieved the disappearance of sound on a scale controller read the result, and the units in which it is expressed, is also determined by the position of the switch.Then set the capacitor back into the device.