Capacitor (ceramic / MLCC)
Capacitor
Stores energy in an electric field. Ceramic caps are small, cheap, non-polarised, and the workhorse for filtering and decoupling.
Schematic symbol
Capacitor (non-polarised)
How capacitor (ceramic / mlcc) appears in a circuit diagram.
Types & variants
Key specs
Capacitance
Farad (F)How much charge it stores. Usually pF, nF or uF.
Voltage rating
VMax voltage before breakdown. Pick at least 2x your working voltage.
Tolerance
%Variation from marked value; ceramics can be loose (±10-20%).
Dielectric class
-C0G = stable/precise; X7R = general; Y5V = bulk but drifts with temp/voltage.
Markings
3-digit code like 104 = 10 x 10^4 pF = 100nF = 0.1uF. (Use the built-in capacitor-code calculator.)
Standard values
Common: 100pF, 1nF, 10nF, 100nF (0.1uF decoupling), 1uF.
How to choose
Decoupling -> 100nF near each IC. Filtering -> match to cutoff frequency. Always voltage rating >= 2x working voltage. Use C0G for timing/precision.
Pinout & package
2 leads, non-polar (any orientation). SMD 0402-1206 or radial disc.
Example circuits
- 0.1uF decoupling cap across IC power pins
- RC low-pass filter
- Timing cap in a 555 circuit
Common failures
Cracks (mechanical/thermal) cause shorts; capacitance drops with applied DC voltage (X7R/Y5V).
How to test
Use a multimeter/LCR meter capacitance mode. A shorted cap reads near 0 ohms in resistance mode.
Substitutes
Same or higher voltage rating; similar capacitance. C0G can replace X7R but not always vice-versa.