Differences

This shows you the differences between two versions of the page.

--- composants:capacitors [2019/09/03 17:01] – created mh
+++ composants:capacitors [2020/06/01 16:35] (current) – external edit 127.0.0.1
@@ Line 10: / Line 10: @@
 ==== Ceramic capacitors ====
+{{composants:ceramic_capacitor.jpg?300}}
 Ceramic capacitors do not have any polarity. The dielectric medium is composed of a thin ceramic layer.
+Ceramic capacitors don't always have their capacitance indicated. Sometimes it's just a number. You can use a chart like [[http://www.electronicsteacher.com/capacitor-chart.php|this one]] to get the capacitor value
 ==== Electrolytic capacitors ====
+{{composants:electrolytic_capacitor.jpg?300}}
 Most of the electrolyte capacitors are polarized. Electrolytic capacitors are known to have a higher volumetric efficiency. This means a small capacitor is able to hold larger amount of charges than a ceramic capacitor of the same size.
+If they are connected with the wrong polarity, they may become very hot and may even explode.
+=== ESR ===
+For electrolytic capacitors, the **Equivalent Series Resistance (ESR)** is an important concept. If the ESR is too high, then the current flow through the circuit would be too small. The figure below shows how the ESR (impedance) of a capacitor changes with resistance. Each curve shows different capacitance values:
+{{composants:capacitor_esr.jpg?500}}
+Note that for each type of capacitor, there is a frequency at which the impedance is at a minimum. This frequency is the **resonant frequency** of the capacitor. Note that as the capacitance becomes larger, the resonant frequency becomes smaller.
 ==== Comparison ====
@@ Line 24: / Line 40: @@
   *Most of the electrolyte capacitors are polarized, but ceramic capacitors are never polarized.
+===== Ressources =====
+[[http://www.electronicsteacher.com/capacitor-chart.php|Capacitor chart]]