Is there a max voltage drop across a capacitor? Or does it always charge up to the same voltage as the supply? If there is a max voltage, then what would happen if the supply voltage far exceeds the max voltage of the capacitor, would the dielectric material break?
\$\begingroup\$
\$\endgroup\$
1
-
4\$\begingroup\$ It'll charge up to the same voltage as the supply, until you exceed its maximum voltage at which point it will break in some manner dependent on a lot of different conditions and what type of capacitor it is. Or was; it probably won't be a very useful capacitor afterward. \$\endgroup\$– HearthCommented Oct 15, 2018 at 18:04
Add a comment
|
3 Answers
\$\begingroup\$
\$\endgroup\$
The cap will try to charge to the supply voltage. On its way to that voltage, if the voltage exceeds the voltage rating of the capacitor, the capacitor will eventually fail. At that point it will be permanently damaged. It may have even externally ruptured.
answered Oct 15, 2018 at 18:08
\$\begingroup\$
\$\endgroup\$
2
Is there a max voltage drop across a capacitor? Or does it always charge up to the same voltage as the supply?
Yes, there is a breakdown voltage associated with capacitors, you must not exceed the rated breakdown voltage ever. Usually it is printed on the capacitor itself, or found in the datasheet, or by identification of a color scheme if you know what company makes it.
If there is a max voltage, then what would happen if the supply voltage far exceeds the max voltage of the capacitor, would the dielectric material break?
If you exceed the breakdown voltage, the dielectric or other capacitor material breaks down and it turns into a resistor and could short. I have seen some capacitors explode this way. Tantalum capacitors should be derated, I usually go ~70% of the breakdown voltage.
answered Oct 15, 2018 at 18:07
-
1\$\begingroup\$ It's printed on the capacitor itself for electrolytic caps and film caps, but ceramic caps often don't have it, and MLCCs are annoyingly entirely bereft of any markings whatsoever. \$\endgroup\$– HearthCommented Oct 15, 2018 at 18:08
-
\$\begingroup\$ To add to this, certain types of capacitors (such as class Y capacitors) are designed to fail open rather than fail short. These are special purpose capacitors, though. \$\endgroup\$ Commented Oct 16, 2018 at 0:21
\$\begingroup\$
\$\endgroup\$
A capacitor will charge up to the supply voltage.
If you exceed the maximum allowable voltage for the capacitor, it will break (read explode) and become like a resistor/short
Capacitor Resource:
