Why do some capacitors have polarity?

In summary, electrolytic capacitors, such as Electrolytic and Tantalum Ones, have polarity because a reverse-bias voltage above 1 to 1.5 V can destroy the center layer of dielectric material, leading to a short circuit and potential explosion. This is due to the charge principle being based on electrolytics, where one end must be positive and the other negative.
  • #1
sinanissa
2
0
Really, after I became an electrical (control) engineer, until now i do not know why capacitors like Electrolytic and Tantalum Ones, have polarity. can anybody answer me please?
 
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  • #2
From http://en.wikipedia.org/wiki/Electrolytic_capacitor"

"This is necessary because a reverse-bias voltage above 1 to 1.5 V[1][2][3] will destroy the center layer of dielectric material via electrochemical reduction (see redox reactions). Without the dielectric material the capacitor will short circuit, and if the short circuit current is excessive, then the electrolyte will heat up and either leak or cause the capacitor to explode."

And this explosion really happened with me once I connected a 1000 F capacitor to a car battery in reverse, it exploded, like a fire cracker!
 
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  • #3
The characteristics has something to do with the chemistry of holding up the charges.
In Polarised caps , the charge principle is based on electrolytics. Hence one end has to be positive and the other negative.
 

1. Why do some capacitors have polarity?

Some capacitors have polarity because they are designed to work with direct current (DC) circuits, where the flow of electricity is in one direction. In these circuits, it is important for the capacitor to be able to store and release charge in a specific direction, which is achieved through polarity.

2. What is the difference between polar and non-polar capacitors?

Polar capacitors have a positive and negative terminal, while non-polar capacitors do not have a designated positive or negative terminal. This is because non-polar capacitors are designed to work with alternating current (AC) circuits, where the flow of electricity constantly changes direction.

3. How do I determine the polarity of a capacitor?

The polarity of a capacitor can usually be determined by the markings on the capacitor itself. The positive terminal is typically marked with a + sign, while the negative terminal may be marked with a - sign or a stripe. It is important to always check the markings before using a capacitor in a circuit.

4. Can I use a non-polar capacitor in place of a polar capacitor?

It is not recommended to use a non-polar capacitor in place of a polar capacitor. Non-polar capacitors are not designed to handle the same voltage levels as polar capacitors, and using them in the wrong circuit can result in damage to the capacitor or other components.

5. What happens if I connect a polar capacitor the wrong way?

If a polar capacitor is connected the wrong way in a circuit, it can cause the capacitor to fail and potentially damage other components in the circuit. It is important to always check the polarity of a capacitor before connecting it in a circuit.

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