The electrodes on polar capacitors are made of aluminum using a thin oxidation membrane. The main characteristic of a polar capacitor is the difference in polarity of the two legs. Therefore, we must be careful when installing it in the circuit. If the installation is reversed, the capacitor will be damaged and even explode. Usually, the working voltage of the capacitor is 2 times the power supply voltage. For example, a capacitor is given a power supply with a voltage of 5V, meaning that the capacitor must have a minimum working voltage of 2x5 volts = 10 volts. You can also use a voltage above this value, for example 16 volts is much safer.