Why the Aluminum Electrolytic Capacitor is Got Hot ?
The in-line electrolytic capacitor itself is not hot, but it is basically hot and hot after being connected to the circuit board. In fact, the main cause of the capacitor heating is three types: 1 ripple current is too large. 2 capacitor The pressure is too high. 3 The outside temperature is too high. Generally, it can be divided into three reasons. The temperature range of a general capacitor is between -40 ° C and 105 ° C. Therefore, if the ripple current is too large, a plurality of capacitors can be connected in parallel to share the ripple circuit. What is the reason for the specific points for everyone?
Ripple is one of the causes of self-heating of capacitors. Capacitors act as charge banks. When the voltage increases, they are charged. When the voltage drops, they discharge to the load; they essentially act as smooth signals. When the capacitor is subjected to a ripple voltage other than a DC voltage, the capacitor will experience a varying voltage and, depending on the applied power source, may also have varying currents, as well as continuous and intermittent ripple power. Regardless of the input form, changes experienced by the capacitive electric field will cause oscillations in the dipole of the dielectric material, thereby generating heat. This reaction behavior, called self-heating, is one of the main reasons why dielectric performance is an important indicator because any parasitic resistance (ESR) or inductance (ESL) will increase energy consumption.
Also before we consider ripple, we must pay attention to the heat generated by the applied DC bias. Capacitance is not an ideal device. A parasitic phenomenon is the shunt resistance (RLi) across the dielectric material that will cause leakage current to occur. This small DC current can cause heat, but unlike other typical applications, the heat is usually negligible. When the working voltage exceeds the maximum withstand voltage of the capacitor, the polarity and capacitance are reversed, and the dielectric properties of the capacitor are degraded, the capacitor heating is mainly caused by the leakage current.
In summary, the main factor causing the heating of the aluminum electrolytic capacitor is the ripple superimposed on the direct current. The popular point is that there is not enough pressure or internal leakage. But there are ways to solve it. For example, if the ripple current is too large, we can connect multiple capacitors in parallel to share the ripple circuit. If the withstand voltage is not enough, multiple capacitors can be connected in series to share the total voltage. The above is the reason why the heat of the capacitor is hot. If you have a good introduction, please leave a message below the article.