The challenging conditions faced by automobiles have compelled component manufacturers in the automotive industry to come up with superior capacitors. Two of these advanced capacitors are professional grade capacitors of tantalum and niobium oxide.
A capacitor is comprised of two conducting plates separated by a dielectric (insulating) medium. One plate maintains a positive charge while the other maintains a negative charge.
Benefits of Professional Grade Tantalum Capacitors
A tantalum capacitor has a pellet of tantalum as the positive end separated from the negative conductor by a dielectric, which in this case is a thin layer of tantalum oxide formed on the tantalum pellet surface.
Professional grade variety of tantalum capacitors has several advantages over standard tantalum capacitors. Manufacturers adopt strict design specifications to construct the capacitors and use thicker and better dielectrics. In addition, the manufactures check the devices for high surge current and burn-in procedures.
The use of these capacitors results in a low failure rate of 0.5% in 1000 hours. In addition, the leakage current is almost 75% less than that in conventional tantalum capacitors. Manufacturers make professional grade capacitors available with low and standard equivalent series resistances (ESR). This makes these components suitable for several types of control circuits in automobiles.
The low ESR capacitors are particularly useful in airbag modules, engine control modules and power supply modules.
Functioning at High Temperatures
Automotive engineering requires placing electronic components close to sources of heat like engines, gearboxes, AC circuits and headlights. The temperatures in these regions may be in the region of 175°C. Since tantalum capacitors can function over a wide temperature range from -55°C to +175°C, they are suitable for use in these regions.
Before deciding on a tantalum or niobium oxide capacitor in a particular automotive circuit, the industry thinks about the nature of the circuit and the device using it. The first factor, which is the maximum voltage drop across the load in the circuit, determines the voltage rating of the capacitor. The second factor is the applied DC voltage. The applied voltage must be 50% of the rated voltage for the capacitors. This takes care of an unexpected surge in voltage. The third factor is the maximum value of the operating temperature. The capacitor selected must be able to withstand the temperature of the operating device.
A circuit operating under high temperature conditions (up to 125°C) can expect to see additional voltage surges. It is crucial that capacitors employed can endure these issues.