While ceramic capacitors offer better dv/dt capabilities, film capacitors are good (with a maximum value of 2200 V/µs) making them suited for use in snubber circuits. Film capacitors also have low equivalent series resistance (ESR), low equivalent self-inductance (ESL) and can tolerate large peak currents.
Film capacitors also have low equivalent series resistance (ESR), low equivalent self-inductance (ESL) and can tolerate large peak currents. Snubber capacitors in series with a small resistor are placed across solid-state switching devices. Snubbers protect the devices from voltage spikes and reduce the rate of rise (dv/dt) across them.
Film capacitors are used in many applications because of their stability, low inductance and low cost. They can also tolerate overvoltage surges.
In this standard, the electrical characteristics of capacitors are described by an idealized series-equivalent circuit with electrical components which model all ohmic losses, capacitive and inductive parameters of a film capacitor:
The most important reliability feature of film capacitors is their self-healing capability, i.e. their abil-ity to clear faults (such as pores or impurities in the film) under the influence of a voltage. The metal coatings, vacuum-deposited directly onto the plastic film, are only 20 ... 50 nm thick.
Film capacitors are one of the most common types of capacitors used in electronics systems today. The most widely used types of film capacitors include polyester, polycarbonate, polystyrene, polypropylene, polysulfone, and Teflon capacitors. A comparison chart of various film capacitors is shown in Table 1.