The voltage ratings for different film materials depend on factors such as film thickness, material quality (free of physical defectsand chemical impurities), ambient temperature and operating frequency, and the safety margin for breakdown voltage (dielectricstrength), In general, however, the rated voltage of a film capacitor depends primarily on the thickness of the plastic film. Forexample, with the minimum usable film thickness of a polyester film capacitor (about 0.7 um), a capacitor rated at 400V DC can beproduced. If a higher voltage is required, a thicker plastic film is usually used, However, the breakdown voltage of the dielectricfilm is usually non-linear, For thicknesses greater than about 5 mils, the breakdown voltage only increases with the square root ofthe film thickness, On the other hand, the capacitance decreases linearly with increasing film thickness., For reasons of availability,storage, and existing processing capabilities, it is desirable to achieve higher breakdown voltages while using currently availablethin film materials. This can be achieved by way of a single-sided partial metallization of the insulating film to produce an internalseries connection of the capacitor. By using this series connection technique, the total breakdown voltage of the capacitor can bemultiplied by any multiple, but the total capacitance will also be reduced by the same multiple, Memory and existing processingcapabilities, it is desirable to achieve higher breakdown voltages whil using currently available thin film materials. This can beachieved by way of a single-sided partial metallization of the insulating film to produce an internal series connection of thecapacitor. By using this series connection technique,the total breakdown voltage of the capacitor can be multiplied by anymultiple, but the total capacitance will also be reduced by the same multiple. Memory and existing processing capabilities,it isdesirable to achieve higher breakdown voltages while using currently available thin film materials, This can be achieved by way ofa single-sided partial metallization of the insulating film to produce an internal series connection of the capacitor. By using thisseries connection technique, the total breakdown voltage of the capacitor can be multiplied by any multiple, but the totalcapacitance will also be reduced by the same multiple. The breakdown voltage can be increased by using a single-sided partiallymetallized film, or the breakdown voltage of the capacitor can be increased by using a double-sided metallized film. Double-sidedmetallized films can also be combined with internal series capacitors by partial metallization. These multiple technology designsare particularly suitable for high reliability applications with polypropylene films.