Is a Smaller Capacitance Error Better For Film Capacitors

Film capacitors are constructed with metal foil as electrodes and plastic films such as polyester, polypropylene, polystyrene, or polycarbonate. These films are overlapped from both ends and wound into a cylindrical structure to form the capacitor. Recently, many beginners have been discussing whether a smaller capacitance error is better for film capacitors.

Performance characteristics of film capacitors:

• Stable capacitance characteristics with temperature variation.
• Good voltage resistance, suitable for high-voltage applications.
• Low loss, suppressing self-heating for energy efficiency.
• Sharp high-frequency characteristics, good for filtering purposes.
• High ripple current tolerance, with a large current density per unit volume.
• Self-recovery function for added reliability.
• No maintenance required for over 10 years in high-temperature environments.

Is a smaller capacitance error better for film capacitors?

If a high level of precision is required for capacitance, it involves selecting from a large number of well-manufactured film capacitors, which naturally comes at a higher price. Therefore, considering the cost perspective, a smaller capacitance error does not necessarily mean it’s better.

In reality, many circuits do not demand high precision in capacitance error. For applications like bypassing, coupling, or low-demand timing and general delay, K-grade capacitors with a 10% tolerance can be chosen. For slightly more demanding applications, capacitors with a ±5% tolerance can be selected.

The capacitance error of film capacitors is typically around ±5%, meeting the capacitance error requirements of the majority of circuits. If the circuit does not demand high precision in capacitance error, capacitors with a ±10% tolerance can be chosen. If uncertain about the selection, consulting experienced manufacturers and considering the specific conditions of the circuit is advisable.

This article is provided by JYH HSU (JEC) Electronics. JEC is a research, development, production, and sales-oriented company specializing in manufacturing and selling various electronic components such as capacitors and resistors.