UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Capacitor voltage ratings: AC / DC / dual

Lucien Nunes · 12th Apr 2021, 7:42 pm

By default, voltage ratings quoted for film capacitors for electronic applications or in an electronic context will be DC, while those for electrical machinery (e.g. motor run caps) are normally AC. The sum of the DC and any superimposed AC peak should not exceed the DC rating.

Additional ratings and parameters come into play with capacitors intended for severe duty such as fast-risetime impulses. It is not then safe to assume that the AC and DC ratings will be in the ratio of sqrt(2) as the dielectric losses and dV/dt may be limiting factors.

12th Apr 2021, 7:42 pm	#3
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: Capacitor voltage ratings: AC / DC / dual By default, voltage ratings quoted for film capacitors for electronic applications or in an electronic context will be DC, while those for electrical machinery (e.g. motor run caps) are normally AC. The sum of the DC and any superimposed AC peak should not exceed the DC rating. Additional ratings and parameters come into play with capacitors intended for severe duty such as fast-risetime impulses. It is not then safe to assume that the AC and DC ratings will be in the ratio of sqrt(2) as the dielectric losses and dV/dt may be limiting factors.