jbcapacitors blog

All capacitors have a voltage rating. This tells you how much voltage the dielectric (insulator) can withstand before allowing DC to pass between its plates. Sometimes a capacitor has a working voltage (i.e. WVDC working voltage DC) and a surge voltage. The working voltage tells you how much voltage the capacitor can withstand long term (for the normal life of the capacitor). The surge voltage is the voltage is can withstand for short periods of time. Generally, if too much voltage is applied to a capacitor, it will fail. In electrolytic capacitors, the forming voltage (voltage used to anodize the plates) and the thickness of the paper element determine the working voltage of the cap. In film type capacitors, the insulating material (polyethylene, polypropylene...) will determine the maximum working voltage.