Home/Technical Glossary/Pulse Width (Resistance Spot Welding) Pulse Width (Resistance Spot Welding) Pulse width (aka pulse duration) in resistance spot welding is defined as the length of time – in milliseconds or line cycles – that the weld current flows through the parts. In some cases there is only one pulse per weld (single pulse), but it is not uncommon to have two pulses per weld (dual pulse). There is also a mode for high frequency inverter welders know as “Pulsation” where the weld pulse is repeated several times.