Lascar el usb act ac and dc millivolt data logger with current clamp input lascar el usb act p the lascar el usb act is a ac and dc millivolt data logger with current clamp input when used with a current clamp this standalone data logger measures and stores up to 127 232 ac and dc current readings over a 0 to 1000a dc measurement range and 0 to 723a for ac in 8216 energy monitoring mode this data is converted into power energy using a user defined voltage value and cost using a