The input power of a LinkZero-AX design in the off-mode is so low that even a few mW of error can make a measurable difference. This makes accurately calibrated equipment and proper testing procedures extremely important. For help with setting up test equipment to accurately measure very low input power, please refer to the PI University course: Testing Compliance to Energy Efficiency Standards, available on the PI website at www.powerint.com/en/pi-university. Shown on this slide is a chart measuring the input power of a brand new LinkZero-AX DER-260 board versus time, at 230 VAC input. To confirm accuracy, this input power was measured with two different watt meters, and both traces are shown here. Notice that when voltage is first applied to the board, the input power is much higher than expected, but it drops off rapidly and settles in the expected range after about 30 minutes. This phenomenon is a result of the manufacturing process of the electrolytic input bulk capacitor, and is only seen during the capacitor burn-in period. The insulation layer within an electrolytic capacitor is formed by an electrochemical process which occurs when a voltage is applied across the capacitor for the first time. It can take up to 30 minutes for the insulation layer to fully form and for the leakage to reduce to its final steady-state value. Again, this process only occurs during the first few minutes of an electrolytic capacitor’s life and is typically described in the manufacturer's datasheet by a plot similar to the one shown here. Notice that the burn-in leakage curve from the datasheet very closely matches the standby input power we measure on the left. For the most accurate input power measurements, PI recommends waiting at least 30 minutes after first powering up a new LinkZero-AX design before taking data.