The above chart shows the drift performance of the tool with constant current. The Y-axis shows the average current across a 5 second window taken every 5 min. As observed, the drift across 60 min is well under 1uA.
The graph shows the step response of the tool as it is measuring the in-rush current of a filament bulb. The tool takes less than 2us to reach the 90% of the final settled value of the current. The overshoot and undershoot are the artifacts caused by the cubic-spline interpolation used in the charting tool.
The power profiler has a linear response from -1A to 1A with compressed range extending to +/-1.2A. Although it can accept currents as high as 3A for short pulses, the measurement is only limited to 1A.
Current profile of a filament bulb turn-ON
This chart shows the current profile of a filament bulb as it is powered ON. Notice the high in-rush current which reaches close to 400mA. This is due to the lower resistance of the filament while the bulb is cold. As it slowly heats up, the current settles to its final value. If this peak current is not considered during the system design, this can cause circuits to trip or battery to fail faster.
Battery voltage profile over time
The above graph shows the battery voltage measured with a WiFi module connected to it. The dips are seen when the WiFi module draws peak currents during the transmit cycle. The battery used is already depleted and hence shows higher drop due to larger internal resistance. Notice how the battery voltage recovers after some time (chart below) when the current is reduced to few micro amps in sleep mode. This is due to the battery chemistry recovering after the peak currents alter the battery state. Using this information, one can easily model the battery for memory effects, internal resistance etc. Peak profile information would also help in deciding the right value of capacitor to add to the circuit to provide surge current. Too low a value can cause pre-mature battery failure and too high a value will add cost and leakage current. The right balance of capacitance can be critical to a long battery life.
Logging data for 1hour
In this video, the current profile of a WiFi device with a sensor profile is logged for about 1 hour. This demonstrates the long term stability of the tool.
More data to be updated...