1. Energy Harvesting Name: Alex Phipps Goals: Key accomplishments.
Measure voltage and current waveforms from the actual circuit in order to verify simulations.
Completely understand Shengwen’s circuits
Key accomplishments.
Gathered and processed data for efficiency of direct charge.
Measured the “efficiency’ of beam3.
Key issues
Finding the best method to measure the currents.
They are on the order of uA.
Efficiencies are incorrect because battery current was measured as an average, while it is not really DC.

2. Measurements Efficiency vs. Input Force can be seen for beam3.
This is the electrical efficiency for the direct charger.
For a 2V Vbattery
There is a 1kohm in the input current path
This will lower efficiency
The shapes should be correct, but the magnitude of the efficiency is not.
The output current was measured as the average and not the RMS.
Output power is therefore low and so is efficiency.

3. Next Experiment Desired measurements
Beam deflection will be measured with the displacement sensor.
This allows mechanical input power (P = Fd) to be found and efficiency through all stages.
RMS current into the battery needs to be measured.
This will be done by measuring the voltage across a resistor.
This process will bring more loss to the system, so it may or may not increase efficiency.