Figure 4

Transient waveforms during the start-up and steady-state operation of the device for a temperature gradient of 13 \(^{\circ }\)C. (a) The voltage across the supercapacitor (\(V_{SCAP}\)), and the signal indicator of the availability of enough energy to perform a transmission (\(V_{PGOOD}\)). (b) The regulated voltage supply (\(V_{DD}\)).