Autonomous Sensors – Power Sources For Autonomous Sensors – Challenges – References – Load And Power Conditioning – Load – Sensors And Signal Conditioning – Microcontrollers – Transceiver – Load Model – Power Conditioning – Linear Regulators – Switching Regulators – Charge Pumps – Control Strategy – Conclusions – References – Ambient Energy Sources – Radiant Energy – Optical Energy – Radiofrequency Energy – Mechanical Energy – Thermal Energy – Magnetic Energy – Biochemical Energy – Conclusions – References – Primary Batteries And Storage Elements – Batteries – General Characteristics – Batteries And Autonomous Sensors – Primary Batteries – Secondary Batteries – Battery Characterization – Proposed Approach – Materials And Methods – Experimental Results – Model Validation – Supercapacitors – Supercapacitor Characterization – Materials And Methods .