Abstract: An electrochemical cell includes a metallic anode electrode and a metallic athode electrode substantially immersed in an electrolyte. As charge or current is passed through the cell from the anode electrode to the cathode electrode, the anode electrode is consumed and the cathode electrode plated, causing the resistance therebetween to change. The change in resistance provides a measure f or both the total charge passed through the cell over an interval of time, and for the total time charge flowed through the cell over an interval of time between resistance measurements.

Abstract: A quasi-passive identification system having an interrogator and a passive ransponder. The interrogator has a signal generator that generates radio-frequency energy under the control of a manual actuator. A preset encoder encodes the radio-frequency energy with an interrogation code to produce an interrogation signal that is radiated by an antenna. The transponder has an receiver for receiving the interrogation signal and separating it into received radio-frequency energy and a coded signal. A decoder decodes the coded signal and looks for a match between the coded signal and the interrogation code. A response transmitter, which is controlled by the decoder, encodes the received radio-frequency energy with the response code and radiates the response signal. When a receiver in the interrogator receives the response signal, the response signal is decoded and analyzed for a proper response. A response indicator is energized when a proper response is received.