Figure 1: Hardware schematic diagram of volt-ampere characteristic detection system. A highly sensitive volt-ampere characteristic detecting system was constructed using a single chip micyoco (SCM), a digital-analog component (DAC), a constant current source component (CCS), a voltage follower, an attenuator, an analog-digital component (ADC), and two electrodes. The detecting electrode was a plane electrode installed a silver head 4 mm in diameter. The negative electrode was silver-gilt like that of the limb lead of an electrocardiograph. The SCM was connected to the USB of a personal computer (PC) through a data line.