Voltage injection type high ohm resistance bridge

We propose a modified Wheatstone bridge for the high-value resistance measurement from 1 MΩ to 1 TΩ. In this system, single voltage source and a resistance voltage divider are used instead of dual DC voltage sources. This bridge has the additional voltage source, which injects voltage to the neutral point of the bridge to achieve balance. This new voltage injection type Wheatstone bridge can calibrate a 1 TΩ resistor with an uncertainty of 23 μΩ/Ω.