The effects of stray parameters mainly from connecting cables on balance equation and sensitivity of bridge are discussed in this paper. It is possible to remove the effects of stray parameters

to a great extent

with a transformer-ratio-bridge adaptable to three terminal measurements. The undefinition of capacitance between two conductors without complete surrounding each other may be eliminated with a three terminal capacitor introduced. Therefore

it is possible to measure small variation of transducer capacity with a transformer-ratio-bridge

if a capacitive transducer is made with three terminal construction. A capacitive displacement transducer

transformer-ratio-bridge

and associated electronic circuit are developed according to this theory. It is shown by testing that a small variation down to 10-3 Pf of capacitance can be measured at 100m long cables

when the carrier frequency is 100KHz. It is also possible to make accuracy measurement at linger cables.