Dc And Ac Bridges. Introduction dc bridges wheatstone bridge kelvin bridge strain gauge bridge circuit ac bridges maxwell bridge hay bridge schering bridge wien bridge anderson bridge resonance bridge similar angle bridge radio frequency bridge substitution technique wagner s ground connection twin t. We can balance the bridge by varying the resistance value of resistor r 3.
The dc bridge uses the dc supply for measuring the resistance. Types of ac bridges resistance measuring bridges. Source and galvanometer with head phone null detector.
Like dc null detectors its only required point of calibration accuracy is at zero.
The ac bridge uses the ac supply. Ac bridge circuits can be of the symmetrical type where an unknown impedance is balanced by a standard impedance of similar type on the same side top or bottom of the bridge. Null detectors for ac bridges may be sensitive electromechanical meter movements oscilloscopes crt s headphones amplified or unamplified or any other device capable of registering very small ac voltage levels. Now let us discuss about these two ac bridges one by one.
