An A.C. bridge for dielectric measurements on electrolytes in the frequency range 1–5000 kilocycles

According to the classification of Hague, this bridge belongs to the class of networks containing only resistance and capacitance and employs the parallel resistance method for comparing capacitors. The audio oscillator is a Hewlett Packard Type 200D which is used up to 10 kilocycles. At radio frequencies a General Radio type 684A modulated oscillator is used as the generator. For low frequency detection a General Radio type 814A amplifier and General Radio type 760A sound analyzer are employed. From 10 kilocycles upwards, a Sargent model 11-UA all-wave radio receiver acts as detector. It is aided by the 814A amplifier up to 200 kilocycles. A one kilocycle beat note from the Sargent receiver is fed to the sound analyzer tuned to this frequency. Balance is observed on the decibel meter of the analyzer in conjunction with headphones. A series of General Radio output transformers are used to couple the bridge to the detector units, Low loss polystyrene-insulated coaxial cable is used for the high frequency components and all these including the bridge are mounted in separately shielded cabinets.