Improved matrix and determinant methods for solving networks
H. J. Orchard · IRE Transactions on Circuit Theory · 1955
wanted harmonics of mains frequencies in low frequency bridge measurements.Carbon resistors and a carbon potential divider were used in this unit. CONCLUSIONSeveral CR bridge and ladder filter networks, all possessing single element frequency control, have been investigated.The bridge networks give exact balance over a wide frequency range, but the useful range for practical applications is quite limited.The ladder filters give an approximate balance, the range of frequencies over which this balance holds being a result of compromise, the higher the impedance of the controlling element, the greater the range.Frequency control of the ladder networks may be effected by means of resistance or capacitance potential dividers.In either case an experimental method of determining the filter parameters may be used with a considerable reduction in time and effort.