Network Analyzers
A third branch of the analogue calculating machine is the network analyzer. To solve problems, this machine uses the laws governing a network of electrical circuits. For example, an electric power company with a system of power lines over hundreds of miles may have a problem about electrical power: will an accident or a sudden demand cause a breakdown anywhere in the system? In the General Electric Company in Schenectady, N. Y., there is a machine called the A.C. Network Analyzer. All the properties of the power company’s network of lines can be fed on a small scale into the analyzer. Certain dials are turned and certain plugwires are connected. Then various kinds of “accidents” and “sudden demands” are fed into the machine, and the response of the system is noted. The answers given by the machine are multiplied by the proper scale factor, and in this way the problem of the power company is solved.
There are two kinds of problems that network analyzers are built to solve: the steady state conditions and the transient conditions. For example, you may not overload a fuse with an electric iron when it is plugged in and being used, but as you pull out the cord, you may blow the fuse: the steady state does not overstrain the system, but the transient does.
Some articles on network analyzers are:
Enns, W. E., A New Simple Calculator of Load Flow in A.C. Networks, Transactions of the American Institute of Electrical Engineers, vol. 62, 1943, pp. 786-790.
Hazen, H. L., and others, The M.I.T. Network Analyzer, Cambridge, Mass.: Massachusetts Institute of Technology, Department of Electrical Engineering, Serial No. 69, Apr. 1931.
Kuehni, H. P., and R. G. Lorraine, A New A.C. Network Analyzer, Transactions of the American Institute of Electrical Engineers, vol. 57, 1938, pp. 67-73.
Parker, W. W., Dual A.C. Network Calculator, Electrical Engineering, May 1945, pp. 182-183.
Parker, W. W., The Modern A.C. Network Calculator, Transactions of the American Institute of Electrical Engineers, vol. 60, Nov. 1941, pp. 977-982.
Peterson, H. A., An Electric Circuit Transient Analyzer, General Electric Review, Sept. 1939, pp. 394-400.
Varney, R. N., An All-Electric Integrator for Solving Differential Equations, Review of Scientific Instruments, vol. 13, Jan. 1942, pp. 10-16.
Some of the articles on applications of network analyzers to various problems are:
Kron, Gabriel, Equivalent Circuits of the Elastic Field, Journal of Applied Mechanics, vol. A11, Sept. 1944, pp. 146-161.
Kron, Gabriel, Tensorial Analysis and Equivalent Circuits of Elastic Structures, Journal of the Franklin Institute, vol. 238, Dec. 1944, pp. 399-442.
Kron, Gabriel, Numerical Solution of Ordinary and Partial Differential Equations by Means of Equivalent Circuits, Journal of Applied Physics, vol. 16, 1945, pp. 172-186.
Kron, Gabriel, Electric Circuit Models for the Vibration Spectrum of Polyatomic Molecules, Journal of Chemical Physics, vol. 14, no. 1, Jan. 1946, pp. 19-31.
Kron, G., and G. K. Carter, A.C. Network Analyzer Study of the Schrödinger Equation, Physical Review, vol. 67, 1945, pp. 44-49.
Kron, G., and G. K. Carter, Network Analyzer Tests of Equivalent Circuits of Vibrating Polyatomic Molecules, Journal of Chemical Physics, vol. 14, no. 1, Jan. 1946, pp. 32-34.
Peterson, H. A., and C. Concordia, Analyzers for Use in Engineering and Scientific Problems, General Electric Review, vol. 48, no. 9, Sept. 1945, pp. 29-37.