An Analog Computer for the Solution of Tangents

This paper describes an electrical computer employing a modified Wheatstone bridge to compute the tangent of an angle between 0° and 90°, given the angle. It can also be used to compute one angle of a right triangle given the two sides of the triangle. It thus complements the Wheatstone bridge circuit which computes the hypotenuse from the other two sides. Only linear elements are used and the accuracy of the angular approximation can be theoretically better than one part in 70,000 and in a practical application, better than one part in 2,500. In addition to the development of the analog circuit, this paper briefly describes some of the design considerations which were employed to permit the analog to be used successfully in field equipment employing plug-in construction and yielding accuracies of better than 0.1 per cent.