Slide rule cursor
OwnerFaiz Mohammad Qureshiinventor
Life of this patent
Estimating the term…
Abstract
A slide rule cursor which is adapted for use with conventional slide rules to provide direct resolution of the resultant value of parallel and/or series impedances. The cursor is not only movable axially along the body of the slide rule in a conventional manner but is also movable perpendicularly to the axial direction of the body of the slide rule. The cursor has printed on it a series of curves from which unique values of a special coefficient referred to as .mu..sub..theta. may be readily obtained for each network of parallel and/or series impedances. This value of .mu..sub..theta. relates the individual impedances in the network through a series of relationships discovered by the inventor to the resultant value of impedance and its angle.
Claims6
A cursor for slide rules, said cursor being adapted for use in association with a selected scale on the slide rule to determine a vector coefficient .mu..sub..theta. which in turn is useful for computing the resultant of two known complex impedances when said two complex impedances are expressed in phasor vector form, wherein the ratio of the magnitudes of said two complex impedances is defined as .rho., the absolute difference between their angles is defined as .theta., and .mu..sub..theta. is defined as (.rho..sup.2 +2.rho.Cos.theta. +1).sup.1/2, said cursor comprising:
- a. cursor face plate means having displayed on one surface thereof first and second co-ordinate axes and at least one coefficient curve defined relative thereto, said first co-ordinate axis representing values of .rho., said second co-ordinate axis representing values of .mu..sub..theta., and said coefficient curve being a precalculated locus of points relating .mu..sub..theta. to .rho. for one selected value of .theta.;
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- b. cursor frame means for holding said face plate means in operative relationship with said slide rule and adapted to permit movement of said face plate means along said selected scale of the slide rule, said frame means further including means permitting movement of said face plate means perpendicular to said selected scale, said second co-ordinte axis and hence said coefficient curve being so scaled and arranged relative to the selected scale on the slide rule that, in operation to determine .mu..sub..theta. for two selected complex impedances,
- i. said face plate means is first positioned such that said first co-ordinate axis passes through the value of .rho. on said selected scale for said two selected complex impedances, and
- ii. said face plate means is then moved sufficiently perpendicularly that said selected scale passes through said value of .rho. on said first co-ordinate axis, such positioning of said face
- plate means resulting in said coefficient curve passing through the correct value of .mu..sub..theta. on said selected scale for said two selected complex impedances, said value of .mu..sub..theta. being useful to calculate the resultant of said two selected complex impedances.
A slide rule for determining a vector coefficient .mu..sub..theta. which in turn is useful in computing the resultant of two known complex impedances when said two complex impedances are expressed in phasor vector form, wherein the ratio of the magnitudes of said two complex impedances is defined as .rho., the absolute difference between their angles is defined as .theta., and .mu..sub..theta. is defined as (.rho..sup.2 +2.rho.Cos.theta. +1).sup.1/2 said slide rule comprising:
- a. a slide rule body having at least one selected scale displayed thereon;
- b. cursor face plate means having displayed on one surface thereof first and second co-ordinate axes and at least one coefficient curve defined relative thereto, said first coordinate axis representing values of .rho., said second co-ordinate axis representing values of .mu..sub..theta., and said coefficient curve being a precalculated locus of points relating .mu..sub..theta. to .rho. for one selected value of .theta.;
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- c. cursor frame means for holding said face plate means in operative relationship with said slide rule body and adapted to permit movement of said face plate means therealong in the direction of said selected scale, said frame means further including means permitting movement of said face plate means perpendicular to said selected scale, said second co-ordinate axis and hence said coefficient curve being so scaled and arranged relative to said selected scale on said slide rule body that, in operation to determine .mu..sub..theta. for two selected complex impedances,
- i. said face plate means is first positioned such that said first co-ordinate axis passes through the value of .rho. on said selected scale for said two select complex impedances, and
- ii. said face plate means is then moved sufficiently perpendicularly that said selected scale passes through said value of .rho. on said first coordinate axis, such positioning of said face plate
- means resulting in said coefficient curve passing through the correct value of .mu..sub..theta. on said selected scale for said two selected complex impedances, said value of .mu..sub..theta. being useful to calculate the resultant of said two selected complex impedances.
Dependencies are inferred from the claim text.