GB595313A - An improved method and apparatus for the recording of electrical impulses - Google Patents

Abstract

595,313. Electric indicating systems. ARNOLD, C. (Standard Oil Development Co.). Oct. 25, 1944, No. 20781. [Class 40 (i)] [Also in Groups XX and XXXVI] In an arrangement for producing a continuous record of small changes in voltage, e.g. due to a pyrometer, light cell or the like, a spark is produced at an instant, during a cycle, dependent on the magnitude of the voltage, the spark passing from a point on a rotating helical conductor to a point on a stationary straight conductor, thereby marking a sensitive paper placed between the conductors at a point dependent on the magnitude of the voltage to be measured. Light reflected from the mirror galvanometer 3 falls on mirror 5 which is rotated in synchronism with helix 11 by motor 15. Light reflected from the mirror 5 passes through slit 6 on to the photo-cell 7 at an instant during the rotation of the mirror 5 dependent on the deflection of the galvanometer mirror 3. The photo-cell output amplified at 8 triggers the gas-valve 10 to produce a pulse amplified at 21 to produce between the helix 11 and the metal plate 13 a spark, which marks the sensitive paper 14 at a point whose lateral position is dependent on the angular position of the helix at that instant, which is in turn dependent on the deflection of the mirror 3. Instead of the rotating mirror 5 and the fixed slit 6, a rotating spiral slit, Fig. 2 (not shown), may be used. Fig. 4 (not shown) indicates how the arrangement may be used to record the absorption spectrum of a sample of material (see Group XX). Reference lines may be produced on the sensitive paper by feeding the grid of valve 10 at appropriate intervals with oscillating current of duration equal to that of one revolution of the helix.