GB1092853A - Regulating device, particularly for actuating an optical filter when measuring brieflight pulses - Google Patents

Abstract

1,092,853. Photo-electric systems. LICENTIA PATENT-VERWALTUNGS G.m.b.H. March 1, 1965 [March 2, 1964], No. 8586/65. Addition to 1, 024, 259. Heading G1A. The device of the parent Specification for measuring the average intensity of light pulses relative to simultaneous reference light pulses in which pulses representative of the difference of intensity between the measuring and reference pulses are fed according to their sign to one of two lengthening circuits before being applied to an integrator, is modified in that the pulse lengthening circuits comprise a single network having two branches each comprising a series connected diode 29, 30, Fig. 2, and Zener diode 31, 32, the branches being poled to conduct in opposite senses. The pulse lengthening circuits are completed by a capacitor 33. The input to the pulse lengthening circuits is normally closed by a short circuit through diodes 38, 39. Pulses are applied to the terminals 40, 41 in synchronism with the light flashes to back bias diodes 38, 39 and allow the "difference" pulses to enter the pulse lengthening circuit. The output at 36 is fed via an integrator 22, Fig. 1 to apply a bias at the point 11 which is such that if the measuring and reference light pulse are equal, the circuit is balanced and the A. C. signal applied at 12, 13 does not pass diodes 15 and 16. Where there is unbalance, pulses of one or other sense pass diodes 15 or 16 to energize a motor 10 controlling an attenuator in the reference light beam in such a sense as to equalize the measuring and reference pulses.