Description:
<jats:p>An integrator circuit is described, together with programmer and timer, which was constructed for measuring signal-current from a photomultiplier tube as used in astronomical photometry. At the end of a timed run, the voltage data are impressed upon a strip-chart pen recorder. The current-range of such instrument encompasses a span from 10−6 to 10−11 ampere, full scale, with stability and linearity. Furthermore, the design is such that, using a suitable programing circuit, any number of identical integrator units can be employed to measure a like number of separate phototube currents simultaneously over a given timed run; and afterwards the separate voltages are recorded in sequence upon the one recorder. This feature makes the herein described system very useful for simultaneous multicolor photoelectric photometry.</jats:p>