Standard control reference for photometer - can operate in various ranges to avoid lengthy calibration procedures

摘要

Reference standards can be provided by reference wires of predetermined thickness which are inserted into the energy emitting (light, ultra-violet, infra-red energy) source to obtain a definite diminution of the signal. In the present proposal the signal setting range means is a short-circuiting switch (s) operative on one (RE) of the two (RA and RE) resistors of the photoelectric receiver (PHE). Modification of amplification factor can be so used and the system can be applied to a uniform or alternating two-ray set up applied to either or both of the two rays.