Photometer for determining concentration of specimen - has photoresistor in bridge network absorbing light transmitted by specimen

摘要

Photometer for determining the concentration of a specimen mounted in a cuvette, has a stable voltage source, a light source, a photo-resistance which is impinged by the light beams originating from the light source and which have travelled to the specimen. The first photo resistance (6) is fed from the voltage source (2) via the main switch (3) and a feed resistor (7). A second photo resistor is also fed via a second feed resistor. Part of the light falling on the specimen is absorbed. The transmitted light from the cuvette is picked up by the first photo resistor. The relationship between the second photo resistor and the feed dropper resistor is fixed and form a bridge network with the first photo resistor circuit.