- Published in issue 11/1994 on page 60
TSL220 - Optical window comparator
When, in an electronic circuit. light is converted into electrical sjgnals, use is normally made of photo diodes, photo transistors or light -dependent resistors (LDRs). These components translate the irradiance into analogue electrical quantities. When these converters are used for measurements on optical signals, the limits of current technology are reached in many cases. Now, new opto-eleclronic components with digital output, such as the Type TSL220 from Texas Instruments offer many new possibilities in this field. This device is an integrated light-to-frequency converter, the frequency of whose digital output depends on the quantity of light falling on to it. The IC, which is housed in a transparent DIL8 enclosure, operates from 5 V and draws a current of only 7-8 mA.