Light intensity measurer esp. for finding colour filtering required - has temp.-dependent component in parallel with variable resistor at balancing input of operational amplifier

摘要

The measuring head contains a light receiver. The electronic evaluator coupled to the head contains a differential amplifier formed from an operational amplifier and an indicator that is pref. digital. An outer circuit containing resistors is used to balance the offset voltage. It is connected to two balancing inputs of the operational amplifier. At least one equalising trimmer is provided. One of the balancing inputs has a parallel circuit (24) consisting of a temp.-dependent component (25) and a variable resistor (26). The former.