Constant current source circuit has resistors and primary and secondary transistors for providing current through load which is independent of temperature variations

摘要

The constant current source circuit has a primary transistor (Q1) coupled at its collector to the supplied load for controlling the current through the load (L), a current path resistor (15) with a zero temperature coefficient, between the emitter of the primary transistor and a reference voltage and 4 series resistors (11,12,1,3,14) connected across a current source. The junction between the first 2 series resistors is coupled to the base of the primary transistor and the junction between the second 2 series resistors is coupled to the base of a secondary transistor (Q2), connected with its collector-emitter path across the second 2 series resistors.