Testing circuit for verification of detector functioning uses parallel circuit arrangement to inject a superimposed variable current without disconnecting the main circuit to the detector

摘要

The test circuit is mounted in parallel with the supply circuit to inject a superimposed current (Is) which is added to the detector current (Ic) or the acquisition circuit current (Ia). One mode of operation uses a generator (7) supplying variable voltage (typically to 24 volts) injecting the superimposed current (Is) through the resistance R4, to add to the acquisition current (Ia) in order to permit detection of the lower threshold current of the acquisition system (3). The system has a secondary mode that allows a variable current regulator to inject the superimposed current, to allow detection of the upper threshold of the acquisition system. The intensity of the two currents (Ia,Is) are measured using ammeters (A1,A2) plugged into the circuit at connector points (13,15,17).