Systems, methods for manufacturing, and devices for producing an output current that simulates a current generated by an optical patient sensor are provided. An optical patient sensor includes a sensor light source having a first characteristic profile and a sensor photodetector having a second characteristic profile. The current source includes a light source having a characteristic profile similar to the first characteristic profile and indicative of interchangeability between the light source and the sensor light source, and a first photodetector configured to produce an output current in response to receiving light from the light source, the first photodetector having a characteristic profile similar to the second characteristic profile and indicative of interchangeability between the sensor photodetector and the first photodetector.
