An optometer measures the photocurrent produced by a photometric or radiometric
sensor, applies a predefined electro-optical calibration factor, and displays the result in optical units.
A photometer system is built by coupling an optometer to a photometric sensor; a radiometer system is built by
coupling an optometer to a radiometric sensor.
A transimpedance amplifier converts the sensor photocurrent to a corresponding voltage, which can be monitored
by a voltmeter to permit derivation of results in optical units.
