Aspects of the present disclosure include methods for determining photodetector gain for a plurality of photodetectors in a light detection system. Methods according to certain embodiments include applying a reference voltage to each photodetector in the light detection system, generating a reference data signal for each photodetector at the reference voltage, irradiating with a light source the photodetectors at a plurality of different applied voltages, generating output data signals for each photodetector at each of the plurality of different voltages and calculating gain of the photodetectors at each of the plurality of different applied voltages based on the output data signals for each photodetector at each applied voltage and the reference data signal. Systems (e.g., particle analyzers) having a light source and a light detection system that includes a plurality of photodetectors for practicing the subject methods are also described. Non-transitory computer readable storage medium are also provided.

A system for measuring a radiant exposure of electromagnetic radiation includes an accumulation detection module having a detector and configured to continuously monitor an electromagnetic radiation received by the detector; and an adaptive circuit configured to periodically interrogate the accumulation detection module; adjust a frequency of interrogation of the accumulation detection module based on an intensity of the electromagnetic radiation received by the detector; and autonomously transmit information related to an amount of the electromagnetic radiation received by the detector to a remote device.

[Task] To provide an automatic analysis apparatus including a photomultiplier tube which controls a sensitivity of the photomultiplier tube without adjusting a high voltage value. [Solution] An automatic analysis apparatus according to the present invention includes a photomultiplier tube which detects light from a reaction vessel; a determination unit which determines an output signal of the photomultiplier tube in a case where the photomultiplier tube is irradiated with first light; and a control unit which irradiates the photomultiplier tube with second light to lower a sensitivity of the photomultiplier tube in accordance with a determination result by the determination unit.

A photometer and a method of performing photometric measurements with this photometer are described. The photometer comprises a photodetector providing a detector signal corresponding to an intensity of light received by the photodetector; and measurement electronics including: an amplifier and a signal processing device configured to determine and to provide a measurement result based on a measurement signal determined by the signal processing device as or based on an amplified detector signal provided by the amplifier. The signal processing device is configured to determine the measurement signal: a) as or based on the amplified detector signal provided by the amplifier being a multistage amplifier including a transimpedance converter and a voltage to current amplifier; and/or b) in form of a noise reduced signal determined by subtracting a previously determined noise offset included in the amplified detector signal from the amplified detector signal.

An optical sensing circuit and an optical sensing method are provided. The optical sensing circuit includes a first photosensitive unit, a second photosensitive unit, an arithmetic unit, and a control unit. The first photosensitive unit and the second photosensitive unit provide a sensing current during a light sensing period. The arithmetic unit generates a combined current according to the sensing current during the light sensing period. The control unit generates a first sensed value and a second sensed value according to the combined current.

An object detector including a light-emitting system to emit light to an object, a light detector, a signal detector, and a threshold adjuster. The light detector receives the light emitted from the light-emitting system and reflected by the object, and output a signal. The signal detector detects the signal output from the light detector based on a threshold value of voltage. The threshold adjuster changes the threshold value between when the light-emitting system emits light to a part of a light-emission range of the light-emitting system and when the light-emitting system emits light to other part of the light-emission range other than the part of the light-emission range.

An aquarium photometer system includes a housing unit, an arm, and a mirror. The housing unit includes a light sensor configured to sense light incident on the light sensor and to convert the incident light to a signal. The housing unit also includes an operational amplifier including a first input node, a second input node, and an output node. The operational amplifier is configured to: receive the signal at the first input node, amplify a difference between the signal at the first input node and a signal at the second input node by a gain factor, and output the amplified signal on the output node. The housing unit also includes a potentiometer connected to the operational amplifier and configured to regulate the amplified signal; and a display connected to the potentiometer and configured to show an intensity of light detected by the light sensor based on the regulated amplified signal. The arm at a first end is connected to the housing unit and configured to move the housing unit around an aquarium case. The mirror is located on a bar and positioned within the aquarium in front of the light sensor and at a focal distance from the light sensor and configured to increase an amount of light incident on the light sensor.

A light sensor having an adaptively controlled gain includes a photoelectric element, an operational amplifier, a comparator, an adaptive gain control circuit, a variable capacitor and a pulse accumulator circuit. The photoelectric element converts light energy into a photocurrent. The operational amplifier outputs an error amplified signal based on a gain multiplied by a voltage difference between an input voltage and a reference voltage. The comparator compares the error amplified signal with a voltage of a reference voltage source to output a comparison signal. The adaptive gain control circuit includes a pulse detector circuit and a gain control circuit. The pulse detector circuit detects the comparison signal and a clock signal to output a pulse detected signal. The adaptive gain control circuit outputs a capacitance modulating signal according to the pulse detected signal. A capacitance of the variable capacitor is modulated according to the capacitance modulating signal.

An optical sensor and a method having a high linearity digital controlling mechanism are provided. An optoelectronic component converts a light energy into a photocurrent. Then, the photocurrent flows to a current mirror and is amplified by a gain to form a charging current by the current mirror to charge a capacitor. A comparator compares a voltage of the capacitor with a reference voltage multiple times to generate a comparison signal. A counter determines a digital value capturing range according to the gain, and counts bit values that fall within the digital value capturing range from the comparison signal to output a counted signal. A noise cancellation processor reduces the digital value capturing range according to the gain, and removes one or more of the bit values that do not fall within the digital value capturing range from the counted signal to output a sensed signal.

A receiver of a pulsed light signal comprises a photodiode adapted to generate an electric current in response to this light signal, having a parasitic capacitance C.sub.d as its characteristic; an electrical ground; and a transimpedance amplifier connected to the input of the photodiode by a linking capacitor C.sub.liaison. It includes an attenuation pad located between the photodiode and the transimpedance amplifier, consisting of a capacitor C.sub.p where C.sub.p=C.sub.d/(α−1), α being a predetermined attenuation, where α>1.