Abstract: Components suitable for use in an evaporative light scattering detector and other devices are disclosed. Methods of making and using components suitable for use in an evaporative light scattering detector and other devices are also disclosed.

Abstract: An analog to digital converter provides a device for characterizing, in digital terms, a first quantity having a magnitude which varies as a function of a second quantity. An output signal is generated having more than two values, the output signal indicating the magnitude of the first quantity in comparison to a reference level and the change in the magnitude of the first quantity as a function of the second quantity.

Abstract: An apparatus measures the mass of a tube and liquid contained in the tube. A stiff beam is fixed at one end and connected to the tube with a magnet thereon. An electric circuit generates a current pulse which vibrates the beam and tube and induces a natural response therein. Movement of the magnet on the beam induces a current in the circuit with the induced current having a frequency of oscillation equivalent to the natural frequency of vibration of the tube and liquid in the tube. The electric circuit includes a comparator and a counter, with the comparator receiving the current induced by movement of the magnet and supplying a pulse signal to the counter having a period equal to the period of oscillation of the beam and the tube. The counter triggers the generation of an additional current pulse after a predetermined number of cycles of the induced current are counted. The current pulses are generated at a frequency lower than the frequency of the natural vibratory response of the beam and the tube.

Abstract: A pump control controls the rate at which liquid is pumped through a tube. The pump has a variable speed shaft with a roller thereon engaged with the tube between the tube inlet the tube outlet for pumping liquid from a supply toward the tube outlet when the pump shaft operates. A first sensor senses liquid at a first location in the tube and a second sensor senses liquid at a second location in the tube between the first location and the tube outlet. A vibratory beam is coupled with the tube between the first location and the second location. An electric circuit transfers energy to a magnet on the beam and induces a natural response in the beam and the tube.

Abstract: A temperature independent dosimeter is provided for measuring an amount of irradiation of a predetermined frequency. A photodiode (24) operating in its photovoltaic mode is irradiated with the irradiation to produce a signal that is amplitude-proportional to the amplitude of the irradiation. The signal is converted by a pair of operational amplifiers (89, 96) to a plurality of pulses that are proportional in frequency to the amplitude of the signal. The plurality of pulses is counted by a counter (20) and the irradiation is terminated when the count reaches a predetermined amount.

Abstract: A circuit is provided for resetting a digital logic circuit, such as a digital counter. A switch 16 provides a first signal when a predetermined condition has occcurred. A flip-flop 24 provides an output reset signal when the flip-flop is in a first state, in response to the first signal. The digital logic circuit to be reset 32 is coupled to the output of the flip-flop 24 for receiving its output reset signal. Feedback means 34, 36, 38 are coupled from the digital logic circuit 32 back to the flip-flop 24 for providing a signal to put the flip-flop into its other state whereby its output reset signal is terminated.

Abstract: A constant current battery charging circuit is provided by which the battery receives a full charge until the battery voltage reaches a threshold. When the battery voltage is above the threshold, the battery receives a trickle charge. The actual battery voltage is compared with a reference voltage to determine whether the full charge circuit should be in operation. Hysteresis is provided for preventing a rapid on/off operation around the threshold. The reference voltage is compensated for temperature variations. The hysteresis system and temperature compensation system are independent of each other. A separate test circuit is provided for testing the battery voltage. During testing of the battery, the full charge circuit is inoperative.

Abstract: Apparatus for applying a radiant beam against an opaque diaphragm (18) to melt an aperture in the diaphragm (18). Bracket means (12) are provided for positioning the diaphragm (18) at a predetermined position, along with a source of the radiant beam (20) and electric circuit means (21) for activating the source (20). Photocell means (52) may be positioned whereby a properly positioned diaphragm (18) initially shades the photocell (52) from the beam, and the beam strikes the photocell (52) when the aperture is formed. Means are provided to shut off the radiant beam responsive to the beam striking the photocell (52). The photocell (52) may be positioned in a pivotable switch arm (46), and the radiant beam source (20) may be a special filament-type light bulb (20) with a focusing reflector (24).

Abstract: A photometric system for determining the absorbance ratio, in a sample, of two different wavelength lights. First and second lights, each having a different wavelength, are passed through the sample in alternation with each other. The radiation intensity from each light that has passed through the sample is detected. A comparator, up/down counter and digital to analog converter are coupled so that a scaling factor is derived which, when multiplied with an analog signal proportional to the intensity of the first light after it has passed through the sample, is equal to an analog signal proportional to the intensity of the second light after it has passed through the sample. The output of the counter comprises a digital word corresponding to the ratio of the absorbance ratio of the first light and the second light.