Abstract: A linear voltage regulator includes an error amplifier receiving an operational voltage and provided a control signal, a pass device controlled by the control signal and providing a load voltage from a power supply, and a leakage circuit controlled by the control signal and consuming a drive-back current. Since the linear voltage regulator includes the leakage circuit, a drive-back current created can be grounded via the switch transistor of the leakage circuit. Thereby an impedance calibration of termination transistors will be normal, and a life span of electronic components will be protected.

Abstract: A weak battery warning circuit includes a warning circuit for generating an alarm; a battery having a cathode connected to ground; and a controlling circuit comprising a transistor, the transistor having an emitter for receiving an input voltage, a base connected to an anode of the battery via a base resistor, and a collector connected to the warning circuit and also connected to ground via a collector resistor. When the voltage of the battery reduces to a predetermined value, the controlling circuit controls the warning circuit to alarm.

Abstract: A control circuit for command signals of a clock generator includes a power supply end, an output end, a control end, a diode, a first resistor and a second resistor. The first resistor, the diode, and the second resistor are connected in series between the power supply end and the ground. The diode has an anode connected to the first resistor and a cathode connected to the second resistor. The control end is connected to a node between the diode and the second resistor; the output end is connected to a node between the diode and the first resistor. The output end outputs the command signals to the clock generator.

Abstract: A power good signal generating circuit includes an NPN transistor, a first resistor, a second resistor, a third resistor, a first power source, and a second power source. The first resistor is connected between a base of the transistor and the first power source. The second resistor is connected between a collector of the transistor and the second power source. The third resistor is connected between an emitter of the transistor and ground. The collector is connected to an output for sending a PG signal and the emitter is connected to an input for receiving a control signal P.

Abstract: A supply voltage switching circuit for a computer includes a chipset, a first transistor and a second transistor. The chipset includes a first MOSFET and a second MOSFET. A 5V system voltage and a 5V standby voltage are respectively inputted to sources of the first MOSFET and the second MOSFET. Gates of the first MOSFET and the second MOSFET are respectively coupled to collectors of the first transistor and the second transistor. Emitters of the first transistor and the second transistor are coupled to a first terminal for receiving a control signal. A 1.8V standby voltage is separately inputted to bases of the first transistor and the second transistor. A 12V system voltage and the 5V standby voltage are respectively inputted to collectors of the first transistor and the second transistor. A second terminal is connected between the drain of the first MOSFET and the drain of the second MOSFET.

Abstract: A supply voltage switching circuit for a computer includes a chipset, a first transistor, a second transistor, and a third transistor. The chipset includes a first MOSFET and a second MOSFET. A 5V system voltage and a 5V standby voltage are respectively inputted to sources of the first MOSFET and the second MOSFET. Gates of the first MOSFET and the second MOSFET are respectively coupled to collectors of the second transistor and the third transistor. A base of the first transistor is coupled to a terminal for receiving a control signal from the computer. The 5V standby voltage is inputted to a collector of the first transistor. Bases of the second transistor and the third transistor are coupled to the collector of the first transistor. A 12V system voltage and the 5V standby voltage are respectively inputted to collectors of the second transistor and the third transistor.

Abstract: A linear voltage regulator is provided for providing an output voltage to a load. In a preferred embodiment, the linear voltage regulator comprises: an operational amplifier receiving a regulated voltage, and a first voltage reference, and providing a driving voltage; a first regulating transistor driven by the driving voltage, the regulating transistor receiving a system voltage, and providing the regulated voltage; a second regulating transistor receiving the regulated voltage, and providing an output voltage, the second regulating transistor controlled by a controlling voltage; a resistive voltage divider receiving the output voltage, and providing a second voltage reference; and a three-terminal adjustable shunt regulator receiving the second voltage reference, and providing the controlling voltage to the second regulating transistor.

Abstract: A system for designing a delayer emulation model (1) includes a delayer emulation model generating apparatus (2). The delay emulation model generating apparatus includes: a delay circuit defining module (20) for defining delay parameters of a delay circuit, and generating the delay circuit; a delay signal setting module (21) for setting a delay interval for the transition from a high voltage to a low voltage and a delay interval for the transition from a low voltage to a high voltage of an input delay signal; a voltage regulation circuit defining module (22) for defining voltage parameters of a voltage regulation circuit, and generating the voltage regulation circuit; a voltage regulating module (23) for regulating a voltage of the input delay signal from the delay circuit according to requirements of an output delay signal; and a model calling module (24) for generating the delayer emulation model by means of calling the delay circuit and the voltage regulation circuit.

Abstract: A linear voltage regulator provides a regulated load voltage to a load. In a preferred embodiment, the linear voltage regulator includes: a regulating circuit for receiving an input voltage and providing an output voltage to a load, the regulating circuit being driven by a driving voltage; and two resistors connected to each other in series receiving the output voltage and providing an adjusting current to the regulating circuit. The linear voltage regulator is capable of providing a greater current to the load, and having a wide range of input voltages.

Abstract: A linearly regulated power supply is provided for providing a regulated load voltage to a load. In a preferred embodiment, the linearly regulated power supply includes: a voltage reference circuit for providing a first voltage reference; a resistive voltage divider connected to the voltage reference circuit for receiving the first voltage reference and then providing a second voltage reference; an error amplifier for receiving the second voltage reference and providing a controlling voltage; and a regulating circuit controlled by the controlling voltage, the regulating circuit receiving a source voltage and then providing a load voltage to a load, the regulating circuit including two transistors connected to each other in parallel for regulating the load voltage. The linearly regulated power supply is capable of providing a greater current to the load and the components of the linearly regulated power supply can be used efficiently.

Abstract: An LED excitation source and module useful for full plate imaging fluorescence instruments as well as methods for calibrating such instruments.

Abstract: A reflective light imaging system for use in high-throughput screening of samples disposed in multiple-well plates. The system can include a set of mirrors and lenses. The first mirror has a central aperture through which light from the object passes. The first mirror has a concave reflective surface that faces the image plane. The next element is a second mirror with a convex reflective surface. The system can include an aberration corrective system positioned between the second mirror and the image plane, and an optical sensor near the image plane. Light from an object passes through the central aperture of the first mirror and is reflected off the convex surface of the second mirror. The light then strikes the reflective surface of the first mirror. The light from the first mirror is then collected by the aberration correction system and transmitted toward the image plane.

Abstract: A Littrow-type spectrometer or monochromator using a folded light path to provide a compact optical instrument is disclosed. Light enters the instrument through an inlet aperture on a planar mirror. The aperture is located at the focus of a parabolic collimator mirror. Collimated light reflected by the parabolic mirror is reflected back to the planar mirror, which is positioned at an angle to the collimated light. The light reflected from the planar mirror is directed at a planar grating that produces diffracted light having all the wavelengths input into the system, including light of a selected wavelength, back towards the planar mirror. Light having the selected wavelength is thus caused to fall on the parabolic mirror. The parabolic mirror then focuses the selected wavelength of light onto a light exit aperture that is juxtaposed to the inlet light aperture. The planar grating can be rotatably mounted to scan the input light spectrum.

Abstract: A modified concentric spectrograph for diffracting light with high stray light rejection without astigmatism is provided. The modified spectrograph includes a grating, a lens, and at least one entrance port and one exit port. The grating has a concave surface and a meridian plane with a first side and a second side. The lens has a substantially planar surface and a convex surface. Preferably, the convex and concave surfaces are substantially concentric. The ports are substantially located on different sides of the meridian plane near a focal plane of the spectrograph. The position of a focal plane may be modified using an optically transmissive triangular prism with a reflective surface, and an optically transmissive block. The position of a focal plane may further be modified with one or more optically transmissive plates. Methods for using the spectrograph are also provided.