Abstract: A transformer isolated switched power supply of the forward converter type which includes a clamping circuit for the switching unit of the power supply which recovers the energy stored in the transformer during each switching cycle without any need to dissipate the energy, and which also serves to reverse the flux in the power transformer during each switching cycle to restore the flux capacity of the power transformer to the same level as in other types of converter circuits.

Abstract: A unity power factor power supply which includes a boost converter connected to the alternating current line which is controlled to draw sinusoidal current from the line by operating as a current regulator having a current reference control signal which tracks the line voltage waveform, thereby to minimize the required input current for a given power output.

Abstract: A high power factor, regulated synchronous converter for converting 110-volt, rectified, 50-60 Hz alternating current into a direct current output, which has enhanced hold up (energy storage). The circuit includes a half-bridge inverter for converting the half-wave rectified voltage into high frequency alternating current in the range of 20-30 KHz. The high frequency alternating current is coupled through an inductance coil to a half-bridge synchronous regulator/rectifier which produces a direct current output. The energy delivered to the half-bridge synchronous regulator/rectifier is stored in a capacitor, and the voltage across the capacitor may be regulated making energy storage independent of the line voltage. Additional synchronous regulator/rectifiers may be coupled to the circuit to produce additional direct current outputs.

Abstract: An isolation circuit for preventing the current surges drawn by a direct current cooling fan from appearing in the output of the power supply. The fan has one terminal connected to one terminal of the power supply, and a regulator circuit connects the other terminal of the fan to the other terminal of the power supply. The regulator circuit includes a capacitor connected across the fan to provide a low impedance circulating path for the current surges, and it also includes a network which provides a constant current to the parallel combination of the fan and capacitor.

Abstract: A system is provided for driving the switching transistors in a push-pull switching mode inverter-type power supply. The system of the invention provides drive current adjusted to the actual power supply load throughout the entire switching cycle from turn-on to the completion of turn-off for each of the switching transistors. There is essentially zero power dissipation in the various elements which make up the system. Moreover, the system obtains substantially all of its drive power from the outputs of the switching transistors themselves, and it provides transformer isolation for the switching transistors.

Abstract: A sample cell is provided for spectrophotometers which is constructed to prevent stray light from being carried to the detector through the wall of the cell. This is achieved by configuring the cell wall in a manner so that it cannot function as a light pipe for the stray light, or by providing light attenuating means in the cell wall, or by providing an appropriate masking means in the wall.

Abstract: A voltage controlled sine wave oscillator is provided in which the frequency of the output signal is a linear function of the amplitude of an input control signal. The output signal may be of constant amplitude with changes in frequency, or its amplitude may be a linear function of its frequency. Two-phase quadrature output signals may be provided for multi-phase applications. The oscillator of the invention in the embodiment to be described herein is solid state, and it makes use of operational integrators, analog multipliers, and associated circuitry to generate the outputs.