Abstract: A DC power source is capable of automatically adapting to either a 120 or 240 VAC input and of providing a single regulated output range for either of the AC voltage levels provided thereto. The power source detects the AC input voltage and automatically doubles the lower voltage while allowing the higher rectified voltage to pass through. The power source includes an electronic switching arrangement responsive to the input voltage level for automatically doubling the lower AC input voltage when detected as well as timing circuitry to allow for transitory fluctuations in the input voltage level while maintaining a level DC output voltage.

Abstract: A circuit for automatically operating a switching power supply is capable of operating from first and second input voltage ranges. The circuit changes the switching power supply from a full-wave rectifier circuit to a voltage doubler rectifier circuit by electrically connecting first and second nodes. The circuit includes a rectifier circuit and a voltage level sensing device for generating an output voltage to trigger a triac, which connects the first and second nodes.

Abstract: A frequency converting device is provided with a converter for converting ac input power into dc power. The device includes an inverter for inverting an output (dc power) of the converter into an ac output power, and adjustment device for adjusting an output waveform of the inverter in accordance with the voltage values of the ac input power. The adjustment device comprises a memory which stores adjustment data corresponding to the voltage value of the ac input power source connected to the converter, and a selector for selecting a certain adjustment data from the memory in accordance with the voltage value of the ac input power to which the device is connected. Thus, even when the voltage of the ac input power is changed, the effective output of the inverter can be kept substantially constant by adjusting on/off times of the switching elements constituting the inverter to vary a duty factor of the inverter output.

Abstract: A power supply circuit including A.C. input of either 110 volts or 220 volts coupled to a full diode bridge, across the output of which are provided series connected capacitors across which the desired system operating voltage appears. A voltage-controlled current generator for driving a diac and triac is connected between the input supply and the bridge capacitors. At 110 volt input, the current generator closes the triac and the circuitry operates as a voltage doubler to provide the desired system voltage. At 220 volt input, the triac remains open, and the full bridge and capacitors provide the same desired system voltage.

Abstract: A supply arrangement selectively operates from either one of dual AC mains supply voltages of, illustratively, 220 or 110 volt RMS AC. When the arrangement operates from the 220 volt AC mains supply voltage, a bridge rectifier, operating as a full-wave rectifier, charges each of series coupled first and second capacitors to one-half the peak of the AC mains supply voltage. During the positive half-period of the AC mains supply voltage, a positive voltage, equal to the difference between the instantaneous mains supply voltage and the DC voltage across the first capacitor is coupled between two terminals of a load such as a degaussing circuit. A corresponding negative difference voltage, is coupled between the two terminals during the other half-period.

Abstract: A load control circuit having an input terminal adapted to receive any one of a number of different input voltage signals including signals of at least first and second type. These signals may be, respectively, DC and AC input signals. Control circuits are provided for operation of the load from the input voltage signal. This control circuit includes at least first part responsive only to said input voltage signal being of first type for coupling said signal of first type to the load, and a second part responsive only to the input voltage signal being of second type for coupling the signal of second type to the load.

Abstract: A supply-voltage discrimination device for adapting a load (8) to a lower or higher alternating-voltage range includes a voltage-dependent resistor (1) thermally coupled to a PTC-resistor (2) and electrically connected in series with said voltage-dependent resistor. The resistors are chosen so that initially the dissipation is mainly determined by the voltage-dependent resistor.

Abstract: A constant voltage or constant current output circuit is disclosed which can be operated with input voltages which fluctuate sharply at nearly any frequency. A pulse width modulated (PWM) switching transistor is used with a choke inverter. The PWM switching transistor is input and output level responsive. A second transistor is connected to the switching transistor and is used to block operation of the switching transistor. The electronic device according to the invention supplies a constant output voltage even at input voltages between 70 and 264 volts and stimulates oscillation absolutely reliably even under maximum load. In addition, the device is suitable for DC and AC voltages of any frequency and merely requires a simply designed voltage regulating circuit that uses only ordinary components.

Abstract: A dual voltage power supply, for example operable from 120 and 240 volts a-c and having three voltage input terminals, is provided with an input filter having three windings on a core and inductively coupled together, the three windings being connected respectively to the three input terminals. Filter capacitors are connected to the windings.

Abstract: A power supply provides a low-level DC voltage to one or more DC load circuits by first rectifying either of the two standard AC voltages and thereafter reducing the rectified AC voltage to the low-level DC voltage. The reduction of the rectified AC voltage to the low-level DC voltage is accomplished by a power transformer which is switched on or off by a pair of switching transistors. The switching transistors are activated by a control transformer operating in combination with a control circuit. The control circuit timely produces various pulse conditions in the control transformer which turns the switching transistors on or off in a prescribed manner.