A novel converter circuit converts AC input voltage within the range of 85-260 VAC to a constant voltage, current limited DC output voltage wth substantially no input voltage, all without the use of a transformer or input voltage-select switch. The AC input voltage is inputted directly to a rectifier and then to the input of a phase-controlling element (SCR) for controlling the phase of the unfiltered rectified signal. A trigger signal-generating circuit generates a trigger signal for regulating the operation of the phase-controlling element. A ripple-removing filter circuit receives the output from the phase-controlling element and removes the ripple component. A voltage-regulating circuit, a current-limiting circuit, and a rapid start-up circuit to facilitate rapid generation of DC output signal soon after energization of the overall circuit by an AC power source are also disclosed.
A method and apparatus for reducing the low frequency electric and magnetic fields associated with electric blankets and mattress pads includes a power form converter inserted between the heating element of the electric blanket or mattress pad and the AC power source. In one embodiment, the power form converter is an AC to DC converter. In another embodiment, the power form converter is a full wave bridge rectifier circuit. The power form converter may either be built into the electric blanket or mattress pad, or may be external so that an existing electric blanket or mattress pad may be used in conjunction with the power form converter.
A device and method for reducing low frequency electromagnetic fields in an electric blanket includes an input, a rectifier filter, and a pair of closely spaced resistance wires. The input is connected to a 60 Hz AC power source to supply power to the electric blanket. The rectifier filter rectifies the input signal and filters out any high order components. The rectifier filter provides a filtered DC signal to apply across the paired resistance wires. In one embodiment, the device and method includes an output for connecting to a conventional electric blanket where the rectifier filter provides a filtered DC signal to the output.
A fuel dispenser system is provided in a standard configuration based upon a single supply voltage requirement that is independent of the available local power supply sources. A supply voltage apparatus integrally coupled to the standard dispenser configuration employs a transformer to adapt the field supply voltage from the local power supply to the voltage level needed by the dispenser devices such as the power supplies.
The present invention is a voltage adapter for a low voltage thermostat which permits the following input voltage ranges: 100-132 VAC/50 or 60 Hz, 200-264 VAC/50 or 60 Hz, and 265-330 VAC/50 or 60 Hz maintaining an output of at or just effectively about 24 VAC.
A ripple reduction circuit includes a controllable switch, an impedance coupled to one of a pair of main current path electrodes of the controllable switch whereby the impedance and the switch are coupled between first and second DC conductors and gating circuitry coupled between one of the conductors and a control electrode of the controllable switch for closing the switch when AC ripple power is carried by the conductors whereby at least a portion of the AC ripple power is removed from the conductors and delivered to the impedance.
