Did You Know...
...that while attempting to develop a super strong glue, 3M employee Spencer Silver accidentally developed a glue that was so weak it would barely hold two pieces of paper together? However, his colleague Art Fry needed the glue. Fry sang with his church choir and marked the pages of his hymnal with small scraps of paper that often fell out. He used Silver's glue to hold the papers in place. Today we call this invention Post-it Notes.
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| Number | Title | Issue Date |
| 7986540 | Controlling switching noise of an inductively loaded thyristor Systems and/or methods that facilitate controlling a rate of voltage change across an inductively loaded thyristor when switched are presented. Based on a received control signal indicating a thyristor is to be switched, a control component controls the rate of volt... | 07/26/2011 |
| 7187569 | Signal generation apparatus and method for seafloor electromagnetic exploration An apparatus for generating electronic signals for application in subsea electromagnetic exploration. A surface generated high-voltage low-current source signal stabilized at a first frequency is supplied to a deep-tow vehicle (18) via an umbilical cable (... | 03/06/2007 |
| 7122070 | Method of and apparatus for electrostatic fluid acceleration control of a fluid flow A device for handling a fluid includes a corona discharge device and an electric power supply. The corona discharge device includes at least one corona discharge electrode and at least one collector electrode positioned proximate each other so as to provide a total ... | 10/17/2006 |
| 7081152 | ESP performance optimization control A gas separation apparatus which uses electrostatic precipitators and a DC power supply is controlled to optimally remove moderate to high resistivity ash. The DC power supply is pulse width modulated to maximize the product of the peak electric field and the averag... | 07/25/2006 |
| 7050313 | Aircraft AC-DC converter An AC-DC converter includes a DC reference voltage generation unit that creates a DC reference voltage waveform based in part on a feedback signal. The AC-DC converter also includes an SCR firing unit that receives a variable frequency power output from the generato... | 05/23/2006 |
| 7034604 | Communications device powered from host apparatus A communications device, such as a transceiver, is used with a fiber optic communication line, wherein the communications device is powered from a host device. A voltage supply circuit, which comprises a full wave bridge rectifier responsive to data and control sign... | 04/25/2006 |
| 6642829 | High-voltage transformer The invention relates to a high-voltage transformer consisting of conventional elements disposed in two different groups, namely positive voltage elements (1-5) and negative voltage elements (1'-5'), both types of elements being separated by a single insu... | 11/04/2003 |
| 6587362 | AC-DC converters with bi-directional thyristor valves An ac-dc converter using bi-directional thyristor valves made up of back-to-back connected thyristors as converter valves. The bi-directional thyristor valves permit operation of the converter as a rectifier or an inverter with both polarities of the volt... | 07/01/2003 |
| 6552598 | Semiconductor high voltage electrical energy transmission switching system and method A method for controlling fault interruption in a high voltage electrical energy transmission system semiconductor high voltage electrical energy transmission switching system which includes a multiple stack of power semiconductor SCR thyristor circuit sec... | 04/22/2003 |
| 6388906 | Backslope regulator system A regulator system includes a circuit regulating the output of a power supply such as a capacitive input filter power supply and preferably also a transformer and full-wave diode bridge. Included are a ramp generator, a zero crossing detector synchronizin... | 05/14/2002 |
| 6385066 | Method and system for detecting a zero current level in a line commutated converter A method and system for determining zero current level occurrences in a reversible power converter without requiring additional component complexity and costs. A digital controller selectively determines the line to line voltage for the most recently fire... | 05/07/2002 |
| 6377482 | Device and method for line-voltage dependent thyristor controlled pre-charging of output capacitors in a three-level pulse rectifier system The invention relates to an apparatus for initial charging of the output capacitors of a three-phase three-point pulsed rectifier system. According to the invention, a thyristor is arranged in each phase between the input terminal and is connected in the ... | 04/23/2002 |
| 6362604 | Electrostatic precipitator slow pulse generating circuit An apparatus and method for generating slow rise-time, high voltage electrical pulses to a load, preferably using an existing transformer/rectifier set or power supply to charge an inversion or high voltage switching circuit to produce the pulsed voltage.... | 03/26/2002 |
| 6108224 | Phase shift triggering circuit for thyristor and an integrated module of the triggering circuit and the thyristor A phase-shift thyristor trigger circuit, including a synchronous signal sampling circuit, a waveform shaping, integrating and comparator circuit, a high-frequency modulating pulse distributor circuit, a power amplification and high frequency pulse rectifi... | 08/22/2000 |
| 6075717 | PWM rectifier control with switching losses equally distributed among multiple switching devices Switching losses are distributed equally between multiple switching devices in a rectifier bridge (50) in which the rectifier bridge comprises at least a first pair of serially connected switching devices (56A, 56B) connected between positive and negative... | 06/13/2000 |
| 6018473 | Power supply and printing machine containing same A power supply includes a diode bridge rectifier. The diode bridge rectifier output provides direct current to a primary capacitor. A current-limiting resistor is connected in series with the rectifier output and the primary capacitor. The current-limitin... | 01/25/2000 |
| 5995395 | Control of a composite bridge at zero voltage The present invention relates to a device for controlling a composite bridge including two anode-gate thyristors, the cathodes of which are connected together to a positive output terminal, the gates of the two thyristors being interconnected. The device ... | 11/30/1999 |
| 5986903 | Control apparatus for a converter for transmitting electric power between an alternating voltage network and a direct voltage network A plant for transmitting electric power between a direct voltage network and an alternating voltage network through a power station. A converter of a station has two current valves connected in series, each having one turn-on and turn-off type breaker and... | 11/16/1999 |
| 5981925 | Power supply for a continuous wave microwave magnetron A power supply for a CW magnetron, devoted for use in microwave heating equipment. A power supply according to the present invention (FIG. 1) has a high-voltage line transformer (1) with secondary winding (2) which is connected through a voltage doubling ... | 11/09/1999 |
| 5982646 | Voltage clamp snubbers for three level converter A three-level NPC converter includes at least one phase leg including four series coupled electrical switches having a first pair junction between the first two switches and a second pair junction between the second two switches. First and second inner sw... | 11/09/1999 |
| 5969959 | Converter circuit arrangement with protection circuit A converter circuit arrangement is specified having a rectifier, an intermediate circuit and an invertor connected thereto. In order to protect the circuit against failures and overvoltage, a protection circuit which comprises, in particular, varistors is... | 10/19/1999 |
| 5963441 | Alternating current rectifier bridge and system for measuring average current per bridge segment A three-phase controlled rectifier bridge for converting alternating current to direct current includes six segments for each of the positive and negative polarities of each of three AC phases. Each of the segments has a semiconductor controlled rectifier... | 10/05/1999 |
| 5852556 | Power converter A power converter comprises a pulse generator capable of outputting two different levels of gate power. A thyristor (LTT) is turned on by the first gate power output from the pulse generator, and the second gate power is supplied to the thyristor (LTT) du... | 12/22/1998 |
| 5838555 | Two-wire power supply electronic switch A two-wire power supply switch connected in series with a load between two poles of an alternating current mains electrical power supply conventionally includes a main triac between two terminals of the switch which is turned on by the conduction of an op... | 11/17/1998 |
| 5757169 | Electric circuit for pulse energized electrostatic precipitator and pulse energized electrostatic precipitator using this circuit An electrostatic precipitator circuit has an input terminal supplied DC voltage, an output terminal connected to a precipitating capacitor, a storage capacitor connected between ground potential and the input terminal, and a recovery capacitor whose one e... | 05/26/1998 |
| 5532562 | Apparatus for controlling DC motor with H-bridge switching circuit A control circuit for an H-bridge circuit comprises a single capacitor, a charge/discharge circuit for charging/discharging the capacitor in response to a control command signal, a voltage detector circuit for detecting a voltage appearing across the capa... | 07/02/1996 |
| 5521810 | Rectifying saturable reactor A rectifying saturable reactor generates a magnetic force in a magnetic iron core in response to a current that flows through an electronic circuit. The saturable reactor makes use of saturable magnetic flux in view of a hysteresis loop of a magnetic mate... | 05/28/1996 |
| 5451846 | Low current compensation control for thyristor armature power supply A control system for energizing a direct current (DC) motor with alternating current (AC) power includes a first voltage sensor for a peak voltage of AC power; a second voltage sensor for a counter electromotive force (EMF) of the motor; a current sensor ... | 09/19/1995 |
| 5347441 | Thyristor converter system with higher harmonics suppression A semi-conductor bridge thyrister converter circuit for converting AC power into DC power with suppression of the higher harmonics generated by the circuit including a semi-conductor converter circuit, a control circuit, and instrument transformers for me... | 09/13/1994 |
| 5337228 | Differential charging circuit A differential charging circuit comprising an active switch device controlled by a differential trigger circuit and a current impedance device to charge a storage battery through an intermediate storage capacitor. A capacitor and commutating inductance ar... | 08/09/1994 |
| 5321343 | Digital motor control system A control system for one or more dc motors in which thyristor power modules selectively gate portions of half cycles of ac voltage to the motor field and armature windings, has digitally implemented parallel inner control loops for the armature which each... | 06/14/1994 |
| 5270912 | Electrofishing apparatus and method To minimize injury during electrofishing while inducing a high degree of electrotaxis, a packet of DC pulses having sharp leading edges and preferably an exponential or square decay are transmitted under water between an anode electrode and a cathode elec... | 12/14/1993 |
| 5155673 | Thyristor converter protection method and apparatus A method and apparatus for protecting thyristors in a power converter from overvoltages. Voltage detectors determine if the forward voltage of each thyristor has increased in the converter. If such an overvoltage occurs during a predetermined period after... | 10/13/1992 |
| 5111379 | Electrofishing apparatus and method To minimize injury during electrofishing while inducing a high degree of electrotaxis, a packet of DC pulses having sharp leading edges and preferably an exponential or square decay are transmitted under water between an anode electrode and a cathode elec... | 05/05/1992 |
| 4811189 | AC rectifier circuit with means for limiting the rectified voltage The invention relates to an AC voltage supplied rectifier circuit with a downstream smoothing capacitor. A prior art problem with this type of circuit was that the inductive impedance of the supply voltage caused a practically umdamped oscillation between... | 03/07/1989 |
| 4785388 | Gate pulse generator for thyristor converter In a gate pulse generator for a thyristor converter of the type in which in order to fire thyristors of the thyristor converter in which each arm is comprised of a plurality of series-connected thyristors, the gate pulses are generated in response to the ... | 11/15/1988 |
| 4780804 | Method and an arrangement for enabling the magnetizing current passing through a transformer to be minimized when an asymmetric load is applied to the secondary side of the transformer The invention relates to a method and to an arrangement for controlling the respective conduction times of two directionally opposed electrical devices (9,10) which are mutually connected in parallel and permit current to pass therethrough solely in one d... | 10/25/1988 |
| 4772998 | Electrostatic precipitator voltage controller having improved electrical characteristics A control system for controlling high power from an AC source for electrostatic precipitators. The AC power is gated both on and off during the same half-cycle of the AC sources. The gating off of the AC power occurs at a time substantially different from... | 09/20/1988 |
| 4744017 | High tension power supply with means for preventing transformer saturation A high tension power supply for use in an x-ray tube drive circuit which uses a step-up transformer to raise an input line signal to the desired voltage level. A partially open bridge or other suitable means permits only half cycles, for example positive ... | 05/10/1988 |
| 4731722 | Low AC harmonic DC power supply A DC power supply which generates little or no harmonics on the supply line includes a bridge circuit having high frequency controlled unilateral switching devices in the four legs thereof and a high frequency filter capacitor connected across two opposed... | 03/15/1988 |
