Abstract: A transient voltage surge suppressor for an electrical circuit having a hot electrical conductor, a neutral electrical conductor, and a ground electrical conductor includes a first surge suppressor connected between the hot and neutral electrical conductors, a second surge suppressor connected between the hot and ground conductors, and a third surge suppressor connected between the neutral and ground conductors; a first over current fuse connected between the hot electrical conductor and the first and second surge suppressors and a second electrical fuse connected in series between the third surge suppressor and the neutral conductor; and a visible indicator connected between the first fuse and the second fuse for illuminating only when both said first and second fuses are intact, and extinguishing when either of the first and second fuses is open.

Abstract: A ground fault circuit interrupter comprises a transformer having a saturable core; a secondary winding on the core; an integrating detector coupled to the secondary winding; and a pulse stretcher connected between the secondary winding and the differential detector for stretching high voltage short duration pulses sufficiently to allow them to be detected by the detector.

Abstract: A ground fault interrupter (gfi) wiring device in the form of a duplex wall receptacle. A pair of electrically conducting members in the form of small buss bars each carry two, spaced contacts. The buss bars are moveable to bring their respective contacts into and out of engagement with fixed contacts on the hot and neutral terminals on the line and load sides of the receptacle. The buss bars are biased toward movement to the circuit-breaking position by respective coil springs extending through openings in a separator member dividing the interior of the receptacle housing into front and rear compartments. One end of each spring rests upon a respective buss bar and the other end is contacted by an integral portion of the front housing section, the springs being compressed to apply a biasing force to the buss bars only upon placing the front housing section in mating engagement with the rear section.

Abstract: A ground fault interrupter (gfi) wiring device includes a latch member having integral abutment, latching and spring portions. In the preferred embodiment, the latch member is formed from a unitary blank of springy sheet metal, the spring portion being a leaf spring formed at one end and biasing the latch member to a latching position to maintain the moveable contact(s) in circuit-making relation with the fixed contact(s) of the device. The latch member is released to permit circuit-breaking movement of the moveable contact(s) by a solenoid having an armature with a relatively enlarged head portion to enhance speed of operation. Optionally, a spring may be provided to maintain the otherwise freely-slidable armature with its end portion in spaced relation to the latch member abutment portion so that the armature gains momentum before contacting the abutment portion to effect unlatching movement of the latch member.

Abstract: An electrical receptacle affording ground fault protection includes a movable latch block having spaced surfaces supporting the free ends of a pair of parallel, electrically conducting arms. The arms are anchored at their opposite ends and are held in a flexed position, with a pair of contacts mounted on the movable, free ends of the arms in engagement with a pair of fixed contacts when the block is in a first, latched position. The latch is released in response to a sensed ground fault in the circuit, permitting movement of the block and free ends of the arms to disengage the movable contacts from the fixed contacts and open the circuit. The movable latch block is of dielectric material and includes a medial wall portion separating the two pairs of movable and fixed contacts, as well as the free ends of the arms. An end wall portion extends upwardly from and laterally across the forward edges of the spaced surfaces, perpendicular and integrally attached to the forward side of the medial wall portion.

Abstract: A duplex wall receptacle having ground fault current interrupting capability includes an internal switch operable by manual depression of a button accessible on the front of the receptacle to test the device for proper operation. A blade of conducting material includes a first end portion which is held in contact with, but physically unattached to, one of the terminals to which one of the hot and neutral lines is attached on one side of the fault sensing means. A medial portion of the blade extends laterally across the interior of the receptacle, and a second end portion is positioned in normally spaced relation to a conducting member which is electrically connected to the terminal to which the other of the hot and neutral lines is attached on opposite side of the fault sensing element. Depression of the test button moves the medial portion and second end portion of the blade, placing the latter in contact with the conducting member to simulate a fault condition.

Abstract: A ground fault receptacle having novel mechanical members for latching and moving the movable, circuit-breaking contacts, and for protecting against line-to-line arcing as the contacts make and break. The movable contacts are carried on a pair of conducting, self-biasing, spring arms which are held in a flexed position by a latch block which moves with the arms and is retained in position by a stem on the reset button and cooperating latch member. The parts are constructed and arranged to permit the use of relatively large test and reset buttons which are centrally arranged on the front of a duplex receptacle housing.

Abstract: A circuit including a differential transformer for sensing an imbalance in the current flow through hot and neutral wires connected between a power source and load and a relay operable to break the connection in response to an imbalance of predetermined magnitude. The two movable relay contacts are placed directly in the two wires and are normally open, being closed when power is supplied to the relay coil, the input side of which is connected to a switching transistor. Features include connection of the relay coil as a series pass element in the feed circuit to reduce power dissipation and heat, decreasing the likelihood of contact chatter or welding, providing increased protection for the switching transistor without increasing relay contact opening time, and providing fail-safe operation for all of the more common types of failures in the protective circuitry. Open neutral and grounded neutral protection are also provided.

Abstract: A process and apparatus (a) for reducing the perceived noise without perceptible loss of fidelity upon aural reproduction, of an audio input signal in electrical form by means of an electronic circuit wherein the upper limit of the bandwidth of the signal is automatically and continuously adjusted in accordance with the relationship of (i) the peak amplitude of the rate of change of the signal with respect to time to (ii) the instantaneous amplitude within a selected frequency band of the signal, and (b) a system for detecting and discriminating between noise and audio transients in the input signal and retaining the audio transients in the output signal.

Abstract: A system for reducing noise transients in electrical carrier signals, carried simultaneously over two separate channels, that are identical in their program component but differ in transient noise content, comprising means for comparing noise transients in the respective channels and for transmitting the electrical sum of the two channels unless the noise transients of the two channels differ by more than a selectable threshold amount, in which case only the carrier signal with the lesser noise transient is transmitted.

Abstract: A system for reducing noise transients in identical electrical carrier signals carried simultaneously over separate channels, comprising means for comparing the noise transients in the respective channels and for transmitting the carrier signal in the channel having the lowest noise transient. The system can comprise means for blanking at least a portion of a carrier signal whose noise transient level exceeds a predetermined value.

Abstract: A system for limiting the instantaneous value of a noise transient, by means of an electronic circuit wherein the amplitude of the total input signal being monitored is compared with a threshold value which is varied continuously according to the peak carrier signal value, and the output signal is maintained below the threshold value.