Abstract: A diode or other axial lead electronic component which requires mounting of its leads in a predetermined orientation is provided with leads of considerably different diameter. A printed circuit board is provided with holes sized to receive respective leads, so that the leads can be inserted into the holes only one way. Instead of having circular cross-sections and different diameters, one lead may have a circular cross-section while all or an end portion of the other lead has a non-circular cross-section with a diameter allowing that lead to fit in only the larger hole of the printed circuit board.

Abstract: Filter circuits of the type having inductance and capacitance elements, wherein the number of magnetic components is reduced by using two transformers to perform the functions of four individual inductors. Each transformer has one end of the primary winding connected to one end of the secondary winding, and a pi or T equivalent circuit in which one of the inductance values is equal in magnitude and opposite in sign to a corresponding equivalent circuit inductance value of the other transformer.

Abstract: A ground fault detector for protecting an electrical power system against ground leakage currents. The detector is of the differential transformer type, in which the primary windings of the transformer are connected in series with the hot and neutral lines of the power system, any unbalance in the currents flowing through these lines being detected by sensing the unbalance voltage induced in the secondary winding of the transformer. The secondary voltage is amplified and employed to actuate a solenoid which trips the system circuit breaker in response to unbalance in line and neutral currents due to the flow of ground leakage current. A secondary winding on the solenoid is connected in the neutral line to cause the detector to operate in response to a neutral to ground fault, which might otherwise go undetected.