Abstract: Apparatus for nondestructive detection of subsurface defects in a continuously moving workpiece of sheet material by using an infrared thermal imager. The temperature of a portion of the surface of sheet material is altered and the presence of subsurface flaws is indicated by development of discontinuities in the surface temperature distribution above the defects. In order to avoid problems due to changes in the infrared emissivity of the surface of sheet material, such as caused by grease patches or oxidized areas as well as errors caused by reflections of other sources of infrared radiation from the surface, the thermal image of the portion is first transferred by contact to a surface of a thermal transfer device whose surface has a high infrared emissivity and a low infrared reflectivity. Then the thermal image of the portion is obtained from the surface of the thermal transfer device.

Abstract: A method for inspecting the placement and alignment of surface mounted components on printed circuit boards during assembly. After the component is placed on the board, an infrared camera provides an image of leads on the component and corresponding soldering pads, to which the leads are to be soldered, on the board in a single exposure. The image is then processed by a computer and the position and orientations of the leads of the component with respect to the soldering pads are determined. As a result, any unsatisfactory misalignment of the component can be detected and defective printed circuit boards identified.

Abstract: An instrument to determine, under actual field conditions, which type of VA demand meters are most appropriate for a particular consumer. The type of electrical load that the consumer places on an electrical supply system can introduce harmonics and phase distortion in the system resulting in VA meters producing incorrect readings. These VA meters are intended to measure the true apparent power S which is defined as S=V.sub.rms XI.sub.rms but, are generally designed to operate according to one of the following approximate formula:(1) S'=V.sub.rect XI.sub.rect X(1.11).sup.2 and(2) S"=.sqroot.P.sup.2 +Q.sup.2 where P is the active power and Q the reactive power.The instrument contains circuit to measure the rms values of the voltage and current waveforms from which the true apparent power S can be obtained as well as circuits to determine the value S' and S" according to the two approximate formula from which error signals e.sub.1 and e.sub.