Abstract: A monitoring circuit for a battery charger, with utility in other applications, includes a main input that receives an initial signal such as the terminal voltage of a battery being charged, and a two-stage comparator, each stage preferably an operational amplifier. The initial signal is applied to the inverting input of the first stage, which is a differencing amplifier that also serves as a gain block; the initial signal is also delayed a brief interval, typically more than a second, and then applied to the non-inverting input of the first stage of the comparator. The inverting input of the second stage of the comparator receives the same signal as the non-inverting input to the first stage, whereas the non-inverting input to the second stage is derived from the output of the first stage.

Abstract: In a scanning acoustic microscope of the reflection type, in which an object is insonified with a series of ultrasonic acoustic pulses in accordance with a preselected scanning pattern and reflected acoustic echo pulses are received and employed to generate an initial electrical signal comprising a sequence of electrical pulses having amplitudes and polarities representative of the magnitudes and phases of the echoes, a directly readable unified interpretative display image is produced from the entire electrical signal; that image includes the usual scanning position and depth information determined by timing of the electrical pulses, together with complete transition information regarding the nature of acoustic impedance changes, based on both the amplitudes and the polarities of those pulses. A compared dual integration method and system, with related gating and display enhancement techniques, comprises the preferred embodiment.

Abstract: A balanced scanning mechanism for driving the transducer of an acoustic microscope or other instrument rapidly back and forth along a linear path comprising the X portion of an X-Y scan pattern comprises first and second carriages guided for movement along an axis X. The transducer is mounted on the first carriage and a counterweight may be mounted on the second carriage; the total mass of each carriage and its contents is equal to that of the other carriage. Drive belts connected to both carriages drive them reciprocally along the X axis with accelerations and velocities that are equal in amplitude but opposite in direction. In some embodiments the two carriages are nested one within the other. In another embodiment the two carriages are mounted closely adjacent to each other on an elongated, rigid guide rail parallel to the X axis, the mass distributions of the two carriages being matched relative to the guide rail.