Abstract: A charging control apparatus comprising a switching circuit for controlling a charging current from a charging power source to a storage battery. A reference voltage is provided which increases with a ramp corresponding to a value equal to, or more than, the maximum ramp value of the charging characteristic of the battery and a reference voltage is also provided which increases with time with a ramp corresponding to a value equal to, or less than, the minimum ramp value of the charging characteristic. The terminal voltage of the battery is sensed by a voltage sensor. A first comparator compares the reference voltage and a first sensed voltage from the voltage sensor. The ramp of the reference voltage is switched in accordance with the output of the first comparator. A second comparator compares the reference voltage and a second sensed voltage from the voltage sensor. The switching circuit is controlled by the output of the second comparator.

Abstract: A test specimen has a carefully controlled series of cracks on its surface and is useful for evaluating surface penetrants employed in non-destructive inspection. A flat brass substrate has a nickel electroplating on one surface, which plating varies in thickness along the length of the panel. The opposing side of the panel has a multiplicity of grooves which locally concentrate strain in the plating when the panel is bent during manufacture, thus providing a crack associated with each groove. In a preferred embodiment, the texture of the cracked surface varies across the panel in the same direction in which the cracks run, thus enabling evaluation of the usefulness of penetrants in finding different size cracks under different surface finish conditions.