Abstract: A holder for compact discs (CDs) or tape cassettes includes back lighting provided by a staggered pattern of discrete points of light. A surprisingly unusual effect occurs as the light shines through the clear plastic cases of the CDs or cassettes. As viewed from the front, the cases appear to sparkle with light.

Abstract: An oscilloscope provides adjustable control of the reference voltage level to the trigger comparator to calibrate the trigger for both gain and offset. An internal computer in the oscilloscope provides a digital input value to a gain digital-to-analog converter (DAC) the analog output of which is provided to the reference input of a level DAC. The level DAC also receives digital input from the control computer and provides its analog output to the reference input of the trigger channel comparator. The digital data value provided to the gain DAC determines the relative gain of the output signal from the level DAC.