AHJ: U3 Hardware1

What technology do modern screens use for backlighting?

• CRT

• LED

• LCD

• DLP

How does a laser printer differ from an inkjet printer?

• Laser printers use liquid ink, inkjet printers use powdered ink

• Laser printers print the whole page at once, inkjet printers print line by line

• Laser printers use 4 color cartridges, inkjet printers use 1 cartridge

• Laser printers use piezoelectric printheads, inkjet printers use thermal printheads

What happens in stage 5 of the laser printing process?

• The paper is pressed against the drum

• Toner is applied to the drum

• The printing drum is charged

• A laser removes charge from parts of the drum

How does a thermal bubble inkjet printhead work?

• Piezoelectric crystals vibrate and force out ink

• UV light is used to cure ink

• Resistors heat up, forming bubbles to eject ink

• Electrostatic charge pulls ink onto the page

How does a microphone convert sound into electrical signals?

• Sound waves vibrate a diaphragm, moving a coil near a magnet

• Piezo crystals change shape when vibrating, generating voltage

• Sound waves induce current in a semiconductor

• Sound waves vary resistance in a resistive material

How do capacitive touchscreens detect touch input?

• Measuring resistance when top and bottom layers contact

• Detecting disruption of electric field between capacitor plates

• Measuring change in capacitance in piezo materials

• Using infrared LEDs and cameras to see touch

Which printers would be best for high volume office printing?

• Laser

• Inkjet

• 3D

• Dot matrix

What technology enables mixing R, G, B subpixels to produce color images on screens?

• LCD

• CRT

• LED

• OLED

How does a 3D printer build up objects layer by layer?

• Spraying glue onto powdered material

• Milling material away using a CNC machine

• Shining UV lasers to cure liquid resin

• Bending and welding thin metal sheets

Why are anti-lock brakes on cars considered a control application of sensors?

• They monitor wheel speeds

• They detect changes in conditions

• They adjust braking pressure based on feedback

• They warn the driver of problems