Mobile Devices
Which wireless technology enables contactless payments on smartphones?+
- • Bluetooth
- • Infrared
- ✓ NFC
- • Wi-Fi Direct
Near Field Communication works within a few centimeters, which suits payments and tap-to-pair.
A laptop display is very dim, but an image is visible when a flashlight is shone on it. What most likely failed?+
- • Digitizer
- • GPU
- • Wi-Fi antenna
- ✓ Backlight
The LCD panel is still forming the image, but nothing lights it from behind, so the backlight (or an older inverter) has failed.
Which reversible connector is standard on most modern Android phones?+
- ✓ USB-C
- • Micro-USB
- • Mini-USB
- • Lightning
USB-C is reversible and supports power, data and display output. Lightning is Apple-proprietary and older iPhones used it.
On a touchscreen device, which component converts finger touches into input?+
- • Backlight
- ✓ Digitizer
- • Inverter
- • Accelerometer
The digitizer is the touch-sensitive layer that converts touches into coordinates. The display can work normally while the digitizer fails.
Which display technology produces its own light per pixel and needs no backlight?+
- • IPS LCD
- • TN LCD
- ✓ OLED
- • VA LCD
OLED pixels emit their own light, so a black pixel is simply off. All LCD types (IPS, TN, VA) need a backlight.
Which LCD panel type offers the best color accuracy and viewing angles?+
- • TN
- • VA
- • CCFL
- ✓ IPS
In-plane switching panels give the widest viewing angles and best color accuracy. TN panels are fast and cheap but have poor angles. VA panels sit in between with strong contrast.
