Filaments Flashcards
1
Q
What are the three types of automotive lightbulbs?
A
- halogen - tungsten filament
- LED
- xenon/high intensity discharge
2
Q
How are halogen lightbulbs used as trace evidence?
A
- has a tungsten filament
- tungsten is rigid and brittle at ambient temperatures and ductile at incandescent operating temperatures
- oxidised when exposed to atmosphere at operating temp - microscopic analysis
- glass can be fused to filament - SEM-EDX
3
Q
How can you tell if the filament of a halogen lightbulb was off?
A
- off: no pronounced distortion
- on: inertial force distortion on hot filament
