technology of a toaster_class presentation
TRANSCRIPT
Judith Lievens
HISTORY
History• Why ?
• Electricity in America
• 1900 Embedded heating
• 1905 Nichrome (Albert Marsh)
• 1909 First electric toaster (Frank Shailor for
General Electrics)
• 1913 Toaster with automatic turner (Lloyd
Copeman)
• 1919 Automatic pop-up (Charles Strite)
•1933 Spring loaded automatic toaster in
households
• 1960’s Common and cheap
• 1980’ … now
PARTS
Parts Shell
Parts Shell - Handle
Parts Shell – Switch&Options
Parts Shell - Slots
Parts Bottom
Parts Crumb Tray
Parts Inside
Lever
Plastic tab
Contacts
Metal tab
Electromagnet
Springs
Selfpositioning slot
PCB
SO WHAT HAPPENS WHEN I TOAST MY SLICE OF BREAD?
So what happens…1. Plug in the toaster
2. Turn the switch
3. Optionally pick ‘bagel’, ‘defrost’ or ‘reheat’
4. Place your slices of bread
5. Push the tray down with the handle
6. Wait or push ‘stop’
7. Take out your bread
8. Empty crumb tray
9. Pull out the plug
10. Eat it!
So what happens… When you turn the
switch?
Variable resistor
So what happens… Pick an extra option?
Extra resistors
LED
So what happens… When I push down?
So what happens…Contacts close – lubicant – electrical circuit
When I push down?
So what happens…Nichrome wires start toasting
When I push down?
So what happens…Electromagnet – metal tab
When I push down?
So what happens…Selfpositioning slot
When I push down?
So what happens…Selfpositioning slot
When I push down?
So what happens…Spring 1: stretches Spring 2: moves
down
When I push down?
So what happens…
Capacitor charges
through resistor
= timer
When I wait?
So what happens…Electromagnet is cut off and lets go
When I wait?
So what happens…Spring 1: relaxes Spring 2: stops
components
When I wait?
So what happens…Plastic tab – pulled upwards – contacts broken
When I wait?
So what happens…Power to
nichrome wires
cut off
When I wait?
So what happens…Selfpositioning slot
When I wait?
So what happens…Selfpositioning slot
When I wait?
So what happens…Normal Closed
↓
Power is cut off
Electromagnet releases tray
Springs relaxes and pulls up the tray with toast
Contact for nichrome wiresis broken
…
When I push ‘stop’?
So what happens… When I eat my toast?