technology of a toaster_class presentation

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?