Judith Lievens

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 plug in the toaster and turn the switch, orpick some extra options!

So what happens… When you turn the

switch?

The switch is a variable resistor.

Meaning that when you turn it, you activated different bigger or

smaller resistors. This causes the current output to be smaller/bigger

so that the timer will be turned off later/sooner.

The extra options are in fact putting extra resistors into the electrical

circuit to stretch (defrost) or shorten (reheat) the toasting time.

This can be caused by placing them in series or in parallel.

So what happens… Pick an extra option?

Now place your bread in the slots and push the handle downwards!

So what happens… When I push down?

When the handle is pushed down, the lever, connected to a main

plastic part which in its turn is the connection between several smaller

parts, is pushed down along with it.

Here’s what happens, all at about the same time.

So what happens… When I push down?

The main plastic part slides

down along an axis that is

greased with lubricant.

So what happens… When I push down?

When the lever is pushed down by the handle, it pulls a whole series

of parts with it. These are all connected to a main plastic part.

One of the parts is the plastic tab.

Through its shape, it forces the contacts to close, closing the electrical

circuit with it, allowing the electric current to flow through it.

So what happens… When I push down?

When electricity runs through

the circuit, a current runs

through the nichrome wires

inside the toaster’s, causing

them to heat up immediately and

start toasting the bread.

The time to toast depends on

the chosen extra options and the

level of toasting, chosen with the

turn switch.

So what happens… When I push down?

The electricity activates the electromagnet which attracts the metal

part that was pushed down along with the rest of the parts.

Thus the main plastic part and all the parts that are connected to it

stay below with it.

So what happens… When I push down?

There is a selfpositioning system for the slots in which the bread is

placed.

It works like this.

There’s a small metal part that sticks out from behind the main plastic

part.

Also the slots are connected by a fine metal thread that’s been

crossed.

In neutral stand, the threads are relaxed and the slots are wide

open, allowing to place bread inside.

So what happens… When I push down?

When the lever is pushed down, this small metal part sticking out, is

pulled down along with is.

Doing so, it pushes the metal thread down and thus toward each

other,

causing the slots to narrow and position the bread inside it so each

side of the bread is just as far from the nichrome wires.

Also connected to the main part is the bottom of the slots so the bread

will be moving down along with

everything else so the bread

can be toasted completely.

So what happens… When I push down?

When the lever is pushed down, the left spring is stretched the

direction of the movement. This spring is now under tension. It wants

to pull the main plastic part and all of its components with it, back

upwards!

The right spring isn’t deformed, it just slides down along the axis.

And now, we wait a little while…

So what happens… When I wait?

As long as the timer is

active, you have to wait for

your toast to be ready.

The timer is actually a

capacitor. This is an electrical

element that is charged by the

remaining current after it’s

passed through the cyclus of

resistors.

The bigger the current the

faster the capacitor is charged.

When it’s fully charged it will

block the current for just a

nanosecond to discharge a

little.

This instant is ‘long’ enough

to…

So, when the capacitor is fully charged, whathappens?

So what happens… When the

capacitor is fully

charged?

The electricity current is blocked for a small instant, but this is

sufficient for the electromagnet to turn off for that time.

Thus the electromagnet lets go of the metal part that now no longer

holds all the parts down by force.

So what happens…

Because the electromagnet no longer holds everything down by

force, the left spring will relax and pull the lever and everything

connected to it up again.

The right spring now serves as a bumper so the main plastic part

doesn’t bump right into the toaster’s shell.

When the

capacitor is fully

charged?

So what happens…

The plastic tab is pulled upwards also.

Through this, the contacts are no longer connected and the

electrical circuit is brutally broken, cutting off the electric current that

was running through the circuit.

When the

capacitor is fully

charged?

So what happens…

There is no longer electricity running through the circuit so no

current through the nichrome wires, either. They will stop toasting

instantly.

When the

capacitor is fully

charged?

So what happens… When the

capacitor is fully

charged?

The selfpositioning system for the slots relaxes also, since the small

metal part that’s sticking out to pull the metal threads down will be

moving upwards again along with the main plastic part.

The bottom of the slots is also connected to this main part so the

toasted bread will pop out, ready to eat!

And what if I don’t have time or don’t feel likewaiting?

So what happens… When I push ‘stop’?

If you’re too impatient, or think

your toast is burning, you can

stop the toaster early by pushing

the STOP button.

This is in fact a ‘normal closed’-

button.

When you’re not pushing it, the

electrical circuit is closed.

When you do push it, the circuit

is interrupted early.

This has the same effect as the

capacitor being fully charged and

blocking the current for an

instant.

Now enjoy your toast!