Tot so what_happens


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Tot so what_happens

  1. 1. Judith Lievens<br />
  2. 2. Sowhat happens WHEN i toast my slice of bread?<br />
  3. 3. Sowhat happens…<br />Plug in the toaster<br />Turn the switch<br />Optionallypick ‘bagel’, ‘defrost’ or ‘reheat’<br />Place your slices of bread<br />Push the tray down with the handle<br />Waitor push ‘stop’<br />Take out yourbread<br />Emptycrumbtray<br />Pull out the plug<br />Eatit!<br />
  4. 4. So plug in the toaster and turn the switch, orpicksome extra options!<br />
  5. 5. Sowhat happens…<br />Whenyou turn the switch?<br />The switch is a variableresistor.<br />Meaningthatwhenyou turn it, youactivated different biggeror smaller resistors. Thiscauses the current output to be smaller/biggersothat the timer willbeturnedoff later/sooner.<br />
  6. 6. Sowhat happens…<br />Pickan extra option?<br />The extra optionsare in fact putting extra resistorsinto the electrical circuit to stretch (defrost) orshorten (reheat) the toasting time.<br />Thiscanbecausedbyplacingthem in series or in parallel.<br />
  7. 7. Now place yourbread in the slots and push the handledownwards!<br />
  8. 8. Sowhat happens…<br />When I push down?<br />When the handle is pushed down, the lever, connected to a main plastic part which in its turn is the connectionbetweenseveral smaller parts, is pushed down alongwith it.<br />Here’swhat happens, all at about the same time.<br />
  9. 9. Sowhat happens…<br />When I push down?<br />The main plastic part slides down alonganaxisthat is greasedwithlubricant.<br />
  10. 10. Sowhat happens…<br />When I push down?<br />When the lever is pushed down by the handle, it pulls a whole series of partswith it. These are all connected to a main plastic part.<br />One of the parts is the plastic tab.<br />Throughitsshape, itforces the contacts to close, closing the electrical circuit withit, allowing the electriccurrent to flowthrough it.<br />
  11. 11. Sowhat happens…<br />When I push down?<br />Whenelectricity runs through the circuit, a current runs through the nichromewiresinside the toaster’s, causingthem to heat up immediately and start toasting the bread.<br />The time to toast dependson the chosen extra options and the level of toasting, chosenwith the turn switch.<br />
  12. 12. Sowhat happens…<br />When I push down?<br />The electricityactivates the electromagnetwhichattracts the metal part that was pushed down alongwith the rest of the parts.<br />Thus the main plastic part and all the partsthat are connected to itstaybelowwith it.<br />
  13. 13. Sowhat happens…<br />When I push down?<br />There is a selfpositioning system for the slots in which the bread is placed. <br />Itworkslikethis.There’s a smallmetal part that sticks out frombehind the main plastic part.<br />Also the slots are connectedby a fine metal threadthat’s been crossed.<br />In neutral stand, the threads are relaxed and the slots are wide open, allowing to place breadinside. <br />
  14. 14. Sowhat happens…<br />When I push down?<br />When the lever is pushed down, thissmall metal part sticking out, is pulled down alongwith is.<br />Doingso, it pushes the metal thread down and thustowardeachother,<br />causing the slots to narrow and position the breadinsideitsoeachside of the bread is just as farfrom the nichromewires.<br />Alsoconnected to the main part is the bottom of the slotsso the breadwillbemoving down alongwith<br />everythingelseso the bread<br />canbetoastedcompletely.<br />
  15. 15. Sowhat happens…<br />When I push down?<br />When the lever is pushed down, the leftspring is stretched the direction of the movement. Thisspring is nowundertension. It wants to pull the main plastic part and all of itscomponentswithit, back upwards!<br />The right springisn’tdeformed, itjustslides down along the axis.<br />
  16. 16. And now, we wait a littlewhile…<br />
  17. 17. Sowhat happens…<br />When I wait?<br />As long as the timer is active, you have to waitforyour toast to beready.<br />The timer is actually a capacitor. This is anelectrical element that is chargedby the remainingcurrentafterit’spassedthrough the cyclus of resistors.<br />The bigger the current the faster the capacitor is charged. Whenit’sfullychargeditwillblock the currentforjust a nanosecond to discharge a little.<br />This instant is ‘long’ enough to…<br />
  18. 18. So, when the capacitor is fullycharged, what happens?<br />
  19. 19. Sowhat happens…<br />When the capacitor is fullycharged?<br />The electricitycurrent is blockedfor a small instant, butthis is sufficientfor the electromagnet to turn offforthat time.<br />Thus the electromagnetlets go of the metalpartthatnownolongerholds all the parts down byforce.<br />
  20. 20. Sowhat happens…<br />When the capacitor is fullycharged?<br />Because the electromagnetnolongerholdseverything down byforce, the leftspringwill relax and pull the lever and everythingconnected to it up again.<br />The right springnow serves as a bumper so the main plastic part doesn’tbump right into the toaster’sshell.<br />
  21. 21. Sowhat happens…<br />When the capacitor is fullycharged?<br />The plastic tab is pulled upwardsalso. <br />Throughthis, the contacts are nolongerconnected and the electrical circuit is brutallybroken, cuttingoff the electriccurrentthat was running through the circuit.<br />
  22. 22. Sowhat happens…<br />When the capacitor is fullycharged?<br />There is nolongerelectricity running through the circuit sonocurrentthrough the nichromewires, either. Theywill stop toastinginstantly.<br />
  23. 23. Sowhat happens…<br />When the capacitor is fullycharged?<br />The selfpositioningsystemfor the slotsrelaxesalso, since the small metal part that’ssticking out to pull the metalthreads down willbemovingupwardsagainalongwith the main plastic part.<br />The bottom of the slots is alsoconnected to thismain part so the toastedbreadwill pop out, ready to eat!<br />
  24. 24. And whatif I don’t have time ordon’tfeellikewaiting?<br />
  25. 25. Sowhat happens…<br />When I push ‘stop’?<br />Ifyou’retooimpatient, orthinkyour toast is burning, youcan stop the toaster earlybypushing the STOP button.<br />This is in fact a ‘normalclosed’-button. <br />Whenyou’renotpushingit, the electrical circuit is closed.<br />Whenyou do push it, the circuit is interruptedearly.<br />This has the same effect as the capacitorbeingfullycharged and blocking the currentforan instant.<br />
  26. 26. Nowenjoyyour toast!<br />