IE1206 Embedded Electronics

Transcription

1 IE06 Embee Elecronics Le Le3 Le4 Le Ex Ex PI-block Documenaion, Seriecom Pulse sensors I, U, R, P, series an parallel K LAB Pulse sensors, Menu program Sar of programing ask Kirchhoffs laws Noe analysis Two-erminals RR AD Le5 Ex3 K LAB Two-erminals, AD, omparaor/schmi Le6 Le8 Ex6 Le3 Ex4 Ex5 Le0 Le7 Le9 Le Le Ex7 Display Wrien exam K3 LAB3 Transiens PWM Phasor jω PWM P AP/IND-sensor K4 LAB4 LP-filer Trafo Sep-up, R-oscillaor L-osc, D-moor, P PWM Display of programing ask Trafo, Eherne conac

2 elecric fiels The force beween charges can be calculae using oulomb's Law. The force beween like charges is repulsive, beween ifferen charges aracive. The elecric fiel E a a poin charge Q can be seen as he force on a "es charge", a "uni charge ( Q + ). The elecric lines of force are saring from a posiive charge an en on a negaive charge. The force lines may no cross each oher. Q Q F k Q 9 E k k 9 0 Nm / r r 4π ε 0 The consan k has a very big value, he elecical forces are srong.

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4 ε 0 ε 0 Plae capacior ε 0 3 ε 0 4 ε Q U A ε A capacior capaciance is proporional o he area A an inversely proporional o fla isance. If he insulaion maerial beween he plaes is polarizable (ε) he capaciance is increase. ε ε 0 0 A A > < 4 A ε 0 A ε 3 ε ε ε r ε 0 0 A/ ε 8,85 pf/m 0

5 Dielecric Mos maerials are polarizable, an will hen increase he elecric fiel, an he capaciance of he capacior if place beween he plaes. Tianie use in ceramic capaciors, he increases he capaciance 7500 imes in comparison o vacuum or air. ε r 7500 ε r is playing he same role for he elecric fiel as µ r oes for he magneic fiel. ε ε ε r ε 0 0 8,85 pf/m

6 Shor, Volage raing High capaciance value coul be obaine wih a small fla isance. The rawback is ha he risk increases for arcing beween he plaes. Each capacior hen has a maximum rae volage which mus no be exceee. A capacior for higher rae volage are necessarily larger han a lower rae volage if he capaciance is he same. Q E U U The elecric fiel E of he capacior is EU/. The air can wihsan.5 kv/mm before arcing!

7 Big area A High capaciance one can ge wih large area A. The capacior can hen be rolle, or ype by mulilayer ype, so ha "he componen surface" is minimize espie he large inner surface. Mulilayer apacior wih ceramic ielecrics ( high ε r ).

8 Very shor isance The elecrolyic capacior is base on exremely small isance beween he elecroes. One elecroe is an aluminum foil, an he ielecric is a hin insulaing oxie layer on he foil. The oher elecroe is he elecrolye iself which of course is in close conac wih he surface of he foil. The capacior mus be polarize correcly, wih he same polariy as when he oxie layer was forme. Oherwise he oxie layer is esruce an he capacior is shore! The capacior is also esroye if he rae volage is exceee.

9 Big area A an very shor isance Tanal elecrolyic capacior have a "sponge forme" elecroe. The oal inner surface A becomes exremely large. The insulaion consiss of an oxie layer so even is small. A 3.5 mm.5 mm 5.5 mm, 4.7µF anal elecrolyic capacior has he equivalen inner area of 40 cm!

10 apaciors

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12 Supercap (9.) Q I U Q The backup capaciors of he ype "Supercap" can be use as a power backup for memories - if one for example nees o move he phone from one room o anoher wihou he phone forgeing is seings. Make a rough esimae of how long he charge in he capacior will las? Assume ha F an U is iniially 5V. The equipmen raws I 0 ma an operaes own o.5v.

13 Supercap (9.) Q I U Q The backup capaciors of he ype "Supercap" can be use as a power backup for memories - if one for example nees o move he phone from one room o anoher wihou he phone forgeing is seings. Make a rough esimae of how long he charge in he capacior will las? Assume ha F an U is iniially 5V. The equipmen raws I 0 ma an operaes own o.5v. Q U Q.5 (5,5),5 As 50 s 3 I min

14 School s bigges supercap? 3000 F 6 Research is going on for energy sorage for rouers in places where baeries wou have 'inappropriae' emperaures. For example, in he eser or in he arcic. School TELEOMUNIATION SYSTEM LAB

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16 apacior ransiens τ R E ur + u E i( ) R+ i( z)z 0 0 The volage across he capacior orginaes from he collece charge. i( z)z i() i() E i () R+ iz ( )z 0 R i () 0 R i () + + u ( ) q( ) 0 i( ) E R e τ τ R

17 apacior ransiens τ R E ur + u E i( ) R+ i( z)z 0 0 The volage across he capacior orginaes from he collece charge. i( z)z i() i() E i () R+ iz ( )z 0 R i () 0 R i () + + u ( ) q( ) 0 The ifferenial equaion has he soluion: E τ i () e τ R R

18 harging a capacior Time consan T R

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20 Parallel connece capaciors (Ex. 9.3) Two capaciors parallel-connece. Wha abou he equivalen capaciance an is rae volage? 4 µf 50V µf 75V

21 Parallel connece capaciors (Ex. 9.3) Two capaciors parallel-connece. Wha abou he equivalen capaciance an is rae volage? 4 µf 50V µf 75V apaciance is ae, he parallel connecion is he same as if plae surfaces were ae. The capacior wih he wors wihsaning volage eermines he equivalen capacior rae volage. I is in his capacior he impac woul occur.

22 Parallel connece capaciors (Ex. 9.3) Two capaciors parallel-connece. Wha abou he equivalen capaciance an is rae volage? 4 µf 50V µf 75V apaciance is ae, he parallel connecion is he same as if plae surfaces were ae. The capacior wih he wors wihsaning volage eermines he equivalen capacior rae volage. I is in his capacior he impac woul occur. ERS µf 50V

23 Series connece capaciors E U ERS + U Q U + E Q ERS Q Q + Q Q Q ERS + Parallel coupling formula for resisors is comparable o series coupling capaciors formula! In a capaciive volage ivier he volages are ivie inversely wih he capacior capaciances. The smalles capacior will have he highes volage will i wihsan i?

24 Example. Series connece capaciors (Ex. 9.4) Two capaciors are connece in series. alculae he equivalen capaciance an specify how he volage is ivie beween he capaciors. E 0 V 6 µf µf ERS +

25 Example. Series connece capaciors (Ex. 9.4) Two capaciors are connece in series. alculae he equivalen capaciance an specify how he volage is ivie beween he capaciors. E 0 V 6 µf µf ERS + No curren/charge can pass hrough a capacior. Two series-connece capaciors mus herefore always have he same charge! Q Q.

26 Example. Series connece capaciors (Ex. 9.4) Two capaciors are connece in series. alculae he equivalen capaciance an specify how he volage is ivie beween he capaciors. E 0 V 6 µf µf Q U ERS Q 6 4 µ F Q Q ,66 V Q ERS + ERS No curren/charge can pass hrough a capacior. Two series-connece capaciors mus herefore always have he same charge! Q Q. E µ U U E U U 0 6,66 3,33 V

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28 Energy in capacior E U W E u u u u p W u u u i p E u u u i q q u Q U Insananeous power: Energy: Sore energy in he elecrical fiel: Remember he formula, bu is allowe o skip he erivaion

29 Energy in capacior W E p( ) u ( ) i( ) W E E

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31 amera Flash (Ex. 9.) Baery wih Volage converer Press W U Q U Q I W P Elecric energy in capacior W? apacior charge Q? The lighning curren (mean value) I? Power uring flash ischarge P? How long o wai for nex flash Laa? U Q I W 6 U J, Ws Q U Q 0, I 00 A / 000 W 5 P 0 kw / 000 U Laa Laa Laa 3 I Laa 00 0,, As 0 s Noways LED Flash?

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33 (Ex. 0.9) Neon lamp Blink-circui wih Neon-lamp a exercise

34 Simulae Neon lamp Tryck på ES, annars ar simuleringen alrig slu

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