TOEFL in ELECTRONICS CIRCUIT

TOEFL in ELECTRONICS CIRCUIT

by : Pangestu Mukti Wibowo

GENERAL DIRECTIONS

1.      This section of the test is designed to measure your ability to recognize language that is appropriate in standard written English. There are two parts to this section with special direction for each

Part one : Reading comprehension 

Part two : Structure

Before you begin each part, carefully read the directions.

2.      Put all of your answer on the answer sheet.

3.      Carefully and completely choose your answer for each question. If you change your mind about an answer after you marked it on your answer sheet, completely erase your old answer and then mark your new answer.

4.      Try to answer every problem even if you are not sure of the answer. Your score on the test will depend on the number of correct answers you have given.

 

Part One
Electronics circuit

By: Pangestu Mukti Wibowo

ELECTRONICS CIRCUIT

An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. To be referred to as electronic, rather than electrical, generally at least one active component must be present. The combination of components and wires allows various simple and complex operations to be performed: signals can be amplified, computations can be performed, and data can be moved from one place to another.

Circuits can be constructed of discrete components connected by individual pieces of wire, but today it is much more common to create interconnections by photolithographic techniques on a laminated substrate (a printed circuit board or PCB) and solder the components to these interconnections to create a finished circuit. In an integrated circuit or IC, the components and interconnections are formed on the same substrate, typically a semiconductor such as silicon or (less commonly) gallium arsenide. An electronic circuit can usually be categorized as an analog circuit, a digital circuit, or a mixed-signal circuit (a combination of analog circuits and digital circuits). Breadboards, perfboards, and stripboards are common for testing new designs. They allow the designer to make quick changes to the circuit during development.

1.      Analog circuit

Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented. Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits. In a series circuit, the same current passes through a series of components. A string of Christmas lights is a good example of a series circuit: if one goes out, they all do. In a parallel circuit, all the components are connected to the same voltage, and the current divides between the various components according to their resistance.

A simple schematic showing wires, a resistor, and a battery the basic components of analog circuits are wires, resistors, capacitors, inductors, diodes, and transistors. (In 2012 it was demonstrated that memoristors can be added to the list of available components.) Analog circuits are very commonly represented in schematic diagrams, in which wires are shown as lines, and each component has a unique symbol. Analog circuit analysis employs Kirchhoff’s circuit laws: all the currents at a node (a place where wires meet), and the voltage around a closed loop of wires is 0. Wires are usually treated as ideal zero-voltage interconnections; any resistance or reactance is captured by explicitly adding a parasitic element, such as a discrete resistor or inductor. Active components such as transistors are often treated as controlled current or voltage sources: for example, a field-effect transistor can be modeled as a current source from the source to the drain, with the current controlled by the gate-source voltage.

When the circuit size is comparable to a wavelength of the relevant signal frequency, a more sophisticated approach must be used. Wires are treated as transmission lines, with (hopefully) constant characteristic impedance, and the impedances at the start and end determine transmitted and reflected waves on the line. Such considerations typically become important for circuit boards at frequencies above a GHz; integrated circuits are smaller and can be treated as lumped elements for frequencies less than 10GHz or so.

An alternative model is to take independent power sources and induction as basic electronic units; this allows modeling frequency dependent negative resistors, gyrators, negative impedance converters, and dependent sources as secondary electronic components.

2.      Digital circuit

In digital electronic circuits, electric signals take on discrete values, to represent logical and numeric values. These values represent the information that is being processed. In the vast majority of cases, binary encoding is used: one voltage (typically the more positive value) represents a binary ‘1’ and another voltage (usually a value near the ground potential, 0 V) represents a binary ‘0’. Digital circuits make extensive use of transistors, interconnected to create logic gates that provide the functions of Boolean logic: AND, NAND, OR, NOR, XOR and all possible combinations thereof. Transistors interconnected so as to provide positive feedback are used as latches and flip flops, circuits that have two or more metastable states, and remain in one of these states until changed by an external input. Digital circuits therefore can provide both logic and memory, enabling them to perform arbitrary computational functions. (Memory based on flip-flops is known as static random-access memory (SRAM). Memory based on the storage of charge in a capacitor, dynamic random-access memory (DRAM) is also widely used.)

Digital circuitry is used to create general purpose computing chips, such as microprocessors, and custom-designed logic circuits, known as application specific integrated circuit (ASICs). Field-programmable gate arrays (FPGAs), chips with logic circuitry whose configuration can be modified after fabrication, are also widely used in prototyping and development.

3.      Mixed signal circuit

Mixed-signal or hybrid circuits contain elements of both analog and digital circuits. Examples include comparators, timers, phase-locked loops, analog-to-digital converters, and digital-to-analog converters. Most modern radio and communications circuitry uses mixed signal circuits. For example, in a receiver, analog circuitry is used to amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values, after which further signal processing can be performed in the digital domain.

Difficult Word	Pronoun Spelling	Meaning
Correspond	ˌkär-,ˌkôrəˈspänd	Sesuai
Dependent	diˈpendənt	Tergantung
Schematic	skē-,skəˈmatik	Skema
Further	ˈfərT͟Hər	Lebih lanjut
Majority	-ˈjär-,məˈjôrətē	Mayoritas

SIRKUIT ELEKTRONIK

Sirkuit elektronik terdiri dari komponen elektronik individu, seperti resistor, transistor, kapasitor, induktor dan dioda, yang dihubungkan oleh kabel konduktif atau jejak yang dapat mengalirkan arus listrik. Untuk disebut elektronik, bukan listrik, umumnya setidaknya satu komponen aktif harus ada. Kombinasi komponen dan kabel memungkinkan berbagai operasi sederhana dan kompleks yang harus dilakukan: sinyal dapat diperkuat, perhitungan dapat dilakukan, dan data dapat dipindahkan dari satu tempat ke tempat lain.

Sirkuit dapat dibangun dari komponen-komponen terpisah yang dihubungkan oleh potongan-potongan kawat individual, tetapi saat ini jauh lebih umum untuk membuat interkoneksi dengan teknik-teknik photolithographic pada substrat yang dilaminasi (papan sirkuit cetak atau PCB) dan menyolder komponen-komponen ke interkoneksi-interkoneksi ini untuk membuat suatu hasil akhir. sirkuit. Dalam sirkuit terpadu atau IC, komponen dan interkoneksi dibentuk pada substrat yang sama, biasanya semikonduktor seperti silikon atau (lebih jarang) gallium arsenide. Sirkuit elektronik biasanya dapat dikategorikan sebagai rangkaian analog, rangkaian digital, atau sirkuit sinyal campuran (kombinasi sirkuit analog dan sirkuit digital). Breadboards, perfboards, dan stripboard biasa digunakan untuk menguji desain baru. Mereka membiarkan perancang membuat perubahan cepat pada sirkuit selama pengembangan.

·         Sirkuit analog

Rangkaian elektronik analog adalah rangkaian di mana arus atau tegangan dapat bervariasi secara kontinu dengan waktu untuk menyesuaikan dengan informasi yang diwakili. Sirkuit analog dibangun dari dua blok bangunan mendasar: rangkaian seri dan paralel.

Dalam rangkaian seri, arus yang sama melewati serangkaian komponen. Serangkaian lampu Natal adalah contoh yang baik dari rangkaian seri: jika seseorang keluar, mereka semua melakukannya. Dalam rangkaian paralel, semua komponen terhubung ke tegangan yang sama, dan arus membagi antara berbagai komponen sesuai dengan ketahanannya.

Skema sederhana yang menunjukkan kabel, resistor, dan baterai Komponen dasar rangkaian analog adalah kabel, resistor, kapasitor, induktor, dioda, dan transistor. (Pada tahun 2012 ditunjukkan bahwa memristor dapat ditambahkan ke dalam daftar komponen yang tersedia.) Rangkaian analog sangat umum ditunjukkan dalam diagram skematis, di mana kabel diperlihatkan sebagai garis, dan setiap komponen memiliki simbol yang unik. Analisis rangkaian analog menggunakan hukum sirkuit Kirchhoff: semua arus di simpul (tempat di mana kabel bertemu), dan voltase di sekitar lingkaran tertutup kawat adalah 0. Kabel biasanya diperlakukan sebagai interkoneksi tegangan nol ideal; setiap resistansi atau reaktansi ditangkap dengan secara eksplisit menambahkan elemen parasit, seperti resistor atau induktor diskrit. Komponen aktif seperti transistor sering diperlakukan sebagai arus terkontrol atau sumber tegangan: misalnya, transistor efek lapangan dapat dimodelkan sebagai sumber arus dari sumber ke saluran pembuangan, dengan arus yang dikendalikan oleh tegangan sumber gerbang.

Ketika ukuran sirkuit sebanding dengan panjang gelombang frekuensi sinyal yang relevan, pendekatan yang lebih canggih harus digunakan. Kabel diperlakukan sebagai jalur transmisi, dengan (mudah-mudahan) impedansi karakteristik konstan, dan impedansi pada awal dan akhir menentukan gelombang yang ditransmisikan dan dipantulkan pada garis. Pertimbangan seperti itu biasanya menjadi penting bagi papan sirkuit pada frekuensi di atas GHz; sirkuit terintegrasi lebih kecil dan dapat diperlakukan sebagai elemen terpusat untuk frekuensi kurang dari 10GHz atau lebih.

Model alternatif adalah mengambil sumber daya dan induksi independen sebagai unit elektronik dasar; ini memungkinkan pemodelan resistor negatif bergantung frekuensi, gyrators, konverter impedansi negatif, dan sumber-sumber bergantung sebagai komponen elektronik sekunder.

·         Sirkuit digital

Dalam sirkuit elektronik digital, sinyal listrik mengambil nilai-nilai diskrit, untuk mewakili nilai-nilai logis dan numerik. [3] Nilai-nilai ini mewakili informasi yang sedang diproses. Dalam sebagian besar kasus, pengkodean biner digunakan: satu tegangan (biasanya nilai yang lebih positif) mewakili biner ‘1’ dan tegangan lain (biasanya nilai dekat potensial tanah, 0 V) ​​menunjukkan biner ‘0’. Sirkuit digital memanfaatkan transistor secara ekstensif, saling terhubung untuk membuat gerbang logika yang menyediakan fungsi logika Boolean: AND, NAND, OR, NOR, XOR dan semua kombinasi yang mungkin darinya. Transistor yang saling berhubungan sehingga memberikan umpan balik positif digunakan sebagai kait dan sandal jepit, sirkuit yang memiliki dua atau lebih status metastabil, dan tetap berada di salah satu dari status ini sampai diubah oleh input eksternal. Oleh karena itu sirkuit digital dapat menyediakan logika dan memori, memungkinkan mereka untuk melakukan fungsi komputasi yang sewenang-wenang. (Memori berdasarkan flip-flop dikenal sebagai static random-access memory (SRAM). Memori berdasarkan penyimpanan muatan dalam kapasitor, memori akses acak dinamis (DRAM) juga banyak digunakan.)

·         Sirkuit campuran

Sirkuit campuran-sinyal atau hibrida mengandung unsur-unsur sirkuit analog dan digital. Contohnya meliputi pembanding, penghitung waktu, loop fase terkunci, konverter analog-ke-digital, dan konverter digital-ke-analog. Sebagian besar sirkuit radio dan komunikasi modern menggunakan sirkuit sinyal campuran. Sebagai contoh, dalam penerima, rangkaian analog digunakan untuk memperkuat dan mengubah sinyal frekuensi sehingga mereka mencapai keadaan yang sesuai untuk diubah menjadi nilai digital, setelah itu pemrosesan sinyal lebih lanjut dapat dilakukan di domain digital.

Part One

Reading Comprehension

Direction: In this Section you will read several passages. Each one is followed by a number of questions about it. You are to choose the one best answer : (A), (B), (C), or (D) to each question. Then on your answer sheet, find the number of the question and fill in the space that corresponds to the letter of the answer you have chosen. This section in designed to measure your ability to read and understand passages. Answer all question about the information ion a passage on the basis what is implied or stated in the passage.

Example:

Read the following passage:

Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented. Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits. In a series circuit, the same current passes through a series of components. A string of Christmas lights is a good example of a series circuit: if one goes out, they all do. In a parallel circuit, all the components are connected to the same voltage, and the current divides between the various components according to their resistance.

Question 1:

What is constructed from two fundamental building blocks?

(A) They are non-private

(B)  Series and parallel circuits

(C)  They are sate governed

(D) They are dependent

    

According to the passage line 1, Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits. Therefore, you should choose (B)

Now let’s Begin to do the reading test.

1.      Electronic circuit consists of components such as?

A.    Tire

B.     Resistor

C.     Soap

D.    Flower

Answer B, in paragraph 1 line 1 until 2 because electronic circuit  is composed of individual electronic components  such as resistor, transistor, capasitors, inductors, and diodes

2.      An electronic circuit can usually be categorized as?

A.    Breadboards

B.     Stripboars  

C.     Perfboards

D.    Analog circuit

Answer D, in paragraph 2 line 7 until 9 because An electronic circuit can usually be categorized as an analog circuit, a digital circuit, or a mixed-signal circuit (a combination of analog circuits and digital circuits).

3.      Analog circuit is constructed from two fundamental building blocks that are?

A.    Series and parallel circuit

B.     Resistor

C.     Broadband  

D.    Baseband

Answer A, in paragraph 3 line 2 until 4 because Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits

4.      Analog circuit analysis employs?

A.    Gause  

B.     Newton  

C.     Kirchhoff’s

D.    Inductor

Answer C, in paragraph 4 line 6 until 7 because Analog circuit analysis employs Kirchhoff’s circuit laws: all the currents at a node (a place where wires meet), and the voltage around a closed loop of wires is 0.

5.      Integrated circuits are smaller and can be treated as lumped elements for frequencies less than?

A.    1000 sekon

B.     60 minute

C.     15 hour

D.    10 Ghz or so

Answer D, in paragraph 5 line 6 until 7 because integrated circuits are smaller and can be treated as lumped elements for frequencies less than 10GHz or so.

6.      What are analog electronic circuits?

A.    An electronic circuit is composed of individual electronic components

B.     Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented

C.    Circuits can be constructed of discrete components connected by individual pieces of wire, but today it is much more common to create interconnections by photolithographic techniques on a laminated substrate 

D.    The design process for digital circuits is fundamentally different from the process for analog circuits. Each logic gate regenerates the binary signal

Answer B,  in paragraph 3 line 1 because Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented

7.    Analog circuit is used for?

A.    As a consequence, extremely complex digital circuits

B.     In prototyping and development

C.     Amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values

D.    As latches and flip flops

Answer C, in paragraph 9 line 1 because analog circuitry is used to amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values

8.      What is alternative model?

A.    The take independent power sources and induction as basic electronic units

B.     These values represent the information that is being processed

C.     Those in which current or voltage may vary continuously with time to correspond to the information being represented

D.   The combination of components and wires allows various simple and complex operations to be performed

Answer A, in paragraph 6 line 1 because alternative model is used to take independent power sources and induction as basic electronic units

9.      What are custom designed logic circuits?

A.    Most modern radio and communications circuitry uses mixed signal circuits  

B.     Known as application specific integrated circuit (ASICs)

C.     The take independent power sources and induction as basic electronic units

D.    An electronic circuit is composed of individual electronic components

Answer C, in paragraph 10 line 2 because custom designed logic circuits, known as application specific integrated circuit (ASICs)

10.  When should more sophiticated approaches be used?

A.    The circuit size is comparable to a wavelength of the relevant signal frequency

B.     Start and end determine transmitted and reflected waves on the line

C.     The components and interconnections are formed on the same substrate, typically a semiconductor such as silicon or (less commonly) gallium arsenide

D.   To be referred to as electronic, rather than electrical, generally at least one active component must be present

Answer A, in paragraph 5 line 1 because the circuit size is comparable to a wavelength of the relevant signal frequency a more sophisticated approach must be used

GENERAL DIRECTIONS

5.      This section of the test is designed to measure your ability to recognize language that is appropriate in standard written English. There are two parts to this section with special direction for each

Part one : Reading comprehension 

Part two : Structure

Before you begin each part, carefully read the directions.

6.      Put all of your answer on the answer sheet.

7.      Carefully and completely choose your answer for each question. If you change your mind about an answer after you marked it on your answer sheet, completely erase your old answer and then mark your new answer.

8.      Try to answer every problem even if you are not sure of the answer. Your score on the test will depend on the number of correct answers you have given.

 

Part Two
Alessandro Volta Biography

By: Arief Wahyuaji

Alessandro Volta Biography

Volta, or to give him his full name Alessandro Giuseppe Antonio Anastasio Volta was born on 18th February 1745 in Como. This is a small town in the duchy of Milan and on the shores of Lake Como in Northern Italy. His father had originally been a member of a Jesuit order, but at the age of 41 he decided to marry a lady who was 22 years younger than himself.

The family was well connected and appeared to be happy even if rather poor. On his father's side he had three uncles. One was a Dominican, one a canon, and the other was an archdeacon. On his mother's side though, the family had more of a leaning toward the law.

The young Alessandro Volta started his education at the school of rhetoric in Como. However shortly after he started there, when Volta was only seven years old his father died. It was said that his father was more accomplished at spending money than making it. In fact Volta said in later years that when his father died he left a small dwelling worth 14 000 lira, and a debt of 17 000 lira.

Then, five years after his father's death his uncles took charge of his education. Initially they sent him to a Jesuit college, but later they changed the course of his education, moving him elsewhere. It was during this period that a friend named Giulio Cesare Gattoni provided books and guidance to help his study of electricity. His uncles had decided it would be best for him to study the law but his interest in the natural sciences was so keen that they allowed him to follow his interests and take up career in physics and chemistry.

Volta became very absorbed in his studies and from the age of about 20 Volta studied science more formally. In particular he took an interest in electricity. He also boldly corresponded with many of the leading scientists of the day. In 1763 when he was just 18 years old, he corresponded with the eminent French physicist and electrical experimenter, the Abbe Antoine Nollet in Paris. Later he wrote to Giovanni Battista Beccaria, professor of physics at the University of Turin and the foremost Italian experimenter in electrostatics. In many of these letters he showed a considerable degree of insight into the phenomenon of electricity that was just beginning to be understood.

Alessandro Volta Biography

Volta, atau memberinya nama lengkapnya Alessandro Giuseppe Antonio Anastasio Volta lahir pada 18 Februari 1745 di Como. Ini adalah kota kecil di kadipaten Milan dan di tepi Danau Como di Italia Utara. Ayahnya semula menjadi anggota ordo Yesuit, tetapi pada usia 41 tahun dia memutuskan untuk menikahi seorang wanita yang 22 tahun lebih muda dari dirinya.

Keluarga itu terhubung dengan baik dan tampak bahagia meskipun agak miskin. Di sisi ayahnya ia memiliki tiga paman. Yang satu adalah seorang Dominikan, yang satu kanon, dan yang lainnya adalah seorang archdeacon. Namun, di sisi ibunya, keluarga itu lebih condong ke arah hukum.

Anak muda Alessandro Volta memulai pendidikannya di sekolah retorika di Como. Namun tak lama setelah ia mulai di sana, ketika Volta baru berusia tujuh tahun ayahnya meninggal. Dikatakan bahwa ayahnya lebih berhasil mengeluarkan uang daripada membuatnya. Faktanya, Volta mengatakan di tahun-tahun kemudian bahwa ketika ayahnya meninggal, dia meninggalkan tempat tinggal kecil seharga 14.000 lira, dan utang 17.000 lira.

Kemudian, lima tahun setelah ayahnya meninggal, paman-pamannya mengambil alih pendidikannya. Awalnya mereka mengirimnya ke perguruan tinggi Yesuit, tetapi kemudian mereka mengubah arah pendidikannya, memindahkannya ke tempat lain. Selama periode inilah seorang teman bernama Giulio Cesare Gattoni memberikan buku dan bimbingan untuk membantu studinya tentang listrik. Paman-pamannya memutuskan akan lebih baik baginya untuk mempelajari hukum tetapi minatnya pada ilmu alam begitu kuat sehingga mereka mengizinkannya untuk mengikuti minatnya dan berkarir di bidang fisika dan kimia.

Volta menjadi sangat terserap dalam studinya dan dari usia sekitar 20 Volta mempelajari sains secara lebih formal. Khususnya dia tertarik pada listrik. Dia juga dengan berani berkorespondensi dengan banyak ilmuwan terkemuka hari itu. Pada 1763 ketika ia baru berusia 18 tahun, ia berkorespondensi dengan fisikawan Prancis terkemuka dan eksperimen listrik, Abbe Antoine Nollet di Paris. Belakangan dia menulis kepada Giovanni Battista Beccaria, profesor fisika di Universitas Turin dan eksperimen terkemuka di elektrostatika di Italia. Dalam banyak surat-surat ini dia menunjukkan tingkat pemahaman yang cukup besar tentang fenomena listrik yang baru mulai dipahami.

Part Two

Structure and Written Expression

Direction : In this section you will see four underlined words or phrases (A), (B), (C), (D) in each sentence. Identify the one underlined word or phrase that must be changed in order for the sentences to be correct. Then on your answer sheet, find the number of the section and fill the space that corresponds to the letter of the answer you have chosen.

Look at the following example:

him also boldly corresponded with many of the leading scientists of the day.

 A                                  B                                          C                           D

Choose (A) it should be “He” because it is functioned as subject

Now let’s Begin to the structure and written test

1.      Volta, or to give him his full name Alessandro Giuseppe Antonio Anastasio Volta

                                   A                                       

was born on 18th February 1745 on Como.

  B                C                                               D

Choose (D) it should be “in” because the year should be begun by preposition “in”.

 

2.      This are a small town in the duchy of Milan and on the shores of Lake Como in

         A                        B                                       C                                          D

 Northern Italy.  

Choose (A) it should be “is” because the exhibition there refers to a singular thing

3.      The family was well connected and appear to be happy even if rather poor.

                    A                          B                             C                       D

Choose (B) it should be “connected and appeared” because it’s passive voice.

4.      The young Alessandro Volta started him education at the school of rhetoric in

                                                   A        B                                                  C     D

Como.

Choose (B) it should “his” because the function of in has a posesive pronount of education.

5.      The young Alessandro Volta start his education at the school of rhetoric in Como.

                                                A                          B       C                            D

Choose (A) it should be “started” because it happened in the pass condition so the verb must be verb 3.

6.      However shortly after he started there, when Volta is only seven years old his

                                     A     B                  C             D

father died.

Choose (D) it should be “was” because it happened in past time.

7.      It was said that his father was more accomplished at spended money than making

                                           A                    B                     C                              D

it.

 Choose (C) it should be “spending” because it is paralelism of using ing-form spending and making.

8.      Initially they sent him to a Jesuit college, but later they changing the course of his

                              A                                                              B                            C

education, and than moving him elsewhere.

                     D

Choose (B) it should be “change” because it is happened in the present condition.

9.      It was during this period that a friend named Giulio Cesare Gattoni provided

     A                                                       B                                                C

books and guidance to help his studied of electricity.

                                                       D

Choose (D) it should be “study” because it is functioned as object.

10.  him also boldly corresponded with many of the leading scientists of the day.

 A                            B                                          C                                  D

Choose (A) it should be “He” because it is functioned as subject.