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Lab. 1 회로의 기초 및 계측장비 사용법

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이 실험의 목표

기초 Analogy 회로의 이해

Analogy 회로 실험을 위한 기초 실험장비 습득 Multimeter를 이용한 Voltage, Current, Resistor 측정법

Color Code에 의한 저항값 읽는 법

Diode의 사용 방법과 기호 이해

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기초 회로 개념

DC 회로에 대한 물리적 model

pump = voltage source

water = flow of current

ocean = ground

pipe = wire

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기초 회로 개념

저항에 대한 물리적 model

pebbles in pipe = resistance to flow of current

Low Resistance High Resistance

Small drop in pressure.

Large current flow through pipe

Large drop in pressure.

Small current flow through pipe

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기초 회로 개념

Symbols

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기초 회로 개념

Circuit Symbols

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기초 회로 개념

Open-Circuit and Short-Circuit Troubles An open circuit has zero current flow.

A short circuit has excessive current flow (As R approaches 0, Iapproaches ).

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기초 회로 개념

Physics와 Electronics의 비교

ELECTRONICS

PHYSICS

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기초 회로 개념

Ohm의 법칙 (V=IR) The effect of changing voltage on current, if resistance is held

constant.

The effect of changing resistance on current, if voltage is held constant.

Dept. of Information and Communication Eng.

기초 회로 개념

Electricity starts with electrons

Every atom contains one or more electrons An atom consists of a nucleus

of protons and neutronssurrounded by a group of orbiting electrons.

Electrons are negative, protons are positive.

In its normal state, each atom has an equal number of electrons and protons.

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기초 회로 개념

Elements with large number of free electrons in their outer rings make good conductors

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기초 회로 개념

+++- -

-

+++- -

-

+++- -

-

+++- -

-(Pressure)

How does electricity flow?What causes electrons to move from atom to atom?

Voltage Pushes the electrons Voltage Pushes the electrons Voltage Pushes the electrons Voltage Pushes the electrons

Voltage

(Electromotive Force)

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기초 회로 개념

How does electricity flow?What causes electrons to move from atom to atom?

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+++-

-

+++-

-

+++-

-

+++-

-

Voltage(Pressure)

(Electromotive Force)

--

- - -- -

- - --

-- - -

--

Voltage Pushes the electrons

Dept. of Information and Communication Eng.

기초 회로 개념

How does electricity flow?What causes electrons to move from atom to atom?

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+++-

-

+++-

-

+++-

-

+++-

-

Voltage(Pressure)

(Electromotive Force)

--

- - -- -

- - --

-- - -

--

The flow of the electrons is referred to as Current

Electron Flow is measured in Amps

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Breadboard의 사용법

Divider

Connected(horizontally)

Connected(horizontally)

Connected(vertically)

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Breadboard의 사용법

Behind the Breadboard Scene

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Breadboard의 사용법

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Note: Banana connectors are not connected internally to the holes in the board.Check continuity of power rails at top and bottom.

Banana connectors

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Breadboard의 사용법

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Multimeter 사용법

Digital multimeter Select the Function: Voltage (DC or AC), Current, Resistance Measurements

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Multimeter 사용법

Switched Type Autoranging Type

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Multimeter 사용법

Multimeter as a Voltmeter To use a multimeter as a voltmeter it is connected in parallel

between the two points where the measurement is to be made

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Multimeter 사용법

Multimeter as a Ammeter To measure current you need to power off the circuit, you need

to break the circuit so that the ammeter can be connected in series

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Multimeter 사용법

Multimeter as a Ohmmeter Component has to be removed from circuit Start at lowest Ohm setting

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Multimeter 사용법

Test circuit:

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DC Power Supply

All electronic circuits need a DC power source to work

The power supply converts the AC into DC and provides one or more DC output voltages.

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저항 읽는 법

Types of Resistors Wire-wound resistors Carbon-composition resistors Surface-mount resistors (chip resistors) Thermistors

Wire-wound

Carbon-composition

Surface-mountThermistors

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저항 읽는 법

Resistor color code Resistors are small, so their R value in ohms is marked using a

color-coding system Colors represent numerical values Coding is standardized by the Electronic Industries Alliance (EIA)

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저항 읽는 법

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Examples

Yellow = 4

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저항 읽는 법

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Five-Band Color Code Precision resistors often use a five-band code to obtain more

accurate R values The first three stripes indicate the first 3 digits in the R value The fourth stripe is the multiplier The tolerance is given by the fifth stripe

Brown = 1%Red = 2%Green = 0.5%Blue = 0.25%Violet = 0.1%

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저항 읽는 법

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Alphanumeric Labeling Two or three digits, and one of the letters R, K, or M

are used to identify a resistance value. The letter is used to indicate the multiplier, and its

position is used to indicate decimal point position.

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Resistor Troubles

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All experienced technicians have seen a burnt resistor.

This is usually caused by a short somewhere else in the circuit which causes a high current to flow in the resistor.

When a resistor’s power rating is exceeded, it can burn open or drift way out of tolerance.

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Diode의 특성

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PN-junction Diode applications Rectifiers Switching diodes Zener diodes Varactor diodes (Varactor = Variable reactance)

Photodiodes

Solar Cells

Light Emitting Diodes

Lasers Diodes

I

Schematic Device

Circuit Symbol

P NID

+ VD –

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Diode의 특성

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Diode의 특성

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(PN- junction I-V Characteristics)

1D

B

qVk T

D oI I e

DI

DV

Diode Equation:

:oI Reverse Saturation current

:Bk Tq

Thermal Voltage (0.0259)

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ID

+VD

–

VD ID

Diode의 특성

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Example: Analyze Diode in a circuit

KVL:Since

at room temperature, we have

9 [V] 1000 DI V

12 0.0259 [V]1 10 1D D

B

qV Vk T

D oI I I e e-æ ö æ ö÷ ÷ç ç÷ ÷ç ç= = - -÷ ÷ç ç÷ ÷ç ç ÷÷ çç è øè ø

9 0.0259 [V]9 [V] 10 1DV

De V

(where )1[pA]oI