Bai 13 Application Circuit

7/30/2019 Bai 13 Application Circuit

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1. Structure of the Lesson

Intro

Class

Class end

Study

Assessment

Review

1. intro Overview of the lesson2. Learning objective present learning objective of the lesson3. Table of Content structure of the topics and subtopics in thelesson

4. Lecture (75-90 minutes) present the lecture in detailed topics that covers all the

learning objectives of the lesson.- each topics should be divided into subtopics

(5-15 min in length is recommended)- if a subtopic goes over 15 minutes divide the subtopic into

series of subtopics.


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CourseCircuit theory and

Laboratory

Lesson # Lesson 13

Title Application Circuits

SME Dr. Nguyen Vu Thang


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Learning Objectives Table of Content

At the end of this lecture, the stud

ents should be able to:

Understand the basic steps of

designing circuits

Know how to write requirement

Able to design circuit schematic,

choose devices

Able to draw circuit layout Able to make PCB circuits

PCB Design Flow

Software Introduction

Battery charger circuit

Thief detector

Blinking LED

DC Motor Driver

Audio Amplifier


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PCB Design Flow


Battery charger circuit Thief detector

Blinking LED

DC Motor Driver Audio Amplifier

Content


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PCB Design Flow

Description and

Requirements

Schematic

design

Layout

Device welding

PCB

TestingReady

to use


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PCB Design Flow

The description will describe:

What is the application

How and where does it work, etc

Requirement point out:Basic technology aspect of the application, such as,electronic parameters: power source, current, voltage.Etc.

The designer then will design circuit schematic.Engineers chose components, circuit topologies, andthen run simulation


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PCB Design Flow

Engineers

Make the circuit layout based on the schematic

Make or order printed circuit board

Weld devices to circuit board

Test the circuit


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PCB Design Flow


Baterry chager circuit Thief detector

Blinking LED


Content


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A lot of software that can help engineer:

Schematic design

Simulation

Layout design.

Software:

One function: for example, schematic design

Multiple functions: for example schematic design

and simulation

Special software: simulate the specific functions


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Software Schematic design Layout design Simulation

Orcad Eagle Altium Proteus Multisim Circuitmaker Hspice

In the table, a list of common circuit software

with their functions are presented.


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PCB Design Flow



Blinking LED


Content


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Description:

There are many devices worked on battery

energy source.

Make a simple battery charger for 12V battery

for motorbike.


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Requirements:

Use wall 220 VAC source

Use to charge 12VDC battery

Charge current: 1.2 A

Maximum current: 2A


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Design:The charger need power supply => chose electric powerAC source.

To charge 12V battery => charger needs a higher voltage

output than the battery => choose 15V.To lower the electric AC voltage => use transformer.

Want 15VDC => need 12VAC output from thetransformer.

After converting to DC, the voltage is unstable => use alarge capacitor and/or a regulator to give stable voltage.

To convert AC to DC voltage we use diode bridge.

The charging current is commonly about 1A.


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Schematic:

220 VAC

15,7 VDC

12 VAC

D1 D2

D3D4


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Operation:

- First half cycle: D2, D4 On; D1, D3 Off

- Second half cycle: D1, D3 On; D2, D4 Off- Output voltage ~= 12x 1.41-2X0.6 ~= 15.7 VDC

(0.6 is voltage drop on diode).

- Charging current ~ = (15.7-12)/3 ~= 1.2 A


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Components list:

- Transformer 220VAC => 12VAC

- 4x Diode 2A- Resistor 3 Ohm


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PCB Design Flow



Blinking LED


Content


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Thief detector

Description:

To detect unwanted objects/people entering

your place through windows or doors.


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Thief detector

Requirement:

Simple and cheap

Not visible by objects/peopleDetect objects in 1-2 meters


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Thief detector

Design:

Two modules:

The 1st module: transmit invisible light => use IR

LED

The 2nd module receive invisible light from 1st

module. It gives alarm when the light is blocked =>

use LDR=> 2 recommended design

2nd1st

Window/gate


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Thief detector

Transmitter design:

The transmitter is composed of a DC source, an IR

LED and a resistor.

IR LED:Forward voltage: 1.2V

Forward current about 15 40 mA.

We use 5V sourceResistor: (5V-1.2V)/(20mA)~= 220 Ohm

Adjust resistor change operation range


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Thief detector

Receiver design:

Receiving the light from IR LED => LDR change its

resistance.

LDR resistance change => condition of the circuit willchange => give out alarm

Signal change is small => amplify the signal.

=> 2 options: use BJT (in schematic 1) or an opamp (inschematic 2)


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Thief detector

Design 1:

LDR

Dark resistance: 100K - M

Light resistance: few hundred .

Resistance depends on how much light it receives.

VR1 value depends on:

Operation range of device

Value of resistor for IR LED.


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Thief detector

Receiver design:

1K

5V

5V

IR LED220

C1815

LED

LDR

VR1


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Thief detector

Components List 1:

C1815 NPN transistor

LDR LED

1K, 220 Ohm resistor

1K Varistor.

5V supply


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Thief detector

Operation:

LDR receive light from a IR LED => resistance ofLDR decrease => Ib increases => Ic increase =>

LED is on.IR light is corrupted by object => LDR has highresistance => Ib decrease => Ic decrease => LED

off.Varistor use to adjust the Ib current also adjustthe range of operation.


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Thief detector

Schematic 2:

As stated in schematic 1, in schematic 2, we can

use the opamp to amplify signal


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Thief detector

Schematic 2:

5V

5V

5V

10k 10k

R3

R2

LDR+

-

R1

100k

LED

LM358

R4

330


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Thief detector

Components List 2:

LM358

R1 = 10k ; R2 = 10k; R3 = 100k; R4 = 330 Ohm LDR

LED

5VDC supply


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Thief detector

Operation 2:

- Lm358 amplifier the difference voltage between 2inputs.

-LDR catch IR light => LDR resistance decrease =>Vminus input < Vplus input => LED is on.

-IR light is interrupted => LDR resistance increase =>Vminus input > Vplus input => LED is off

-R3: can be replaced by a varistor to adjust not onlyrange but also sensitive of operation.


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PCB Design Flow



Thief detector

Blinking LED

DC Motor Driver

Audio Amplifier

Content


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Blinking LED

Description

There are so many application with blinking

LED: advertisement, warning signal vv

This example introduce a simple way to make a

blinking LED circuit.


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Blinking LED

Requirement

LED can blink with the frequency adjustable.

Range of frequency: smaller than 30 Hz then

humans eye can see LEDs blinking.

Duty circle from 0% to 100%.


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Blinking LED

Design

Use an opamp with 2 inputs:

One input have constant input voltage

One input have voltage changes. We can use a

structure of resistance and capacitor to make the

voltage change.

=> structure as shown in the figure


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Blinking LED

Schematic

LM358

-

+

R1

R2R3

C1+V

-V

Out

V1

V2


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Blinking LED

Component List

- Resistor R1=R2=R3 = 1.2M

- Non-pole capacitor C1 = 10uF (104)

- Dual supply source +V, -V

- LM358


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Blinking LED

Operation

R2, R3 voltage divider feed-back resistor.

V2 act as reference voltage.

R1, C1 delay maker. C1 charge and discharge create voltage in V1.

Output is square wave.

By changing R1,C1 => creating difference

frequency. By changing R2, R3 => creating difference duty

cycle


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Blinking LED

Use the opamp LM358

Divider factor k = R3/(R2+R3)

Period T = 2.R1.C1.ln[(1+k)/(1-k)]

For T 25Hz, choose:

R1 = 1.2M (Standard resistor value)

C2 = 10uF (Standard capacitor value for non-polar)

K = 1/2 then R3 = R2 = 1.2M

T= 26.337 Hz


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PCB Design Flow



Thief detector

Blinking LED

Audio Amplifier

Content


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Audio Amplifier

Description

Create a simple audio amplifier to play music.

Two schematic design of Audio Amplifier.


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Audio Amplifier

Requirement

Input: from micro around 24 mV

Power source: 10-15V

Speaker: use common one: 8-10 Ohm

Power: 5-30W


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Audio Amplifier

Schematic 1


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Audio Amplifier

Components list 1

- R1, R3: 27k Ohm

- R2: 100k Ohm

- R4: 15k Ohm

- R5: 330 Ohm

- R6: 22k Ohm

- R7: 1k Ohm

- R8: 470 Ohm

- R9, R10 : 1 Ohm

- PR1 : varistor 470 Ohm

- C1: 10uF- C2: 470uF

- C3: 220uF

- C4: 330uF

- C5: 2200uF

- C6: 2200uF

- Diode: 1n4148 x2

- Q1: BC109

- Q2: N3906

- Q3, Q4: TIP41, TIP42


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Audio Amplifier

Operation 1

- C1: Signal pass-in

- C6: power source decoupled capacitor

- R5, C3: source Low-pass filter for stage 2

- R3, C2: source Low-pass filter for stage 1- R1, R2: Q1 bias, mode A

- R4: Q1 load.

- Q1: input amplifier

- Q2: pre-power amplifier- Q3, Q4: push-pull power amplifier

- D1, D2: Q3, Q4 thermo stabilizer.


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Audio Amplifier

Operation 1

Q1 form the first stage of amplifier.

R1, R2, R4 bias Q1 work on A mode.

After the first stage, the current still is small =>need a extra amplifier stage.

Q2 work on A mode to form pre-power amplifier.

Q3 and Q4 form a pair of push pull amplifier toamplify the audio signal to the speaker.

D1 & D2 form a thermo stabilizer for Q3 & Q4.


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Audio Amplifier

Operation 1 Static mode

Q1, Q2 operate in A mode

Q3, Q4 operate in A or AB mode

PR1 use to adjust B terminal of Q3, Q4 has the

same voltage => C point = Vc5 = supply

voltage = 7.5V


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Audio Amplifier

Operation 1 positive half cycle input

B terminal of Q1 raise => IcQ1 raise => UR4

raise => Uc Q1 down => Ub Q2 down => Ic Q2

down => UA & UB down

UA down => Ic Q3 raise

UB down => Ic Q4 down

C point raise, charge C5


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Audio Amplifier

Operation 1 negative half cycle input

B terminal of Q1 down => IcQ1 down => UR4

down => Uc Q1 raise => Ub Q2 raise => Ic Q2

raise => UA & UB raise

UA raise => Ic Q3 down

UB raise => Ic Q4 raise

C point down, discharge C5


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Audio Amplifier

0

0

0

0

t

t

t

t

Input Signal

Q1

Output Signal

Q2

7.5V


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Audio AmplifierSchematic 2

+

-

+

-

+

-

Output

R1

R18

+

-

R2R3

C1

R5

R6R7R8

R9 R10

VR2

VR1 R11

R12

R13 R14

VR3

R15 R16

U2

15V

15V

15V

15V

15V

15V

15V

C2

C3

C4

C5

C6

Input

U3

U4

U1

R4


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The whole schematic 1 can be replaced by just 1LM386 IC.

Schematic 2 present a upgrade version of audioamplifier => can adjust bass and treble volume.

U1 form a low-pass filter to extract basscomponent.

U2 form a high-pass filter to extract treblecomponent.

U3 form a mixer. It mixes the bass & treblecomponents. The bass & treble components ratiocan be adjust by R3 and R4.

U4 is LM386 form a power amplifier.


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C1, C2, R1, R2, R3 ,R4 , R5 configure U1 as alow-pass filter.

C3, R6, R7, R8, R9, R10 configure U2 as a high-

pass filter.C4, C5 are coupled capacitor.

VR1, VR2, R11, R12, R13, R14 configure U3 as

a mixer.VR3, R18, R15, R16 configure U4 as a invertamplifier.


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Audio Amplifier

Components list 2

R4=R5=R9=R10=R13=R14=R15=R16 = 10k

C1=C2=C4=C5=C6 =10uF

R2=R6= 22k

R3=R7= 1k

R11=R18= 22k VR1 = VR2 = VR3 = 1k


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Audio Amplifier

Draw the circuit using one of the circuit software.

Run simulation to check the functions of the circuit.

Different conditions and inputs: source, input, conditions

Check the voltages, currents at different points.If the circuit do not work well, can based on the

simulation to find out the effect and change the design.


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Audio Amplifier

Layout

Layout software support many footprints for common

components.

If your components footprint does not exist in layout software

library, you have to create it.

After choosing right footprints for your component you do the

placement step. Try to arrange your component neatly and

logically.

After placement step, you do the routing step. Make sure, all

the wires are routed.

Create PCB making file and send to PCB service provider.


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Audio Amplifier

Layout


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Audio Amplifier

WeldingTake all the components in your design frommarket.

Prepare soldering iron, soldering wire, and otherssoldering toolsSolder all the component on the PCB.

Make sure all our components was soldered inright place and direction.

Use your multi-meter to check all the solderpoints.


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Audio Amplifier

Testing

Provide 15VDC for the circuit.

Use multi-meter to check the C-point. If it is

7.5VDC then provide the signal for Audio_in

input.

Use oscilloscope to check the output signal.

If everything goes right lets play the music.

Assessment Quiz 1


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Design a sound detector

Assessment Quiz 1


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R1

R2

R3 R4 R5

R6

C1

C2

2.2K 3.3K 220K 1.2K

270

470K

0.1uF

0.1uF

BC574

BC574

BC574

5V

RELAY

T1

T2

T3

R1 = 2.2K

R2 = 470K

R3 = 3.3K

R4 = 220KR5 = 1.2K

R6 = 270

C1 = C2 = 0.1uF

BC574

RelayMic

Assessment Quiz 1


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T1 act as first stage of amplifier

T2 act as second stage of amplifier

T3 act as a switch to drive relay

MIC can detect sound from animals and human. Small signal from MIC is amplified by 2 transistors

T1&T2.

After 2 stages of amplifier, the signal is used todrive Relay through T3.

Relay can use to control LEDs, Buzzers v..v

Assessment Quiz 1


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Design an IR detector

Assessment Quiz 1


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Design an IR detector

9V

Q1

BP109

Q2

BP238

D1

390

LED

R1

Q1: phototransistor

Q2: BP238 npn transistor

R1 = 390 Ohm

D1: LED

When Q1 received IR light,

resistance of Q1 decreases. The

current in the Base of Q2

increases then the current flows

through Q2. LED D1 turn on.

Assessment Quiz 3


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Design a high current 12V regulator

Assessment Quiz 3


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IC1

7812

230V

AC

12

T1

B1

C1

47000uF

C2 C3

470uF10u

F

V out

R1

0.1 Ohm

5W

R2

R3

0.1 Ohm

5W

0.1 Ohm

5W

0.1 Ohm

5W

R4

Q3

TIP2955

Q2

TIP2955

Q1

TIP2955

Assessment Quiz 3


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7812 has a stable output voltage of 12V. Seri of Q1,Q2,Q3 has high Ice are used to push the

output current higher.

List of component:

T1: 220VAC-24VAC transformer B1: Diode Bridge

R1=R2=R3=R4= 0.1 Ohm 5W

C1= 4700uF

C2=470uF

C3=10uF

IC1 : 7812

Q1,Q2,Q3: TIP2955

Assessment Quiz 4


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Design a thermo protector

Assessment Quiz 4


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Assessment Quiz 4


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LM35LM339

5V

GND

NC

COM

NO

RELAY

T1

BC574

VR1

5V

R1

10

kOhm

10

kOhm

5V

LM35 thermo sensor

LM339 op-amp

R1= 10k

VR1 = 10k

BC574

Relay

Assessment Quiz 4


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When the temperature changes, the output of

LM35 changes.

The signal of LM35 is compared to reference

which can be adjusted by VR1 through LM339

The output of op-amp LM339 feeds to T1

which acts as a switch to control relay.

Assessment Quiz 5


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Design a ramp signal generator

Assessment Quiz 5


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230V : 12V 1N4007 1N4007

1N4007

1N4007

1N4007

C1

2200uF

D1 D5

D3D4

D2 R3

1K

R4 100

C2

1000uF

10V

D7

10V stab

BC547

BC547

Q2

Q1 BC547

Q3

10V

D6

R1

10K

R2 1k

C3

2uF

R6

10k

1N4148

1N4148R5

470

13V5 unstable

100Hz ramp

signalA

Assessment Quiz 5


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R1 10 kohm 0.25W R2 1 kohm 0.25W

R3 1 kohm 0.25W R4 100 ohm 1W

R5 470 ohm trimmer R6 10 kohm 0.25W

C1 2200 uF 25V electrolytic C2 1000 uF 25V electrolytic

C3 2.2 uF 25V

D1-D5 1N4007 D6-D7 10V zener diode 1W

D8-D9 1N4148

Q1-Q3 BC547 TRANS

Transformer 230V primary and 12V 200 mA secondary

Assessment Quiz 5


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D1-D4 act as diode bridge

D5 protecting diode

R2,R1 bias Q1

D6, Q1 ,R3 create current source. Q2,Q3 and C3 are main parts of oscillators. By

charging and discharging C3 we have ramp signalat the output.

R5 is used to adjusted the speed of charging anddischarging C3.

Documents

Bai 13 Application Circuit