EE400 GRADUATION PROJECT

EE400

GRADUATION PROJECT

NEAR EAST UNIVERSITY

LEFKOSA

ELECTRIC& ELECTRONICS DEPARTMENT

CAGAN GUNGOR 93016

CONTE1'TS

ı- Contents Introduction

Importance of Power Supplies In Laboratories Brief Description of the Project

How It Works

3.1-The Protection Unit

3.2-The Control and Regulation Unit 4- Technical Specifications 5- Equipment List 6- Conclusion 7- References Figures: Figure I­ Figure 2-Figure 3-Figure

4-Supply and Regulation Circuit

Circuit Board of Regulation and Protection Unit The Ammeter and The Voltmeter

.J . •

ıical

education period, in the university it is very important to have

•• dk~s about our job, as it is the only bridge between real life and our

laboratories have an important aim in preparing students to their

~C

I· ıiııg theoretical with your experimental knowledge, and then

CONTE1'ıS

ı- Contents Introduction

Importance of Power Supplies In Laboratories Brief Description of the Project

How It Works

3.1-The Protection Unit

3.2-The Control and Regulation Unit 4- Technical Specifications 5- Equipment List 6- Conclusion 7- References Figures: Figure I­ Figure 2-Figure 3-Figure

4-Supply and Regulation Circuit

Circuit Board of Regulation and Protection Unit The Ammeter and The Voltmeter

ii- ODUCTION

In our theoretical education period, in the university it is very important to have

"- ,I practical works about our job, as it is the only bridge between real life and our

education. So laboratories have an important aim in preparing students to their Combining theoretical with your experimental knowledge, and then

1- THE I~IPORTANCE OF POWER SUPPLIES IN LABORATORIES

re precise results while working in laboratories, at first you must be . and most important is your equipment must be precise. The errors of measarements, or supplies should not exceed the limits.

• A~~ording to these points power supplies are one of the main units of the laboratories. They are main error sources in an experiment as the power is supplied by these equipment. In other words they are the starting point of errors.

light of these concepts, as an electronics engineer today, it will be good examine a power supply, of course a laboratory model. I chose a very good model, easy to construct but so powerful as my graduation project EE400.

--

BRl£F DESCRIPTION OF THE PROJECT

er supply that i have chosen is a good type as it has wide range of full function protection. This device have current fuse function facility, have short-circuit protection, and have a cooler fan for heavy ork conditions. This wide range of output makes possible to supply power rated circuit or to recharge a car battery with the same device. digital panel meters makes the measurements easily readable, this reduces error percentage, made by the experimenter.

Another facility that differs this device from others is the stability under heavy load. Classical power supplies have current variation in order to stabilize the volıaae. But our project subject hero cuts off the voltage as soon as the desired

---ı cerrenr is reached. This gives full protection for the connected device.

\ı:Jıcıdıer goodness of this supply is the construction·costs. As it does not cost much having these precise preferences, for an amateur, or professional it is a good choice for experimenters.

An AC output makes it more useful when needed to use AC directly, but of course in a constant voltage.

HO". IT WORKS (INTERNAL STRUCTURE)

have a stable output power, in heavy load conditions the supply is rith high tolerance equipment. Starting with a powerful transformer, dge rectifier, a big powerful capacitor for filtering and at the end high

ı:,..-.a:-

output transistors are chosen for heavy loads. If these tolerance limits are dıosen a problem of burning the loaded equipment will rise.

-~ ington output transistors are used in the supply. For example, taking into amside:ration that for a ,SA output with current gain of 5, we need IA of eoııector current for the second transistor. Again for a IA current we need

A collector current for the third transistor with a current gain of 20.

complete the protection against heavy loading, the cables used inside the s-ppl:y connecting the transformer to rectifier and to the circuit is chosen as

---ı 6iı:::kas 6-7 mm. This also reduces the heat loss in the cables.

ormer with 27 volts AC output loads the rectifier and the filtering ı::ac«.iııoı and a maximum of 35 volts DC output is obtained.

ıut transistor behaves like a resistor when you want lower currents to

OIIIDUt. For example if you want 4A with 6 volts the rest must be used on

uıauuL transistor which is 4A with 29 volts and this makes I 16W of power

ipated on the transistor of course standard case is not enough to take uıch heat so the supply is equipped with a big cooler body made of aJ,woınum and with a cooler fan. This easily can be seen that the power dts.sıpatedon the transistor is much more in lower potentials.

equipment that used in the supply may differ from the list, this is not so tas the equivalent parts are used instead.

CllONUNIT

seen from the main diagram of the supply that the AC output has

•a

+

ction only as it does not need more of this.

DC voltage is obtained it is directed to a 0.3 Ohm resistor for

D - £ a voltage drop when loaded. This signal (difference ) is used to en the protection will be active. A 27 Ohm resistor is put for enabling ~tting. As seen 0.3 Ohm resistor is also enough to have this control,

erse of loss of power, the internal cable resistance are much more important re thick diameters. The main protection is obtained by a kind of a · .ator with T2, T3. When the current limit is exceed, enough current flows P 1 to T2 to make it biased. This continues with the biasing of T3. ause of this from IN4448 the collector of T4 is taken to zero voltage. ause of this the series T5,T6,T7 is also taken to zero, deactivating the supply output.

This continues until the switch Ta is pressed. When the reset switch is pressed the voltage of protection unit is canceled resetting the whole supply unit . From Tl an indicating led shows that the problem is active until it is reset.

ill REGCLATION UNIT

ion is obtained by T4. From ZPD3 a reference voltage o the emitter of T4. The regulation part is separated

_ 5. T6 and T7. In order to minimize the equipment in

.-sıde.ra:Iİons an extra transformer is not used to regulate the voltage, aııse in this case the regulation is referred from the earth so 0-4V DC can not be used. This is because of the base-emitter . 7 volt of T4 makes 4 volts.

lır E

m

of using another zener diode is not the optimum solution because

use a zener of 0.7 volts for example as a reference to T4, the less sensitive. So the zener diode used is the optimum one. In the using a 7.5 V zener diode makes the usable range 8.7 to 34

cmcATIONS

input voltage input current

AC output 3 A cont DC variable output 5A max

-5 A DC output current

Electronic current fuse protection with reset Circuit Protection

eavy Duty (Aluminum body

+

cooler fan ) Digital Display Easy Reading

Optimum Equipment Configuration, Easy Service Sensitive Regulation to Output Power

'LCillCATIONS

input voltage input current

AC output 3 A cont DC variable output 5A max

-5 A DC output current

Electronic current fuse protection with reset Circuit Protection

Heavy Duty (Aluminum body

+

cooler fan ) Digital Display Easy Reading

Optimum Equipment Configuration, Easy Service Sensitive Regulation to Output Power

:l.P~IE..~1LIST ransformer Rectifier Filter Capacitor Transistor Transistor Transistor Transistor Transistor Zener Diode Silisium Diode Potentiometer Potentiometer Resistors 270hm lOOOhm 5600hm 6800hm lkOhm 2.2k0hm lOkOhm lOhm 5W Capacitors 220uF/40V 47uF/40V 4.7nF 47nF 470pF 220/24V, 6A B 40 C 7500/5000 10 000uF/40V 2N 3 772, 2N3771 BDY 16B BC 141 BCY 58 C BCY78 C ZPD3 IN4448 lOOOhm0.25W linear 5k0hm 0.25W linear Digital Ammeter Digital Voltmeter

CONCLUSION

ding one of the important device of a laboratory, a power supply gives a lot experience to the electronic engineers. Also to make precise measurements, to experiment a device without overloading and burning it, and having a ge variety of voltage and current output, can be very important to the engineers of electronics.

REFERENCES

-Funkschau electronic magazine (Germany) -Elo electronic magazine (Germany)

-MC electronic magazine (Germany)

-Hilf, W: Nausch, A: m68, Teil 1 (Grundlagen und Architechur) Munchen -Hunstman, C: Cawthran, D: The power concept Dez 1983

-Raven, J.G.: Berkhoff, E.J., Kraus, V.E.: Application of power supplies June 8-10 1983, Chicago

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id pattern. It is a bıittıe it will fracture.

oles with a pen ~ •... arp corner, su verhanging It can making interconr.e components side ,ıow quickly ci quite neat. Another e placed exa that the back ....•

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components across the back ( non sounds a bit messy but it's surprısing ied, and with a bit of care they look ard is that components and wiring can ırcuit diagram. The main disadvantage is bit of a rat's nest if it try to built a is that the finished job doesn't look

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tal tags mounted on an insulating two or more further metal tags own onto a chassis.

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Compone to remove them. ·

.lP~IENT LIST Transformer Rectifier Filter Capacitor Transistor Transistor Transistor Transistor Transistor Zener Diode Silisium Diode Potentiometer Potentiometer Resistors 270hm lOOOhm 5600hm 6800hm lkOhm 2.2k0hm lOkOhm lOhm 5W Capacitors 220uF/40V 47uF/40V 4.7nF 47nF 470pF 220/24V, 6A B 40 C 7500/5000 10 000uF/40V 2N 3 772, 2N3771 BDY 16B BC 141 BCY 58 C BCY78C ZPD3 IN4448 lOOOhm 0.25W linear 5k0hm 0.25W linear Digital Ammeter Digital Voltmeter

CONCLUSION

uilding one of the important device of a laboratory, a power supply gives a lot ıfexperience to the electronic engineers. Also to make precise measurements, r to experiment a device without overloading and burning it, and having a large variety of voltage and current output, can be very important to the engineers of electronics.

RENCES

electronic magazine (Germany) -·~C electronic magazine (Germany)

- •..• itf W: Nausch, A: m68, Teil 1 (Grundlagen und Architechur) Munchen

-Hunstman, C: Cawthran, D: The power concept Dez 1983

-Raven, J.G.: Berkhoff, E.J., Kraus, V.E.: Application of power supplies June 8-10 1983, Chicago

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CONSTRUCTlt!

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TS AND PROJ~Y.9F.S

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'•. ' '.! "''~"::} .. \, .. ~/:;, There are several different ways of building electronic proj~cts:-0

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plest by far is to use a printed circuit board. Other methods of

nstruction include stripboard ( verboard) , matrix board and tag strips. Each

ID

C CIRC

hod has advantages and disadvantages.

1. Matri

oard

This is a phenolic material ( like very hard cardboard) perforated in a grid pattern. It is a brittle material though quite strong dont bent it too much or it will fracture. Cutting it to size is a simple matter. Score along a line of holes with a pen knife or similar, clamp it along the score on the edge of a harp corner, such as the edge of a bench or table, and bend or strike the overhanging portion sharply.-lt should fracture cleanly along the score.

It can use it by inserting the components through the holes and making interconnections oy joining the components across the back ( non components side) of the board. It all sounds a bit messy but it's surprising how quickly circuits can be assembled, and with a bit of care they look quite neat.

Another advantage of matrix board is that components and wiring can be placed exactly as shown on the circuit diagram. The main disadvantage is that the back of the board becomes a bit of a rat's nest if it try to built a complex circuit. Another minor drawback is that the finished job doesn't look

ike a totally professıonaı unit.

2. Tag

Tag strips consist of a series of metal tags mounted on an insulating strip. The strips in turn are mounted on two or more further metal tags which are used to screw the whole lot down onto a chassis.

Component leads should never be wrapped more than three quarter way round a tag. If you ~wist them right round you'll have an awful job trying to remove them, if you need to.

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TS AND PROJ~TS

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There are several different ways of building electronic pr~j~c~.~~ .. implest by far is to use a printed circuit board. Other methods of

onstruction include stripboard ( verboard) , matrix board and tag strips. Each

PRACTICAL GUIDE

ELECTRONIC CIRC

ethod has advantages a · advantages.

1. Matrix B

This is a phenolic material ( like very hard cardboard ) perforated ın a grid pattern. It is a brittle mater ;aı Lhough quite strong dont bent it too much or it will fracture. Cutting it to size is a simple matter. Score along a line of holes with a pen knife or similar, clamp it along the score on the edge of a sharp corner, such

overhanging portion ~-It can use making interconne components side how quickly circui. quite neat. ,

f a bench or table, and bend or strike the leanly along the score.

the components through the holes and the components across the back ( non nds a bit messy but it's surprising na with a bit of care they look

be placed exacnv that the back o

complex circuit. ike a totally pro1~~

is that components and wiring can curt diagram. The main disadvantage is

f a rat's nest if it try to built a hat the finished job doesn't look

2. Tag

gs mounted on an insulating or more further metal tags onto a chassis.

rapped more than three quarter ou'II have an awful job trying Tag strips c

strip. The strips in which are used to

Component way round a tag. If to remove them, if y

strip construction is quickly, cheap and simple but the method e for small scale projects as intertag wiring is otherwise extensive tedious.This method also wastes space.

. Veroboard

This is made from a material similar to that used for matrix board,but •.. ıines of copper (refers to as ' strips' or 'tracks') embedded in it. The

•. ,n~ are spaced 0.1" apart and the holes in the strips though which

ponents are inserted,are also at 0.1" intervals.

Veroboard is easıly obtainable in large pieces which can be used for

cı uig job or cut down to suit a smaller circuit. It is simple to use and if the

omponent layout is worked out in advance.It can result in a neat finished ppearance.It is fairly easy to make mistakes,though. One important point to ateh is that components which are not meant to be connected are isolated y cuts in the copper strıp ( these are easily made either with a suitable ized drill bit or with a special tool ) . A wise constructor will always check the layout against the circuit diagram to make sure that all components are ın the right holes ın the right notes,in the right strip, and that the leads of a

ransistor,for example,are cniy ıoined to those components shown on the circuit, and to no o~ers. Two oıher points to note are that the loose copper which results fror. cutting the tracks is not joining adjacent strips, and that after soldering,no solder bridges have been accidentally made.

Printed cırc The board thin copper shee formed by etching

electronic circuit building enormously. ot phenolic resin or glass fibre with a nerally ) one face. lntercomponent wiring is ·ıanted copper so that only the tracks and ain. Holes are drilled for the components

he non - copper side and their leads oards have a number of etnoos ot construction. The biggest is that of the wiring is right there etched

such that in many instances

which are then insertec soldered dırectly to significant advantace

mistakes are less onto the board, an

onıy fit the right way round. The finished article looks onal. It is how most professional equipment is made.

ı

he disadvantages are that prınted cırcuıt boards are more expensive er methods; there is also less personal involvemen•.

ost component suppliers stock PCB material for those who wish to

ke their own. It is not that difficult but may be messy and even

ngerous, because of the powerful cherical used

to

etch away· the

nted copper

o

Good solde · aid it become adept

x- Puchase a g x- Use only acid flux.

x-A new, quite hot and tı

before the coppe flow all over th

x- Keep or sponge.

x- Make insulation and

x- With and tin the in

x-Attach in a lead to be ;::,,..;....-.: le _ between 15

a

· n lead contert atts To do this ~0 fresh clean co ,. esin cored so ·· frequently with a da

soldered is clean. wax,

rrave

=sult in interior joints.

ire, it will be necessa oıaering them together.

not make more than a narı turn sequent removal difficul..

and apply solder to the · ·

he solder just commences to now in a high resistance joint ( known as ent damage and evaporates the tin

x-

Keep

on the connecti a dry joint). T component, ag~i~

x-

Let th vıng the connection. Then check tor

oeen moved will nav nd will fracture easily.

ııne appearance, ma

fairly straightforward components. The value and wattage roiect, there's little tha, can go wrong. A color code chart is iar with how to read the value painted on ~:-;€ body of the component. Resistors are

esn't matter which w-;;y round put them in.

he leads too

•rA the end or the main body

excessive heat to the leads oo long. It ıs sufficient just

••• u joint a little extra may do

e harm than In many in portant and It ca

esistor in a circuit is not too vaıue up or one value down nge in a circuit's operating may be substituted

h high wattage resistors or

naving a smaller tolerance ıerance rating of the same ,;;placed by a 4k7, 5% type. substituted for quarter watt renditions. For ey

here a 3k3 va . ,ıgn stabılity re .ating may al

alue. For exa Similar!.,. resistors provide

ratings. The im - polarized types must take care others are non -types. These ar,

A polarize is which. Many a Some have a ' + that it have inse They won't work.

or shapes and sizes, types and

ıa[ there are polarized and non

auacitors are polarized and it connected in a circuit. Al the y specify polyester and ceramic e inserted either way rouno. marking to indicate which lead

adjacent to the negative lead. e respective leads. Always check capacitors the right way round.

rated circuit. A wrongly even at low voltages ) ma eneraı capacitor values

ded unless it is very of the particular capacito..

••vuolytic and tantalums. go

type th

in a ma" o substitutıo circuit works mpoı tant, particular rated at lower voltage

a

::-ıroject calls for e same value

ı:::

an

Diodes are wrong way round.: Fortunately,they

a:·

It may be a ban or the body ma construction dia Alternatively, a construction dia these relate to Any accompanying generally rate ) , it is always specified neve diode for a ge

lways a right way and a well destroy the device. ·"'entifying the cathode en "r;';:lcent to the cathode

e generally indicate on

olarity of any diodes.

either the circuit or

es and markings an

e

II

ntioned in the parts list

age. However, as diodes ar reverse voltage, not conduc •.:

having a higher ratin;;, ver substitute a silicone

=ther the right one or · ~ •••••.•. f..,j..

For mo rarely possibl as ' just the s the parts list,

A transı

hich some one may re,.. ...

The construction diagram or component rıay with a project will

,~ate which way the pins are to be inserted in a PCB. Connected

orrectly, there is a good change you will destroy the device when first

uched on.

Incredibly, not all transistors of the same type number have the same

·, ı connection. Sometimes a manufacturers may vaıy the pin connections of

type at different times ! Transistor pin connections and orientations are gıven in the construction diagrnm or component overlay.

Transistors ( and diodes) may be damaged by excessive heat when

oldering. Although, these days, it is no longer really necessary to use a ' neatsink ' ( pliers or a special tooı .) when soldering small transistors leads a ittle care and speed when soldering is a good idea. Just get the solder flowing neatly over the Juıııt 'wettiı ıg' it properly, and things should be fine.

on't overdo it.

10. lnteg

Integrated always have som end of the case '-'r should be inserts are the right to get opt agai

Because These are pl and into whic some IC 's are are worth cons Like trans the soldering, it ·

CMOS

IC'c-the right way round. They

e Torm a small scallop in one

o c;1 pin at one end. They

rawings. Do make sure they cause once in they're very hard g a bit more. on IC sockets. ical pin connections to the IC

not always worthwhile because costs more than the IC, but they narı they look, but don't overdo solder ' bridge ' between the pins. are very tough, once soldered in, They she:,ı~

small static c foam or foil-wra them up with

ev are easily damaged by quite nserted in a conductive plastic em carefully. Take care to pick the ends of the package,

touching the pıns. Make sure you have them correctly oriented before erting them into a PCB.

When soldering CMOS IC's use an iron having an earthed tip and

ıJarrel. If you're unsure about these use a clip lead to connect the iron's carrel to the negative supply rail on the board. These , ııe.:.ısures ensure you don't ' blow' CMOS IC's from either static or leakage currents.

Always leave CMOS IC's until last when assembling

a

project. Once

removed from the packaging, · them quickly an solder those pins

connected to the power rails, generally pins 7 and 14 ror most 14 pin

packages, but check the . dıagram beforehand. This ensures any static

charges are dissipated by the other components.

11. LE

ittle solid state indicators and for

are red, yellow and green

e are availably shortlv. Some Light emitting

that reason are

although orange are a are clear but glo

Being diocıe.., incorrectly connec indicated in se

ere are not usually damaged if

ç poıarity of the leads may be

is to have a flat section on the ave one lead shorter than the ill last forever. We don't know

-case adjacent

~o

other, the cathco

of any that ha' ..,. They

exceeded. You will circuit. Don't eve test one is to

Led ~c~

component over'r

...••t current ratina and if this is ected in series with a LEU ın a a battery. Best way to

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