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SPECIAL PURPOSE DIODE (CURRENT REGULATOR DIODE) GROUP 5 6 AVIONICS 2

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AZILA BT. ARZMI MUHAMMAD SYAUQI B. ZAKARIA ANWARUL IZAAN B. ANWAR NURHASNANEY BT. SULAIMAN MUHAMMAD FARIZ CHE AZIZ MUHAMMAD ZUNNUR AZEEM

E NAM

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CURRENT REGULATOR DIODE

Introduction  History  Construction and Basic Idea  Equivalent Circuit and Symbol  How does it work  Significant Characteristic/s  Applications

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CURRENT REGULATOR DIODE

HISTORY OF CRDs..

 First introduced in late 1960s …  Many of the device were granted MIL – classification …  However in the late 80s and early 90s , there were numerous cuts in u.s military programs  As a results …  For that reason …  Despite the problem, CRDs are still popular and readily available in united states for the following major sources:- such as …

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CURRENT REGULATOR DIODE

BASIC IDEA CRDs are drastically different from any of the diode. CRDs maintains a relatively constant device current over a wide range of forward operating voltages. Other purpose of CRDs is:-

 To create current source.  To provide a constant current regardless of changes in the input voltage or load current.  To regulate current over a wide voltage range.

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CURRENT REGULATOR DIODE

CONSTRUCTION..  Today the most common diodes are

made from …  It is a JFET with the gate shorted to the source, and function like …  They allow a current through them to rise to a certain value, and then level off at a specific value.  current regulator diode is also called …

Example Circuit

Equivalent Circuit & Symbol i ode D t n e t Curr

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an Const

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SYMBOL

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Constant Current Diode

Circuit diagram If we were to build a circuit like figure (a)

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Constant Current Diode

Graft The graft for this diode Is figure (b)

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How Does CCD Operate?

The circuit of CCD is a current generator in series with parallel of the dynamic impendence In the junction capacitance.

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How Does It Work

Significant Characteristics i ode D t n e t Curr

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an Const

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CHARACTERISTICS

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Constant Current Diodes POV

VL

Ratings

Zk

IP Zt

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SPECIFICATIONS

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POV

(VL)

(IP)

Peak Operating Voltage The maximum allowable value of Vf

Maximum Limiting Voltage The voltage at which the diode starts to limit current

Regulator Current Regulated value of forward current for forward voltages between VL & POV

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SPECIFICATIONS(cont)

Minimum Minimum Dynamic Dynamic Impedance(Zt) Impedance(Zt)

Operated in the current limiting region of operation

Minimum Minimum Knee Knee Impedance(Zk) Impedance(Zk)

Operated at the knee voltage of the operating curve

*Minimum forward impedance of a constant current diode

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Figure 1

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Application

 Application  automatically limit current through an LED or laser diode over a wide range of power supply voltages.  charging of small secondary-cell batteries-large secondary

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Conclusion

 CRDs are drastically different from any of the diode.  Its maintains a relatively constant device current over a wide range of forward operating voltages.  Its allow a current through them to rise to a certain value, and then level off at a specific value.

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References

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Wikipedia Current source and voltage references By Linden T. Harrison Integrated publishing Electrical Engineering Training Series Semiconductor Component Industries,LLC reference text book,Wikipedia & www.avtechplus.info/diode/faq

Encyclopedia special diode

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Constant Current Diode Team TEAM

FRIENDS

THANK YOU! (“,)v

REFERENCES MDM NAJIHAH

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Team best!