The document discusses two specialized semiconductor devices - the unijunction transistor (UJT) and the silicon controlled rectifier (SCR). It provides details on their operation and applications. Specifically:
- The UJT and SCR are specialized transistors that act as electronic switches. They are smaller, more efficient, and reliable than previous switching devices.
- The UJT can be used as a trigger for an SCR or in oscillator circuits due to its ability to produce spikes and a sawtooth waveform. The SCR is used in high-voltage, high-current applications like motor speed controls.
- The document provides circuit diagrams and explanations of how each device works, including how they are turned on and off and
Silicon Controlled Rectifier (SCR) is a unidirectional semiconductor device made of silicon.SCR is a three-terminal, four-layer semiconductor device consisting of alternate layers of p-type and n-type material.
This ppt provides a brief overview on thyristors commonly known as SCRs. V- I characteristics curve, triggering methods, protection methods, series and parallel operations of SCRs, applications are discussed in this slide.
Silicon Controlled Rectifier (SCR) is a unidirectional semiconductor device made of silicon.SCR is a three-terminal, four-layer semiconductor device consisting of alternate layers of p-type and n-type material.
This ppt provides a brief overview on thyristors commonly known as SCRs. V- I characteristics curve, triggering methods, protection methods, series and parallel operations of SCRs, applications are discussed in this slide.
The full basics of electronics can be look over in our link http://bit.ly/2PPv0mv
Resistors are very useful components in healthcare electronics so every healthcare engineers to learn about all these kinds of basic components
The basics of electronics can be watched through the link http://bit.ly/2PPv0mv
A Diode is a semiconductor device with two terminals, typically allowing the flow of current in one direction only.
a thermionic valve having two electrodes (an anode and a cathode).
The complete list of thyristor family members include diac (bidirectional diode thyristor), triac (bidirectional triode thyristor), SCR (silicon controlled rectifier), Shockley diode, SCS (silicon controlled switch), SBS (silicon bilateral switch), SUS (silicon unilateral switch) also known as complementary SCR or CSCR, LASCR (light activated SCR), LAS (light activated switch) and LASCS (light activated SCS).
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch.
The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. The low cost per unit, combined with its unique characteristic, have warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.[1] The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction transistor (PUT), is still widely available.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
As we have discussed that out of various triggering methods to turn the SCR, gate triggering is the most efficient and reliable method. Most of the control applications use this type of triggering because the desired instant of SCR turning is possible with gate triggering method.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
The full basics of electronics can be look over in our link http://bit.ly/2PPv0mv
Resistors are very useful components in healthcare electronics so every healthcare engineers to learn about all these kinds of basic components
The basics of electronics can be watched through the link http://bit.ly/2PPv0mv
A Diode is a semiconductor device with two terminals, typically allowing the flow of current in one direction only.
a thermionic valve having two electrodes (an anode and a cathode).
The complete list of thyristor family members include diac (bidirectional diode thyristor), triac (bidirectional triode thyristor), SCR (silicon controlled rectifier), Shockley diode, SCS (silicon controlled switch), SBS (silicon bilateral switch), SUS (silicon unilateral switch) also known as complementary SCR or CSCR, LASCR (light activated SCR), LAS (light activated switch) and LASCS (light activated SCS).
A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch.
The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers. The low cost per unit, combined with its unique characteristic, have warranted its use in a wide variety of applications like oscillators, pulse generators, saw-tooth generators, triggering circuits, phase control, timing circuits, and voltage- or current-regulated supplies.[1] The original unijunction transistor types are now considered obsolete, but a later multi-layer device, the programmable unijunction transistor (PUT), is still widely available.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
As we have discussed that out of various triggering methods to turn the SCR, gate triggering is the most efficient and reliable method. Most of the control applications use this type of triggering because the desired instant of SCR turning is possible with gate triggering method.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
Offering range of ours consists of Standard Spray Booths, Paint Mixing, Feeding & Controlling Equipment, Shot Blasting, Car Refinishing Booths, Car Care Products and many more to name.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
Semiconductor Diode :
What is Semiconductor Diode?
How is it Work?
What are the Types?
Current Flow in Forward And Reverse Bios?
What is Light Emitting Diode (LED)?
What is Zener Diode?
and in aditional :
P-N Junction and its formation
Formation of Depletion Layer
External Biasing of P-N Junction
V-I Characteristics of P-N Junction
Zener Breakdown
Avalanche Breakdown
Comparison between Zener and Avalanche Breakdown
Catalog thiết bị đóng cắt Fuji Electric - 05 - Limit Switch
*********************************************************************
CTY TNHH HẠO PHƯƠNG - Nhà phân phối chính thức các thiết bị điện công nghiệp và tự động hóa của hãng FUJI ELECTRIC JAPAN tại Việt Nam
Xem chi tiết các sản phẩm Fuji Electric tại
http://haophuong.com/b1033533/fuji-electric
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
Catalog thiết bị đóng cắt Fuji Electric - 08 - Circuit Protector
*********************************************************************
CTY TNHH HẠO PHƯƠNG - Nhà phân phối chính thức các thiết bị điện công nghiệp và tự động hóa của hãng FUJI ELECTRIC JAPAN tại Việt Nam
Xem chi tiết các sản phẩm Fuji Electric tại
http://haophuong.com/b1033533/fuji-electric
Business Valuation Principles for EntrepreneursBen Wann
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Memorandum Of Association Constitution of Company.pptseri bangash
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A Memorandum of Association (MOA) is a legal document that outlines the fundamental principles and objectives upon which a company operates. It serves as the company's charter or constitution and defines the scope of its activities. Here's a detailed note on the MOA:
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2. Since the development of the transistor, continuous
research in the field of semiconductors has provided many
additional semiconductor devices. Some if these devices have
been adopted to applications that were normally impossible. These
devices, now considered as innovations in military and commercial
equipment, may become as commonplace as the junction transistor
is today. Indications are that development and applications for
solid state devices will continue to expand. In all cases, where
other devices were previously used, the solid state devices are
smaller, more efficient, less expensive, and more reliable.
Two of these devices, the uni-junction transistor (UJT)
and the silicon controlled rectifier (SCR), will be discussed in
detail during this lesson.
Special Purpose DevicesSpecial Purpose Devices
3. 2 Types; Silicone Controlled Rectifier, [SCRSCR]
Unijunction Transistor, [UJTUJT]
Both are classified in the family of electronic switches called,
Thyristors.
Electronic Switches are; 1. Faster
2. Less Expensive
3. Last Longer
4. Have No Arc or Spark as do
manual switches & relays.
Applications SCR; 1. High Voltage & Current
>2000 V & >1500 A
2. Speed Controls for motors
Applications UJT; 1. Trigger for an SCR
2. Oscillator
Special Purpose DevicesSpecial Purpose Devices
SCR
4. SCR, Gated ON
G
A
K
PP
PP
NN
NNGATE, G
ANODE, A
CATHODE, K
4 Layer PNPN Device, W/3 PN Junctions.
Looks like a diode, acts like a diode, current flows like a diode, W/ an
extra element called a Gate.
A small + DC or + spike applied to the Gate will turn on [Gated On] the
device provided forward biasing is set on the Anode & Cathode. Once
ON, Stays ON.
To Turn OFF, forward biasing must be removed or reversed Biased.
The GATE WILL NOT SHUT DOWNGATE WILL NOT SHUT DOWN conduction. [Latching Current must be
removed].
Special Purpose DevicesSpecial Purpose Devices
SCR; Silicone Controlled Rectifier.
6. PC; 52A
Special Purpose Devices
SCR; Efficient Power use.
P = I X E
PLAMP = ILAMP X ELAMP
PLAMP = 50 ma X 11v
PPLAMPLAMP = 550 mW= 550 mW
P = I X E
PSCR = ISCR X ESCR
PSCR = 50ma X 1v
PPSCRSCR = 50 mW= 50 mW
LAMP
SCR
12VDC
7. Special Purpose Devices
SCR; Control Ckt PC 52A. Operate Mode.
OO
NN
EE
R2
10 KΩ
R1
1KΩ
R3
100KΩ
RESET
OPERATEOPERATE
S2
C1
1µf
1
2
3
4
5
+DC+DC
S1
- 9- 9
VDCVDC
+12+12
VDCVDC
SCR
++
++
L1
II
Reset
8. PC 52B
Special Purpose Devices
SCR; Control Ckt PC 52A. Reset Mode.
OO
NN
EE
R2
10 KΩ
R1
1KΩ
R3
100KΩ
OPERATE
RESETRESET
S2
C1
1µf
1
2
3
4
5
+DC+DC
S1
- 9- 9
VDCVDC
+12+12
VDCVDC
SCR1
++
--
L1
II
Closing S2 Grounds the +
plate on Cap C1 causing it
to discharge thus Reverse
Biases SCR1, ceasing
Conduction.
9. Special Purpose Devices
SCR; Ckt PC 52B. Conducting.
G
SCR1
2N1596
R2
100 Ω
R3
100 KΩ
R1
10 KΩ
C1
4.7mfd
1mfd
C2
1
2
4
5
6
7
3
L1
PC 52B, Cutoff
11. Continue UJT
PP
NN
NN
EE
BB22
BB11
EE
BASE 1BASE 1
BASE 2BASE 2
RRB2B2
RRB1B1
Base 2Base 2
Base 1Base 1
EmitterEmitter
NITA LESSON;NITA LESSON;
Per Instructor Discretion.
Special Purpose Devices
UJT; Unijunction Transistor
12. Continue, UJT Ops
Special Purpose Devices
UJT; Unijunction Transistor
The position of the emitter fusing on the N material determines how
much voltage is required to turn on the UJT @ the Emitter.
EE
BASE 2
BASE 1BASE 1
RB2
RB1RB1
EE
RB2
RRB1B1
BASE 2
BASE 1BASE 1
PP
NN
NN
EE
BB22
BB11
EmitterEmitter toto Base 1Base 1.
RR↑↑, VV↑↑
EmitterEmitter toto Base 1Base 1.
RR↓↓, VV ↓↓
Current, UJT isCurrent, UJT is
ConductingConducting
13. Special Purpose Devices
UJT; Oscillator PC 51. Operation, C1 Charge.
0 V
0 V
0 V
C1
Charges
C1
Discharges
1
3
5
Q1
2N4891
2
4
R3
470 Ω
R4
100 Ω
R1
18 KΩ
R2
100
KΩ
C1
.0015 µF
1212
VDCVDC
The RC TC
determines
Charge
Time &
Frequency
++
C1 Discharge
14. Trouble Shoot
Special Purpose Devices
UJT; Oscillator PC 51. Operation, C1 Discharge.
Output; ++ & -- Spike. Saw tooth @ TP3.
1
3
5
Q1
2N4891
2
4
R3
470 Ω
R4
100 Ω
R1
18 KΩ
R2
100
KΩ
C1
.0015 µF
1212
VDCVDC
The RC TC
determines
Charge
Time &
Frequency
++
0 V
0 V
0 V
C1
Charges
C1
Discharges
+ SPIKE+ SPIKE
Output @Output @
TP2TP2
- SPIKE- SPIKE
Output @Output @
TP4TP4
15. Special Purpose Devices
UJT; Oscillator PC 51, 2 Ckt. What is the Malfunction?What is the Malfunction?
NO Output
R1
R2
C1
R3
R4
5
3
1
.0015µf 25µfC2
100KΩ
R5
R6
R7
R8
2N4891
Q1 Q2
2N4891
100Ω
470Ω470Ω 47KΩ
1MΩ
2
4
8
7
9
10
O
5.01 VDC5.01 VDC
10.7 VDC10.7 VDC
.214 VDC.214 VDC
10.7
VDC
0
VDC
.214
VDC
NO Output
Terms
16. SCR;SCR; Silicon Controlled Rectifier.
Referred to as a Gated Diode.
To Turn ON, F Bias + on Gate Cathode junction.[ Gated On]
To Turn OFF, R Bias Anode/ Cathode thus removes
Latching current.
Latching Current, the minimum amount of current that can flow
through an SCR and hold it in the Break over condition or
conduction.
UJT;UJT; Unijunction Transistor.
Referred to as a Double Based Diode.
Location of the emitter joined to the N material [PN Junction]
determines the amount of voltage required @ the emitter to cause
conduction through the Emitter.
3 Waveforms Produced, + & - Spike, Saw tooth.
Main Use, Oscillator & Switching Trigger.
SCR & UJT;SCR & UJT; Both in the Family called Thyristors, [Electronic Switches].
Special Purpose Devices
SCR & UJT; Terms.
Review Questions
17. 1. One of the main uses of a UJT is as a _________, __________
.
2. Why is the UJT often used instead of a conventional transistor?
__________________________________________________ .
3. The UJT is also called a _________ _____ ______ .
4. What is the Basic purpose of a SCR? __________ ________ .
5. How is an SCR turned on ? __________________________ .
6. What family of transistors does the SCR & UJT belong to ?
__________ .
7. Draw the schematic symbol for a UJT & SCR.
8. How many PN Junctions does the SCR contain ? ____ .
9. How is an SCR turned Off ? __________ _______
__________.
Special Purpose Devices
Review Questions;
Answers; 1- 9
18. Answer; 10
Special Purpose Devices
Review Questions;
10. Refer to PC 51; The following DC voltages are present: TP4 = 10.7 VDC,
TP3 = 0 VDC, TP2 = .21 VDC. What is the Malfunction ?
a. C1 Open
b. R1 Open
c. R2 Short
d. Q1 Open
11
33
55
Q1Q1
2N48912N4891
22
44
R3R3
470470 ΩΩ
R4R4
100100 ΩΩ
R1R1
18 K18 KΩΩ
R2R2
100100
KKΩΩ
C1C1
.0015.0015 µµFF
1212
VDCVDC
PC 51PC 51