Three Terminal Devices1
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Three Terminal Devices
Three Terminal Devices
1. BJT2.FET3.UJT
Three Terminal Devices- BJTBJT – NPN - BC 107, BC 108 , BC 109
PNP – SL100 and SK100
Emitter
Base
Collector
Three Terminal Devices- BJTBJT – BC548
BC548
EmitterBase
Collector
Three Terminal Devices- BJT
Three Terminal Devices- BJTTesting of BJT using MultimeterSet the Dial to Continuity Tester
PNP BJT:black lead to base, red lead to collector, result = 675black lead to base, red lead to emitter, result = 688
red lead to base, black lead to collector, result = OL = No conductionred lead to base, black lead to emitter, result = OL = No conduction
black lead to emitter, red lead to collector, result = OL = No conductionred lead to emitter, black lead to collector, result = OL = No conduction
Three Terminal Devices- BJTTesting of BJT using MultimeterSet the Dial to Continuity Tester
NPN BJT:black lead to base, red lead to collector, result = OL = No conductionblack lead to base, red lead to emitter, result = OL = No conduction
red lead to base, black lead to collector, result = 600 – 700 vred lead to base, black lead to emitter, result = 600 – 700 v
black lead to emitter, red lead to collector, result = OL = No conductionred lead to emitter, black lead to collector, result = OL = No conduction
Three Terminal Devices- BJT
Applications of BJT•Amplifiers•Switches
Three Terminal Devices- FETFET – JFET – BFW10
Three Terminal Devices- FETFET – JFET – BFW10
S - SourceD- DrainG - GateB - Body or Casing
Three Terminal Devices- FETFET – MOSFET – IRF540
Gate
Drain
Source
Three Terminal Devices- FETJFET – Testing Using Multimeter
1. Connect the negative lead to gate and positive lead to source . Next connect the negative lead to gate and
positive lead to drain. Both the connections should show high resistance.
2. Connect the positive lead to gate and negative lead to source . Next connect the positive lead to gate and negative lead to drain. Both the connections should
show high resistance.
Three Terminal Devices- FET
Three Terminal Devices- FET
Applications of FET•Low Noise Amplifier
•Buffer Amplifier•Analog Switch•Chopper circuit
Three Terminal Devices- UJT
UJT – 2N2646Lead Identification
E- EmitterB1, B2 - Base
Three Terminal Devices- UJT
Testing Using Multimeter1) With a Digital Multimeter, set in the
Ohms position, read the resistance between the Base 1 and Base 2; then
reverse the meter-leads and take another reading. Regardless of the meter-lead
polarity the measured resistance should approximately be equal (high resistance).
2) Now connect the negative (-) lead of the ohmmeter to the emitter of the UJT. With the positive (+) lead, measure the
resistance from the emitter to Base 1 and then from the emitter to base 2. Both
readings should indicate high resistance and about equal to each other.
3) Exchange the negative lead to the emitter with the positive lead. Measure
with the negative lead the resistance between emitter and Base 1 and from
Base 2 to emitter. Both readings should show low resistance and about equal to
each other
Three Terminal Devices- UJT
UJT – 2N2646Characteristics
Three Terminal Devices- UJT
UJT – 2N2646Applications
relaxation oscillatorto measure magnetic flux