Basic Electrical Components Short notes | Sensor & Industrial Instrumentation - Electronics and Communication Engineering (ECE) PDF Download

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Basic Electrical Comp onen ts
Basic electrical comp onen ts are fundamen tal building blo c ks in sensor and industrial
instrumen tation systems. They pro cess, condition, and transmit signals from sensors to
con trol systems, ensuring accurate measuremen t and con trol in industrial applications.
1. Key Comp onen ts
1. Resistors:
• Opp ose curren t flo w, us ed for signal conditioning and curren t limiting.
• Ohm’s La w: V = IR , where V is v oltage, I is curren t, and R is resistance
(? ).
• Applications: V oltage dividers, pull-up/pull-do wn resistors, sensor biasing.
• P o w er dissipation: P =I
2
R =
V
2
R
.
2. Capacitors:
• Store and relea se electrical energy , used for filtering and timing.
• Capacitance: C =
Q
V
, where Q is c harge and V is v oltage.
• Imp edance: Z
C
=
1
j?C
, where ? =2pf is angular fre quency .
• Applications: Noise filtering, coupling/decoupling in sensor circuits.
3. Inductors:
• Store energy in a magnetic field, used in filters and energy storage.
• Inductance: V
L
=L
dI
dt
, whereL is inductance (H) and
dI
dt
is the rate of c hange
of curren t.
• Imp edance: Z
L
=j?L .
• Applications: Inductiv e sensors, EMI suppression.
4. Dio des:
• Allo w curren t in one direction, used for rectification and protection.
• Ideal dio de equation: I
D
=I
S
(
e
V
D
nV
T
-1
)
, whereI
S
is saturation curren t, V
D
is dio de v oltage, V
T
˜ 25 m V at 25°C, a nd n is the idealit y factor.
• Applications: Signal clipping, o v erv oltage protection in sensor circuits.
5. T ransistors (BJT and MOSFET):
• Amplify or switc h s ignals in sensor in terfaces.
• BJT (NPN): I
C
= ßI
B
, where ß is curren t gain, I
C
is collector curren t, I
B
is
base curren t.
• MOSFET: I
D
=
1
2
k
n
(V
GS
-V
TH
)
2
in saturation, where k
n
is a constan t, V
GS
is gate-source v oltage, and V
TH
is threshold v oltage.
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Page 2


Basic Electrical Comp onen ts
Basic electrical comp onen ts are fundamen tal building blo c ks in sensor and industrial
instrumen tation systems. They pro cess, condition, and transmit signals from sensors to
con trol systems, ensuring accurate measuremen t and con trol in industrial applications.
1. Key Comp onen ts
1. Resistors:
• Opp ose curren t flo w, us ed for signal conditioning and curren t limiting.
• Ohm’s La w: V = IR , where V is v oltage, I is curren t, and R is resistance
(? ).
• Applications: V oltage dividers, pull-up/pull-do wn resistors, sensor biasing.
• P o w er dissipation: P =I
2
R =
V
2
R
.
2. Capacitors:
• Store and relea se electrical energy , used for filtering and timing.
• Capacitance: C =
Q
V
, where Q is c harge and V is v oltage.
• Imp edance: Z
C
=
1
j?C
, where ? =2pf is angular fre quency .
• Applications: Noise filtering, coupling/decoupling in sensor circuits.
3. Inductors:
• Store energy in a magnetic field, used in filters and energy storage.
• Inductance: V
L
=L
dI
dt
, whereL is inductance (H) and
dI
dt
is the rate of c hange
of curren t.
• Imp edance: Z
L
=j?L .
• Applications: Inductiv e sensors, EMI suppression.
4. Dio des:
• Allo w curren t in one direction, used for rectification and protection.
• Ideal dio de equation: I
D
=I
S
(
e
V
D
nV
T
-1
)
, whereI
S
is saturation curren t, V
D
is dio de v oltage, V
T
˜ 25 m V at 25°C, a nd n is the idealit y factor.
• Applications: Signal clipping, o v erv oltage protection in sensor circuits.
5. T ransistors (BJT and MOSFET):
• Amplify or switc h s ignals in sensor in terfaces.
• BJT (NPN): I
C
= ßI
B
, where ß is curren t gain, I
C
is collector curren t, I
B
is
base curren t.
• MOSFET: I
D
=
1
2
k
n
(V
GS
-V
TH
)
2
in saturation, where k
n
is a constan t, V
GS
is gate-source v oltage, and V
TH
is threshold v oltage.
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• Applications: Amplifiers, switc hes in signal conditioning.
6. Op erational Amplifiers (Op-Amps):
• High-gain amplifiers f or signal pro cessing.
• Ideal c haracteristics: Infinite input imp edance, zero output imp edance, infinite
gain.
• V oltage gain (in v erting): A
v
=-
R
f
R
in
.
• V oltage gain (non-in v erting): A
v
=1+
R
f
R
in
.
• Applications: Sensor signal amplification, filtering, comparators.
2. Role in Sensor and Instrumen tation Systems
• Signal Conditioning: Resistors, capacitors, and op-amps filter and amplify sensor
outputs fo r accurate measuremen t.
• In terfacing: T ransistors and dio des in terface sensors with con trol systems.
• Noise Reduction: Capacitors and inductors suppress noise and electromagnetic
in terference (EMI).
• Po w er Managemen t: Resistors and dio des regulate p o w er to sensors.
3. Practical Considerations
• Comp onen t Selection: Cho ose comp onen ts based on sensor signal range, frequency ,
and en vironmen tal conditions (e.g., temp erature stabilit y).
• T olerance and Drift: Use lo w-tolerance resistors and capacitors for precision.
• P arasitic Effects: A ccoun t for parasitic capacitance/inductance in high-frequency
applications.
• P o w er Rating: Ensure comp onen ts handle exp ected p o w er lev els (e.g., P =I
2
R for
resistors).
4. Applications in Industrial Instrumen tation
• In terfacing sensors (e.g., thermo couples, strain gauges) with data acquisition sys-
tems.
• Signal amplification and filtering for accurate con trol in P LCs.
• Protection circuits for robust op eration in harsh indust rial en vironmen ts.
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