Malaysian Institute of Aviation Technology
Assignment 1
AAB31502 (Electronic Instrument System)
Answer all the questions
1. Describe the purposes, functions and operations of Build-in Test
Equipment (BITE).
2. Describe the differences of these three types of display; CRT, LCD and
LED in term of its constructions, advantages and disadvantages.
3. Explain the differences between conductive and static dissipate
materials for ESD protection.
4. Find the static voltage susceptibility range value for the type of devices
given in Table 1. Identify which is the most sensitive device to static
voltage.
Table 1
Malaysian Institute of Aviation Technology
1. Describe the purposes, functions and operations of Build-in Test
Equipment (BITE).
→ Purpose
• To assist the user to properly maintaining the aircraft systems in both
•
•
fault isolation and verification of system operation in the most ‘cost
effective manner’.
Isolate failing LRUs where it will be removed to be repaired elsewhere.
Information from BITE system may also be accessed to assist with the
investigation of an accident or incident
→ Functions
•
•
•
Fault Detection where it is performed continuously during system operation
Fault Isolation. The BITE initiate signals to isolate defective components once defect is
sensed. Technician may also access the BITE and identify the faulty components.
Verification can also be performed by operational check run through by the system after
repair. Monitor and verify correct operation after properly repaired.
→ Operations
•
•
•
•
Operational checks the systems upon initialization of the systems (Power Up) BITE
programs performed check of input signals, protection and control circuitry.
In normal operation, BITE monitors and detects hardware faults or excessive signal
distortion which may cause faults.
Once failure detected, BITE perform isolation of the components, and initiates warning,
caution or advisory.
BITE shall records these faults in its non-volatile memory
Malaysian Institute of Aviation Technology
2. Describe the differences of these three types of display; CRT, LCD
and LED in term of its constructions, advantages and
disadvantages.
→ Constuctions
•
•
•
CRT is an evacuated glass envelope containing an electron gun and a
fluorescent screen to accelerate and deflect the electrons.
Meanwhile, (LCD) liquid crystal display is composed of several layers
which include two polarized panel filters and electrodes.
On the other hand, (LED) is made by depositing the three layers of
semiconductor material on a substrate
→ Advantages
• CRTs have fast response times and no motion artifacts. It is also best for rapidly
•
•
moving or changing images. CRTs are less expensive than comparable displays
using other display technologies
LCD able to produce very bright images due to high peak intensity. Very suitable
for environments that are brightly lit . Emissions produce considerably lower
electric, magnetic and electromagnetic fields than CRT.
lower energy consumption, longer lifetime, improved robustness,
smaller size, faster switching, greater reliability
3. Explain the differences between conductive and static dissipate
materials for ESD protection.
→ Conductive materials have a low electrical resistance, electrons flow easily across the
surface or through the bulk of these materials.
→ Charges go to ground or to another conductive object that the material contacts or
comes close to.
→ Conductive materials are classified “Antistatic”.
❖ For the dissipative materials, the charges flow through the material slowly and in a
somewhat more controlled manner than with conductive materials
❖ Dissipative material slows ESD to give it time to be discharged to ground through the
ground wire
Malaysian Institute of Aviation Technology
4. Find the static voltage susceptibility range value for the type of
devices given in Table 1. Identify which is the most sensitive device
to static voltage.
Type of device
CMOS logic
TTL logic
Bipolar junctions transistors
Dynamic memories
VLSI microprocessor
MOSFET transistors
Thin film resistors
Silicon controlled rectifiers
Typical static voltage susceptibility
250V to 1kV
550V to 2.5kV
150V to 5kV
20V to 100V
20V to 100V
50V to 350V
300V to 3kV
4kV to 15kV
Silicon controlled rectifiers are most sensitive to static voltage