4.1 State the light-altering principle of operation of the liquid crystal display (LCD) - NSC Electrical Technology Digital - Question 4 - 2019 - Paper 1
Question 4
4.1 State the light-altering principle of operation of the liquid crystal display (LCD).
4.2 With reference to encoders and decoders, answer the questions that foll... show full transcript
Worked Solution & Example Answer:4.1 State the light-altering principle of operation of the liquid crystal display (LCD) - NSC Electrical Technology Digital - Question 4 - 2019 - Paper 1
Step 1
State the light-altering principle of operation of the liquid crystal display (LCD)
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The light-altering principle of an LCD relies on the manipulation of light by liquid crystals. When an electric current passes through the liquid crystals, they change orientation, allowing or blocking light to pass through. This change creates images or display information by controlling the level of light that reaches the viewer.
Step 2
4.2.1 Draw the circuit diagram of a simple two-digit-binary-input-to-four-digit-decimal-output decoder using two NOT gates and FOUR gates
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The circuit diagram consists of two inputs (binary digits A and B) connected to two NOT gates which produce the inverted outputs. These outputs are then fed into a combination of AND gates to derive the four output lines corresponding to the decimal values 0 to 3. Mark each part of the circuit for clarity.
Step 3
4.2.2 Complete the truth table of the two-digit-binary-input-to-four-digit-decimal-output decoder on the ANSWER SHEET FOR QUESTION 4.2.2.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The truth table for the two-digit-binary-input-to-four-digit-decimal-output decoder is as follows:
A
B
Outputs
0
0
0
0
1
1
1
0
2
1
1
3
Step 4
4.3.1 Label input W
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Input W is the binary digit representing the value that will be decoded in the BCD-to-seven-segment decoder.
Step 5
4.3.2 Explain the function of the driver transistors found in the BCD-to-seven-segment display decoder
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The driver transistors in a BCD-to-seven-segment display decoder are responsible for providing the necessary current to each segment of the display. They act as switches that enable the segments to illuminate based on the decoded input.
Step 6
4.3.3 Complete the truth table of a BCD to seven-segment decoder connected to a seven-segment display in TABLE 4.3.3
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The truth table for the BCD to seven-segment decoder is as follows:
B
C
D
A
a
b
c
d
e
f
g
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
0
1
1
0
0
0
0
0
0
1
0
1
1
0
1
0
0
0
0
0
1
1
0
1
1
1
0
0
0
Step 7
4.4.1 Draw the logic circuit of this half adder using an AND gate and an exclusive OR gate only
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The logic circuit of a half adder consists of an XOR gate to produce the sum output and an AND gate to produce the carry output. Connect the two inputs (A and B) to these gates appropriately to ensure accurate results.
Step 8
4.4.2 Complete the truth table of this flip flop in TABLE 4.4.2.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The truth table for the half adder is:
A
B
Σ
C0
0
0
0
0
0
1
1
0
1
0
1
0
1
1
0
1
Step 9
4.5.1 Draw the logic circuit of this flip flop on the ANSWER SHEET FOR QUESTION 4.5.1, using NAND gates only
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The logic circuit for the clocked RS-type flip-flop can be constructed using two NAND gates. Connect the SET (S) and CLEAR (R) inputs appropriately to control the output states based on the clock signal.
Step 10
4.5.2 Complete the truth table of this flip flop in TABLE 4.5.2.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The truth table for the clocked RS flip-flop is:
CLK
S
R
Q
Q'
0
0
0
Q
Q'
0
1
0
1
0
0
0
1
0
1
1
1
1
-
-
Step 11
4.6 Name TWO applications of counters
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Digital clocks, which rely on counters for timekeeping.
Event counters, used in various applications to count occurrences of specific events.
Step 12
4.7 Describe how data is introduced to the register.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Data is introduced to the shift register in parallel, meaning all bits enter the register simultaneously. This is typically done using data inputs, which can be connected to a data source or another part of the circuit.
