# Electrical Technology Grade 12 Eastern Cape Mock 2023 Memo

> Grade 12 Electrical Technology memorandum from the Eastern Cape Mock Exam 2023 (English), 14 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/elec-tech-memo-sept2023-digital-english/1d2b04e7-c486-4f4e-9494-b0ccbcaf2ebb
- Updated: 2026-09-27
- Subject: Electrical Technology
- Grade: Grade 12
- Language: English
- Document type: Memorandum
- Year: 2023
- Exam period: Eastern Cape Mock Exam
- Curriculum: CAPS
- Pages: 14

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## About this document

Electrical Technology · Grade 12 · Eastern Cape Mock Exam · 2023 · English. Memorandum, 14 pages. Read online or download the PDF.

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## Document text

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### Page 1

NATIONAL
                   SENIOR CERTIFICATE

                           GRADE 12

                    SEPTEMBER 2023

ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS
              MARKING GUIDELINE

MARKS:   200

               This marking guideline consists of 14 pages.

### Page 2

2                    ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS               (EC/SEPTEMBER 2023)

INSTRUCTIONS TO MARKERS

1.   All calculations with multiple answers imply that any relevant, acceptable answer
     should be considered.

2.   Calculations:

     2.1     All calculations must show the formulae.

     2.2     Substitution of values must be done correctly.

     2.3     All answers MUST contain the correct unit to be considered.

     2.4     Alternative methods must be considered, provided that the correct
             answer is obtained.

     2.5     Where an incorrect answer could be carried over to the next step, the
             first answer will be deemed incorrect. However, should the incorrect
             answer be carried over correctly, the marker has to re-calculate the
             values, using the incorrect answer from the first calculation. If correctly
             used, the candidate should receive the full marks for subsequent
             calculations.

     2.6     Markers should consider that learners answers may deviate slightly from
             the marking guideline depending on how and where in the calculation
             rounding off was used.

3.   This marking guideline is only a guide with model answers.

4.   Alternative interpretations must be considered and marked on merit. However,
     this principle should be applied consistently throughout the marking session at
     ALL marking centres.

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### Page 3

(EC/SEPTEMBER 2023)   ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS              3

QUESTION 1: MULTIPLE-CHOICE QUESTIONS

1.1     B✓                                                                   (1)

1.2     A✓                                                                   (1)

1.3     C✓                                                                   (1)

1.4     D✓                                                                   (1)

1.5     D✓                                                                   (1)

1.6     B✓                                                                   (1)

1.7     D✓                                                                   (1)

1.8     B✓                                                                   (1)

1.9     D✓                                                                   (1)

1.10    D✓                                                                   (1)

1.11    D✓                                                                   (1)

1.12    B✓                                                                   (1)

1.13    A✓                                                                   (1)

1.14    D✓                                                                   (1)

1.15    C✓                                                                  (1)
                                                                           [15]

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### Page 4

4                    ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS             (EC/SEPTEMBER 2023)

QUESTION 2: OCCUPATIONAL HEALTH AND SAFETY (GENERIC)

2.1     •   Integrity ✓
        •   Sense of responsibility ✓
        •   Emphasis on quality
        •   Discipline
        •   Sense of teamwork                                             (Any 2 x 1)     (2)

2.2     An event that causes grave or severe physical injury to a person, ✓
        threatening their health and safety. ✓                                            (2)

2.3     • Avoid direct contact with any chemical ✓
        • Always wear personal protective clothing
        • Always read and be aware of the warning symbols on containers
                                                                    (Any 1 x 1)           (1)

2.4     An unsafe act is the wilful performance of a task or activity in a manner that
        may threaten the health and safety of everyone. ✓
        A calculated risk is the probability that injury or damage may occur while
        using dangerous equipment. ✓                                                      (2)

2.5     • To prevent oneself from being electrocuted. ✓
        • To prevent injury                                               (Any 1 x 1)     (1)

2.6     This could damage the equipment and render the equipment unsafe ✓ and
        compromise the safety of the user. ✓                                              (2)
                                                                                         [10]

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### Page 5

(EC/SEPTEMBER 2023)          ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                     5

QUESTION 3: SWITCHING CIRCUITS

3.1    3.1.1   Monostable multivibrator ✓                                                  (1)

       3.1.2   Bistable multivibrator ✓                                                    (1)

3.2                                                   RF
                                                           ✓

                                                         + 12 V. ✓
                                                A
                                                     -
                                                B    +
                                                         - 12 V. ✓        R1
                                    C1 .    ✓                                    VOUT. ✓
       VC
                                                                          R2

                                      t
                                                                                           (5)

3.3    3.3.1   Bistable ✓multivibrator ✓                                                   (2)

       3.3.2   Resistors 𝑅1 and 𝑅2 are pull-up ✓ resistors. ✓                              (2)

       3.3.3   When set is pressed, it pulls pin 2 ‘low’ ✓ (0 V) and cause the
               output to go ‘high’. ✓ turning the LED on. ✓                                (3)

       3.3.4   Threshold pin 6 is purposefully held at 0 V ✓ causing the IC not to
               reset, ✓ keeping the output high ✓ when 𝑆1 is pressed.                      (3)

3.4    3.4.1   The output signal represents an inverting Schmitt trigger ✓ because
               the output signal is inverted✓ with reference to the input signal. ✓        (3)

       3.4.2                                        ✓
                         ✓                      + VCC
                      VIN                                                   ✓
                                                ✓                        VOUT

                                                    ✓           RF   ✓
                                                -VCC

                                                                R1   ✓

                                                                         0V
                                                                                           (7)

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### Page 6

6                        ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                                     (EC/SEPTEMBER 2023)

3.5     3.5.1 The gain of the amplifier is determined by the ratio ✓ of the feedback
              resistance ✓ to the input resistance of each. ✓                                                            (3)

        3.5.2 VOUT = - (V Rf + V Rf + V Rf ) ✓
                         1 R1   2 R2   3 R3

                                                   100 kΩ                100 kΩ                100 kΩ
                          = − (200 mV 20 kΩ + 300 mV 10 kΩ + 400 mV 25 kΩ ) ✓

                           = −(200 mV × 5) + (300 mV × 10) + (400 mV × 4)✓

                           = −5,6 V ✓                                                                                    (4)

        3.5.3 VOUT             = VIN × Gain

                                   VOUT
                     Gain AV   =                   ✓
                                   VIN
                                             5,6
                               = 0,2 + 0,3 + 0,4 ✓

                               = 6,2 V ✓                                                                                 (3)

        3.5.4 With a variable resistor in the feedback loop, the gain ✓ of the amplifier
              can be varied / controlled. ✓                                                                              (2)

        3.5.5 If R2 is changed to 5 kΩ, the gain for V2 will increase, ✓ causing the
              total output voltage to increase. ✓                                                                        (2)

3.6              +V                                                                   C
                                                                                      F    ✓
           Input ✓
                                                            R                         +V ✓
                0V                            VIN               IN   ✓
                                         t                                        -
                0V                                                                                             V
                                                                                                              OUT   ✓
                                                                                  +
           Output ✓
                                                                                      -V
               - VSAT                                                                                          0V

                                                                                                                         (6)

3.7    •     The inputs draw zero current. ✓
       •     The two inputs will always have the same voltage. ✓
       •     The capacitor will charge at a constant rate, when a constant current is
             supplied. ✓                                                                                                 (3)
                                                                                                                        [50]

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### Page 7

(EC/SEPTEMBER 2023)             ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                   7

QUESTION 4: SEMICONDUCTORS

4.1                                            Vcc +

                         +

                                                               Output

                            -

                                                   Vcc -
       Drawing correct. ✓
       Inputs and Output labelled correct. ✓
       Positive and Negative supplies labelled correct. ✓                                   (3)

       4.2.1    The signal will be 10 times greater than the input signal/the output
                will be 1 V. ✓ and the output signal will be 180° out of phase with the
                input signal.✓                                                              (2)

       4.2.2    The signal will be 11 times greater than the input signal/the output
                will be 1,1 V ✓ and the output signal will be in phase with the input
                signal. ✓                                                                   (2)

       4.3.1    No, the output signal is incorrect. ✓ The output signal should be 180°
                out of phase with the input signal because the circuit is an inverting
                amplifier. ✓                                                                (2)

       4.3.2                     R
                VOUT = VIN (R f ) V ✓
                                  IN
                                       150 × 103
                3 V = 20 × 10−3 (                  ) V✓
                                         RIN

                RIN = 1 000 Ω
                RIN = 1 kΩ ✓                                                                (3)

       4.4.1    Trigger ✓                                                                   (1)

       4.4.2    • Pin 6 sets the voltage at which the 555 IC will trigger. ✓
                • It is used to maintain the voltage across the timing capacitor ✓
                  which is then discharged through Pin 7. ✓                                 (3)

       4.4.3    The 555 IC can only operate at power supply voltages between
                +5 V ✓ to +18 V. ✓                                                          (2)

       4.4.4    The RS flip-flop stores the incoming information temporarily, ✓ until
                new information is received. ✓                                             (2)
                                                                                          [20]

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### Page 8

8                    ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS              (EC/SEPTEMBER 2023)

 QUESTION 5: DIGITAL AND SEQUENTIAL DEVICES

 5.1    •   Liquid crystal is placed between two transparent plates. ✓
        •   The transparent plates are polarised. ✓
        •   A reflecting metal surface is mounted behind the lower plate. ✓
        •   A transparent plastic plate is placed on top of the upper polarised
            plate. ✓                                                                           (4)

 5.2    • In common anode ✓ all eight LEDs are internally connected together to a
          common positive voltage rail. ✓
        • In common cathode ✓ all eight LEDs are internally connected to a
          common 0 V ground. ✓                                                                 (4)

 5.3    •   Input voltage: 2 V (2,1 to 2,5 may also be taken as correct) ✓
        •   Current flow: 20 mA ✓
        •   Reverse voltage: 6 V
        •   Power: 600 mW
        •   Soldering time: 5 s                                            (Any 2 x 1)         (2)

 5.4    5.4.1
                                                                                      +5V

                                           R1   R2   R3

                                      S1
                            1              ✓
                                                                           ✓           A0
                                      S2
                            2                   ✓         ✓
                                                              ✓
                                      S3
                            3                                                          A1
                                                                           ✓
                                                                                               (6)

        5.4.2    W=0✓
                 X =1✓
                 Y =0✓
                 Z =0✓                                                                         (4)

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### Page 9

(EC/SEPTEMBER 2023)          ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                    9

5.5
                         C                                   S
                                               =1
                         A
                                     =1
                         B
                                               &             Co
                                                        >1
                                     &
       NOTE:
       1 mark for each logic gate.
       A mark is allocated to a logic function only if the relevant function’s inputs
       and outputs are connected correctly and labelled correctly where applicable.       (5)

5.6    5.6.1
                                 D                                      ✓
                                                                                 Q
                                                    ✓               ✓
                             CLK

                                                                                 Q
                                                                     ✓
                                                        OR

                             D
                                                        &
                                                                    >=1              Q

                         CLK

                                                                    >=1              Q
                                                        &
                                          =1

                NOTE:
                1 mark for each NAND gate = 2
                1 mark for each NOR gate = 2
                1 mark for the NOT gate
                1 mark for the latch = 1                                                  (6)

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### Page 10

10                   ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS            (EC/SEPTEMBER 2023)

        5.6.2

                                                                         ✓✓✓

                              1 mark for each correct row on the table                     (3)

 5.7    5.7.1

                 NOTE: A mark is allocated for the correct count at each clock pulse
                       e.g. the count at clock pulse 3 should be 011 and at clock
                       pulse 8 the count should be 000.                                    (8)

        5.7.2    The circuit in FIGURE 5.6 is synchronous. ✓                               (1)

 5.8    A synchronous counter uses a common clock pulse ✓ that tries to clock all
        the various JK flip-flops simultaneously. ✓

        An asynchronous counter has a clock pulse only on the first JK latch ✓ that
        serves as the LSB. The output of each JK latch is set as the clock pulse for
        the next JK latch. ✓                                                               (4)

 5.9    •   SIPO (Series-In-Parallel-Out) ✓
        •   PIPO (Parallel-In-Parallel-Out) ✓
        •   SISO (Series-In-Series-Out) ✓
        •   PISO (Parallel-In-Series-Out)                                (Any 3 x 1)       (3)

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### Page 11

(EC/SEPTEMBER 2023)           ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                             11

5.10
                                                ✓ Drawing correct
                                                ✓ Q 0 to Q 2 = 1 Mark

                                                Q2                 Q1                 Q0

               ✓ Data in
                                      SET                SET                SET
                                  D         Q        D         Q        D         Q
               ✓      Clock
                                      CLR   Q            CLR   Q            CLR   Q

                ✓ Reset
        MARKING NOTE:
        • Each correct label receives 1 mark. NB: Q0 to Q2 together counts as
          one label.
        • 1 mark is awarded for the sketch if it is correct.                                           (5)
                                                                                                      [55]

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### Page 12

12                   ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                          (EC/SEPTEMBER 2023)

 QUESTION 6: MICROCONTROLLERS

 6.1    Microcontrollers are used in industrial control devices:
        • Industrial instrumentation ✓
        • Monitoring ✓
        • Process control
        • Cooling systems                                                               (Any 2 x 1)      (2)

 6.2    NOTE:
                                               Fetch instruction
                                                  (and data)

                                                                           ✓

                         Execute instruction                       Decode instruction

                           ✓                                                  ✓

                                                     ✓
        NOTE: 1 mark for each correct label = 3
              1 mark for correct connection and direction = 1                                            (4)

 6.3    A microprocessor is simply an IC which has only the Central Processing Unit
        (CPU) inside it. ✓
        A microcontroller is essentially a complete, small-scale computer ✓ with all
        the necessary devices required to function, ✓ embedded together on a
        single IC chip. ✓
                                             OR

        A microprocessor is an Integrated Circuit (IC) with only a Central Processing
        Unit (CPU).
        A microcontroller is a complete, small-scale computer with all the necessary
        devices required to function, embedded together on a single IC chip.                             (4)

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### Page 13

(EC/SEPTEMBER 2023)             ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS                     13

  6.4

                                                 CPU / SVE

                                 BUSSES
                                 BUSSE

          NOTE:
          • 1 mark is awarded per label.
          • The 6th mark is awarded if the learner has all labels correct and the
             sketch is also drawn correctly.
          • The positioning of the components may differ from that of the marking
             guideline.                                                                             (6)

  6.5     •   Memory data register ✓
          •   Memory address register ✓
          •   Counter register ✓
          •   Control register
          •   Current-instruction register                                      (Any 3 x 1)         (3)

  6.6     It receives analogue data ✓ and converts the data into digital format which
          is then made available to the microcontroller to do further calculations. ✓               (2)

  6.7
                            ✓                                                   ✓

                         Receiver                                        Transmitter
                                                     ✓
                       Transmitter                                        Receiver
                                              (simultaneous) ✓
                                                             ✓                                      (4)

  6.8     •    Half-duplex ✓
          •    Full duplex/duplex ✓                                                                 (2)

  6.9     6.9.1       The Memory Data Register (MDR) stores a copy ✓ of the current
                      instruction to be executed. ✓                                                 (2)

          6.9.2       The Current Instruction Register (CIR) splits the instruction into two
                      parts. ✓ One part is decoded by the control unit ready for
                      execution, ✓ the other part is the address of the data stored that
                      needs to be used together with that instruction. ✓                            (3)

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### Page 14

14                    ELECTRICAL TECHNOLOGY: DIGITAL ELECTRONICS             (EC/SEPTEMBER 2023)

6.10   Takes up a lot of space on the logic chip for the parallel paths. ✓
       Makes manufacturing the logic chip more complex. ✓                                       (2)

6.11   6.11.1    •   Point of sale (POS) terminals ✓
                 •   Metering instruments ✓
                 •   Large special automated machines ✓
                 •   Modems
                 •   Computer Numerically Controlled machines (CNC) Robots
                 •   Embedded control computers
                 •   Medical instruments and equipment                 (Any 3 x 1)              (3)

       6.11.2    Differential ✓                                                                 (1)

6.12   In legal data flow the data lines will follow on another after a specific
       action ✓ and they will not cross one another or move against the other
       flow. ✓

       In illegal data flow the data lines will just end without reaching a function. ✓
       The data lines may also move against the flow of other lines or the data lines
       may cross other data lines. ✓                                                            (4)

6.13

       1 mark for each correctly placed label = 6
       1 mark for each correctly placed flow line = 2                                          (8)
                                                                                              [50]

                                                                               TOTAL:          200
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