CETa Associate Level Certification — Questions and Answers

Question 1: What is thermal runaway in a BJT circuit, and what component is commonly used to prevent it?

Reverse breakdown; prevented by a Zener clamp
Uncontrolled increase in IC due to temperature rise; prevented by emitter resistor (RE) (Correct answer)
Oscillation at high frequency; prevented by a bypass capacitor
Base current cutoff; prevented by voltage divider bias

Correct answer: Uncontrolled increase in IC due to temperature rise; prevented by emitter resistor (RE)

Thermal runaway occurs because rising temperature increases IC, which further heats the device; an emitter resistor provides negative feedback to stabilize the operating point.

Question 2: In a D flip-flop, what happens to the output Q on the active clock edge when D = 0?

Q becomes 1
Q retains its previous value
Q becomes 0 (Correct answer)
Q toggles

Correct answer: Q becomes 0

A D flip-flop transfers the D input directly to Q on the active clock edge, so Q = 0 when D = 0.

Question 3: What is the purpose of a priority encoder?

Detects parity errors
Outputs the binary code of the highest-priority active input (Correct answer)
Converts binary to BCD
Selects one of many data sources

Correct answer: Outputs the binary code of the highest-priority active input

A priority encoder resolves simultaneous inputs by outputting the binary address of the highest-priority (typically highest-numbered) active input.

Question 4: In the Norton equivalent circuit, the Norton current is equal to:

The open-circuit voltage divided by load resistance
The current through the internal resistance
The short-circuit current at the terminals (Correct answer)
The Thevenin voltage divided by load resistance

Correct answer: The short-circuit current at the terminals

Norton current (IN) is measured by placing a short circuit across the output terminals and measuring the resulting current.

Question 5: In a J-K flip-flop, what is the output behavior when both J and K inputs are held HIGH (logic 1) and a clock pulse is applied?

The output remains in its previous state.
The output toggles to the opposite state. (Correct answer)
The output is reset to 0 (LOW).
The output is set to 1 (HIGH).

Correct answer: The output toggles to the opposite state.

When both J and K inputs of a J-K flip-flop are held HIGH, the flip-flop is in the 'toggle' mode. On each active clock edge, the output Q will invert to the opposite of its current state.

Question 6: What is the phase angle between voltage and current in a purely capacitive AC circuit?

Current and voltage are in phase
Voltage leads current by 90°
Current lags voltage by 45°
Current leads voltage by 90° (Correct answer)

Correct answer: Current leads voltage by 90°

In a purely capacitive circuit, current leads the voltage by 90 degrees.

Question 7: Which symbol on a component datasheet indicates the maximum continuous operating temperature?

T_MAX (maximum temperature)
T_J (junction temperature) (Correct answer)
T_A (ambient temperature)
T_STG (storage temperature)

Correct answer: T_J (junction temperature)

T_J or junction temperature is the critical maximum operating temperature for semiconductors, as exceeding it causes permanent damage.

Question 8: What is the primary purpose of improving the power factor in an AC circuit, ideally towards unity (1.0)?

To increase the circuit's resonant frequency.
To decrease the apparent power consumed by the load.
To reduce the total current drawn from the source for the same amount of real power. (Correct answer)
To maximize the phase angle between voltage and current.

Correct answer: To reduce the total current drawn from the source for the same amount of real power.

Power factor is the ratio of real power (used to do work) to apparent power (total power supplied). A low power factor indicates that a significant portion of the current is not performing useful work. By improving the power factor towards unity (1.0), the apparent power becomes nearly equal to the real power. This means less total current is required from the source to deliver the same amount of real power, which reduces energy losses in the distribution system and allows for more efficient operation.

Question 9: A power supply's output has 50 mV of ripple superimposed on 12 V DC. To best display the ripple on an oscilloscope without saturating the input, the technician should:

Use AC coupling and set sensitivity to 20 mV/div (Correct answer)
Use DC coupling and set sensitivity to 5 V/div
Use DC coupling and increase the timebase to 1 s/div
Use DC coupling and set sensitivity to 20 mV/div

Correct answer: Use AC coupling and set sensitivity to 20 mV/div

AC coupling blocks the 12 V DC component so the oscilloscope can be set to a sensitive range that reveals the small ripple without overdrive.

Question 10: In a common-emitter BJT amplifier, which parameter is primarily responsible for the upper cutoff frequency limitation at high frequencies?

Miller-multiplied collector-base capacitance (Cµ) (Correct answer)
Base spreading resistance only
Emitter bypass capacitor
Power supply impedance

Correct answer: Miller-multiplied collector-base capacitance (Cµ)

The Miller effect multiplies the collector-base capacitance Cµ by (1 + |Av|), creating a dominant pole that limits high-frequency response.

Question 11: A technician is troubleshooting a digital logic circuit and finds that the output of a specific IC is always LOW, regardless of the inputs. The VCC and GND pins are confirmed to have the correct voltage. Which of the following is the most likely fault?

The output of the IC is internally shorted to ground. (Correct answer)
The system clock frequency is too high.
An open circuit on one of the logic inputs.
The subsequent IC in the signal path has a shorted input.

Correct answer: The output of the IC is internally shorted to ground.

If the output of an IC is permanently stuck in a LOW state (stuck-at-0 fault) even when the inputs should produce a HIGH output, and power connections are correct, it strongly indicates an internal failure. A common internal failure mode is for the output driver transistor to be shorted to the ground plane.

Question 12: A circuit has a 24V source with two resistors in series: 6Ω and 18Ω. What is the voltage across the 18Ω resistor?

12V
24V
6V
18V (Correct answer)

Correct answer: 18V

Using the voltage divider: V18 = 24 × (18 / (6+18)) = 24 × 0.75 = 18V.

Question 13: Which Boolean identity is known as the 'absorption' law?

A · 1 = A
A + 0 = A
A + AB = A (Correct answer)
A + A = A

Correct answer: A + AB = A

The absorption law states A + AB = A, because A already 'absorbs' the term AB.

Question 14: A half-wave rectifier is connected to a 120V RMS transformer secondary. What is the approximate average DC output voltage (ignoring diode drop)?

84.8V
120V
170V
54V (Correct answer)

Correct answer: 54V

For a half-wave rectifier, Vavg = 0.318 × Vpeak = 0.318 × (120 × 1.414) ≈ 0.318 × 169.7 ≈ 54V.

Question 15: When using a signal generator to inject a test signal into an amplifier, the output is absent. The technician should NEXT:

Replace the amplifier transistors
Change the signal generator waveform to square wave
Verify the generator output with an oscilloscope before injecting (Correct answer)
Increase the generator frequency

Correct answer: Verify the generator output with an oscilloscope before injecting

Confirming that the signal generator is actually producing an output before injection prevents misdiagnosis caused by a faulty or misconfigured generator.

Question 16: What is the hexadecimal representation of decimal 255?

FE
F0
EF
FF (Correct answer)

Correct answer: FF

255₁₀ = 15×16¹ + 15×16⁰ = FF₁₆, since F represents 15 in hex.

Question 17: A technician connects a voltmeter with an input impedance of 10 MΩ across a 10 MΩ resistor in a circuit. What is the effective resistance seen by the circuit?

5 MΩ (Correct answer)
20 MΩ
10 MΩ
1 MΩ

Correct answer: 5 MΩ

Two equal resistances in parallel yield half the value: 10 MΩ ∥ 10 MΩ = 5 MΩ, significantly loading the circuit.

Question 18: A 7812 three-terminal linear voltage regulator produces which regulated output voltage?

12V (Correct answer)
8V
5V
15V

Correct answer: 12V

The 78XX series regulators output a voltage equal to the last two digits; the 7812 outputs a fixed +12V regulated output.

Question 19: A boost (step-up) switching converter is required when:

Galvanic isolation between input and output is required
The regulated output voltage must be lower than the unregulated input voltage
The regulated output voltage must be higher than the unregulated input voltage (Correct answer)
The load requires very low ripple current

Correct answer: The regulated output voltage must be higher than the unregulated input voltage

A boost converter stores energy in an inductor during the switch on-time and releases it at a higher voltage during the off-time, producing a DC output greater than the DC input.

Question 20: What is the conductance of a 25Ω resistor?

0.04 S (Correct answer)
25 S
4 S
0.4 S

Correct answer: 0.04 S

Conductance G = 1/R = 1/25 = 0.04 siemens (S).

Question 21: The maximum reverse voltage a diode can withstand without breakdown is called the:

Holding voltage
Knee voltage
Peak Inverse Voltage (PIV) or Peak Reverse Voltage (PRV) (Correct answer)
Forward voltage rating

Correct answer: Peak Inverse Voltage (PIV) or Peak Reverse Voltage (PRV)

The PIV (or PRV) rating specifies the maximum reverse voltage a diode can block; exceeding it causes destructive avalanche or Zener breakdown.

Question 22: Which law states that the algebraic sum of all currents entering and leaving a node equals zero?

Ohm's Law
Kirchhoff's Current Law (Correct answer)
Norton's Theorem
Kirchhoff's Voltage Law

Correct answer: Kirchhoff's Current Law

Kirchhoff's Current Law (KCL) states that the sum of currents into a node equals the sum of currents out of the node.

Question 23: The process of adding impurities like phosphorus or boron to an intrinsic semiconductor like silicon is known as:

Annealing
Diffusion
Recombination
Doping (Correct answer)

Correct answer: Doping

Doping is the intentional process of adding impurities (dopants) to an intrinsic (pure) semiconductor to alter its electrical properties. Adding a pentavalent impurity like phosphorus creates an N-type semiconductor (excess electrons), while adding a trivalent impurity like boron creates a P-type semiconductor (excess holes).

Question 24: A resistor has the following color bands: Yellow, Violet, Orange, and Gold. What is the nominal resistance and tolerance of this component?

47 kΩ ±10%
470 Ω ±10%
4.7 kΩ ±5%
47 kΩ ±5% (Correct answer)

Correct answer: 47 kΩ ±5%

The resistor color code is read as follows: Yellow (4), Violet (7), Orange (multiplier of 1,000). This gives a nominal value of 47 x 1,000 = 47,000 ohms, or 47 kΩ. The fourth band, Gold, indicates a tolerance of ±5%.

Question 25: When using signal injection to troubleshoot an audio amplifier, where should you begin injecting the test signal?

At the speaker output
At the input of the first stage (Correct answer)
At the final power amplifier stage
At the power supply filter capacitor

Correct answer: At the input of the first stage

Signal injection typically starts at the input of the first stage and progresses toward the output to isolate the faulty stage.

Question 26: An oscilloscope shows a sine wave with a period of 4 ms. What is its frequency?

250 Hz (Correct answer)
400 Hz
4 kHz
25 Hz

Correct answer: 250 Hz

Frequency f = 1/T = 1/0.004 s = 250 Hz.

Question 27: Which of the following will cause the resonant frequency of a series LC circuit to decrease?

Decreasing the inductance.
Increasing the capacitance. (Correct answer)
Adding a resistor in series.
Increasing the source voltage.

Correct answer: Increasing the capacitance.

The formula for resonant frequency (f₀) in an LC circuit is f₀ = 1 / (2π√(LC)). This formula shows that the resonant frequency is inversely proportional to the square root of both the inductance (L) and the capacitance (C). Therefore, increasing either the capacitance or the inductance will cause the resonant frequency to decrease.

Question 28: In a series RC circuit, if the capacitor is shorted, what will the voltage across the resistor measure?

The capacitor's rated voltage
Full supply voltage (Correct answer)
Zero volts
Half supply voltage

Correct answer: Full supply voltage

A shorted capacitor acts as a wire, so all supply voltage drops across the resistor in series with it.

Question 29: In two's complement representation using 8 bits, what is the decimal value of 11110000₂?

-16 (Correct answer)
-8
240
-15

Correct answer: -16

11110000₂ in two's complement: invert to 00001111 (15) then add 1 = 16, so the value is −16.

Question 30: A technician measures an AC motor load and finds the real power is 1200 W and the apparent power is 1500 VA. What is the power factor of this load?

0.8 lagging (Correct answer)
1.25 leading
0.9 lagging
1.0 (unity)

Correct answer: 0.8 lagging

The power factor (PF) is defined as the ratio of real power (P) to apparent power (S). The formula is PF = P / S. Given P = 1200 W and S = 1500 VA, the power factor is 1200 / 1500 = 0.8. Since motors are inductive loads, they cause the current to lag the voltage, resulting in a lagging power factor.

Question 31: Which type of voltage regulator uses a zener diode connected in parallel with the load as its primary regulation element?

Series pass regulator
Switching regulator
Shunt regulator (Correct answer)
Buck-boost regulator

Correct answer: Shunt regulator

A shunt regulator places the regulation element (zener diode or transistor) in parallel with the load to clamp the output voltage at a fixed level.

Question 32: Transformer voltage regulation (VR%) is calculated based on the change in secondary voltage between:

Cold startup and steady-state thermal equilibrium
No-load and full-load conditions at rated input voltage (Correct answer)
Minimum and maximum input voltage at constant load
Full-load and maximum overload conditions

Correct answer: No-load and full-load conditions at rated input voltage

Transformer VR% = ((Vno-load − Vfull-load) / Vfull-load) × 100%, measuring the voltage rise when load is removed due to internal impedance.

Question 33: A technician is analyzing an AC circuit and notes that the current waveform leads the voltage waveform. Which of the following best describes the load?

Primarily inductive
Primarily capacitive (Correct answer)
The load is at resonance.
Purely resistive

Correct answer: Primarily capacitive

In an AC circuit, the phase relationship between current and voltage depends on the type of load. For a capacitive load, the current leads the voltage. Conversely, for an inductive load, the current lags the voltage. In a purely resistive circuit, the current and voltage are in phase.

Question 34: What is the voltage across an open-circuit branch in a parallel circuit if the source is 15V?

7.5V
15V (Correct answer)
0V
Infinite

Correct answer: 15V

All branches in a parallel circuit share the same voltage as the source; the open branch still has the full 15V across it.

Question 35: What is the primary purpose of a filter capacitor placed after a rectifier in a DC power supply?

To increase the ripple frequency
To limit the peak output current
To step up the DC output voltage
To smooth the pulsating DC output by reducing ripple (Correct answer)

Correct answer: To smooth the pulsating DC output by reducing ripple

A filter capacitor charges to the peak voltage and slowly discharges between peaks, reducing the ripple and smoothing the pulsating DC into a more stable output.

Question 36: In a digital logic circuit, a gate output is stuck HIGH regardless of input combinations. Which fault is least likely?

Open output pin (Correct answer)
Faulty pull-up resistor holding output high
Output pin shorted to VCC
Internal gate failure

Correct answer: Open output pin

An open output pin would float or be pulled by external components rather than being stuck definitively HIGH; the other faults directly drive the output high.

Question 37: A low-pass RC filter has R = 1 kΩ and C = 0.1 µF. What is its cutoff frequency?

approximately 15,920 Hz
approximately 1592 Hz (Correct answer)
approximately 159 Hz
approximately 6283 Hz

Correct answer: approximately 1592 Hz

fc = 1/(2πRC) = 1/(2π × 1000 × 0.0000001) ≈ 1592 Hz.

Question 38: What is propagation delay in a logic gate?

The setup time of a flip-flop
The gate's noise immunity threshold
The frequency of the clock signal
Time for the output to settle after an input change (Correct answer)

Correct answer: Time for the output to settle after an input change

Propagation delay (tpd) is the time interval between a change at the input and the resulting change at the output of a gate.

Question 39: A technician is designing a circuit that needs to select one of eight data inputs and route it to a single output. Which digital logic device is most suitable for this task?

Encoder
Demultiplexer (DEMUX)
Decoder
Multiplexer (MUX) (Correct answer)

Correct answer: Multiplexer (MUX)

A Multiplexer (MUX), also known as a data selector, is a combinational logic circuit designed to switch one of several input lines through to a single common output line. An 8-to-1 multiplexer would use three select lines (2^3 = 8) to choose which of the eight inputs is passed to the output.

Question 40: In a UJT (Unijunction Transistor), conduction begins when the emitter voltage reaches:

The supply voltage VBB
The peak-point voltage VP, which equals ηVBB + VD (Correct answer)
Zero volts
The valley voltage VV

Correct answer: The peak-point voltage VP, which equals ηVBB + VD

The UJT fires (turns on) when the emitter voltage reaches VP = ηVBB + VD, where η is the intrinsic standoff ratio and VD is the diode drop (~0.7 V).

Question 41: What is Ohm’s Law?

V = IR (Correct answer)
V = I + R
V = R/I
V = I/R

Correct answer: V = IR

Ohm's Law is a fundamental principle in electronics that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The formula V = IR states that the voltage across a conductor is directly proportional to the current flowing through it, given a constant resistance. This law is crucial for analyzing and designing circuits.

Question 42: In AC circuit analysis, Kirchhoff's Voltage Law (KVL) applies to:

Only series circuits, not parallel
Phasor (complex) voltages around a loop (Correct answer)
Only DC circuits
Only resistive AC circuits

Correct answer: Phasor (complex) voltages around a loop

KVL applies to AC circuits using phasor (complex number) representation, so phasor voltages around any closed loop sum to zero.

Question 43: Impedance matching between a source and load in an AC system is important primarily to:

Reduce capacitive reactance
Minimize current flow
Increase the resonant frequency
Maximize power transfer from source to load (Correct answer)

Correct answer: Maximize power transfer from source to load

Maximum power is transferred when the load impedance equals the complex conjugate of the source impedance.

Question 44: A 1kΩ and 3kΩ resistor are connected in series across a 20V supply. What is the power dissipated by the 3kΩ resistor?

25 mW
75 mW (Correct answer)
300 mW
100 mW

Correct answer: 75 mW

I = 20V/4kΩ = 5mA; P = I²R = (0.005)² × 3000 = 0.000025 × 3000 = 0.075W = 75mW.

Question 45: How many states does a 3-bit Gray code counter have?

16
7
6
8 (Correct answer)

Correct answer: 8

A 3-bit counter can represent 2³ = 8 unique states; Gray code provides all 8 states with only one bit changing at a time.

Question 46: In a switching power supply, the inductor's primary function during the switch off-time in a buck converter is to:

Provide a current path for the catch diode only
Step down the input voltage through transformer action
Block high-frequency switching noise from reaching the output
Act as an energy storage element that continues supplying current to the load (Correct answer)

Correct answer: Act as an energy storage element that continues supplying current to the load

During the switch off-time, the inductor's magnetic field collapses and releases stored energy, maintaining continuous current flow to the load through the freewheeling diode.

Question 47: What does the term 'skin effect' refer to in AC circuits?

Capacitive coupling between conductors
Tendency of AC current to flow near the conductor surface at high frequencies (Correct answer)
Insulation breakdown at high voltages
Impedance mismatch at circuit boundaries

Correct answer: Tendency of AC current to flow near the conductor surface at high frequencies

The skin effect causes AC current to concentrate near the outer surface of a conductor as frequency increases, effectively reducing the conductive cross-section.

Question 48: When an oscilloscope probe is switched to the ×10 position, how does this affect the observed waveform amplitude compared to ×1?

The amplitude is unchanged but bandwidth increases
The amplitude doubles and noise decreases
The displayed amplitude appears 10 times larger
The displayed amplitude appears 10 times smaller (Correct answer)

Correct answer: The displayed amplitude appears 10 times smaller

The ×10 probe divides the signal by 10 before it reaches the scope input, so the displayed voltage must be multiplied by 10 to get the actual signal.

Question 49: What is the primary purpose of power factor correction in industrial AC systems?

To reduce reactive power demand and improve efficiency (Correct answer)
To increase the impedance seen by the source
To raise the supply voltage level
To increase the resonant frequency of the system

Correct answer: To reduce reactive power demand and improve efficiency

Power factor correction (typically using capacitor banks) reduces reactive power, lowering apparent power demand and reducing I²R losses in the distribution system.

Question 50: The power factor of an AC circuit is defined as:

Apparent power divided by true power
True power divided by apparent power (Correct answer)
True power divided by reactive power
Reactive power divided by apparent power

Correct answer: True power divided by apparent power

Power factor equals true (real) power divided by apparent power, or equivalently cos(θ).

Question 51: What is the minimum PIV (Peak Inverse Voltage) rating required for diodes in a full-wave bridge rectifier with a 24V RMS transformer secondary?

24V
16.97V
33.94V (Correct answer)
48V

Correct answer: 33.94V

In a bridge rectifier, each diode must withstand a reverse voltage equal to Vpeak = 1.414 × 24V ≈ 33.94V.

Question 52: A 100Ω resistor and a 900Ω resistor form a voltage divider across 10V. What is the voltage across the 100Ω resistor?

5V
0.1V
9V
1V (Correct answer)

Correct answer: 1V

V = 10V × (100/1000) = 1V using the voltage divider formula.

Question 53: Which flip-flop condition is considered FORBIDDEN in an S-R (Set-Reset) latch?

S=0, R=0
S=1, R=0
S=1, R=1 (Correct answer)
S=0, R=1

Correct answer: S=1, R=1

When both S=1 and R=1, the latch enters an indeterminate state because both outputs try to be active simultaneously.

Question 54: Which in-circuit test method introduces a known-good signal at each stage to verify signal flow?

Signal injection (Correct answer)
Component substitution
Voltage substitution
Signal tracing

Correct answer: Signal injection

Signal injection introduces an external test signal at each stage input, allowing the technician to confirm signal flow forward through the circuit.

Question 55: What is lockout/tagout used for?

Label software programs
Enhance internet access
Mark expiration dates
Prevent unauthorized operation during maintenance (Correct answer)

Correct answer: Prevent unauthorized operation during maintenance

Lockout/Tagout (LOTO) is a safety procedure used to ensure that dangerous machines or equipment are properly shut off and cannot be started up again prior to the completion of maintenance or servicing work. It involves physically locking and tagging energy-isolating devices to prevent the release of hazardous energy. This protects workers from unexpected startup or energy release.

Question 56: What is the transconductance (gm) of a MOSFET in the saturation region given ID = 4 mA and VGS – VTH = 2 V?

0.5 mA/V
4 mA/V (Correct answer)
2 mA/V
8 mA/V

Correct answer: 4 mA/V

In saturation, gm = 2·ID / (VGS – VTH) = (2 × 4 mA) / 2 V = 4 mA/V.

Question 57: Which BCD encoding assigns weights 8-4-2-1 to the four bit positions?

Natural BCD (8421) (Correct answer)
Excess-3
Gray code
2-out-of-5 code

Correct answer: Natural BCD (8421)

Natural BCD (8421) assigns positional weights 8, 4, 2, 1 from MSB to LSB, directly representing decimal digits 0–9.

Question 58: What causes a race condition (hazard) in combinational logic?

Unequal propagation delays causing momentary incorrect output glitches (Correct answer)
Insufficient power supply
Clock skew in flip-flops
Using too many logic gates

Correct answer: Unequal propagation delays causing momentary incorrect output glitches

A logic hazard occurs when signal paths through a circuit have unequal delays, producing brief spurious output transitions.

Question 59: Which of the following Boolean expressions correctly represents one of De Morgan's theorems?

NOT (A AND B) = (NOT A) AND (NOT B)
NOT (A OR B) = (NOT A) OR (NOT B)
NOT (A AND B) = (NOT A) OR (NOT B) (Correct answer)
A AND B

Correct answer: NOT (A AND B) = (NOT A) OR (NOT B)

De Morgan's theorems are fundamental rules in Boolean algebra for converting between AND and OR operations with negation. One of the theorems states that the complement of a product of variables is equal to the sum of the complements of the variables. In Boolean terms, this is expressed as NOT (A AND B) = (NOT A) OR (NOT B).

Question 60: How can you safely test a powered circuit?

Use bare hands
Apply water cooling
Handle with insulated probes and follow safety procedures (Correct answer)
Touch all terminals

Correct answer: Handle with insulated probes and follow safety procedures

When testing a powered circuit, safety is paramount to prevent electric shock and damage to equipment. Always use test probes with proper insulation and ensure your hands are dry and free from conductive materials. Following established safety procedures, such as wearing appropriate PPE and understanding circuit hazards, minimizes risks during live circuit diagnostics.

Question 61: What happens to the total capacitance when capacitors are connected in series?

Total capacitance decreases (Correct answer)
Total capacitance remains unchanged
Total capacitance equals the largest capacitor
Total capacitance increases

Correct answer: Total capacitance decreases

Capacitors in series have a total capacitance less than the smallest individual capacitor, calculated by the reciprocal sum formula.

Question 62: A 100Ω resistor dissipates 4W of power. What current flows through it?

2A
0.04A
0.2A (Correct answer)
400A

Correct answer: 0.2A

Using P = I²R, I = √(P/R) = √(4/100) = √0.04 = 0.2A.

Question 63: What is the resonant frequency of a series LC circuit with L = 10 mH and C = 10 µF?

approximately 503 Hz (Correct answer)
approximately 1592 Hz
approximately 159 Hz
approximately 50 Hz

Correct answer: approximately 503 Hz

fr = 1/(2π√LC) = 1/(2π√(0.01 × 0.00001)) ≈ 503 Hz.

Question 64: What happens to the total current in a parallel circuit when an additional branch is added?

Total current decreases
Total current becomes zero
Total current stays the same
Total current increases (Correct answer)

Correct answer: Total current increases

Adding a branch lowers equivalent resistance, so total current from the source increases.

Question 65: What does RAM stand for in digital systems?

Rotational Allocation Memory
Rapid Access Management
Random Access Memory (Correct answer)
Read Access Module

Correct answer: Random Access Memory

RAM stands for Random Access Memory, which is a type of volatile computer memory that can be read from and written to quickly. It is used to store data and program instructions that the CPU needs to access immediately for active processing. The term 'random access' means that any byte of memory can be accessed directly, regardless of its physical location.

Question 66: A technician suspects a leaky electrolytic capacitor. Which symptom best supports this diagnosis?

No deflection on ohmmeter needle
Lower than expected resistance reading on ohmmeter (Correct answer)
Correct capacitance value on LCR meter
Infinite resistance in both directions

Correct answer: Lower than expected resistance reading on ohmmeter

A leaky capacitor has internal resistance paths causing lower-than-expected resistance readings, indicating dielectric breakdown.

Question 67: In a series RLC circuit, if XL > XC, the circuit is said to be:

Resistive only
Inductive and current lags voltage (Correct answer)
At resonance
Capacitive and current leads voltage

Correct answer: Inductive and current lags voltage

When XL > XC, the net reactance is inductive, so the circuit behaves inductively and current lags behind voltage.

Question 68: In a shift register, what happens to the data bits on each clock pulse?

Data is written in parallel to all stages
Each bit moves one position in the direction of shift (Correct answer)
Bits toggle their state
All bits are cleared to zero

Correct answer: Each bit moves one position in the direction of shift

A shift register moves (shifts) each stored bit one position left or right with each active clock edge.

Question 69: Apply De Morgan's theorem to simplify (A·B)':

A'·B'
A'+B' (Correct answer)
A+B
A'·B

Correct answer: A'+B'

De Morgan's theorem states (A·B)' = A' + B': the complement of a product is the sum of the complements.

Question 70: What does a logic probe help to detect?

Analog distortion
Digital logic levels (Correct answer)
Voltage drop
Resistance variations

Correct answer: Digital logic levels

A logic probe is a specialized handheld test instrument used to detect and display the logic state (high, low, or pulsing) of digital signals in a circuit. It typically uses LEDs or a small display to indicate these states, making it easy to troubleshoot digital circuits. Unlike an oscilloscope, it provides a quick, simple indication of logic levels rather than detailed waveform analysis.

Question 71: Which type of fire extinguisher is appropriate for electrical equipment fires?

Class A (water-based)
Class B (foam-based)
Class D (dry powder for metals)
Class C (non-conductive agent such as CO₂ or dry chemical) (Correct answer)

Correct answer: Class C (non-conductive agent such as CO₂ or dry chemical)

Class C extinguishers use non-conductive agents (CO₂, dry chemical, or clean agent) appropriate for energized electrical equipment fires, preventing shock hazard to the user.

Question 72: In an AC circuit, reactive power is measured in:

Volt-amperes (VA)
Volt-amperes reactive (VAR) (Correct answer)
Decibels (dB)
Watts (W)

Correct answer: Volt-amperes reactive (VAR)

Reactive power, which represents energy stored and returned by reactive components, is measured in volt-amperes reactive (VAR).

Question 73: Which digital-to-analog converter (DAC) architecture uses a ladder network of only two resistor values (R and 2R)?

Delta-sigma DAC
Flash DAC
Binary-weighted resistor DAC
R-2R ladder DAC (Correct answer)

Correct answer: R-2R ladder DAC

The R-2R ladder DAC requires only two resistor values and scales well to high bit counts, unlike the binary-weighted design.

Question 74: What does it mean when a logic probe LED remains continuously lit (not pulsing) on a digital circuit node?

The node is stuck at a constant HIGH logic level (Correct answer)
The node is in a high-impedance (floating) state
The probe battery is low
The node is switching at a very high frequency

Correct answer: The node is stuck at a constant HIGH logic level

A continuously lit LED on a logic probe indicates the node is held at a constant HIGH logic state rather than toggling.

Question 75: In a center-tap full-wave rectifier, what minimum PIV rating must each diode have if the transformer secondary is 50V RMS (each half)?

35.35V
70.7V (Correct answer)
50V
100V

Correct answer: 70.7V

In a center-tap rectifier, each diode must withstand 2 × Vpeak of the half-secondary voltage: 2 × (50 × 1.414) = 141.4V — but if the question means full secondary 50V RMS, then PIV = 2 × 70.7 ≈ 141.4V. For a 50V half-winding Vpeak = 70.7V, PIV = 2 × 70.7V = 141.4V; the closest listed option for a half-winding of 25V RMS is 2 × 35.35 = 70.7V.

CETa Associate Level Certification

The CETa Associate Level Certification validates fundamental knowledge in electronics technology, suitable for entry-level technicians.

Questions

120 min

Time Limit

75%

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