Practice Test Geeks(ISCET) International Society of Certified Electronics Technicians Practice Test

ISCET Cheat Sheet 2026

The 30 highest-yield ISCET facts, distilled from real exam questions. Print it, save it as a PDF, or study it here โ€” free, no sign-up.

75 questions
120 min time limit
75% to pass
  1. In an N-channel JFET, pinch-off voltage (Vp) is the gate-to-source voltage at which: โ†’ The channel is fully depleted and drain current drops to nearly zero
  2. Three resistors of 6ฮฉ, 12ฮฉ, and 4ฮฉ are connected in parallel. What is the equivalent resistance? โ†’ 2ฮฉ
  3. In a MOSFET, the gate terminal is insulated from the channel by which material? โ†’ Silicon dioxide (SiO2)
  4. Which oscilloscope control is used to shift the waveform vertically without changing the amplitude scale? โ†’ Position (vertical)
  5. In an RL circuit, the time constant ฯ„ is defined as: โ†’ L / R
  6. A PIN diode is commonly used in RF applications because: โ†’ Its intrinsic (I) region provides a voltage-controlled resistance at RF frequencies
  7. What is the conductance of a 25ฮฉ resistor? โ†’ 0.04 S
  8. Which instrument is best suited for checking the switching speed of a transistor in a digital circuit? โ†’ Oscilloscope
  9. Which of the following Boolean expressions correctly represents one of De Morgan's theorems? โ†’ NOT (A AND B) = (NOT A) OR (NOT B)
  10. A capacitor is rated 47 ยตF, 50V AC. Operating it at 60V would most likely cause: โ†’ Dielectric breakdown and possible failure
  11. When using a digital multimeter to measure resistance, the display shows "OL". What does this indicate? โ†’ The measured resistance is too high for the selected range, or the circuit is open.
  12. An SCR in a power control circuit fails to trigger. Which component should be checked first? โ†’ The gate triggering circuit
  13. What is the diffusion capacitance of a forward-biased p-n junction proportional to? โ†’ Forward bias current
  14. In a digital logic circuit, a gate output is stuck HIGH regardless of input combinations. Which fault is least likely? โ†’ Open output pin
  15. Which measurement technique is used to eliminate the resistance of test leads when making a precise 4-wire (Kelvin) resistance measurement? โ†’ Current is forced through two leads while voltage is sensed on two separate leads
  16. A zener diode is primarily used in circuits for: โ†’ Voltage regulation
  17. A Zener diode is used primarily in which region of its V-I characteristic? โ†’ At the Zener breakdown voltage
  18. In a RISC (Reduced Instruction Set Computer) architecture, which characteristic distinguishes it from CISC? โ†’ Most instructions execute in a single clock cycle
  19. What is the primary advantage of using a Darlington transistor pair configuration? โ†’ Very high current gain (ฮฒ_total โ‰ˆ ฮฒโ‚ ร— ฮฒโ‚‚) with improved drive capability
  20. What is the key difference between a latch and a flip-flop in digital sequential circuits? โ†’ Latches are level-triggered, while flip-flops are edge-triggered.
  21. Which color is typically used for ground wires in electronics? โ†’ Green or green/yellow
  22. A technician is substituting components to isolate a fault. What is the main risk of this method? โ†’ It may damage the replacement component if the root cause is not addressed
  23. What logic function does a half adder implement? โ†’ Adds two bits and produces a sum and carry-out
  24. What is the maximum power transfer condition in a DC circuit? โ†’ Load resistance equals source resistance
  25. A 50V source drives current through a series circuit of 10ฮฉ, 15ฮฉ, and 25ฮฉ. What is the voltage drop across the 15ฮฉ resistor? โ†’ 15V
  26. What is the relationship between the diffusion length (L) and minority carrier lifetime (ฯ„) and diffusivity (D)? โ†’ L = โˆš(D ร— ฯ„)
  27. When using a wattmeter to measure power in a circuit, the wattmeter reads zero even though voltage and current are present. This MOST likely indicates: โ†’ The load is purely reactive (no resistive component)
  28. Which doping profile produces an abrupt p-n junction as opposed to a graded junction? โ†’ Ion implantation with a step-function profile at the metallurgical junction
  29. What does it mean when a logic probe LED remains continuously lit (not pulsing) on a digital circuit node? โ†’ The node is stuck at a constant HIGH logic level
  30. The unity-gain frequency (fT) of a BJT is defined as the frequency at which the common-emitter current gain (|hFE|) equals: โ†’ 1
Turn these facts into recall:
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