Fundamentals of Electricity and Electronics practice questions

Answer: C) It holds voltage steady by controlling field current

• AIncorrect. An inverter converts DC to AC.
• BIncorrect. Storing energy is the battery's job.
• CCorrect. Adjusting field current keeps output voltage within limits.
• DIncorrect. Circuit breakers and fuses provide overcurrent protection.

Answer: A) Wear a grounded wrist strap during removal and ship the unit in a static-shielding bag

Standard ESDS practice is to ground the technician with a wrist strap and to keep the part in static-shielding packaging. Ordinary plastic, rubbing with dry synthetic materials, and touching connector pins can all cause damaging static discharge.

• ACorrect. A grounded wrist strap keeps the technician at the same potential as ground, so static drains away harmlessly. Static-shielding packaging protects the unit from charge during transport.
• BIncorrect. Ordinary plastic packaging can build up a triboelectric charge and gives no static shielding. ESDS parts need anti-static or static-shielding packaging.
• CIncorrect. Rubbing pins with a dry synthetic brush can generate static and send a discharge straight into the sensitive circuits.
• DIncorrect. The connector pins lead directly to internal circuits, so touching them is a likely ESD path. ESDS units should be handled by the case and the pins left uncovered only when necessary.

Answer: A) To provide a low-resistance electrical path between the parts

Bonding jumpers give a low-resistance electrical path between parts. This equalizes static charge, reduces radio interference, and provides a return path for normal, fault and lightning currents.

• ACorrect. Bonding ties parts together electrically. This equalizes static potential, reduces radio noise, gives a return path for normal and fault current, and helps carry lightning current safely.
• BIncorrect. Bonding jumpers are light, flexible straps. They carry no structural load; fasteners and structure do that.
• CIncorrect. Bonding does the opposite. It connects parts electrically so no potential difference builds up between them.
• DIncorrect. A bonding connection must have low resistance so it can carry current without heating or arcing.

Answer: C) 16 volts

• AIncorrect. The source voltage divides between the two resistors.
• BIncorrect. 8 volts is the drop across the 4-ohm resistor.
• CCorrect. Current is 24 ÷ 12 = 2 A; 2 A × 8 Ω = 16 volts.
• DIncorrect. The drops split in proportion to resistance, not equally.

Answer: B) Fit a grommet in the hole, or support the bundle so it clears the edge

Where wiring passes through holes in structure, it must be protected from sharp edges. This is normally done with a grommet in the hole or with clamps that hold the bundle clear of the edge.

• AIncorrect. Tape wears through and comes loose with vibration. It is not an accepted substitute for edge protection at a hole.
• BCorrect. A grommet covers the sharp edge of the hole, and cushioned clamps keep the bundle from touching the edge. This prevents abrasion of the insulation.
• CIncorrect. Primer prevents corrosion, not chafing. A thin coating gives no lasting protection against a vibrating bundle.
• DIncorrect. Wiring needs some slack. A taut bundle strains terminals and can still saw against the edge.

Answer: A) In series with the load

• ACorrect. All the current must pass through the ammeter, so it is placed in series.
• BIncorrect. Voltmeters are connected in parallel.
• CIncorrect. This could short the battery.
• DIncorrect. It must be in the circuit.

Answer: A) Stores charge; blocks steady DC

• ACorrect. A capacitor stores energy in an electric field and blocks steady direct current.
• BIncorrect. That is a motor.
• CIncorrect. That is a diode.
• DIncorrect. That is an ammeter.

Answer: C) The wire is unbroken

• AIncorrect. A continuity check end to end does not show this.
• BIncorrect. A break shows very high (infinite) resistance.
• CCorrect. Near-zero resistance shows a continuous path.
• DIncorrect. A reading shows the meter is working.

Answer: C) It is the same

• AIncorrect. Each branch sees the source voltage.
• BIncorrect. Voltage divides in series circuits.
• CCorrect. Each parallel branch has the full source voltage across it.
• DIncorrect. Branch voltages are equal, not summed.

Answer: A) A rectifier

• ACorrect. A rectifier, typically built with diodes, converts AC to DC.
• BIncorrect. An inverter converts DC to AC.
• CIncorrect. A transformer changes AC voltage only.
• DIncorrect. A thermocouple measures temperature.