Electrical Systems Flashcards
7 cards from real ASE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electrical Systems flashcards as text
During cranking, the voltage drop across the positive battery cable measures 1.1 V. What is the most likely cause?
Answer: High resistance in the positive cable or its connections
A cable-side voltage drop above about 0.5 V during cranking indicates excessive resistance in the cable or terminals.
After all modules have gone to sleep, which parasitic draw reading is generally acceptable on most late-model vehicles?
Answer: 50 mA or less
Most manufacturers allow roughly 50 mA or less of key-off draw once modules enter sleep mode.
A hydrometer reading of a fully charged lead-acid battery cell at 80°F should be approximately:
Answer: 1.265
A fully charged cell typically reads about 1.265 specific gravity at 80°F.
A 12-volt circuit has a total resistance of 4 ohms. How much current flows?
Answer: 3 A
By Ohm's law, I = E/R, so 12 V divided by 4 ohms equals 3 A.
A battery at rest shows an open-circuit voltage of 12.4 V. What is its approximate state of charge?
Answer: 75%
About 12.6 V is full charge and 12.4 V corresponds to roughly 75% charge.
An AC ripple reading of 1.2 V AC at the alternator output terminal most likely indicates:
Answer: A faulty diode or stator winding
AC ripple above about 0.5 V AC points to a failed rectifier diode or stator winding.
In a series circuit, what happens to total current when an additional resistor is added?
Answer: Current decreases
Adding series resistance raises total resistance, so current drops per Ohm's law.