Electrical and Electronic 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 and Electronic Systems flashcards as text
During cranking, a voltage drop test across the positive battery cable (battery post to starter terminal) should generally read no more than:
Answer: 0.5 volt
Most manufacturers allow about 0.5 V maximum drop on the starter's positive cable circuit under load.
After all modules go to sleep, what is a typical maximum acceptable key-off parasitic draw on most late-model vehicles?
Answer: About 50 mA or less
Most vehicles specify roughly 50 mA or less once modules have entered sleep mode.
A 12-volt circuit has a total resistance of 4 ohms. How much current flows?
Answer: 3 amps
Using Ohm's law, I = E / R, so 12 V / 4 Ω = 3 A.
A voltmeter connected across an open switch in a 12-volt series lamp circuit will read:
Answer: Battery voltage (about 12 volts)
With no current flow, there is no drop across the lamp, so the full source voltage appears across the open.
When a good silicon diode is tested with a DMM on the diode-check function, the expected readings are:
Answer: About 0.5–0.7 V one direction and OL in the other
A good diode conducts in one direction (about 0.5–0.7 V drop) and blocks in the other (OL).
An AC ripple reading above about 0.5 volt AC at the alternator output most likely indicates:
Answer: A failed rectifier diode or stator winding
Excessive AC ripple means the rectifier is not converting AC to DC properly, typically from a bad diode or stator.
On a standard ISO mini relay, terminals 85 and 86 are connected to:
Answer: The relay control coil
Terminals 85 and 86 are the coil (control) side, while 30 and 87 are the switched load contacts.