Marine Technician Electrical & Electronics Flashcards
7 cards from real MTC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Marine Technician Electrical & Electronics flashcards as text
What is the purpose of a marine battery combiner (ACR — Automatic Combining Relay)?
Answer: To automatically connect house and start batteries in parallel when either is being charged
An ACR closes when it senses charging voltage, combining battery banks to accept charge, and opens when voltage drops to prevent cross-discharge.
On a marine diesel engine's electronic fuel injection system, the common rail stores fuel at pressures typically ranging from:
Answer: 5,000–30,000 PSI
Common rail diesel systems maintain fuel at extremely high pressures (5,000–30,000+ PSI) to enable precise, multi-event injection through solenoid-controlled injectors.
Which condition would cause a marine GPS chartplotter to display an 'HDOP HIGH' warning?
Answer: Available satellites are clustered in one area of the sky, reducing geometric accuracy
HDOP (Horizontal Dilution of Precision) is high when visible GPS satellites have poor geometric spread, reducing the accuracy of position calculations.
A marine technician is diagnosing an engine that cranks but won't start. The CKP (crankshaft position sensor) signal is absent on a scan tool. This most directly affects:
Answer: The ECM's ability to determine crank position for spark and injection timing
Without a CKP signal, the ECM cannot determine piston position, preventing it from triggering spark events and fuel injection at the correct crank angle.
In marine electrical systems, a 'bonding system' connects all underwater metal components to:
Answer: A common negative conductor that terminates at the sacrificial anode system
The bonding system equalizes electrical potential between underwater metals, directing any galvanic current through sacrificial zinc anodes rather than through the metals themselves.
What marine electronics standard defines the sentence format '$GPRMC' and similar GPS data strings?
Answer: NMEA 0183
NMEA 0183 is the older ASCII-based standard that defines sentence structures like $GPRMC (Recommended Minimum GPS data) transmitted as serial text strings.
When an outboard engine's TPS (Throttle Position Sensor) fails and reads maximum throttle at idle, the most likely symptom is:
Answer: Engine runs at maximum RPM regardless of throttle input
A TPS stuck at WOT (wide-open throttle) voltage causes the ECM to deliver maximum fuel and ignore actual throttle position, resulting in uncontrolled high RPM.