🔍 Key Concepts

• Signal ground vs. chassis/earth ground in electronic/electrical diagrams • Common ground symbols used in marine electronics schematics • How grounds are typically connected relative to the signal circuit and power supply

💭 Think About

• Look at the symbols for each labeled component (1–4) and decide which one most closely matches the standard symbol for a signal reference point. • Consider which component is tied to the return path for the signal, not necessarily to the vessels hull or earth. • Ask yourself: which labeled point is used as the common reference for voltages in the signal portion of the circuit?

✅ Before You Answer

• Verify which label is connected to multiple parts of the signal circuitry as a common reference node. • Check if any label clearly uses a ground-type symbol distinct from power positive or negative terminals. • Confirm that the chosen label is associated with signal return/reference, not just mechanical mounting or shielding.