🔍 Key Concepts

• Typical DC voltage levels used for digital logic circuits in marine electronic displays • Common dual supply voltages (±) used for analog and sweep/deflection circuits • Typical high-voltage range required for the CRT (cathode-ray tube) anode in radar or older electronic displays

💭 Think About

• Ask yourself: does a single display power supply in a CRT-type marine display usually feed only one part of the system, or several different sections (logic, analog, and high-voltage)? • Look at each option: which voltages are normally associated with logic ICs, which with analog/sweep circuits, and which with the CRT anode? • Consider whether it makes sense, from a design standpoint, for the display power unit to have multiple different outputs to run all internal circuits.

✅ Before You Answer

• Verify what standard logic ICs (TTL/CMOS) typically use as a supply voltage (in volts DC). • Confirm that analog and sweep circuits commonly need a positive and negative supply (±), and what that typical magnitude is. • Check that a CRT’s high-voltage anode usually requires a DC voltage in the kilovolt (kV) range, and see which option(s) reflect that.