Schematic Interpretation Flashcards

On a schematic diode symbol, the bar at the tip of the triangle identifies which terminal?

Answer: Cathode

The bar marks the cathode, and the triangle points in the direction of conventional current flow.

A diode symbol whose cathode bar has small bent ends (Z-shaped) represents which device?

Answer: Zener diode

The bent-end cathode bar is the standard symbol for a Zener diode used for voltage regulation.

Unless otherwise noted, relay contacts on an aircraft schematic are drawn in which condition?

Answer: De-energized (coil not powered)

Relay and switch contacts are conventionally shown in the de-energized, normal (shelf) position.

On a schematic, two lines that cross with no dot at the intersection indicate what?

Answer: The wires are not electrically connected

A junction dot is required to show a connection; crossing lines without a dot are not connected.

What do the dots placed near transformer windings on a schematic indicate?

Answer: Winding terminals that are in phase with each other

Dot notation marks terminals of the windings that have the same instantaneous polarity.

A capacitor symbol with one straight plate and one curved plate typically indicates what?

Answer: A polarized capacitor, with the curved plate as the negative side

In US convention, the curved plate marks the negative lead of a polarized (electrolytic) capacitor.

How does an aircraft wiring diagram differ from a schematic diagram?

Answer: The wiring diagram shows physical connections, wire numbers, connectors, and splices

Wiring diagrams detail physical routing information such as wire IDs, connector pins, and splices, while schematics show function.