resistor spark plug (ignition system component). A shielded aircraft spark plug with a built-in carbon resistor between its terminal end and center electrode. Shielded ignition leads have a metal braid around the insulator, and this braid, with the insulator and conductor, acts as a capacitor and stores electrical energy.
When the spark jumps the gap in the spark plug, the energy stored in the lead capacity causes the spark to continue after the fuel is ignited. This prolonged spark needlessly wears away the spark plug electrodes. The built-in resistor causes enough opposition to this current to reduce the spark duration and increase the life of the spark plug electrodes.
resolution (radar technology). The ability of radar to show discrete targets separately. The better the resolution, the closer two targets can be to each other and still be detected as separate targets.
resolution advisory (air traffic control). A display indication given to the pilot by the traffic alert and collision avoidance system (TCAS II) recommending a maneuver to increase vertical separation relative to an intruding aircraft.
Positive, negative, and vertical speed limit advisories constitute the resolution advisories. A resolution advisory is also classified as corrective or preventive.
resonance (electrical). The condition in an electrical circuit in which the inductive reactance and the capacitive reactance are equal. The reactances are determined by the frequency, and a circuit is resonant for a very narrow band of frequencies.