relay vs impulse relay

relay and impulse relay both are nouns.

Word	Noun	Adjective	Verb	Adverb
relay	Yes	No	Yes	No
impulse relay	Yes	No	No	No

As nouns, impulse relay is a hyponym of relay; that is, impulse relay is a word with a more specific, narrower meaning than relay:

relay: electrical device such that current flowing through it in one circuit can switch on and off a current in a second circuit
impulse relay: a relay that maintains either contact position indefinitely without power applied to the coil.

Other hyponyms of relay include bistable relay, keep relay, latching relay, stay relay, monostable relay.

relay (noun)	impulse relay (noun)
the act of passing something along from one person or group to another	a relay that maintains either contact position indefinitely without power applied to the coil.
electrical device such that current flowing through it in one circuit can switch on and off a current in a second circuit
a race between teams; each member runs or swims part of the distance
a crew of workers who relieve another crew
a fresh team to relieve weary draft animals

relay (verb)	impulse relay (verb)
pass along
control or operate by relay