A relay lets an electrical signal operate contacts that switch another circuit.
RF PREP // ABOUT
Free amateur radio study, without the tracking.
RF PREP is a free study service for the amateur radio community. It presents the correct answer, a concise explanation, and a key takeaway without including incorrect answer choices.
Privacy
RF PREP itself does not collect or request personal information, set cookies, run behavioral analytics, or accept or serve advertising. Ordinary web-server logs, if maintained by the hosting provider, are outside the RF PREP application.
Study use
RF PREP is an independent study aid and is not affiliated with or endorsed by the FCC or NCVEC. Users should rely on current FCC rules and official question-pool material where authoritative information is required.
Terms
The service is provided as-is for personal study and community use. No guarantee is made that every explanation is error-free or that study alone will result in passing an examination.