A device, operated by an electric current, and causing by its operation abrupt changes in an electrical circuit (making or breaking the circuit, changing of the circuit connections, or variation in the circuit characteristics).
"Got my recordings today. Was very impressed with the quality. One record was in such bad shape I never would have believed anything could be done with it. Dr Coban is great to work with and really shows he cares, not only by the great work he does, but also by the way he treats his costumers. Thanks a million! I will be sending more records in ..."