Current conveyor
A current conveyor is an abstraction for a three terminal analogue electronic device. It is a form of electronic amplifier with unity gain. There are three versions of generations of the idealised device, CCI, CCII and CCIII. When configured with other circuit elements, real current conveyors can perform many analogue signal processing functions, in a similar manner to the way op-amps and the ideal concept of the op-amp are used.