to assemble a circuit you just need to connect one end of a wire to the battery and the other to the light bulb ( could be another electrical device) now take an other wire and connect on end of it...
Circuit on a circuit board receives electronic signals from the input port, processes it into electronic signals suitable for the machine at the output port and delivers output electronic signal at...
A circuit board
It is a board containing devices passive and/or active that can be installed on a system to make it whole. Usualy refered a PCB OR PRINTED CIRCUIT BOARD.