Conventional current is the flow of mobile positive charge carriers. This direction of flow is shown in the circuit below:
In a metal, the only mobile charge carriers are electrons so the physical current is in the opposite direction of the conventional current. When analysing a circuit it usually does not make any difference if the current is assumed to flow in one direction or the other — it does not cause problems to assume and work with conventional current.
Fischer-Cripps. A.C., The Electronics Companion. Institute of Physics, 2005.
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