1/N CHECK SYSTEM

PURPOSE:To prevent relay not selected from being actuated in error by flowing a small current not actuating normally a load to the load to attain checking and driving or stopping the load depending on the propriety of the result of check. CONSTITUTION:A current ICHK shown in dotted lines via a contact dc6 from a 1/n check circuit 7 is flowed in the timing in caption (c). The current ICHK is a current value insufficient for the operation of a relay 2 to be driven being a load and the relay 2 is not actuated. When the current ICHK is flowed, that is, the circuit 7 checks the current ICHK in the timing shown in (d). When the result of the check is good, a drive circuit 1 flows a normal drive current Im as shown in (e) to actuate the relay 2 and if not good, the drive of the load is intermitted. Thus, even if two pass selection relays are selected in error at the same time, it is found out in advance.