IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINE

PURPOSE:To make an ignition device go off without using a semiconductor element between secondary winding and a spark plug, by driving a current controlling device only at a conducting period of time when an ignition signal is inputted, while feeding high voltage to the spark plug at ignition timing. CONSTITUTION:A shift register SR1 is reset by a cylinder discriminating signal S2, and outputs a pulse signal in selecting it from terminals 0-3 in order at every ignition signal S1, while each of monostable multivigrators MM2-MM5 outputs each of ignition signals S3-S6 of the specified width. On the other hand, an MM1 outputs a pulse signal S9 of the specified frequency and a pulse signal S10 of the opposite phase to the former, and these signals are fed via a theoretical circuit after giving driving signals S11-S14 to ignition coils 21 and 25 via transistors Tr1-Tr4 and feeding ignition currents J1-J4 to each of spark plugs 22, 23, 26 and 27 in a correspondent manner. Thus, no radio noise is produced there, and an ignition device is able to make it excellent in reliability in an inexpensive manner.