The Fiat Uno ignition system is divided into two circuits, the low tension (LT) circuit and the high tension (HT) circuit. The low tension (sometimes known as the
primary) circuit consists of the battery, the lead to the ignition switch, the lead from the ignition switch to the low tension or primary coil windings, and the lead from the low tension coil windings to the contact breaker points and condenser in the distributor.
The high tension circuit consists of the high tension or secondary coil windings, the heavy ignition lead from the center of the coil to the center of the distributor cap, the rotor arm, and the spark plug leads and spark plugs. High tension voltage is generated in the coil by the interruption of the low tension circuit. The interruption is effected by the opening of the contact breaker points in this low tension circuit. High tension voltage is fed from the center of the coil via the carbon brush in the center of the distributor cap to the rotor arm of the distributor.
The following circuit and schematic diagram shows typical ignition circuit of Fiat Uno which consists of primary and secondary winding, ignition switch, condenser, sparking plugs, rotor, distribution cap and battery.