A semiconductor switch is employed in Component A generator instead of conventional mechanical switch in aircraft lightning actual transient test. One order of magnitude noise reduction is observed in open circuit voltage responses. Causes of the noises are discussed. Electro-magnetic (EM) shielding at both ends of cables under test becomes unnecessary in most cases for Component A measurements with introduction of the semiconductor switch. Simple shielding for Component H measurements is developed considering frequency range and levels of noises associated with the Component H responses. The semiconductor switch of the generator shows durability through three thousand shots of operation.