What type of input is applied to the stator windings of a control transformer?

A control transformer is specifically designed to provide a low voltage output from a higher voltage input, making it essential in electrical applications for operating control circuits. The type of input applied to the stator windings of a control transformer is electrical. This input consists of alternating current (AC) that flows through the windings, creating a magnetic field. This magnetic field then induces a voltage in the secondary winding, resulting in the desired output voltage.

Understanding this function is crucial in applications where precise control and operation of electrical devices are necessary. The other options do not apply in this context; mechanical input involves physical forces, thermal input relates to temperature changes, and optical input pertains to light signals, none of which are relevant to the operation of a control transformer.