Control transformers are a type of two-winding transformer deployed in electronic circuits that require constant voltage levels. The transformers use capacitors or other filtering options to minimise output variations and deliver a constant voltage. The best control transformers are made of high-grade materials, including copper windings. Insulating the wiring using electrolytic grade super-enamelled wire or other high-grade insulating materials, forges a strong mechanical bond and offers effective protection from the elements. Sealing the surface through vacuum impregnation of the surface with VT polyester resin or any other suitable material blocks the entry of moisture. The most common uses of control transformers are in industrial applications that involve relays and solenoids, in starter coils, timers and indicating lamps. The application of control transformers regulates the voltage, which may vary greatly on energising electromagnetic devices for the first time. The various models of single phase control transformers vary in terms of the input voltage, frequency range, output voltage and current. Installation of control rails often requires a DIN rail. A good accessory to have, which will improve certain applications, is a snap-on adapter for the DIN rail. Opt for control transformers and accessories from top manufacturers that undertake quality and safety tests and ensure their transformers comply with the relevant standards.