You will need
  • transformer, resistor, capacitor
Device for reducing the voltage at the base of the transformers are usually used in alternating current. If there are surges, it is recommended to use stabilizing devices (ferroresonant stabilizers). The projected increase in voltage may compensate for an ordinary autotransformer. This device also will provide a reduction in the magnitude of the voltage within the specified range. At the heart of all these devices use different types of transformers.
For low-power consumers in alternating current you can use a damping resistor or capacitor. The value of the resistor (in ohms) can be calculated by the following formula: R = Uпад/I = (IP - U)/I. Capacitance (in microfarads) of the quenching capacitor can be calculated by the formula: C = 3200 I/, where R is the resistor value, Ohm; I is consumed by the device current, A; Uпад – voltage, which needs quenching resistor, In; IC – voltage network; U – voltage power supply devices, V.
To reduce the supply voltage in DC current, in most cases, are used sequentially included in the circuit the Zener diode, microbore stabilizer (ROLL) or switching Converter. Various types of these devices designed to reduce voltage to a certain value. The above electronic devices based on the properties of semiconductors. So their use requires a solid knowledge in electronic engineering.