I want to reduce a voltage from 220 V to 110 V but I do not want to use a transformer, because besides being expensive, I need a high power (more than 100 W).
Unfortunately, the best way to reduce high alternating voltages (110 V or 220 V) is still the transformer. Other methods exist but are not always applied. They are:
a) Use a resistor of the same value as the load in series. In this case, however, the resistor will dissipate the same energy as the load and the losses will be very large. In addition, this method is only valid if the load is fed by a constant current. Valid example: a resistor in series with a lamp or an LED for powers up to a maximum of 5 or 10 W.
b) A capacitive reducer (see our article on sources without transformer). However, the transformer will be larger the higher the current required by the load. This method only applies to currents up to a maximum of 200 mA.
c) Use a switched power supply, but in this case, it is necessary to see if the load supports this type of power, with a frequency different from the one used in the network and with characteristics that allow to use waveforms that are not sinusoidal. It applies to the case where it is necessary to reduce the alternating voltage of the network to a lower DC voltage, which can be rectified in a transformer with ferrite core.
In short, to reduce high alternating voltages to smaller alternating voltages the best solution is still the transformer.
