What does it mean to buck or boost a voltage with the use of a transformer?
Transformers of 2 windings can be reconnected as an auto transformer depending on the relative connection of the secondary with respect to the primary. One can obtain ether the sum of the input and output, or the difference between the input and output voltages. An example would be: 120 volt primary, 12 volt secondary. By connecting the secondary winding to one end of the primary, the secondary may be 132 volts, or by reversing the secondary leads the output may then be 120 volts minus 12 volts or 108 volts. The boosting transformer connection is often used where consistently low voltage prevails. For example, you may have 105 volts in which case you use a transformer reconnected to boost this voltage as outlined in the above procedure. The output voltage would be 10% greater than the input of 105 volts or approximately 116 volts. This type of transformer connection is often used for boosting 208 volts to 230 volts.
