voltage bucking!

A voltage buck converter is a step down (switching) power supply.

See this Application note for a nice overview:

(If the link doesn't work, go to

Cheers

PeteS

If a transformer has several windings and they are connected in series they will either add or substract from the total voltage. That is called series aiding or series bucking.

Simple "buck" circuit analogy:

The 1.5 volt battery "bucks" the 12 volt battery, resulting in 10.5 volts across Rload

For completeness, here's a "boost" circuit:

The 1.5 volt battery "boosts" the 12 volt battery, resulting in 13.5 volts across Rload

The terms "buck" and "boost" are most often associated with DC to DC converters.

In the real world circuits the "bucking" or "boosting" is not done with batteries. Generally speaking, a voltage is created in a coil, and the coil is electronically switched so that the voltage in it either adds to ("boosts") the input voltage or opposes ("bucks") the input voltage.

Ed