True, clicking ads and pop-ups can expose your computer to malware.
In sinusoidal functions or in waves, "phase" has two different, but closely related, meanings. One is the initial angle of a sinusoidal function at its origin and is sometimes called phase offset or phase difference. Another usage is the fraction of the wave cycle that has elapsed relative to the origin.
Answer: To be useful for most household applications, DC voltage is passed through a step-down transformer.
Explanation: Voltage coming through AC or DC outlets is typically far too high for most household appliances to handle, so the current is passed through a step-down transformer to reduce the voltage to a usable level.