Half-wave Rectifier

Since diodes restrict the flow of current to one direction, they can be used to convert an AC power supply, which switches polarity from + to - many times a second, into a straight DC supply.

The simplest rectifier uses one diode, like this:

Called a half-wave rectifier, this circuit takes an AC signal in and chops off anything that falls below 0 Volts.

Signal In:

Signal Out (Half-wave):

The half-wave rectifier is used in AM radios to rectify the signal. But for a rectifier in a power supply, it leaves something to be desired -- we lose half the power! Luckily, we can do better.

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