Rectification and Diodes Pages 450 – 454 (please read these pages for more details than I can comfortably give you!!)

Rectifying AC Rectification: The process of converting AC voltage and current from a source into DC that is used by the device. Rectifier: The device that completes the rectification process Diode: An electrical device that only allows current to pass through it in a single direction. They are placed strategically in a circuit to turn AC into DC. Circuit diagram symbol: Triangle points in the direction the conventional current will pass through the diode.

Half-wave rectification When half of an AC cycle is used (the other half is blocked) A diode is placed in series with the secondary output of a terminal and the load resistor. The diode prevents one direction of the AC circuit (either + or -) to flow, so the current through the resistor becomes DC Forward-biased diode: the direction in which current is able to pass through the diode Reversed-biased diode: the direction in which current is not able to pass because the potential difference is the wrong polarity (direction)

Problems with half-wave rectification Current is not constant. It is more of a pulse. Current must be “smoothed out”—uses a capacitor in parallel with the resistor. Creates a smoother curve that more closely represents a DC constant current

Full-wave rectification More complex circuit At least 2 diodes used (4 used in a diode bridge) Capacitor and resistor parallel combination still used

Wheatstone Bridge Used in DC circuits Useful for determining the value of an unknown resistance based on how it interacts with other known resistors