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Diode and Rectifier

A diode lets current through in only one direction, with an almost constant voltage drop while conducting. A silicon diode typically has a voltage drop of about 0.7 V, nearly independent of the current. A bridge rectifier uses four diodes to turn both half-cycles of an AC voltage into the same polarity.

V_D\approx0.7\ \text{V}

voltage drop across a silicon diode in forward bias

I=\dfrac{V_S-V_D}{R}

current through a diode in series with a resistor

Symbols

$V_D$	voltage drop across the diode	V
$V_S$	source voltage	V
$R$	series resistor	$\Omega$

Example

$V_S=5$ V, $R=330$ Ω:

$I=(5-0.7)/330\approx13$ mA.

Reverse bias means (almost) no current – do not mix up forward and reverse bias.

Practise diodes and transistors for free →

Zener Diode →

Part of Electronics: Diodes and transistors.