Diode

A semiconductor that lets current flow in one direction only.

Symbol: IEC 60617 (triangle + bar)

How it works

A diode conducts current in the forward direction once the voltage across it exceeds its forward voltage drop (roughly 0.7V for silicon, 0.2-0.3V for Schottky), and blocks current in the reverse direction.

This one-way behavior is used to protect circuits from reversed power connections, to convert AC to pulsating DC (rectification), and to clamp voltage spikes from inductive loads like relay coils and motors.

CircuitForge models a diode's I-V curve with the standard exponential diode equation, using the forward voltage, saturation current (Is), and ideality factor (n) as the tunable parameters.

Key Formulas

Shockley Diode EquationI = Is × (e^(V/(n*Vt)) - 1)

Common Mistakes

Using a diode to drop voltage without a current-limiting resistor. Once the forward voltage threshold is met, the diode acts like a short circuit. Without a resistor, it will draw infinite current and destroy itself.

Common Variants

1N4148 Diode

A fast, small-signal switching diode used in logic-level and signal circuits rather than power rectification.

1N4001 Diode

A general-purpose 1A rectifier diode — the standard choice for converting AC to pulsating DC or blocking reverse power.