# Ideal Diode Current and Voltage Calculator

## This calculator solves for any single missing value in the ideal diode I-V equation for a forward-biased PN-junction diode. Parameters are current, saturation current, voltage, temperature, and ideality factor.

_{D}):

_{S}):

_{D}):

### Using the Ideal Diode Calculator

To use this ideal diode equation calculator, enter any four of the five variables and select the desired units. Then, push the *Calculate* button. The calculator will solve for the missing parameter. The five variables in the ideal diode formula are:

- Diode current (
*I*)_{D} - Saturation current (
*I*)_{S} - Forward-bias voltage (
*V*)_{D} - Ideality (correction) factor (
*n*) - Temperature (
*T*)

### Basics Operation of a Forward-Biased PN Junction Diode

A PN diode primarily allows current to flow in one direction. When the diode is forward-biased, as illustrated in Figure 1, the current increases exponentially.

*Figure 1. **Exponential I-V curve of a forward-biased PN junction diode*

*Figure 1.*

### Ideal Diode Current Equation

The forward-biased diode current equation used in this calculator is:

$$$ I_D = I_S \cdot \left( e^{(\frac{qV_D}{nkT})}-1 \right) $$

where:

*I _{D}* = Diode current in amps (A)

*I _{S}* = Saturation current in amps (A)

*V _{D}* = Forward voltage across the diode in volts (V)

*e* = Euler’s constant = 2.71828

*q* = charge of an electron = 1.6E-19 in coulombs (C)

*n* = Ideality diode correction factor

k = Boltzmann’s constant = 1.38E-23

T = Junction temperature in kelvin (K)

The ideality factor, *n*, is 1 for ideal diodes and, typically, a value between 1 and 2 for non-ideal diodes.

To learn more about the P-N junction diode, please check out these other All About Circuits resources:

- The Exponential Current–Voltage Relationship in Forward-Conducting Diodes (technical article)
- The PN Junction Diode and Diode Characteristics (video tutorial)

0 Comments