shape

Junction Capacitance / Depletion Layer Capacitance Calculator

Junction Capacitance / Depletion Layer Capacitance Calculator

Junction Capacitance / Depletion Layer Capacitance Calculator

Calculate the junction capacitance using the equation:
\[ C = A \sqrt{\frac{q\,\epsilon_s\,N}{2\,(V_{bi}+V_R)}} \] where:
– \( \epsilon_s \) is the semiconductor permittivity (F/m), – \( A \) is the junction area (m²), – \( N \) is the doping concentration (m\(^{-3}\)), – \( V_{bi} \) is the built‑in potential (V), and – \( V_R \) is the reverse bias voltage (V).

* Enter all values in SI units.

Step 1: Enter Parameters

Example: 1.04e-10 F/m (for silicon)

Example: 1e-6 m²

Example: 1e23 m\(^{-3}\)

Example: 0.7 V

Example: 0 V (no external reverse bias)

Formula: \( C = A \sqrt{\frac{q\,\epsilon_s\,N}{2\,(V_{bi}+V_R)}} \)


Practical Example:
For a silicon diode with \( \epsilon_s = 1.04 \times 10^{-10} \) F/m, \( A = 1 \times 10^{-6} \) m², \( N = 1 \times 10^{23} \) m\(^{-3}\), \( V_{bi} = 0.7 \) V, and \( V_R = 0 \) V,
\[ C = 1 \times 10^{-6} \sqrt{\frac{(1.602\times10^{-19})(1.04\times10^{-10})(1\times10^{23})}{2(0.7)}} \approx 1.32 \times 10^{-11}\, \text{F} \quad (13.2\, \text{pF}) \]

Previous Post
Common Emitter
Next Post
V₍CE(sat)₎ Calculator

Comments are closed