diff --git a/ntnu/tfe4152/summary/summary.md b/ntnu/tfe4152/summary/summary.md
index d6f3d38..4806a79 100644
--- a/ntnu/tfe4152/summary/summary.md
+++ b/ntnu/tfe4152/summary/summary.md
@@ -5,4 +5,6 @@ date: 2020-12-16
 math: true
 ---
 
-## Test
\ No newline at end of file
+## Dioder
+
+$$ \Phi_0 = \frac{k_B T}{q}\ln\left(\frac{N_A N_D}{n_i}\right) $$
\ No newline at end of file