# Energy drop across a diode

1. Jun 17, 2013

### MHD93

A typical silicon diode has potential difference of 0.7V when forward biased, to what kind of energy is the (0.7V)*(I)*($\Delta$t) converted? thermal energy only? isn't there potential energy through the electric field in the pn junction?

2. Jun 17, 2013

### Staff: Mentor

Unless you have an LED, the energy is released mainly as heat.
For every electron, sure. And if electrons cross the junction, they release this energy.

3. Jun 17, 2013

### MHD93

If this potential energy were released into kinetic, then there's no net change in electrons' energy across the diode, and therefore $\Delta$V is zero not 0.7V. what's wrong?

4. Jun 17, 2013

### Staff: Mentor

Kinetic energy of what?
Electrons are not free in the metal, they cannot just get kinetic energy and "fly in some direction".
Even then, their potential energy would change, and you have a voltage difference.