Diode lab experiment

[Joe Bachi]

Hey guys,
I recently had a lab session where we measured the current and the voltage drop across a 1N4004 diode
While analyzing the results i got something seemed wrong
Why is there a current passing through the circuit when the voltage source is only 0.5 V?
Shouldn't it be over 0.7?
I tried to apply KVL and ended up getting a negative value inner resistance

V(AK) is the voltage drop measured across the diode
Any and all help is appreciated
Thank you in advance

 

[duke37]

The diode has a logarithmic response to voltage. If I remember rightly, the current goes down by a factor of 10 for every 60mV drop. Thus if you can measure very, very low currents, you can go below 0.5V.

Diode data sheets may give the answer you require.