PN Diodes

How do I find a Diode with a 0.7 V Drop .???

by JerryAm
October 04, 2020
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1 Answer

Answer by mrobbins

Hi @JerryAm, look at this blog post: https://www.circuitlab.com/blog/2020/08/10/ideal-diodes-in-circuitlab/

And try this simulation in particular:

There are two diode simulation models in CircuitLab: - a "real" PN-junction diode - an "ideal" diode which

For a real PN diode, there's a relationship between current and voltage, roughly

$$I_D \propto e ^ { \frac {V_D} {25 \ \text{mV}}}$$

It just turns out that for a wide range of typical currents and typical diodes, you'll get $V_D \approx 0.7 \pm 0.1$, but this is just a convenient approximation.

+1 vote
by mrobbins
October 05, 2020
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