1N34 (germanium diode) incorrectly simulated?

[ericfont]

Try this simulation of a 1N34. When inputting voltage from 0 to 500 mV, the current only reaches 1.363 micro amps:

But germanium diodes are typically said to have a rough threshold around 300 mV, and all datasheets and plots of 1N34 diodes I can find on the internet show the current should be well into the milli amp range by the time its voltage is 500 mV, for instance:

I looked at

circuitjs1/src/com/lushprojects/circuitjs1/client/DiodeModel.java

Line 90 in dd47cf4

addDefaultModel("1N34", new DiodeModel(200e-12, 84e-3, 2.19, 60, "germanium"));

but it seems to match what https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/spice-models gives. Though there are some parameters left out from that...maybe they are necessary? Or maybe there is some other error simulating it in DiodeModel.java?

Thanks as always for such a great tool.

[ericfont]

I don't notice any glaring issues with the two Shottkey diodes, which are also low-threshold diodes and match my limited understanding. But the 1N34 seems way off...maybe it should just be deleted from that menu if fixing its simulation is too hard.

[pfalstad]

Have you seen this:

https://forum.allaboutcircuits.com/threads/error-in-1n34-spice-model.48758/

I tried it with MacSpice and got exactly the same results. I guess the model is just bad. Deleting it from the menu seems like a good idea.

vin 1 0 0.5V

.MODEL D1N34 D(IS=200P RS=84M N=2.19 BV=60 IBV=15U
+ CJO=4.82P VJ=.75 M=.333 TT=144N)

DX 1 0 D1N34

.control
* dispose of any 'save' statements from previous runs
delete all
* perform a transient analysis
tran 0.01ms 10ms 0.0ms 0.2ms
plot i(vin)
.endc

[ericfont]

Ahh. Yeah...just delete it for now.