Next installment. First I tried the current mirror with 2K resistors between +300V and the emitters. This works fine, but is also no more stable than the first solution. It presumably also wastes more power as R2 has to be higher - it is setting the current, so I chose 100K here to get 2mA:
<https://lh3.googleusercontent.com/-jZxqDiexrus/WOE53m-lGiI/AAAAAAAAAic/jUVDBH1pLhMrDElle_f30WLp2QJZCw3IwCLcB/s1600/CMF.JPG> Next I tried the current limiter as described in several places, but in particular here <http://electronicdesign.com/power/current-limiter-offers-circuit-protection-low-voltage-drop>as suggested by Tomasz. I used an Rsense (R3) of 330 Ohms as I wanted 2mA. This was not successful. With test loads it delivers <2mA (or exactly 2mA for a short circuit!). So I tried a 6844A nixie (which is what started off this whole current source thing). It delivered approx 0.5mA, so the tube barely lit. <https://lh3.googleusercontent.com/-DzPAZS8OZN8/WOE63Kl33WI/AAAAAAAAAio/l24DP892H8QI40j-AlBtayGszcil7W1RgCLcB/s1600/CL.JPG> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/b89e7779-fc4c-40c7-8c72-091ee33c9b45%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
