When measuring milliamp-range current across milliohm resistance, your voltage will be in the microvolt range, which means that noise can easily creep-in and affect your mesurements.
With TTL-level signals, VIL(max) is 0.8V, so your sensing resistor could probably go up to 0.5V without disastrous effects, but you will need to experiment a bit. I think that works out to about 130 ohms. Also be aware the accuracy of this resistor directly affects the accuracy of your current-reading, so 1% or 0.1% resistors should be used. Also, you want to take readings with no nixies on to determine the "floor" of your current reading, then subtract that from your actual measurements. -- 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/28c27c21-caf1-43e2-9d3b-87a3dc5dbfe7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
