> My understanding is that a MPSA42 is an NPN transistor and the MPSA92 is a > PNP. My understanding of how an NPN transistor works is that when the base > “P” is turned on the circuit from collector to emitter is shorted. When the > base is off the circuit is open. I’m trying to use the decimal point on a > Nixie tube rather than an LED for the alarm. So, I have the collector hooked > to the tube the emitter hooked to the ground, and the base hooked to 5V > signal, I also have a 10K resistor between base and 5V. However, no matter > what the decimal point stays lit!! Even when the signal is off. The only time > it isn’t lit is if the base is open, if I even touch the base the decimal > point lights up!! The transistor has the the imprint A42 B331. It appears to > be a knock off and that could be where my problems are coming from. I’ve > tried looking for a datasheet, but to no avail. Any help would be > appreciated.
Probably some sort of leakage. Maybe add a 10k pulldown resistor from the base to ground. If that doesn't work, try disconnecting it from 5V and ground the base directly. - John -- 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/8B608F3F-04A3-4A89-B12B-5C081D01D5D7%40mac.com. For more options, visit https://groups.google.com/d/optout.
