Hello!
I am creating a Nixie Tube watch that should be really cool and I'm excited to share it (when it works)!
A problem I'm having, is that I designed the watch to use 4 shift registers (3.3v) that output into 1k resistors, and then to a MMDTA42-7-F (datasheet) transistor.
I may have jumped the gun on assuming I could use a 1k resistor for the base of these transistors to simply put it into saturation. Does it stand to reason that I burned out these transistors with an incorrectly chosen base resistor? My nixie tubes are meant to run around 1.5mA to 2.5mA. I think my order of magnitude is wrong and I should have used a base transistor along the lines of 10k-30k. I wasn't planning on using the base resistor to limit the current in the transistor in any way..
Anyway, what are your thoughts on the subject?
I am creating a Nixie Tube watch that should be really cool and I'm excited to share it (when it works)!
A problem I'm having, is that I designed the watch to use 4 shift registers (3.3v) that output into 1k resistors, and then to a MMDTA42-7-F (datasheet) transistor.
I may have jumped the gun on assuming I could use a 1k resistor for the base of these transistors to simply put it into saturation. Does it stand to reason that I burned out these transistors with an incorrectly chosen base resistor? My nixie tubes are meant to run around 1.5mA to 2.5mA. I think my order of magnitude is wrong and I should have used a base transistor along the lines of 10k-30k. I wasn't planning on using the base resistor to limit the current in the transistor in any way..
Anyway, what are your thoughts on the subject?