Good morning,
I stumbled upon this site a few days ago while I was looking for information on the 2n3906 transistor, and transistors in general. That said, I'd like to pose a question, in hopes that there's someone on these boards that can help me out.
Right now, I'm working on a project to use a 2N3906 transistor as a remote temperature sensor. I understand that this can be done by applying two consecutive currents with a known ratio. (I'm using a ratio of 10, for simplicity.)
There's a non-ideality factor that comes into play as well though. Everything I've read has implied that it is a constant, and that some manufactuerers of the 2N3906 chip even pre-trim the chip to a specific non-ideality factor. While I haven't found any manufacterers that actually do this, I did try calibrating these chips at three different temperatures to see if the non-ideality factor was consistent. (If it did, I could just solve for it.) Well, it wasn't. I got a different value for the non-ideality factor at every temperature.
I was wondering if anyone here has any experiance with this. I'm wondering if I misinterpreted the documentation I've read on this sort of thing. Perhaps the non-ideality factor isn't a constant at all. Is this the case?
There is a bit of noise in the line, but its in the area of 0.000005 volts. Not sure what the frequency is, my oscilloscope is a little old and I can't measure anything that small with any sort of accuracy. Shouldn't matter though with a magnitude that small, am I right?
I stumbled upon this site a few days ago while I was looking for information on the 2n3906 transistor, and transistors in general. That said, I'd like to pose a question, in hopes that there's someone on these boards that can help me out.
Right now, I'm working on a project to use a 2N3906 transistor as a remote temperature sensor. I understand that this can be done by applying two consecutive currents with a known ratio. (I'm using a ratio of 10, for simplicity.)
There's a non-ideality factor that comes into play as well though. Everything I've read has implied that it is a constant, and that some manufactuerers of the 2N3906 chip even pre-trim the chip to a specific non-ideality factor. While I haven't found any manufacterers that actually do this, I did try calibrating these chips at three different temperatures to see if the non-ideality factor was consistent. (If it did, I could just solve for it.) Well, it wasn't. I got a different value for the non-ideality factor at every temperature.
I was wondering if anyone here has any experiance with this. I'm wondering if I misinterpreted the documentation I've read on this sort of thing. Perhaps the non-ideality factor isn't a constant at all. Is this the case?
There is a bit of noise in the line, but its in the area of 0.000005 volts. Not sure what the frequency is, my oscilloscope is a little old and I can't measure anything that small with any sort of accuracy. Shouldn't matter though with a magnitude that small, am I right?