OK, I pretty much never used one. When the circuit would come alive, the sc ope tells you if a transistor is bad. If not, the DVM or ohmmeter will. (yu p, that old, I know others are older and actually want to query them so I c an make sure not to do what they did)
At any rate, the boredom does set in once in a while and go looking for tro uble. In the B&K 520B transoistor tester, I may have found it. That is unle ss an answer comes too quiclky... ...
%he print is here :
Any trouble with it and I'll rip it and throw it in Dropbox, whatever. You might not need it for my question though.
The question : How the hell does it tell the collector from the emitter ? M ost bipolar transistors (and that's it when it comes to this) will amplifiy i connected with the collector and emitter leads reversed. At low voltages of course. Most B-E junctions Zener out on you at five or six volts, but t easting that way cannot reallt be called non-destructive because the transi stor REALLY doesn't like it.
That tester has to work with DUTs from what, 50 volts to twelve hunder ? Ga ins from 40 to 1,000 ? Well 400.
It is p[robably reasonable to assume a bipolar has more gain when the termi nals are used according to Hoyle, 100 the right way, reverse collector and emitter and get what, 5 ? But the tester has no way to figure that out beca use it has nbo idea what it is testing. What coul tell the difference in a vertical or horizontal output in a reactive scanning CRT system, would fry most small signal transistors. just to find out what it is.
The way the thing works is it figures out if it IS. If it IS it figures it is good, and IDs the leads. You know, it might be worth keeping around just to IS the leads of old ass surplus components that are unmarked or marked with somehithng from Mars or Venus or whatever. You know like from 1980 or something.
But anyway, y'all engineers in here, some of you know alot about the actual construction of transistors. I find the subject fascinating but really, it was never in my interest to spend alot of tine on it because I just wasn't going for that kind of job and probably never would. Plus I suck at chemis try so...
Anyway, it's not so muh that I want to know how THIS unit tells the collect or from the emitter, it's also that I ask, how would YOU do it ?
It is not a really important thing. Take care of business first. But when y ou want to break off thre mule team, the race, the game and all that shit, just WHAT tells them ?
I am sure that with enough time (and eyesight) I could figure it out eventu ally. But that - well, maybe I should.
To fix the freq counter recently, I had to print out the print. Eight pages I taped together. Then it made sense.
Maybe I should do that with this, but I don't have it in that format. I wou ld have to cut it up on the PCC and then print it, and I ain't doing screen captures because it is too hard to get the sizes right. Unless I , well of course if I get the right software.
But the thing is, this has bothered me for a long time. Tnen, now, matters not. With such a wide range of possible devices, how can this thing non-des tructively determine those pins ?
You hook up the three leads. You run the switch through all its ppositions which makes an audio signal when a good transistor is detected. Seems to me , most transistors should check good at two positions.