High voltage circuits, switch mode power supplies, motor control, switching regulators, inverters, solenoid drivers. A couple of application circuits using the MJE have been discussed in the following articles:. Simple Transformerless Power Supply. If you have any circuit related query, you may interact through comments, I'll be most happy to help! Your email:.
|Published (Last):||22 September 2015|
|PDF File Size:||18.37 Mb|
|ePub File Size:||15.72 Mb|
|Price:||Free* [*Free Regsitration Required]|
Welcome, Guest. Please login or register. Did you miss your activation email? This topic This board Entire forum Google Bing. Print Search. Read times. Here's a drawing that shows how I understand the test to be done. Several videos show it done this way.
Conflicting videos show that the last transistor in the drawing should be OL so that the middle and right pins would pass no voltage in either direction. One method condemns my transistors while the other says they're good. What do you guys say? I have no schematic. The markings are all I have. PNG According to a quick search, D appears to have a built-in diode. That's what you are measuring in the last two pictures.
And the pinout makes sense, it is B-C-E left to right. Posts: Country:. Quote from: ataradov on November 26, , am. Hi all! If you like the post, please press "thanks". Okay guys. I get what you're saying. Are you saying this does not apply in my application? I think that's what the two of you are telling me.
Just trying to learn. You have to check the datasheet for your current transistor. The other post told you that there is a diode connected with the transistor and when you measure you are not actually measuring the "NPN" transition of the transistor, but you are measuring the "PN" transition of the diode.
A transitor is a "double diode" a diode is a "half transitor" in terms of how they are built. Thank you nsrmagazin. I had looked at every datasheet I could find, but didn't understand the circuitry. So I resorted to YouTube. Here's an image of the circuitry on one datasheet. I've added red to what I suspect you're saying explains why E will flow to C, but not vice-versa.
I must learn more about how these circuits work. Thanks to both of you. I am sorry to offend you, but truth hurts and it does not change! If you don't understand these basic principles, you are a long way from bulding and measuring circuits. I always feel so stupid. Sooner or later, I get a message such as yours.
Maybe some day you'll need to know about my area of expertise. Wimberleytech Super Contributor Posts: Country:. Quote from: billbyrd on December 03, , pm. Thank you sir! I was beginning to think I had mistakenly walked in to a phD class room. The following users thanked this post: Wimberleytech.
Benta Super Contributor Posts: Country:. Quote from: billbyrd on November 26, , pm. If you are working on circuits without knowing the basics you risk hurting yourself. The very least you can burn your circuit. Its better to start with the principles that you don't know, instead of just getting a ready answer. EDIT: and I did not say you are stupid!
What I meant is you should start with the beginning! Finally found two things that I could actually measure, an opamp and what I think is a transformer. I replaced the opamp and all the caps. I have vac going to the transformer and about 1 volt coming out. Out of circuit, the primary and secondary if that's what they are test open. So I don't have any way of knowing what to order.
The boards ultimately produce 12vdc. Any help with be appreciated. The forward voltage drop across the base emitter junction is higher than the drop across the base-collector junction. With older meters you can use the resistance range. The lower resistance is the base collector junction because it has larger area. Newer meters you'll need to use the diode test function to get enough voltage to get the junction to conduct. If it's not just a transistor I can't say what to expect.
But I used the method in the first paragraph for 40 years. I learned it from a semiconductor physicist who was teaching an intro electronics class in the building next to where I was looking at rocks through a microscope all day. I didn't take the course, I just went to the lectures for a break.
In the 40 ears since, I have encountered two people who knew how to do this. Everyone knows how to find the base, but knowing how to identify the collector and emitter is is uncommon in my experience. I find that sad as it is so simple and logical. Back to the drawing board. I became convinced that either the transistors were all bad or the pin out on the package was wrong.
When I heard the explanation from the physicist. I didn't run home because it was over a mile and up and down hill, but I went as quickly as I could walk which is miles per hour. I pulled one of the remaining transistors out of the package and tested it. After that I had great fun with anyone I ran into who was seriously good at electronics. I'd ask them. I look forward to a post from you saying the problem is resolved. If not, I look forward to resolving it. Can't always get it right the first time.
I've never played with big transistors, just small ones. Quote from: rhb on December 07, , am. Here is my junction tester curve tracer that I built in or ' It is currently connected to my analog scope B in a dedicated test setup. That's just an octopus!
That's not a curve tracer for determining transistor parameters. The octopus is a great diagnostic tool, but it will not give you they kind of results a Tek gives. The OP is wanting a cheapie and small Quote from: rhb on December 08, , am.
I conflated this with another thread. One glass of wine to many. Quote from: rhb on December 08, , pm. You're the 3rd person to know how to tell them apart, but using the reverse breakdown is a new one on me. So yes. You certainly do.
I learned another way to do it. Learning something new always makes my day. At least if it isn't a "do do that again" something new.
13005D Datasheet, Equivalent, Cross Reference Search
MJE13005 = ST13005 = PHE13005
13005D View Datasheet(PDF) - Jilin Sino-Microelectronics
High Voltage Transistor MJE13005 – Datasheet, Application Notes