NICE and simple video! FYI for all new to electronics: This test is for an "NPN" transistor, where the emitter needs negative potential applied. For any PNP transistor, you need to reverse the leads and apply positive voltage to the emitter instead
If the transistor tests okay, according to your method, it also is a method to determine the EBC pins on an unknown transistor. Been at this for 50 years and your test is new to me. Thanks a lot.
Excellent video - your explanations are clear and the filming was also spot on. I have several 2N3055s that are over 40 years and and did not realize a quick and simple test would determine any bad ones.
Nice way to check them out. Wish you would zoom in a little more for us old timers like me who can't see very well anymore even with our binoculars on, just kidding they are bifocals.
well thanks for the video since i didn't actually knew how to identify the various connections.. on this specific type of transistor... since i will use a few of the for a step up booster well knowing how to identify Collector Emitter Base!!!
This is a great video! --- I did not know how to check a transistor --- NOW I KNOW HOW ---Thank you very much for your clear explanation along with the great video!
I got the same multimiter 20 years ago. I use a diode scale. Base colector, base emiter watching polarity, this old multimeter can measure hFe also. Is the simplest way for me.
I have two 2N3055 (Motorola) both have tested good on diode mode base-collector and base-emetter. So signal on reverse path. BUT one of them i am not capable of reeding resistance before and after shorter base to collector and the one is good I am reading is 19Mohms ans shorted is 11Mohms... Is this a good sign?
Thanks, I had no idea how to check them... I have a question if you happen to read this, I have an older (1970ish) Sansui 5050 stereo that I think the output transistors went bad on. (if the volume is turned all the way up, there is a very faint signal going to the speakers) I have a couple of sets of output transistors that came in a box of stuff, I don't know if the numbers are the same (I would doubt it), can I just put those in the stereo? Or not a good idea? Tom
Not a good idea...you need to verify you are putting in the correct parts or you could damage something. Your output tranistors may be fine....you may have bad capacitors....hard to say without troubleshooting the unit properly
LOL - VERY CONVENIENT when you have them out of circuit but mine are totally inaccessible ... would be nice to have an explanation of how to test them when IN circuit
That would be nice, but there will always be some other electronic components paralleled across the transistor's pins. About the best I've found is to try using the diode function on your multimeter. If that doesn't work switch to the Ohms scale on your meter and look for a diode-like resistance difference between E-B and B-C. Good luck.
hi, very informative video, thanks for sharing :) by the way, do you know what is the maximum and minimum current most of darlington metal type can handle at the base? i have google research the data sheet but this what i have here looks like it was not publish online. i got it from scrap electronic part, i got lucky to find 1 that i test with diode meter and looks fine but i don't know how much current it could handle at the base, i'm worried
I am doing the same thing and I am getting continuity between emitter and collector in one of the two and in the other ( both st 4917070) I am not getting any readings when shorting base with colector as in the video.
Check and make sure you have good connections to the transistor being tested first. If connections are firm, and reading is erratic suspect the transistor of being faulty. Or always check with a new one to see if it acts the same way.
No, you will be reading thru other components, in the circuit that the transistor is connected with. 40 meg ohms will read thru many components, this way of being a single test, all that's being done it your checking "if" the transistor will be saturated to turn-on.
Xlnt video. With my Tripp PR-3A 13.8 volt regulated power supply using an RCA 2n3055 transistor, I'm reading a voltage output of 9.2 volts yet the result of the test proves a resistance drop across the collector and base. So is the transistor "mostly" dead or is it... dead? Should i be looking elsewhere for its shortcoming of viability? (It's a line from a movie) Thanks. Greg@GregWilliams.us
I don't know if these can partially fail or not. I would think they'd either be good or bad - no in between. But anything is possible I suppose. You could check the regulator to see if it is working properly but most of the time the problem with these power supplies is one or more bad pass transistors.
There a many fake transistors on ebay (and sometimes reputable suppliers), including 2n3055's. There are obvious visual signs like the cases are sometimes smaller, or the ink is not solvent resistant like authentic brands (and so the ink smudges with rubbing alcohol). Some fakes look authentic. Inside, instead of having a 4-6 mm silicon die they use a small 2 mm die and no internal heat dissipating baffle. I would be interested in seeing someone test those electrically to prove counterfeit.
An easy way to show they are counterfeit is the fakes have massively more gain than a normal 2n3055. I measured the hfe of the fakes at around 200 to 400 but a regular 2n3055 should be under 50
Ok so that's simple enough. I was going in a complete opposite direction, thermal characteristics, the fake ones with smaller dies should get much hotter. Though I could figure out how to calculate wattage, I didn't understand how to read the thermal characteristics of the datasheet, nor calculate the expected temperature at room temperature. I couldn't figure out how long it was going to take to reach a maximum temperature for a given wattage. Measuring the gain in current seems simpler and straighforward. Thank you.
NICE and simple video! FYI for all new to electronics: This test is for an "NPN" transistor, where the emitter needs negative potential applied. For any PNP transistor, you need to reverse the leads and apply positive voltage to the emitter instead
If the transistor tests okay, according to your method, it also is a method to determine the EBC pins on an unknown transistor. Been at this for 50 years and your test is new to me. Thanks a lot.
Excellent video - your explanations are clear and the filming was also spot on. I have several 2N3055s that are over 40 years and and did not realize a quick and simple test would determine any bad ones.
Brief and with laser precision to the point. A+
Congratulations man, you're a good teacher. It's very cool.
Nice way to check them out. Wish you would zoom in a little more for us old timers like me who can't see very well anymore even with our binoculars on, just kidding they are bifocals.
Also, Use the diode test function of the DMM, Testing each of the PN junctions of the transistor. [ B-E and B-C]
well thanks for the video since i didn't actually knew how to identify the various connections.. on this specific type of transistor...
since i will use a few of the for a step up booster well knowing how to identify Collector Emitter Base!!!
This is a great video! --- I did not know how to check a transistor --- NOW I KNOW HOW ---Thank you very much for your clear explanation along with the great video!
Thanks good and clear demonstration
how about MJ15004 transistor ......you think is same messurments or way doing thanks good video
The 4 megaohm position, so not the diode mode?
I got the same multimiter 20 years ago. I use a diode scale. Base colector, base emiter watching polarity, this old multimeter can measure hFe also. Is the simplest way for me.
Perfect tutorial, thank you.
I've got 2 similar ones on an EMC G110 guitar amp that need checking.... thanks for the info👍
felicitaciones es el MEJOR video de como comprobar los trancistores
Excellent video. Thanks for the help.
I have two 2N3055 (Motorola) both have tested good on diode mode base-collector and base-emetter. So signal on reverse path. BUT one of them i am not capable of reeding resistance before and after shorter base to collector and the one is good I am reading is 19Mohms ans shorted is 11Mohms...
Is this a good sign?
great i found very helpful thanks .
Thanks for your time 741...
Thanks, I had no idea how to check them... I have a question if you happen to read this, I have an older (1970ish) Sansui 5050 stereo that I think the output transistors went bad on. (if the volume is turned all the way up, there is a very faint signal going to the speakers) I have a couple of sets of output transistors that came in a box of stuff, I don't know if the numbers are the same (I would doubt it), can I just put those in the stereo? Or not a good idea? Tom
Not a good idea...you need to verify you are putting in the correct parts or you could damage something. Your output tranistors may be fine....you may have bad capacitors....hard to say without troubleshooting the unit properly
Thanks!
Can you show the someday ! How the AC (127_128_188_187 etc )series transistor test ?
Thank you
helpful, camera needed to show initial close up of connections
Steel case vs aluminum case, which better? Sorry for out of the box
Greetings from Indonesia
LOL - VERY CONVENIENT when you have them out of circuit but mine are totally inaccessible ... would be nice to have an explanation of how to test them when IN circuit
That would be nice, but there will always be some other electronic components paralleled across the transistor's pins. About the best I've found is to try using the diode function on your multimeter. If that doesn't work switch to the Ohms scale on your meter and look for a diode-like resistance difference between E-B and B-C. Good luck.
Very handy trick...
hi, very informative video, thanks for sharing :)
by the way, do you know what is the maximum and minimum current most of darlington metal type can handle at the base? i have google research the data sheet but this what i have here looks like it was not publish online. i got it from scrap electronic part, i got lucky to find 1 that i test with diode meter and looks fine but i don't know how much current it could handle at the base, i'm worried
Thank you.
I am doing the same thing and I am getting continuity between emitter and collector in one of the two and in the other ( both st 4917070) I am not getting any readings when shorting base with colector as in the video.
continuity means it is shorted and bad.
In my case reading comes and goes not hault,is it faulty transistor?
Check and make sure you have good connections to the transistor being tested first. If connections are firm, and reading is erratic suspect the transistor of being faulty. Or always check with a new one to see if it acts the same way.
IN MY CASE I DON'T CONNECT POSITIVE LED IN BASE BUT MY TRANSISTOR SHOW VALUE EMITTER TO COLLECTOR.I WANT TO KNOW MY TRANSISTOR IS GOOD OR NOT.
How did he know the range needed to measure the transistors?
Can the output transistor shorten by itself or are other components involved ?
Can be either or. In my case transistors only failed - came from a power supply that had it's leads shorted for an extended period of time.
Nice teacher
Can you check the transistor on the circuit board?
No
No, with 40 meg ohms from the meter you would be reading thru other components.
18 people can't admit they don't know how to use the Digital Multimeter. 😄😃😆
Lol 👍
Good video
can you test this in circuit as well?
No, the other components in the circuit may give false results
No, you will be reading thru other components, in the circuit that the transistor is connected with. 40 meg ohms will read thru many components, this way of being a single test, all that's being done it your checking "if" the transistor will be saturated to turn-on.
nice video
Xlnt video. With my Tripp PR-3A 13.8 volt regulated power supply using an RCA 2n3055 transistor, I'm reading a voltage output of 9.2 volts yet the result of the test proves a resistance drop across the collector and base. So is the transistor "mostly" dead or is it... dead? Should i be looking elsewhere for its shortcoming of viability? (It's a line from a movie) Thanks. Greg@GregWilliams.us
I don't know if these can partially fail or not. I would think they'd either be good or bad - no in between. But anything is possible I suppose. You could check the regulator to see if it is working properly but most of the time the problem with these power supplies is one or more bad pass transistors.
are these pnp or npn
NPN
2N3055..is..NPN, TIP2955..is...PNP. same voltage and current outputs.
There a many fake transistors on ebay (and sometimes reputable suppliers), including 2n3055's. There are obvious visual signs like the cases are sometimes smaller, or the ink is not solvent resistant like authentic brands (and so the ink smudges with rubbing alcohol). Some fakes look authentic. Inside, instead of having a 4-6 mm silicon die they use a small 2 mm die and no internal heat dissipating baffle. I would be interested in seeing someone test those electrically to prove counterfeit.
An easy way to show they are counterfeit is the fakes have massively more gain than a normal 2n3055. I measured the hfe of the fakes at around 200 to 400 but a regular 2n3055 should be under 50
Ok so you would rig about a couple Ammeters to check current at the base and compare it to an ammeter at the output.?
chriskazaglis yes
Ok so that's simple enough. I was going in a complete opposite direction, thermal characteristics, the fake ones with smaller dies should get much hotter. Though I could figure out how to calculate wattage, I didn't understand how to read the thermal characteristics of the datasheet, nor calculate the expected temperature at room temperature. I couldn't figure out how long it was going to take to reach a maximum temperature for a given wattage.
Measuring the gain in current seems simpler and straighforward. Thank you.
chriskazaglis you don't even need two anmeters the base current will be (V - 0.6) / R
Can’t see what your doing
Video not clear
Was there any specific reason to use and old style analog meter and not a DDM?
not sure what you are asking...I used a digital meter in this video
@@SevenFortyOne ... Sorry, yes I see that, I don't know what I was thinking ... can I blame it on a rough day 🤣😂
No worries! I know how it goes sometimes 😃