I've also used the Ic / Ie method. That method and this one are great since I have a ton of SMD transistors on breakout boards. Mostly for prorotyping but still very useful.
I love this stuff! Built the M328 LCD 12864 transistor tester, got it off of Ebay for under 15 bucks. But the old school way looks a lot more fun, using the live circuit and scientific calculator.
You should allow the transistors to sit at ambient room temp before testing because the heat from your fingers will influence the gain on your transistors.I also have the first transistor tester you used which is actually very accurate even using 9volts. I also use several types of curve tracers but have found using the same method you use yields excellent results as long as temperatures are steadily controlled for the devices under test. I’m not criticizing your work by the way, you did a great job! Very informative!
Love your approach to DIY practicality rather than absolute measurements for precision work. I would think most of your viewing audience are simply trying to gain general knowledge in electronics. Those seeking accuracy to the micro ampere (NASA rocket scientists) need to entertain themselves elsewhere. Your content & method of delivery matches your audience. Well done !
good video, I'm replacing transistors in my stereo. I like to dump my tranny's on a n anti-static pad and use the wrist wire while handling them. I suppose it might be overkill, but good practice. Love your videos Paul.
Noob here, how did you calculate the 1.7mA current? And can you talk the differences of NPN und PNP transistors (where and why are they used and so on) Thank you for Video, its very helpful
@@heyho1202 difference in npn and pnp transistors is that not both were invented at the same time and when they were they were not the same price , other then that they are mirror images of each other like good and evil , everything you need to make you can make with any of them , unless you need both kinds then you need both kinds
Sorry, also forgot to mention... you’ll need appropriate therapy if you watch it, could be costly! You can thank my daughter for singing it almost hourly to me
Just the guy I wanted to talk to! But first, what about MOSFETs? I been wanting to ask you if you know anything about the raido kits from RadioShack? It's the old ones that you connect wires on the board with the spring looking things. I don't know if it's all there. I don't know if it's worth anything. I know you did videos with the computer radio whatchmacal it. I was wondering if you are interested in it? Its in the box, old as dirt looking, ill send it if you want. Id like to See a video with it!!
I have that exact same tester no instructions I'm trying to test irfp260n MOSFETs the tester shows the same results for all fets I test but when I install in a amp adj the Bias to draw 200ma the bias volts are all different some may be 1.9 v or 1.5 some may go as high as 2.3 so is my tester not working properly I'm trying to match fet but just not getting the results I'm looking from the tester ?
Maybe a stupid question: do you need to use both methods or just one? In other words, if you have a transistor checker is that good enough or should you use that AND the circuit on the breadboard?
Noob here... I saw a video on cloning the famous Moog ladder filter. They put emphasis on matching the transistors. So here is my noob question: why? Thanks for your kindness.
3:03 I just went through a stash of 2N3904s and all of the tested between 171 and 190 for hFE, exceot for one extreme outlier, which tested 230. Is that normal with an outlier so many standard deviations from the mean?
You only matched it for that one current or voltage ...Good if you use it at 6.5 V only. Matched set are tested for a range of performance value . Most people match MOSFETs and just buy larger sized transistors when needed because a balance transistors circuit is a bad design. Where do you use matched transistors? Plastic is not used, Non conductive material is used to avoid ESD damage or electrostatic charge build up.
Those transistor testers are useless as Hfe is done at about 2mA. That is not a typical in use current. The Hfe varies along the current curve differently on each transistor.
Excellent video, I was getting sick of spending extra for matched transistors. I wonder how many on eBay use this method to make extra money out of fools like me?
Hi, I need to combine two transistors. The schematic is simple and I can do it on a PCB header. I have only two questions: I have a power supply that goes from 9V to 12V. Does it have to be 10V or is 12V or 9V ok? Are the resistors good for 1/2W? Thanks in advance for your reply.
for the biasing of 1.7ma the math for the required R is the difference between the 22k and 10k divided by 2 then V/ by that R correct?...so 12000/2=6000..10/6000=1.7ma ....is this correct?
Ground to Vc is what I did and it seemed to work well. I made a little jig and set it aside. I powered it with a 17 volt supply instead of a 10v which may have given me a little more resolution? Confirmed them on my transistor tester although I feel that the jig is more accurate.
Transistors are very sensitive to temperature. Hotter they get, the harder they work and the harder they work the hotter they get. So you match them so they will react the same. Otherwise you get uneven application, and one Will burn itself out.
My thoughts too? I tried it with a 9VDC PSU & the outputted Vcc Signal was between 2.9 & 3.1V The 2n3904 NPN Transistors generally spat out a reading of around 6V.
Can anyone recommend a prebuilt unit that does what this breadboard does? I would love to build this but my understanding of electronics is poor. I simply would like to find a matched pair of transistors for my amplifier. Did not realize how difficult it would be . this is a good video but I can not see how it if built do to camera angle and zoom.
This reduces the danger of one the transistors reacting to heat at a different rate than the other causing ever greater current to flow through it and thus heating up even more. This vicious circle will could ultimately burn the transistor out and ruin your day.
I've seen that some techs and even engineers don't care much about using the HFE function that usually comes on cheap multimeters. But I found out it is extremely important when repairing an audio amplifier or even a high amp power supply. I still don't understand why high end multimeters don't include this function. Does anybody know why?
Almost no one needs to match transistors because there are special circuits that require a matched pair, but instead of using two separate transistors, the circuits use a dual transistor in a single package or an integrated circuit made to have matched transistors.
Multi meter test a transistor in the unused range (low voltage range) If you want to match a transistor you need to test at the design use values . That transistor tester is just a check to see if it is dead .
Awe I thought I came up with that saying..... damn you convergent evolution!! Bringing us the house cat over and over again and stealing mah sayings probably b4 I evolved them!!!
Its too bad someone does not sell a breadboard kit to build a tester for us dummies who can't read schematics. It all sounds good but my electrical skills are very bad and have no idea how you make that tester to match transistors.
So I’ve been collecting a packs of components, just received a pack of transistors. I checked out the seller to see if they had some others I wanted and noticed they had some bad feedback... “Warning - this seller sells fake transistors”. I didn’t know it was a thing! I thought a 2N2222 was a 2N2222?! So my question is how do they “fake”. It’s not like a brand?! Are we just talking poor quality? Or dangerous? And yer, I got them cheap - my fault I know 😒
