I see so many people recommend power Darlington transistors and they never know that power Darlingtons are for collector voltages above 12 volts. A Darlington can be used at low voltage, but the collector can never go below two Vbe drops or about 1.2 volts. If the supply voltage is 2.8 volts, then half of the power will be dissipated in the Darlington! At 12 volts supply, ten percent of the power will be wasted heating the Darlington. If you want high gain, use two separate transistors with their collectors separate, not connected together so the second transistor can fully saturate to just a fraction of a volt and not waste power. I like your video. Thanks.

Informative, well presented in a very clear manner. Thanks and please keep up the technical videos. They are appreciated.

I'm at this phase and this is a big help. I can live with this list. Thanks, the Video work is well done.

Your teaching style is great! Really enjoy your videos

The magazine "Elektor" used a rather neat idea... TUP, TUN, DUS, DUG - a selection that fitted basic criteria for Transistor Universal PNP. Transistor Universal NPN, Diode Universal Silicon, Diode Universal Germanium

For audio output stages I've got some NJW3281G, NJW1302G pair - the FJP ones you mention don't have secondary breakdown graphs in the datasheet which seems odd. IRF in particular lie completely in their datasheets about current rating. I've seen 180A or something quoted for a TO220 MOSFET and in a tiny tiny footnote they admit the bond-wire limit is far less! I think the logic is that the current rating of a power MOSFET is actually an power rating in disguise - ie its the current at which the die fails on a water-cooled diamond heatsink! I'd advise using only these parameters of a MOSFET: drain-source voltage, on-resistance + associated gate drive voltage, total gate charge. Throw in some commonsense about the package power dissipation too.

Great stuff! thanks. I was about to flag the tiny blunder (922), but then I noticed it's already been fixed up 👌

Thanks John!

Hi John, Hope you are well! Yes Thumbs up for BD139 & BD140, I always have a few spare for projects ;)

I’d list them, but I keep probably over 100 transistors and their complementary in quantities over 200, many of them into the 1000s. Example I just bought 1500 each of 2N5551 and 2N5401 all because one of your videos reminded me to, thanks! To throw some examples out there if you like working on vintage electronics, I like to keep MJ21193/MJ21194 on hand, can be used for outputs in many amplifiers, MJE15032, MJE15033, MJE15034, MJE15035, KSC2690/KSA1220, honestly there are many I wouldn’t be without. I’ve just slowly built a collection and I hate having to wait on parts to be delivered. Thank goodness for Mouser and Digikey and their cheap 2nd day shipping! As to your questioning the PD of the transistors, like 125-150 watts for a TO-220. I question those too, same with other components. I recently ordered some very decent quality resistors from Mouser and they’re being sold at 3 watt resistors and they’re about the size of a standard 1/8 watt metal films. I question how something so tiny can dissipate 3 watts.

Ive pulled transistors from various things. 13003: Power (darlington?) transistor. Quite useful and can be found in your nearest cfl. C1815: Generic audio transistor.

Great stuff, I certainly learned something

I use the KSC1845 and complement on some audio amplifier IPS circuit

For hobbyists, I found that the Velleman transistor kit in the cardboard/blister pack gives a reasonable assortment of transistors upto 1.5A rating.

Please try to do a video on designing a class AB amp using any of your power BJTs which you just showed now

You could consider using 2N6292(Vce=70v, Ic=7.0 A) and its complementary pnp, 2N6107(Vce=70v, Ic=7.0A), they are very good to be used in VAS stage. I use them instead of BD139 and BD140 transistors. And there are 2N5551(Vce=160V, Ic = 600mA)(npn)and its complementary pnp 2N5401(Vce=150V and Ic=600mA), which can be used in the input stage.

While they are probaply pretty much the equivalent of the 3904 in europe, the BC547/557 are my go-tos when i don't have anything specific i need. They are very simmilar to the 337/327 but with more gain (up to 800 for the C variant) at the cost of collector current. Super cheap and great to have stock piled. For mosfets i like to keep some irf740s and 820/840s in stock, they have a very high drain-source voltage, great when fudging into tube circuits but also decent for common purpose

@emileduvernois6680

3 жыл бұрын

Do you mean that transistors are specific to a continent or another?

@uzmeyer1752

3 жыл бұрын

@@emileduvernois6680 There at leased used to be some different regional availability. Now, I can only speak for Germany/Austria, but when i got into electronics around 2010 the 2N series just wasn't a thing here. All the german tutorial sites used BC500 series and they were available for cheap in local shops. Through youtube i watched a lot of english content and those always used 2N2222/3904, but none of the german online shops had those. I just checked, my local store currently has 2N3904s, but quite expensive and a major online shop has them at the same prices as BC500. Neither have 2N3905s. Of course, today it is much easier to order from other places or china direct, so i do have a bunch of 2N types stocked, though not nearly as many as BC series.

@emileduvernois6680

3 жыл бұрын

@@uzmeyer1752 Ja, ich hatte auch gehört vom BC547 als ich mich mit einem bisschen Elektronik beschäftigte im 20. Jahrhundert, in Frankreich. Ich wusste aber gar nicht, dass er eine Europäische Spezialität war. Ich danke Ihnen für den Bescheid.

Devices I used a lot for audio...2n2222, 2n2907, 2n3053, 2n4037, these are early 1970's devices that worked well and had several sources. Almost all of the 2N devices are hard to find now. When Motorola became On Semicoductor, they dropped a lot of devices for linear work. Same with TI. Everybody consolidated in the 1990's.

For output stage of small amplifiers there are also TIP36 and BD243. About BC639 as VAS stage?

ztx650/ztx651 a great low to mid power BJT as it can take a bit of current. Not got the highest gain or work at the highest frequency but great in basic switching circuits, also I personally like using at as an emtter follower in a class A amplifier.

@joinedupjon

6 жыл бұрын

Apparently also has favorable characteristics for the Joule Thief circuit according to wiki... you can get lower Vce(sat) but ztx650 is likely to be on hand for home experimenters, at least in the UK... quite a common part for magazine projects iirc - and also has a cool name - sounds like a fast Japanese motorbike.

I often use BC550/560 or 2N5401/5551 for higher voltage amplifier input stage, 2N5401/5551 or KSA1381/KSC3503 for VAS (depends on my goal), 2SA1387/2SA4793 for driver (or pre-driver for TEF circuit), NJW1302/3281 or 2SA1943/2SC5200 for the final stage.TO-92 package seems to become obsolete soon or later. it's getting harder to get low noise figure, low Cob, and high fT transistor here. i might migrate to SOT23 package..

That was a great information.

I'm liking the PSMN017-30PL power mosfet. Rdson of 0.017Ω and a gate charge of 10.7, it's FoM of 0.17 blows your IRFZ44's out of the water, and has a comparable price. Downsides are lower voltage ratings.

The higher power ratings of MOSFET transistors come from the possibility to operate them at 175 °C in contrast to bipolar transistors at 150 °C. The channel type transistor allow for higher operating temperatures than junction type transistors. The TO-220 package is limited to currents of 50 A per lead.

Going back to the 70s I recall working for a HiFi amplifier manufacturer, making a very good 25watt amp. At one point in time the standard output transistors were on a long delivery so it was necessary to use an alternative both physically and electrically similar. The distributor came up with one that was almost a carbon copy. The only difference was the HF which extended from 5 mhz to 30mhz. Boy did we have issues with HF stability!! It just loved to oscillate in the 20mhz. Obviously not audible but really heated things up. The cure was very simple, a ferrite bead was placed over the base connection to the first power amplifier transistor. Problem solved!. At that frequency the smallest amount of inductance was all that was required.

@russellhltn1396

6 жыл бұрын

The manufacturer wouldn't have been Bryston by chance, was it? I had some problems with them.

@MichaelBeeny

6 жыл бұрын

Hi Russell, no it was very early Cambridge Audio P50 to be exact.

@n.shiina8798

6 жыл бұрын

which Bryston did you have? I restored my 8BST without problem. I use MJ21193/94 though, for the final stages.

@russellhltn1396

6 жыл бұрын

I don't remember. It was around 1980-1982. We had it at the radio station and it kept burning out speakers.

@n.shiina8798

6 жыл бұрын

sounds like excessive DC offset.. i do burned out speaker by oscillation but it was a ribbon tweeter. the woofer is doing fine

here's my addons:: - BC517 for monstrously hi gain (but kinda sux) - 2SC3356 (or 3355) for signal radio (it's SMD and supposedly max 12V but goes beyond, ultra cheap and apparently good on ebay) -BF245 jfet, low noise + UHF -2N7000 el cheapo MOSFET TO92 -IRLZ44N logic level mosfet (it's "L") -HGTG30N60A4D ("rich kids" IGBT, good all around.... LOL) ...and 2N2222 BC547 are apparently good wherever you buy em

One transistor you didn't mention is a VHF BJT with low junction capacitances, for use in RF and IF circuits. One cheap example is the 9018 (C9018 or SS9018). Thanks.

@sakenitro

5 жыл бұрын

Th 2N3866 is a VHF BJT. I've used it up to the lower spectrum of the UHF band aswell. Sure, it's not the cheapest transistor but it sure works great for RF amplification.

It is sometimes not very easy to find a complimentary power transistor to a given npn or nMOS device. So I usually look first for a suitable pnp or pMOS device at look for a complimentary device which fits the device the best. In this way I've found some good combinations like: STP10P6F6 / STP16NF06 or IRF4905 / IRFZ46N. I would be interesting for me if you have found also some of your own pairings or pairings which fit better that the manufacturer suggestion.

John, what is your take on SS8050/8550 small amplifier transistors? Also, are TIP31/32 obsolete for audio amplification? Many thanks for your answers in advance.

Hi john, thanks for sharing you favorite transistors. Do you happen to use IGBT's sometimes ? I often replace faulty IRF730 (and alike) mosfets with STGP10NC60 in the primary of switching PSU's. I have no particular technical justifications to that, they just happen to be easier to get in my case (RS in Europe). I assume IRF730 and alike are slowly slipping towards end of life nowadays.

BC550B/C / BC560B/C. Basically the European relatives of 2SC945 et.al. (but in oldschool EBC pinout like 2Nxxxx), and rather ubiquitous "low-noise" (high beta even at low Ic) transistors. Not great for Early effect (being a 45 V, high beta part) but not as bad as BC337/327, I think... If you need to build circuits that have to run on very low voltages like 1.5 V (maybe a mic preamp), keeping some 30 V process parts like 2N5089/2N5087 in stock may be worth it as well. These seem to have very low saturation voltage.

I know they're common parts. But for me: Low power, high gain BC548. Medium power BFY51 High power TIP120. All NPN. It's very very rare I'll use a PNP. I do have a single ZTX500 laying around somewhere though, if the need ever arises.

What makes a transistor low noise?

Maybe a dumb question but the use of the FJP transistors were for output stages in AB amplifiers. Is that correct? What are some suggestions for transistors to use in the power or A stage? Just curious and wondered if there was a rule of thumb when it came to these circuit components.

A little more Snickers please. Good video, keep up the good work!

For low voltage have good price/power IRF3205 , good old Classic is IRF640N, litle bit more expensive is IRFP250 and very good for high speed switching apps but more dificult to drive IRFB/P 4227 From bjt my favorites 2SA/SC 1943/5200 , MJL21194G; KD503, BC546,7 /556,557 , etc Some opamps to good have TL071,072,074 NE5534

I like having MPSA56 and MPSA06 around. The higher voltage rating makes them pretty useful as a substitute in many different circuits

What can I use for my flyback? Or can I make a fancier driver?

The rated power dissipation for the IFRZ44N as example is the total power that can dissipate the transistor ***if*** it is maintained at 25C. You probably need large heat-sinks to maintain it at 25C under that power dissipated. in fact, without heat sink, the IFRZ44 would raise by 60 degree Kelvin per Watt ( see its Thermal Resistance). So, if you use it without heat-sink, at 1 W, you raise its temp to 85 C ( 25C + 60C). At 2W, you raise its temp to 145 C and without heat-sink, at 3W you have probably destroyed it (see figure 1 in its datasheet, the maximum usable temp is around 175 C)

@JohnAudioTech

6 жыл бұрын

I assume you mean the junction temperature is 25 Deg C. The die inside the transistor package will have some thermal resistance to the die attach point on the copper slug in the transistor. The heat then disperses through the slug and into an external heatsink. All of this will have a significant thermal resistance rated in kelvin/watt which will raise the junction temperature. I'd have to research this to see if it can work at the high power rating that are specified on these TO-220 devices.

@Basement-Science

6 жыл бұрын

Basically to reach these power dissipations/currents that are rated at 25C you need to cool the package to sub-zero temperatures. So you need a heat pump, or some Peltier-cooler setup to achieve it. Noone in their right mind would do this with something like an IRFZ44. You´re better off with a real high power mosfet. But for very high power applications this is sometimes done.

Around 12:00 "How do they come up with these values?" Well, the quoted power dissipation is simply the maximum allowable rise in junction temperature divided by the thermal resistance from junction to case. In other words, they assume a perfect heatsink that can keep the case at ambient temperature. For MOSFETs, the "junction" temperature is the die temperature. For example, if we have a maximum junction temperature of 175° C and ambient is 25° C, then the maximum allowable rise is 150° C. If you have a device with a thermal resistance junction to case of 1° C/W, then it can dissipate 150/1 = 150 W of power when the case is kept at 25°C. If the thermal resistance junction to case of 1.5° C/W, then it can dissipate 150/1.5 = 100 W of power., and so on. Of course, in reality, the heatsink will have a thermal resistance from case to ambient and you can often find that figure specified for a particular heatsink. Perhaps you might pair up a device with a thermal resistance junction to case of 1.5° C/W with a heatsink of 0.5° C/W, giving a total thermal resistance of 2° C/W _junction to ambient,_ which would then only be able to handle 150/2 = 75 W.

I like Jfets so the MPF 102 is a good one...or like the J111, and the j310. Nice video..

@JohnAudioTech

6 жыл бұрын

I should have had the MPF102 on the list. I keep a few of them around.

My personal stash - can do almost anything aidio.3904, 3906, TIP31, TIP32, MJE2955T, MJE3055T

I work on rarely old transistor radio from.the 1960,s I want to keep some.gemeral purpose transistors on hand ,any suggestions

I did not know about the fT or Fom specs. Thanx. Do you know where I could get T0-92 and TO-39 form factor heatsinks? I was surprise the TIPxxx darlingtons were not on your list.

@daftbeyer

6 жыл бұрын

to92 heathsink? That is quite ambicious I would say.

Good video, good advice. I always like the ZTX series too; you should check them out.

A bit advanced for me in my current state of development. What I need is to know how to read the spec sheets. Suggestion: Show a one Transistor Circuit and how changing Transistors changes the Circuit.

SS8050/SS8550 -- complimentary pair of TO-92 transistors rated for up to 1.5A (but only 25v)

@Asyss_Complex

4 жыл бұрын

I have those, I recently used them for a project (both of them). They're quite useful. What else do you recommend? I have over 15 different transistors, but as the saying goes better safe than sorry.

@silentbloodyslayer98

4 жыл бұрын

Yes! I used them for a 2.5W amplifier project they are cheap and they gave me no problems. My suggestions are tje obvious 2n3904/2n3906, msa29 for high input impedance amplifiers and the s8050/8550 and nothing else, maybe some 2n7000 for simple logic

where can I get matching transistor to buy

After some research, high mosfet current values in TO-220 packages are correct (eg. 75A). This seems wrong as wire of similar size to the legs of the package would not be rated for this. The difference is a mosfet can be rated to run at 100 degrees quite happily and large PCB traces and heatsinking contribute to the device and its leads coping with such high amperages. A wire on the other hand gets rated to stay at a low temperature with only 'in air' cooling. Hope this helps.

Greate video! I have a '76 Earth Producer amp head. The eight T03 power transistors (Signetics 59-4004-B) I googled the hell out of it, with no luck. Don't know if they are pnp, or npn, all I know is they are poop. I would live to use something cool & modern. High quality sound is what I'm after. Any advice would be greatly appreciated. Thanks!

I use the IRFZ14 a lot, mostly because I bought too many a long time ago and I am constantly trying to use them up xD But they are also really good mosfets. Better than most. 60v, 10amp continuous, 0.2 ohm RDSon. It has a FOM 2.2.

How about some germanium's...like 2sb175, 2sb187, 2sb185...these are in vintage transistor raido from about 1960. And the infamous always failing Russian AF117's

I've often wondered the same about the current ratings for MOSFETs. I think I have a lack of understanding because I have fried MOSFETs believing the ratings.

I always wondered about those small legs putting out such a high current without burning like a fuse. How?

@boonedockjourneyman7979

6 жыл бұрын

This sort of discussion misses the point. Look at failure modes not gut feelings. Find out how each type of transistor fails. You will learn something and get away from amateur hour reasoning. You will also be surprised.

There are a lot of us would like a audio amp circuit that would run on 9-12 v dc and put out about 30 watts RMS of usable audio power. You may have already posted one, I could not find any in your previous videos. There may be posts of said amp on the web, I like your channel the best and hope you have one, if not, it's OK, I will look other places. Thanxz

@JohnAudioTech

6 жыл бұрын

30 watts before clipping would not be possible at 9-12v supply with typical load impedance (4 or 8 ohms). The limited supply voltage does not allow enough voltage swing in the output to drive such impedances to that power level. To get this amount of power from 9-12v supply, would require a booster supply to raise the supply voltage higher for the amplifier (the amp would technically not be running on 9-12v anymore). Another way is to use a low speaker impedance of less than 2 ohms which may be unrealistic in most cases. Another way still is to use an impedance matching output transformer to boost a high current output to drive 4 or 8 ohms to 30w. Such an audio grade transformer would be rare and very expensive.

@gkdresden

4 жыл бұрын

@@JohnAudioTech by use of an H-Bridge output you can theoretically achieve 18 W @ 4 Ohm and 12 V. The practical limit is probably 15 W. It is relatively easy to generate a -12 V power rail from a +12 V / 0 V power supply by use of + to - converter. Using such a symmetric power supply you can generate 60 W @ 4 Ohm.

The reason why the power MOSFETs handle more power than BJTs is because they don't have safe operating area limitations that BJTs have. MOSFETs don't go into thermal runaway like BJTs.

You left out 2N3055 and 2N2222 (PN2222). These were the most popular back in 70s.

@elpechos

6 жыл бұрын

Uh oh, John explicitly asked not to mention the 2N2222 in the comments at 50 seconds

The TIP 31 and TIP 32 transistors...

@HillsWorkbench

6 жыл бұрын

Yeah, I used to use a lot of the TIP series.

@ArcadeJason

6 жыл бұрын

was going to say the same thing i knew somebody else would have said this lol

I got enough with my bipolar wife!! (JK)

@abelincoln7473

6 жыл бұрын

boy do i want to make a joke about required "gate voltage" here.....

I wonder why no one mentioned 2N3055. It is a great Power transistor.

@YTANDY100

6 жыл бұрын

@rrangana11 the tip3055 is the same TR , it has the same voltage and current rating as the TO3 version , not sure about the PD tho :-)

@SmithKerona

6 жыл бұрын

2N3055 is a dead 60's era transistor that should never be used in modern circuits. Why would anyone use it when there are cheap and far better modern power transistors?

@2guitarme

6 жыл бұрын

what better modern one would you recommend?

@SmithKerona

6 жыл бұрын

Toshiba manufactures many great power transistors. Look at their power devices catalog if you get a chance. I really like the 2SA1943/2SC5200 complimentary pair. They have constant hFE vs IC curve from few mA to several Amps which makes the transistors suitable for any low frequency linear applications. ON SEMICONDUCTORS manufactures transistors specifically for audio applications such as NJW3281G/NJW1302G complimentary pair. Hope that helps!

@johnyang799

5 жыл бұрын

@@SmithKerona Would you recommend some 20 to 30v transistors for best linearity? Price is not a concern but needs to be available. Thanks!

11:07 Look at car amplifiers. they do it all the time. they can handle it. 11:46 again, look at car amplifiers, they do it all the time. some of the newer TO-3P MOSFETs and IGBT's can do over 100A with around 400W dissipation ratings.

@Asyss_Complex

5 жыл бұрын

bassblaster505 Those transistors are really powerful

3:17 KSA1845 is complement with KSA992, not KSA922.

@JohnAudioTech

6 жыл бұрын

Thanks! I wrote the number down wrong. Corrected in the description.

there's also cheaper stp14nk50zfp

its a good mos but its not going to disapate no 150 watts of heat

Excellent. Do many more of these. But, go learn about failure modes. Your gut feeling stuff has nothing to do with EE reality.

irfz44n fries at 10amps at high frequencies it trash

@legobuildingsrewiew7538

5 жыл бұрын

cant use it for flybacks man

Very cool...