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Hardware Hacking Hardware

You Can Have My TIPs When You Pry Them From My Cold, Dead Hands 170

Posted by samzenpus from the oldie-but-goodie dept.
szczys writes: Should you trash brand new parts developed decades ago and adopt newer models? The argument centers around TIP parts which are a standard type of transistor developed in 1969. This debate started out with a post from Tom Jennings who is known as the creator of Fidonet but works a lot with electronic hardware. Adam Fabio — himself an Electronics Engineer — picked up on the argument for the other side. He attests that if used in the proper application these parts are second to none.
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You Can Have My TIPs When You Pry Them From My Cold, Dead Hands More

You Can Have My TIPs When You Pry Them From My Cold, Dead Hands

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  • adam fabio (Score:1)

    by Anonymous Coward

    Are we supposed to know who adam fabio is? Why do you think its important to tell the readers who Tom Jennings is but not who adam who is?

  • If the part were critical, it'd be running hot enough that you had to worry about using the right one. If it's still cold even when you're pumping power through it, you've probably got lots of design headroom for evaluating other parts...

  • TIP series are good devices (Score:2, Informative)

    by Anonymous Coward

    ...but the things expected have evolved from that time until now. The TIP devices, being bipolar technology, are inherently less efficient than their modern cousins, which are mostly CMOS FET technology. The operation of bipolar and FET transistors is fundamentally different, and what is taught today very often overlooks bipolar devices altogether. Further, the older devices tend to be physically larger than modern equivalents, which is a natural consequence of the lower efficiency demanding more surface

    • And yet, carburetors are used for a lot of engines - small engines such as those in lawn mowers or chainsaws and also in light aircraft engines.

      Sometimes the smaller device does not mean better - SMT parts, for example, are more difficult to solder pretty much require etching a PCB (instead of using a perfboard or point-to-pont construction). Also, if I am building an electronic load or an analog amplifier, the transistors are going to dissipate a lot of heat anyway, so I might as well get a TO-3 part.

      • Carburetors are evil! They tried to kill Harrison Ford (Han Solo) [go.com] and should be banned

    • being bipolar technology, are inherently less efficient than their modern cousins, which are mostly CMOS FET technology.

      This is not insightful or informative, it's plain wrong. Firstly, the competitor to BJT is MOSFET, not CMOS, since the latter implies two transistors not one. Secondly BJT and MOSFETs have substantially different characteristics. BJTs are faster linear amps, MOSFETS are faster at power switching, whereas BJTs handle very high powers better MOSFETS have better drive characteristics etc etc.

    • Re: (Score:3)

      by Vapula ( 14703 )

      Bipolar transistors and FET works on very different principles. For example, the input capacitance of a FET is much higher which can bring some problems in "high frequency" (sometimes, not so high) designs.

      FET are also more sensitive components (Vgb can get quite high due to static electricity and lead to component destruction) and may need special driver circuits (for example to make the switch faster).

      And, don't forget that more and more of "today's" components are SMD only... which makes using them on a

      • Re: (Score:2)

        by lowen ( 10529 )

        Gate capacitance on a junction FET (not all FET's are MOSFETs) and base to emitter capacitance on a typical bipolar are comparable. However, the best-case use for a bipolar is a cool little magnetic device called a transfluxer (no, I am not making that up; see US Patent number 4,459,653 for the 'bifluxer' variant and the citations to the original, Google's link is https://www.google.com/patents... [google.com] ). A transfluxer-based inverter is very close to being as efficient as a MOSFET design. (And, don't worry, t

        • Re: (Score:2)

          by lowen ( 10529 )

          But of course I had to misremember intersil when I meant International Rectifier (HEXFET is a trademark of I-R, by the way).

    • ... what is taught today ...

      Your electronic gear is no longer repairable. Just toss it out for the latest and greatest. Stay calm and carry on.

    • Re: (Score:2)

      by Agripa ( 139780 )

      The TIP devices, being bipolar technology, are inherently less efficient than their modern cousins, which are mostly CMOS FET technology.

      They are less efficient in most although not all hard switching applications but most power MOSFETs now are not suitable for linear applications.

      Further, the older devices tend to be physically larger than modern equivalents, which is a natural consequence of the lower efficiency demanding more surface area to radiate waste heat.

      And if your application calls for high powe

  • Do something productive ... (Score:4, Insightful)

    by MacTO ( 1161105 ) on Tuesday August 18, 2015 @12:07AM (#50336939)

    If you're actually concerned about this, rewrite the tutorials rather than complaining about them. A big part of the reason why reach for those parts is because someone taught them how to use them.

  • old clunky junk (Score:3)

    by mirix ( 1649853 ) on Tuesday August 18, 2015 @12:13AM (#50336949)

    Not sure why the "hobbyist" community holds onto old crud like this when newer things are cheaper and better, win win. Darlingtons are terribly inefficient. It will work fine for turning on a lamp from your arduino but so will 10,000 different FETs.

    Like people using ua741 opamps that are older than me. At least move into 1980 and use an LM358 or something. Same price or cheaper, and the input actually goes to one rail. Still very old junk, but significantly less so.

    I guess people read some circuit from 1975 and figure they need to use the same parts verbatim, buy a bunch and are stuck with them making new circuits, that they then post, and more noobs buy the same old junk!

    • Re: (Score:3)

      by Mashiki ( 184564 )

      The same reason why some people still build stuff using tubes even though a IC could do it, easier, faster, and cheaper.

      • Except when it can't There's a great deal of continued tube use in harsh environments, where the temperature sensitivity of semiconductors presents a very real limitation, or where their very small size makes them more vulnerable to radiation damage, there's the behavioral differences when overdriven, and the list goes on.

    • You're one to talk... you use a PDP-11! I at least send mail from my "modern" IMSAI 8080.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      "Like people using ua741 opamps that are older than me. At least move into 1980 and use an LM358 or something. Same price or cheaper, and the input actually goes to one rail. Still very old junk, but significantly less so."
      My favorite is the oldy-moldy OP-10. I happened to be interested in a _very_ low Input Impedance Op Amp at one time, (Not FET stuff...). Ten OP-10s in parallel brought the Input Impedance below 0.01 Ohms, and with some attention paid to topology, a linear sensitivity down to the 1:1 Pic

    • Re:old clunky junk (Score:5, Insightful)

      by serviscope_minor ( 664417 ) on Tuesday August 18, 2015 @03:55AM (#50337421) Journal

      Looks like we have a component snob here.

      Some people are amazingly derogatory about the "maker community". I wouldn';t exactly class myself as one but I don't get the hate. As far as I can tell, the maker community is about making (duh) *things*. The point being, the final thing is what matters and the process of getting there is "whatever works". This is fine. The emphasis is not on building something using the best tools available, it's about getting to the end goal.

      Makers as a result tend to only care about the guts of the circuits and stuff if those affect the final thing. Hence the near obsession with Arduino. It reduces 99% of the work to an already solved problem, even if the solution is in some sense not optimal.

      But they're not trying to make the smallest/cheapest object, they're trying to make AN object generally that no one else has.

      And you know what? There's nothing wrong with that.

      Not sure why the "hobbyist" community holds onto old crud like this when newer things are cheaper and better, win win. Darlingtons are terribly inefficient. It will work fine for turning on a lamp from your arduino but so will 10,000 different FETs.

      Who cares? The price probably isn't significant part of the overall cost. $MAKER has a box of darlington pairs, all $MAKER's friends have them and he can probably pick up a replacement in a Maplin on a Sunday if he blows out one away from his normal supply.

      Hobbyists oddly enough don't tend to have a trade account with Farnell or want to wait until Tuesday morning (which to them translates to next Saturday) to get the part.

      And if the maker in question has a circuit known to work and give enough power, there's no point saving a buck but adding a few hours to a multi-hundred hour project.

      Like people using ua741 opamps that are older than me. At least move into 1980 and use an LM358 or something. Same price or cheaper, and the input actually goes to one rail. Still very old junk, but significantly less so.

      I say this as someone who refularly uses the sub 3V micropower rail to rail single supply op-amps from TI and Linear (ever seen an 8 pin BGA before?). A 741 is essentially a tank with 8 pins. For low spec stuff the performance is perfectly fine. If you don't need low power, rail to rail operation or high speeds they work and do the job perfectly. They are also infeasibly robust.

      For a circuit which only needs a 741, you may as well design it for one. There's lots of pin compatible ones you can swap in at a pinch if you really need. But again it doesn't matter.

      741 does the job if the job is not to have the most optimised circuit but instead one that does the job.

      I guess people read some circuit from 1975 and figure they need to use the same parts verbatim, buy a bunch and are stuck with them making new circuits, that they then post, and more noobs buy the same old junk!

      No the problem is yorr goals and attitudes are different from other people's. You don't understand them so you assume they're idiots. I know a bunch of them and they're not.

      If you tried to make some of the stuff they made they'd probably be shaking their heads in week 3 when you've been poring over datasheets and finally sent your circuitboard plans off to be made when they'd have their 4th arduino already bodged inside the laser cut wood case with duct tape and jumper wires with the thing mostly working.

    • holds onto old crud like this when newer things are cheaper and better

      Monkey see, monkey do.

      The vast majority of hobbiest, and definitely in the subset of the Arduino crowd are not practising electronics engineers, they are people of all backgrounds dabbling into electronics and achieving great things. Ultimately though they achieve their goals without ever understanding how or why. By reading an online tutorial, sometimes even basic enough not to include a schematic but an actual drawing of a part and coloured lines showing the hookup they are building things that work, they

    • A real hobbyist uses whatever is in the drawer.

    • Re: (Score:2)

      by AmiMoJo ( 196126 )

      Many of these hobbyists don't have the understanding needed to select suitable replacement parts. Even just picking a newer op-amp is hard for them, because they don't really understand op-amps or how to read datasheets or what parameters they need to look at. Forget about changing a few passives to account for different parts.

      Thus they tend to rely on old circuits and information, and thus want to use those old parts. If you look on Make half the electronics tutorials are clearly written by people who don'

    • Cheaper?

      It's hard to be cheaper than something that is already in your junkbox. Don't have a junkbox? Show up at a hamfest and some time around noon somebody will give you a ready filled junk-box for free. Most likely it is the junkbox of a recent silent key (ham who died).

      Don't worry. Some day those old parts will be rare and expensive so they will only get used for fixing old stuff and maybe making audio amplifiers for people who are nostalgic for the sounds of their childhood. Hobbyists will then be bui

    • Re: (Score:2)

      by Agripa ( 139780 )

      Like people using ua741 opamps that are older than me. At least move into 1980 and use an LM358 or something. Same price or cheaper, and the input actually goes to one rail. Still very old junk, but significantly less so.

      The 358 is not always a good replacement for the 741 although in most circuits it would not matter. It's input bias current is the opposite, it has no input offset voltage adjustment, and single operational amplifiers are more useful in circuits where the power supply is bootstrapped.

      There

  • Where are the advantages? (Score:5, Insightful)

    by marcansoft ( 727665 ) <hector@marcansoft.UMLAUTcom minus punct> on Tuesday August 18, 2015 @12:13AM (#50336951) Homepage

    I have no doubt that old-school TIP series transistors still have plenty of uses today, but the article is completely devoid of any examples. All it is saying is "look, these things aren't unusably bad for driving motors - they're just bad." Tom's post is still dead-on - using old school NPN BJTs for switching heavy loads today is completely dumb, and just because he exaggerated a bit about just how bad it can get doesn't mean he's wrong.

    I was hoping for some insight, like a discussion of robustness (I've blown FETs way more easily than I've blown BJTs), or perhaps use in analog applications, or anything else really. But nope. TFA is literally just confirming the findings that it's trying to disprove, while providing absolutely no counter-examples. Somehow feels like par for the course for Hackaday these days...

    I use old school jellybean parts all the time, sometimes because it really doesn't matter (driving a relay? meh, throw a BC547 on it, who cares, it's relatively low power anyway), sometimes because it's all I have lying around, but sometimes using ancient devices is actually very dumb, and I wouldn't turn a motor on and off with a BJT these days.

    • Re: (Score:2)

      by Alioth ( 221270 )

      There are also some pitfalls of MOSFETs he should really mention (probably why people are using these old BJT power transistors is they are a bit more forgiving in this respect). When driving motors and relays, you often get some inductive 'kick', and this will capacitatively couple across the MOSFET's gate and go right back to the microcontroller's pin. Usually this results in just the microcontroller crashing, but it may also result in latch-up which can quickly destroy the microcontroller (I've seen it h

      • To be fair, I always had to put diodes across motors and relays when using BJTs. I'm not sure if it coupled back through the transistor or the rails, but I certainly got micro resets and crashes if I didn't. It's always a good idea regardless of what switching technology you use.

        • Re: (Score:2)

          by Agripa ( 139780 )

          I have not encountered this problem myself although I might not have noticed and I tend to be paranoid about interface circuits anyway. My guess is that the excessive reverse transfer capacitance of the MOSFET allows the high dV/dT from the inductive kickback to get into the microcontroller. This would be exasperated by a drive circuit intended for the "high impedance" input of the MOSFET compared to a bipolar transistor where the low impedance drive circuit would just absorb it.

    • Re: (Score:2)

      by Agripa ( 139780 )

      For many loads however using a bipolar transistor is more economical than a MOSFET simply because of economics. Current density of a bipolar transistor is higher allowing less die area making them less expensive. Insulated gate bipolar transistors have the same advantage over MOSFETs.

      This becomes more important at higher voltages where MOSFET die size scales by the square of the voltage but it still applies at low voltages.

  • We actually use them in our telescopes (Score:5, Informative)

    by NixieBunny ( 859050 ) on Tuesday August 18, 2015 @12:52AM (#50337047) Homepage
    The TIP120 is not too efficient, but if you're already going to be dropping a couple volts in the transistor, it simply doesn't matter. Our radio telescopes use very low resistance coils to control the attenuation of a microwave signal using a device called a ferrite modulator. Its voltage drop is about 1 volt, and the lowest power supply available is 5V, so it works fine. Plus, we have a bin with 50 of the darn things in the parts cabinet. So there, Tom! (I jest. He's one of my best friends.)

  • Needless limiting of options (Score:5, Insightful)

    by Ashtead ( 654610 ) on Tuesday August 18, 2015 @01:11AM (#50337085) Journal

    Where to begin?

    Should one even bother to do anything about advice from someone who goes on about enhancement MOSFETs while everything else is rubbish, and then present the circuit symbols for Junction FETs as examples? Makes one wonder what else is inaccurate there.

    The actual advice of throwing out anything designed in the past century is at sensitiveresearch.com/DoNotTIP/index.html [sensitiveresearch.com].

    Where not only the so-called TIPs, (by which is meant a certain series of reasonably popular power transistors in TO220 packages, designed by Texas Instruments) but also other devices such as 2N2222, LM386, and "bipolar transistors" and so on, are no longer to be used. Just because they might not be the best choice for switching loads controlled by an Arduino or similar.

    This makes for a needless limiting of options -- If all one ever does is to turn things on or off from some microcontroller maybe, but with whatever designs I make I find that to be a small fraction of what is happening. The rest are things like multi-frequency linear or RF where all kinds of semiconductor devices might be applicable. Even vacuum tubes in some cases.

    And then looking around the site and discovering the author is in his own words, "reasonably obsessed with the early history of electronic (not necessarily digital) computing" --- and then he advocates discarding what amounts to the elements of the analog electronic computers? This does not ring true.

    • Analog computers weren't built of TIP120s or LM386s or 2N2222s. They were built with 12AX7s and 5U4Gs, and the later ones of Philbrick K2-Ws. By the time the TIP120 came out, DEC was building PDP-11s out of TTL chips. TTL is rather dumb nowadays, as we have CMOS.

      One thing is true about the old parts, though... you can still buy them. I've had occasion to work on some 15 year old electronics, and none of the bigger chips are made any longer. We can still get 741s to fix our 40 year old spectrometer, but no

      • The 7400s stayed in use for a long time in education, as they were a lot more durable than their CMOS counterparts in the 4000s. TTL doesn't die if you handle it without antistatic precautions.

      • Re: (Score:2)

        by tlhIngan ( 30335 )

        Analog computers weren't built of TIP120s or LM386s or 2N2222s. They were built with 12AX7s and 5U4Gs, and the later ones of Philbrick K2-Ws. By the time the TIP120 came out, DEC was building PDP-11s out of TTL chips. TTL is rather dumb nowadays, as we have CMOS.

        Actually, they were. Because digital computers either were too big, too unreliable, or too hard to use.

        Discrete logic was brought into play by Apollo (you can thank the Apollo Guidance Computer for basically bringing the 74xx series logic chips to

    • Re: (Score:2)

      by Alioth ( 221270 )

      What's most inaccurate is that he says that using a MOSFET means always a really simple circuit with the microcontroller directly connected to the gate of the MOSFET and nothing else in the circuit (except the pulldown resistor). In Microcontroller And MOSFETs 101 you soon learn about inductive loads and the problems they can cause, relays are the popular example - when you turn off the current to the relay you get a big voltage spike over the MOSFET. This capacitatively couples over the gate and zaps the o

      • That doesn't say much good about the design of the microcontroller. Output circuits should be designed to snub overvoltages.

    • Where not only the so-called TIPs, (by which is meant a certain series of reasonably popular power transistors in TO220 packages, designed by Texas Instruments) but also other devices such as 2N2222, LM386, and "bipolar transistors" and so on, are no longer to be used. Just because they might not be the best choice for switching loads controlled by an Arduino or similar.

      So, I am not an EE, but it seems like what he's actually saying is that the MOSFET takes an order of magnitude less turn-on current and that it wasts an order of magnitude less power as heat. Is that true? And if so, why would you not want to save power? Are your driver transistors doubling as a heater?

      • Re: (Score:2)

        by Ashtead ( 654610 )

        Where not only the so-called TIPs, (by which is meant a certain series of reasonably popular power transistors in TO220 packages, designed by Texas Instruments) but also other devices such as 2N2222, LM386, and "bipolar transistors" and so on, are no longer to be used. Just because they might not be the best choice for switching loads controlled by an Arduino or similar.

        So, I am not an EE, but it seems like what he's actually saying is that the MOSFET takes an order of magnitude less turn-on current and that it wasts an order of magnitude less power as heat. Is that true? And if so, why would you not want to save power? Are your driver transistors doubling as a heater?

        A lot of the energy budget depends on the circumstances. When running on batteries, power draw is much more of a concern than when running on mains power. Similar with heating -- it may or may not be anything that needs to be attended to. Now having said that, there are several good reasons to use the MOSFET instead of the bipolar transistor, but they are not so overwhelmingly good that it makes sense to discard all kinds of bipolar transistors just because ot that.

        The turn-on current for the MOSFET comes

  • TIP? (Score:3)

    by Anne Thwacks ( 531696 ) on Tuesday August 18, 2015 @03:39AM (#50337375)
    I presume TIPxxx refers to "Texas Instruments Plastic" transistors. These have proprietry TI part numbers - although many were later second sourced.

    The parts were widely used because they were very cheap, and widely available. The early ones used a plastic that tended to burst into flames if the device was overloaded.

    There are generally perfectly adequate alternatives with the European Standard numbers (BCxxx). It is unclear why these people are promoting a strangely obsolete technology, and the OP is not much help in understanding any of the relevant issues.

  • ... for those who never used or heard of it, was a peer-to-peer messaging and file interchange network where a peer was a BBS accessed by dial-in modem. This was in the days before ubiquitious tubed internet access. For folks that didn't have access to usenet at school it was THE place to be. https://en.m.wikipedia.org/wik... [wikipedia.org]

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