hybridfree/eevblog-posts huggingface dataset:
Transistor Test with M644 - Page 1
Forum section: electronics / beginners

author: ko4nrbs
author_rank: Regular Contributor
timestamp: April 25, 2021, 02:12:11 am
content: Testing a NPN transistor with my M644 and am unsure of the results. The transistor is a 2KBP02 (ECG182). I get the following readings with the M644.BJT-NPNB-39UF-533This same transistor when tested with my multimeter gave the following results.Used Diode Function in the meter.1. Connecting Base to the emitterPositive lead to the transistor’s BASE (B).Negative lead to the transistor’s EMITTER (E).Read-.792. Connecting Base to the collectorPositive, lead to the BASE (B), and negative lead to the COLLECTOR (C).Read- .593. Connecting emitter to the BasePositive lead to the transistor’s EMITTER (E).Negative lead to the transistor’s BASE (B)Read- .1064. Connecting the collector to the BasePositive lead to the COLLECTOR (C) and Negative lead to BASE (B).Read-.1045. Connecting collector to emitterPositive lead to the COLLECTOR (C) and Negative lead to EMITTER (E).Read-.5166. Connecting emitter to collectorPositive lead to EMITTER (E) and Negative lead to the COLLECTOR (C)Read-.504What am I seeing?Thank you,Bill

author: Jwillis
author_rank: Super Contributor
timestamp: April 25, 2021, 04:10:48 am
content: Unlike diodes , some transistors can have a really low ability to block reverse voltages. What your seeing is the forward voltage and reverse voltage of each junction. The only one that is normally important is the Vbe or forward voltage between the base and emitter . That will read between .6 and .8 Volts depending on the transistor being tested . Darlingtons will have higher Vbe because of the structure of having two transistors . This can be as high as 1.5 volts Vbe

author: ko4nrbs
author_rank: Regular Contributor
timestamp: April 25, 2021, 12:13:56 pm
content: So the transistor is ok?Bill

author: Jwillis
author_rank: Super Contributor
timestamp: April 25, 2021, 10:54:06 pm
content: Yes . Your first test indicates that the forward voltage between the Base and Emitter or Vbe is 533mV and a B(Beta or hfe ) is 39 . Using a plain diode tester can give you all kinds of weird readings when testing a transistor because transistors don't work exactly like 2 diodes tied together. The transistor tester goes though a series of measurement tests which includes passing a voltage and current across all three junctions. Then it makes calculations based on those measurements giving a result .Transistors have four operation modes for the two types NPN or PNPNPN PNPVe < Vb < Vc active reverseVe < Vb > Vc saturation cut offVe > Vb < Vc cut off saturationVe > Vb > Vc reverse activeThe tester can work out the Type of transistor , Vbe and Gain (Beta) by the measurements taken .If a transistor fails it usually fails shorted .So the test would indicate three low resistive values between pin 1 , 2 and 3 .
Transistor  tester - Page 1
Forum section: electronics / beginners

author: Cactus
author_rank: Contributor
timestamp: December 08, 2018, 12:58:13 pm
content: Well i built one of those transistor testers bought from china, its the M12684 graphics type with the red circuit board. The kit seems to work ok but with one problem, when i conect it up to a power supply, be it a bench supply or a battery, it reads the voltage as 20v and i dont know why.I have checked the board and components but i can't seem to find anything I have done wrong and I am not sure where to go next. Im hoping i have just made a small error somewhere and cant see it.I would appreciate any helpful thoughts other forum members may have as im still very much a beginner.Thanks

author: JoeO
author_rank: Frequent Contributor
timestamp: December 08, 2018, 01:09:51 pm
content: How about posting clear pictures of both sides of your board.

author: ledtester
author_rank: Super Contributor
timestamp: December 08, 2018, 01:23:10 pm
content: If the following schematic of the M12864 matches what you have, the battery voltage is read on pin 28 via the resistor divider network formed by R11 (10K) and R12 (3.3K), so I would check those resistor values.I would also check the voltage on pin 28 when the device is powered up. If the tester is reporting a battery voltage of 20 V, that means it's seeing 20*(3.3/13.3) = 4.96 V on pin 28. A 9V battery should present 9*(3.3/13.3) = 2.23 V.

author: Cactus
author_rank: Contributor
timestamp: December 08, 2018, 02:04:33 pm
content: Wow folks thanks for such quick replies. I will check this out when i get home and report back.

author: Cactus
author_rank: Contributor
timestamp: December 08, 2018, 03:51:09 pm
content: Ledtester you were bang on target. Im afraid i made an error and had a 33k resistor where i should have had a 3.3k resistor. with your help i have learned from it and fixed te problem. My tester is now showing 9.1v, happy days!I hope one day i may know enough to be able to help someone on here! Thank you so much

author: JoeO
author_rank: Frequent Contributor
timestamp: December 08, 2018, 07:03:22 pm
content: So where was the 33K ohm resistor supposed to be soldered?

author: Cactus
author_rank: Contributor
timestamp: December 08, 2018, 08:53:07 pm
content: Looking at the schematic above - R10 i believe

author: Cactus
author_rank: Contributor
timestamp: December 08, 2018, 08:53:38 pm
content: Looking at the schematic above - R10 i believe
Transistor testing - Page 1
Forum section: electronics / beginners

author: ironsniper1
author_rank: Regular Contributor
timestamp: April 12, 2025, 01:34:44 am
content: Hey all I am trying to repair a Kortek KTX-26 CRT monitor chassis for an old arcade machine and I keep getting a short on a capacitor,I have removed two D1138 Transistors and tested them with my multimeter and they tested good and I bought a cheap tester and I think they tested good but I am not sureCan someone take a look at these readings and tell me if both are good or bad or just one is good or bad?

author: Grandchuck
author_rank: Super Contributor
timestamp: April 12, 2025, 12:17:50 pm
content: both look good

author: ironsniper1
author_rank: Regular Contributor
timestamp: April 16, 2025, 01:45:49 am
content: thank you for that, i am still chasing issues, i have a D1880 that i think it testing bad but i am not sure, with positive on base and negative on emitter i get 0.018v in diode mode and with negative on base and positive on emitter i get the same, i think this is bad but not sure

author: Grandchuck
author_rank: Super Contributor
timestamp: April 16, 2025, 11:52:02 am
content: that sounds like a shorted junction

author: ironsniper1
author_rank: Regular Contributor
timestamp: April 17, 2025, 05:11:16 am
content: Got another one and it tested the same so I am back to square one on this thing, I have a short to ground on a few different components but I have no idea what is causing it

author: Grandchuck
author_rank: Super Contributor
timestamp: April 18, 2025, 01:18:49 pm
content: This might helphttps://marsonotv.blogspot.com/2010/09/troubleshooting-horizontal-deflection.html

author: ironsniper1
author_rank: Regular Contributor
timestamp: April 20, 2025, 03:31:50 am
content: Thanks but not really helpful as it doesn’t really help with my chassishttps://imgur.com/a/H53qd3Y

author: Grandchuck
author_rank: Super Contributor
timestamp: April 20, 2025, 12:46:53 pm
content: The circuit I attached shows a driver transformer for the HOT. In-circuit testing of the transistor can be misleading because the secondary of the transformer has little resistance to ground.I don't know if that is relevant to what you are doing but just wanted to point that out. Good luck.

author: ironsniper1
author_rank: Regular Contributor
timestamp: April 21, 2025, 12:59:56 am
content: the hot is being tested out of circuit
Transistor to Amplify Radio Signals Sub-100Hz - Page 1
Forum section: electronics / beginners

author: Geschwessaut
author_rank: Newbie
timestamp: December 09, 2020, 04:18:46 am
content: Hey guys,Completely new to radio receiver circuits. So I was trying to pick up radio signals from 0-100Hz. I connected an antenna to the analog pin on my 16-bit resolution ADC which was hooked up to my Arduino and, as I was anticipating I got 0 readings. I did a little bit of problem solving and finally stumbled upon the solution to use a transistor to amplify the signal and make it readable to my ADC. I have 2n2222 transistors, however I am new to transistor amplification circuits and don't know what transistor I would need to amplify signals received by my antenna on the breadboard. Could anybody give me an idea of what transistor I would use for this, or if this is even possible?

author: Berni
author_rank: Super Contributor
timestamp: December 09, 2020, 06:44:13 am
content: You do realize that in order to have an antenna that efficiently picks up 100Hz needs to be a 700km piece of wire.This is one of the reasons 100Hz is not typically used for radio communication, the antennas for it are humongous. You can make low frequency antennas a more manageable size by using coils instead.Also the power grids run at 50/60 Hz so there is a massive amount of interference there along with its harmonics.
Transistor Vce derate?  (vs datasheet max?) - Page 1
Forum section: electronics / beginners

author: max_torque
author_rank: Super Contributor
timestamp: February 11, 2018, 09:19:59 pm
content: Say i have a nominal 60v transistor (Vce max) how close can it be run, in a practical circuit, to that limit, and what happens if that threshold is exceeded?(ie typically, how much safety factor is built into a typical transtor datasheet?)

author: Benta
author_rank: Super Contributor
timestamp: February 11, 2018, 09:37:07 pm
content: It can be run to 60 V without problems (unless spikes etc. can be present).What you have to watch is SOA and RBSOA, which can be tricky to analyze.

author: rstofer
author_rank: Super Contributor
timestamp: February 12, 2018, 02:55:19 am
content: It depends on where the number showed up on the datasheet. If it was under Maximum Ratings then that is the maximum number before magic smoke leaks out. If the number had a margin, they would have jacked up the spec.For the 2N2222a datasheet, the Maximum Rating for Vce is 50 VDC. It is also listed as the minimum breakdown voltage but there is no maximum so all they will guarantee is 50VDC.I wouldn't expect any slack on the Maximum Rating. If I designed above the rating and it worked, great! But if it came apart, it's my fault. Maximum is kind of self-defining...http://web.mit.edu/6.101/www/reference/2N2222A.pdf

author: David Hess
author_rank: Super Contributor
timestamp: February 12, 2018, 06:35:32 am
content: Transistor Vceo is tested and sometimes graded to make different part numbers. In practice it is the guaranteed minimum value and it is not uncommon to find transistors which actually have a maximum Vceo considerably higher than the datasheet specification.For low voltage and power applications, I usually derate the peak operating Vceo to 2/3rds or less of the datasheet maximum. Sometimes transistor Vceo degrades with age if its quality is poor.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: February 12, 2018, 09:44:26 am
content: Most quality brands will have a Vceo greater than claimed. Sometimes quite a lot greater. This is usually only a problem area with substandard parts.As mentioned, much more of a problem is assessing power handling and SOA, especially sincesomemanufacturers are prone to exaggerate here. For example, stating a Ptot which relies on the case being at 25C but then admitting that the minimum thermal resistance even with direct mounting makes that impossible.
Transistor Voltage and Current Regulation. - Page 1
Forum section: electronics / beginners

author: Mint.
author_rank: Frequent Contributor
timestamp: February 19, 2012, 12:10:57 am
content: Can somebody please plain to me how these two circuits work.The first one is constant current.The second is constant voltage.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 19, 2012, 12:33:13 am
content: Both of these circuits are taking advantage of the fact that there will be a fairly constant drop of 700 mV from the base to the emitter of a transistor when the transistor is on.In the constant current circuit, the two diodes will raise the base of the transistor up to ~1.4V. 700 mV is then dropped from the base to the emitter. This means that 700 mV is left and that is being dropped across the 700 Ohm resistor. This means 1 mA of current is then flowing through that resistor. The current through the collector (which the potentiometer is connected to) will be virtually the same as what flows through the emitter. (The base current is neglected since is is typically much smaller in comparison.) The 5.6k resistor is just to limit current through the diodes and base/emitter junction.The voltage regulator circuit is relying on the same property. So the battery or voltage reference forces the base to 5.7V. 700 mV is then dropped between the base and emitter. This makes the output fixed at a constant 5V.
transistor yihua 853d - Page 1
Forum section: electronics / beginners

author: pasfox
author_rank: Newbie
timestamp: September 13, 2018, 12:01:28 am
content: You can help me with the part number of the transistor Q1 and the zener diode DZ1 of the yihua 853d heat station?

author: nAyPDJ
author_rank: Contributor
timestamp: November 08, 2018, 06:45:39 am
content: Mine reads 1AM.
transistor - Page 1
Forum section: electronics / beginners

author: jamesho
author_rank: Newbie
timestamp: August 17, 2013, 04:09:35 pm
content: Can any one help me identified this component.http://picpaste.com/IMG_20130817_155042-wBRcGJAd.JPGI assume its a transistor.The Marking on it that I can see areNEC ?82 P47Its from a 12V car inspection lamp (strip light).Thanks

author: RoadRunner
author_rank: Frequent Contributor
timestamp: August 17, 2013, 04:36:37 pm
content: its D882.

author: Stonent
author_rank: Super Contributor
timestamp: August 17, 2013, 04:49:25 pm
content: Quote from: Gaurav on August 17, 2013, 04:36:37 pmAnd the datasheet. NEC's part business is now called Renesas.http://documentation.renesas.com/doc/DocumentServer/D17116EJ2V0DS00.pdf

author: edavid
author_rank: Super Contributor
timestamp: August 17, 2013, 04:50:10 pm
content: Quote from: Gaurav on August 17, 2013, 04:36:37 pmBy which he means 2SD882http://groups.ist.utl.pt/lee/SUBA/Suba_files/2sd882.pdf(oops)

author: Stonent
author_rank: Super Contributor
timestamp: August 17, 2013, 04:56:46 pm
content: Hmm I was thinking the same thing...

author: jamesho
author_rank: Newbie
timestamp: August 24, 2013, 08:01:34 pm
content: Thanks guys! Most helpful. All back up and running now.
Transistors - Page 1
Forum section: electronics / beginners

author: Rihards Veips
author_rank: Contributor
timestamp: April 04, 2014, 09:01:03 pm
content: Is there a way to multiplex transistors like an LED cube?{With an Arduino} (Can't figure out how it would work with transistors)I need that for my lighting project to drive ~64 relays o-o[3x3x9 Transistor Tower]

author: Simon
author_rank: Unknown
timestamp: April 04, 2014, 09:06:41 pm
content: err 3x3x9 is not a cube.You give practically no detail of what you are trying to do. how do you want to control it ? this sounds like a need for an mcu driving a multiplexer driving a bank of latches

author: Rihards Veips
author_rank: Contributor
timestamp: April 04, 2014, 09:24:42 pm
content: I think I figured it out - I connect all the BASE pins in collumns and the collumns on the output pins of the Arduino then connect the COLLECTOR to the GROUND pin on the Arduino And if I am using a different power source for the relays I connect the negative to the ground of the transistor and the relay input to the EMMITER and the positive to the relay with a diode and a resistor.

author: mariush
author_rank: Super Contributor
timestamp: April 05, 2014, 12:31:29 am
content: I don't understand what you're trying to do. I don't know what you mean by relays.. if you mean the classic mechanical relays, those aren't really designed to work like leds, to be turned off and on several times a second (not to mention it will be very noisy)If you want to make a LED cube, here's some videos that might help you out:https://www.youtube.com/playlist?list=PL0JWuCHXfJ2zXVRqFRFVq-lNt_xtCYMjxIn some of those videos he explains the theory behind it, the circuit, everything.

author: David_AVD
author_rank: Super Contributor
timestamp: April 05, 2014, 12:44:21 am
content: If you only want one relay on at a time, you could multiplex the drives in theory. In practice I doubt if would be worth it due to the extra diodes required to stop the interaction between rows and columns.Just use 8 octal driver chips such as the UCN5821. They can drive the relays directly, have the back-EMF diodes inside and can be cascaded to simple serial control.
Transistors - YouTube list of videos on the basics - Page 1
Forum section: electronics / beginners

author: ez24
author_rank: Super Contributor
timestamp: September 16, 2017, 03:50:33 am
content: Subject Name+URL Notes============================================================================Transistor …..Filipe PaixãoHistoryTransistorBen Eater……………..TransistorDavid Williams……………..TransistorSteel Wheels Down……………..Transistorw2aewTransistorDrCassette……………..TransistorEEVblog……………..TransistorExamFear Education……………..TransistorhumanHardDrive……………..TransistorMateo AboyTransistorTampatecTransistorThe Offset VoltTransistorbooksofscienceTransistorColumbia Gorge Community CollegeTransistorGreatScott!TransistorK TemkinTransistorKevin DarrahTransistorMake:TransistorMichel van BiezenTransistorSparkFun ElectronicsTransistorAllAmericanFiveRadioTransistorCodeNMoreTransistorDave FisherTransistorDrMattMarshallTransistorelectronzapdotcomTransistorEngineering Diary- Embedding .TransistorGeeky PeekTransistorLearn EngineeringTransistorLouis RossmannTransistorMohamed BakrTransistorProfessor Curtis MeyerTransistorStan GibiliscoTransistorKenneth FinneganTransistorradiofun232TransistorRichard's Electronics LabTransistorSimply ElectronicsTransistorCody A JonesTransistorENGR 313TransistorMrCircuitMatt

author: ez24
author_rank: Super Contributor
timestamp: September 16, 2017, 03:54:19 am
content: The list is sorted by score, highest score starts at the top.Stats:Started with 2587 videos. After dups were deleted = 2089. After videos that did not have "transistor" or "BJT" in the title were deleted = 511. Watched 511 videos and deleted those that were poor quality and scored the remaining like:Num of videos Views Time Playlist Music Score' 1 = 1 <5k = 1 ' < 10min = 1 No = 1 Yes = 1' 2 – 5 = 2 '5k- 50k = 2 '10 to 20 -= 2' >5 = 3 > 50k = 3 '> 20 = 3 Yes = 3 No = 3For complete score results see the attached sheet

author: Brumby
author_rank: Unknown
timestamp: September 16, 2017, 05:25:20 am
content: Quote from: ez24 on September 16, 2017, 03:50:33 amIt's the format of the URL.You put the "watch" parameter in for a specific video. Previously you have used the "channel" or "user" options.This will give you a link to a search result that has several videos on transistors...https://www.youtube.com/user/filipedpaixao/search?query=transistor
"Transparent" 7 segment display - LCD - Page 1
Forum section: electronics / beginners

author: made2hack
author_rank: Frequent Contributor
timestamp: March 01, 2021, 01:43:33 pm
content: Hi all,So this is what I want to do. Shine a light through a 7 segment display so that the segments get projected on a wall. Or the negative of the 7 segments, as the segments would be the dark area blocking the light.However, I'm not sure what flag or filter to search for on TME or Mouser, etc. Essentially I want a 7 segment or any LCD for that matter that has no reflective backing. Essentially is "transparent" so that another light shines through it.I can swear I saw this feature before somewhere on my searches but I can't seem to find the search option. Any ideas what transparent or reflective sheet removed LCDs are called?Thanks in advance,

author: jpanhalt
author_rank: Super Contributor
timestamp: March 01, 2021, 02:03:18 pm
content: What you are probably looking for is a transmissive LCD :https://newvisiondisplay.com/lcd-modes/The LCD mask used in mask SLA (MSLA) 3D printers might work. For example:https://www.amazon.com/Elegoo-Mars-Replacement-Screen-Printer/dp/B087JB7TZZWith any LCD, you will need polarization to see the image.

author: made2hack
author_rank: Frequent Contributor
timestamp: March 07, 2021, 03:11:33 pm
content: So for it to work, the polarizing layer has to be maintained?Thanks

author: jmelson
author_rank: Super Contributor
timestamp: March 07, 2021, 05:32:15 pm
content: Quote from: made2hack on March 07, 2021, 03:11:33 pmThe typical transflective LCD has one polarizer on the front, and depends on the rear reflector to transmit polarized light back through the LED and front polarizer again. A transparent LCD would need two polarizers, one front and one on the back. Most LCDs work with circularly polarized light, and the electric field lines up the crystals to interfere with the circular polarization, turning the segment dark.Jon

author: jbeng
author_rank: Regular Contributor
timestamp: March 07, 2021, 06:04:11 pm
content: As Jpanhalt said, what you are looking for is a transmissive-type display.Most numeric LCD displays are supplied as transflective or reflective devices, so transmissive ones can be somewhat difficult to find. However, youcanconvert either transflective or reflective displays to transmissive, provided you have the appropriate polarizing film.Basically, you just remove the transflective/reflective backing by carefully peeling it off the display and then replace it with transparent polarizer. By rotating the polarizer 90 degrees, you can convert it from the standard look of dark segments on a light background to the inverse (light segments on a dark background). I've done this successfully.
Transparent CAN bus isolators for avoiding ground loops  - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: March 30, 2021, 05:01:46 am
content: My understanding of CAN bus is that ACKs occur within the time span of a single bit in the sending frame so propagation delays introduced by 'transparent' isolators effectively increase the cable length which can be a problem if you are close to the edge of the allowable baud rate/cable length envelope.This Kemei isolator says the loopback time is 110 nano seconds.https://copperhilltech.com/can-11-can-bus-din-rail-isolated-repeater/Wikipediahttps://en.wikipedia.org/wiki/Category_5_cablesays CAT5 cable has about 5 nano seconds propagation delay per meter, so does that make each isolator equivalent to an extra 11 meters of cable, or are there other things I need to take into account?Also the isolated output doesn't have a terminal for the isolated ground reference which seems a bit strange. Is that normal?

author: Berni
author_rank: Super Contributor
timestamp: March 30, 2021, 05:26:03 am
content: They are probably relying on the leakage on the CAN lines and the ESD diode to keep the internal isolated ground close enough for it to work. Since its isolated it can float to anything it wants and since its connected to the CAN lines it will float to that potential.And yes any delay is similar to adding cable length. Due to how CAN works it still needs to get the acknowledge bit in time from behind the isolator. You need something more application specific to avoid that, like a CAN forwarder that treats both sides as two separate CAN network and just forwards any packets it sees onto the other one. The CAN forwarder always acknowledges it so you have no confirmation it was delivered, but it means you can have as much cable length as you want by stringing enough of these.CAN is not very good for long cables in general. RS485 is more suited for it
Trap For Young Players - Page 1
Forum section: electronics / beginners

author: German_EE
author_rank: Super Contributor
timestamp: August 30, 2015, 02:37:59 pm
content: We often hear the phrase "trap for young players" from Dave and this afternoon I came across an idea which is so simple that I really should have thought about it forty years ago when I first started building stuff.I was in the shack of another radio ham and we had spent the afternoon repairing a frequency counter that had a display fault. The problem had been fixed and I was just about to put the top cover back on when my friend stopped me. Grabbing hold of the counter he turned it upside down and gave the base of the unit a few hard slaps, out tumbled two solder balls and a short length of insulation. OK, the insulation probably would not have caused a problem but the solder balls may have shorted out something critical and it turns out that Felix does this as a last item on everything he constructs and repairs, turns it upside down and beats it up a little.Perhaps the fact that Felix works on satellites where service calls are awkward if something breaks may have something to do with this but it's something I had never thought of doing.Try this out on your project and see what falls out on to the workbench.

author: Kjelt
author_rank: Super Contributor
timestamp: August 30, 2015, 02:46:18 pm
content: I always visually inspect the pcb after service if there are any solder remains etc.Shaking softly and listening if something is loose inside is also one of the things I dobeforeI start working on it.Maybe satellite technology is made to be slapt and shaken around to a couple of G's but hard slapping leadfree smt might also cause a new problem
Treadmill motor mcb dead - Page 1
Forum section: electronics / beginners

author: bighamsport
author_rank: Newbie
timestamp: December 22, 2023, 09:26:32 pm
content: I have an older treadmill that doesn’t work. I used a tester and there seems to be power everywhere except none from the motor control board up to controls. Matrix rep walked me through some things and said MCB is bad. $1200 for new one. What I would like to do is bypass everything and use an external power source to power the motor. The motor is a Johnson JM02-001, DC100V, 3250 RPM, 23A motor. What is cheapest way to control the motor speed? I’ve read I might need a PWM, or maybe a rheostat or potentiometer?

author: BeBuLamar
author_rank: Super Contributor
timestamp: December 23, 2023, 03:35:51 am
content: You need a DC drive but a 3.2HP at 100V is hard to find and I would expect the cheap one around $500.
Trembler Coil - Solid State Alternative - Page 1
Forum section: electronics / beginners

author: mr2lw
author_rank: Newbie
timestamp: October 17, 2023, 10:22:34 am
content: HiI'm currently working on a homemade spark exciter for a Jet engine. I'm building a jet car.My current solution works well to generate a periodic spark at the igniter plug. It consists of a coil with a built-in trembler/buzz coil mechanism, which takes 12v and rapidly connects and disconnects one side of the coil, generating large AC spikes on the output. I'm then rectifiying this back to DC and storing it in a capacitor, which then discharges at a voltage set by a spark gap and sends the spark to the igniter plug.While this works well, i'm concerned that the trembler coil is hard to come by (it's from an old eastern european car) and is mechanical in nature. I therefore expect it to fail at some point. What is a recommended alternative to this trembler coil to charge the capacitor from a 12v DC source? Some people have suggested a flyback transformer, or a ZVS circuit to replace the coil/trembler components completely. Are there any solid state alternatives to just the trembler mechanism that can switch the 12v supply to the coil on and off as per the existing setup, or am i better off finding a different way of charging the capacitor altogether? Interested to hear your thoughts.Current setup can be seen working here -Thanks in advance!

author: mr2lw
author_rank: Newbie
timestamp: October 18, 2023, 12:58:28 pm
content: Any ideas?

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 18, 2023, 03:40:36 pm
content: Auto ignition coil and a drive circuit? Very common HV project, tons of solid state examples around the web.What is the purpose of using regulated DC for ignition?

author: mr2lw
author_rank: Newbie
timestamp: October 19, 2023, 06:12:52 am
content: Thanks! i'll have a look at that.It's what the original exciter unit would have supplied to the ignitors, so i want to emulate that as closely as possible. The igniter plug is designed specifically for this type of spark across it. I did try with AC directly across it but it didn't really work and started to damage the plug.

author: MathWizard
author_rank: Super Contributor
timestamp: October 20, 2023, 10:04:41 pm
content: What can be done with the HV from an old CRT TV or monitor ? I'm not saying that's good or bad for the OP, I'm just wondering what sort of spark gap discharge they might get in open air. I bet there's youtube video's of crazy and dangerous CRT PSU experiments.

author: langwadt
author_rank: Super Contributor
timestamp: October 20, 2023, 11:23:58 pm
content: what voltage is the capacitor charged to?

author: Terry Bites
author_rank: Super Contributor
timestamp: October 20, 2023, 11:34:35 pm
content: You might start here if you want a free running sparker.https://320volt.com/en/basit-mosfetli-flyback-surucu-devresi/orhttps://www.instructables.com/super-simple-ignition-coil-drivers/For real GT igntion systems you need something with a more lethal output current pulse.A shock you wont forget even if you live to remember it!see attached.
triac - Page 1
Forum section: electronics / beginners

author: Riccardo_Tommasin
author_rank: Contributor
timestamp: August 26, 2020, 07:41:39 am
content: Hi, i've got a triac driving a motor. It has a problem: it briefly gives out voltage spikes resulting in the motor changing speed quikly and then resetting to the default speed. The cycle repeats every 2 seconds. I'm driving the triac based on the mains voltage waveform position (through a microcontroller interrupt).I've changed the triac from BTA08 to BTA137 due to shipping time.I'm adding the circuit schematic.Sorry for my english but i'm not very good

author: madires
author_rank: Super Contributor
timestamp: August 26, 2020, 08:56:02 am
content: The MOC3023's datasheet shows two circuits for inductive loads. They are a little bit different.

author: Riccardo_Tommasin
author_rank: Contributor
timestamp: August 26, 2020, 10:07:21 am
content: the design it's almost the same. The only different thing is the placement between the triac and the poc (pin 4 and 6 are inverted) but isn't it the same thing ?

author: emece67
author_rank: Frequent Contributor
timestamp: August 26, 2020, 10:54:20 am
content: .

author: Riccardo_Tommasin
author_rank: Contributor
timestamp: August 26, 2020, 11:12:03 am
content: not exactly 2 seconds, it's a bit more inconsistent.It's not a software issue, with another triac it works a treat.

author: Andy Watson
author_rank: Super Contributor
timestamp: August 26, 2020, 11:33:15 am
content: Quote from: Riccardo_Tommasin on August 26, 2020, 10:07:21 am"Almost", but not exactly. As Madires has indicated, you have to allow for the motor behaving as an inductive load. Remember that the main triac turns off when thecurrentfalls to zero - with an inductive load this will be some timeafterthe voltage has passed through zero. If the triac is conducting when your next "on" pulse arrives it will effectively be conducting for a whole cycle - i.e. full power.

author: Riccardo_Tommasin
author_rank: Contributor
timestamp: August 26, 2020, 12:51:59 pm
content: yes, at higher motor speeds the problem dissapears. but i need low speeds
TRIAC - Page 1
Forum section: electronics / beginners

author: Jakobhoy
author_rank: Newbie
timestamp: December 09, 2024, 08:46:48 pm
content: Hi I need to replace a TRIAC on a circuit board. The existing one is called: Q6015L6 and underneath: 5EH3J.I am unable to find a replacement with the same name. Could anyone please help in providing an alternative more common component to replace it with?

author: inse
author_rank: Super Contributor
timestamp: December 09, 2024, 09:02:46 pm
content: Simply search for Q6015 TRIACLooks like an ordinary 600V 15A TRIACAvailable at Farnell, Newark, Aliexpress and Ebay (if you dare)

author: fzabkar
author_rank: Super Contributor
timestamp: December 09, 2024, 09:31:19 pm
content: Q6015L6TP, available from Mouser, Digikey, Farnellhttps://web.archive.org/web/20211028021142/https://m.littelfuse.com/~/media/electronics/datasheets/switching_thyristors/littelfuse_thyristor_qxx15xx_qxx16xhx_datasheet.pdf.pdf
Triac burst; capacitive supply - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 16, 2016, 06:03:26 am
content: 1. Attached is the circuit for capacitive supply making +5Vdc from 220Vac. Earlier I was using old zero cross ckt as marked in schemtaic , but now I have changed it to new zero cross ckt.2. Is this new zero cross circuit ok? Old zero cross ckt was reference I took from internet source.3. Problem is when I turned on this circuit suddenly triac burst.I have placed Q1 in the circuit as I have +5V powered micrcontroller whereas zener had 9.1V across it. So placed a bc547 which acts as gate.4. One issue I found that pin of R8 & microcontroller were not soldered i.e R8 was floating. Bt how does it can cause triac to burst? Or is there any other reason?Load is always 700ohm resistive one.
Triac circuit connections - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: June 15, 2020, 04:49:31 pm
content: I have a beefy triac module I bought years ago until it smoked (there was a thread). I have discovered the only thing that smoked was a terminal block, due to a lose connection. So I was intending on putting it back into service. The thing is, the PCB terminal points are not marked.Does it actually matter which way the IN and OUT go?

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: June 15, 2020, 06:51:40 pm
content: The two main terminals can be swapped, but the gate still needs to be switched with respect to the correct main terminal.

author: paulca
author_rank: Super Contributor
timestamp: June 18, 2020, 07:22:06 am
content: Quote from: Ground_Loop on June 15, 2020, 06:51:40 pmSo the circuit is already built. I have read a few guides for setting up my use case again, some mention terminal numbers to connect line in and line out, but my board has no labelling on the terminals.I have used this device for years, so I'm wondering how I wired it before!

author: paulca
author_rank: Super Contributor
timestamp: June 29, 2020, 11:12:47 am
content: So I assumed the two input terminals could be used in an polarity. It worked.However it quickly became apparent the device had issues beyond a loose connection as under 13Amps of load the live wire became increasingly hot which transferred through mains cable all the way back to the plug and made the live pin too hot to touch.IR camera revealed the source of the heat was the plastic terminal clamp itself. Registering 105*C after only 5 minute of operation.I removed the terminal clamp and soldered the mains wires directly to the board.Operating temp around the new connections fell to less than 60*C.Put back into service I was able to brew a beer operating the device at 1500W (50% duty) for over an hour.Successful repair and no need to buy a replacement device.
Triac - Dimmer vs Speed control - Page 1
Forum section: electronics / beginners

author: nowlan
author_rank: Frequent Contributor
timestamp: August 26, 2015, 02:31:55 pm
content: Hello,I was wondering if there is a difference. Ive been told not to use a light dimmer to speed control motors.

author: that_guy
author_rank: Contributor
timestamp: August 26, 2015, 03:25:21 pm
content: Could be for a couple of reasons:1. The Triac in the light dimmer is not rated for the current required by the motor.2. The Triac in the light dimmer is a 4 quadrant device and there is no external snubber circuit.So, which triac is in your light dimmer and how is it cooled?

author: rsjsouza
author_rank: Super Contributor
timestamp: August 26, 2015, 03:42:29 pm
content: Please take a look atthis reference.Common Triac-based dimmers are leading-edge, which usually causes trouble with inductive loads such as CFLs, motors, etc.

author: DmitryL
author_rank: Regular Contributor
timestamp: August 26, 2015, 04:03:04 pm
content: Problems with motors ? Hm, it depends on the motor type. Hand mains-powered drills have synchronous motors and a simplest triac-based dimmer as a speed control.
Triac drive - Page 1
Forum section: electronics / beginners

author: hfleming
author_rank: Regular Contributor
timestamp: April 22, 2023, 10:27:49 am
content: Hi all,Have recently attempted to repair a PCB used in an oven. I noticed that they drive the triacs switching the lamps, fans directly from the microcontroller, without any isolation. Of course, the one triac failed, direct short circuit between the gate and the other 2 terminals, thereby taking out the micro, and everything else on that port of the micro. Is it normal nowadays to drive a triac directly? I have always learnt to drive a triac via an optocoupler or pulse transformer to avoid exactly this very situation. I guess it is a cost-cutting excercise, but is it normal to do drive triacs directly from a micro nowadays without isolation of the gate?

author: wraper
author_rank: Unknown
timestamp: April 22, 2023, 10:48:24 am
content: Isolation generally is used not to prevent control circuit failure but to isolate control circuit from mains voltage. Also optotriacs fail more often than triacs themselves, so their use only decreases reliability. If isolation is not needed, it's better to drive triacs directly.

author: hfleming
author_rank: Regular Contributor
timestamp: April 22, 2023, 11:20:07 am
content: …leading to a very expensive repair.

author: wraper
author_rank: Unknown
timestamp: April 22, 2023, 01:05:40 pm
content: Quote from: hfleming on April 22, 2023, 11:20:07 amAs far as manufacturer cares, it's cheaper and more reliable overall. Also if manufacturer does component level repair to begin with, MCU firmware is not an issue. If it does not, it doesn't care how many components fail at once as board will be thrown out anyway.

author: hfleming
author_rank: Regular Contributor
timestamp: April 22, 2023, 03:02:13 pm
content: I can see that approach in all sorts of that domestic devices. Replace the whole PCB, if it is still available, but at half the price of a whole new device… the throw away and replace mentality…
Triac for touch lamp - Page 1
Forum section: electronics / beginners

author: malium
author_rank: Contributor
timestamp: October 03, 2013, 12:46:53 pm
content: Hello, me againQuick one, I have the:http://www.nxp.com/documents/data_sheet/MAC97A8_A6.pdfMAC97A6 (08h) in the touch lamp gone under. As this can not be bought here, can somebody please see if I could use BT137-600E instead or even better, some of below:http://www.nxp.com/documents/data_sheet/BT137-600E.pdfhttp://pdf.datasheetcatalog.com/datasheets/151/323032_DS.pdfhttp://www.bourns.com/pdfs/tic226.pdfhttp://pdf1.alldatasheet.com/datasheet-pdf/view/20139/POINN/TIC226D.htmlhttp://pdf1.alldatasheet.com/datasheet-pdf/view/22031/STMICROELECTRONICS/BTA08-600B.htmlThis are all available.Also, I noted that pins on the MAC are positioned different than on the others, can than the alternative be used?Many thanks!

author: David_AVD
author_rank: Super Contributor
timestamp: October 03, 2013, 09:04:09 pm
content: The original TRIAC is a sensitive gate type and works in all four quadrants. Best bet is to make sure the replacement one has these features as well. You still need a suitable voltage and current of course.

author: Paul Price
author_rank: Super Contributor
timestamp: October 04, 2013, 01:38:00 am
content: http://www.nxp.com/documents/data_sheet/BT137-600E.pdfBT137 would work well as robust replacement, just get remember the pinout is different, so put it in the right way.
Triac help - Page 1
Forum section: electronics / beginners

author: Flump
author_rank: Frequent Contributor
timestamp: April 24, 2014, 07:11:24 am
content: I am using a BTA 41 Triac in a crowbar circuit which is triggered by a zener diodethe weird thing is the crowbar triggers at slightly different voltages 16.5 and 13.somethingdepending on which way wound i have the + and - on the Triacanyone got any ideas why this should be, I thought it was just two diodes inside so shouldn'tmatter which way the + and - go as it just goes closed circuit when tripped.http://www.farnell.com/datasheets/1689729.pdf

author: miceuz
author_rank: Frequent Contributor
timestamp: April 24, 2014, 07:32:40 am
content: Posting your schematics would really help the people to answer your question.

author: David_AVD
author_rank: Super Contributor
timestamp: April 24, 2014, 08:08:00 am
content: The MT1 and MT2 terminals on the TRIAC are not always interchangeable from a trigger point of view. Check the data sheet for the TRIAC you're using and read the section about the different quadrants.

author: Richard Head
author_rank: Frequent Contributor
timestamp: April 24, 2014, 09:59:25 am
content: That simple circuit is known to be dubious at best. The problem is that the zener leakage current and variable triac trigger current all contribute to alter the trigger point.A much better option is to use a comparator. This eliminates both issues.Also, thyristors have a higher surge current rating than triacs, so would be a better choice.Dick
TRIAC + OPTOTRIAC - Page 1
Forum section: electronics / beginners

author: Lucky-Luka
author_rank: Unknown
timestamp: June 10, 2022, 08:53:38 am
content: Hi allI have found a schematic for a circuit that allow to use Arduino to pilot a 220V light.How the values of the resistors on the right side of the optotriac are found?what power rating do they need?Thanks

author: Zero999
author_rank: Super Contributor
timestamp: June 10, 2022, 09:53:13 pm
content: The resistor in series with the gate limits the gate current, before the TRIAC turns on, which will cut-off the current. The gate-A2 diode ensures the TRIAC will not turn on by any leakage curren through the opto-coupler.

author: james_s
author_rank: Super Contributor
timestamp: June 10, 2022, 09:56:28 pm
content: Ohms law can be used to calculate the dissipation, ordinary 1/4W resistors ought to be just fine. To get the values I normally just use whatever is shown on the datasheet for the optocoupler and it has always worked.

author: langwadt
author_rank: Super Contributor
timestamp: June 10, 2022, 10:03:27 pm
content: for small loads like a light something like OMRON SSR G3MB-202P is much simpler

author: james_s
author_rank: Super Contributor
timestamp: June 11, 2022, 01:02:29 am
content: Simpler yes, but much simpler? A triac, optocoupler and 3 resistors isn't exactly a complex circuit and there is some learning opportunity.
TRIAC output deformed - Page 1
Forum section: electronics / beginners

author: ashisalluneed
author_rank: Newbie
timestamp: May 17, 2024, 06:39:18 pm
content: hello everyone ,i am working on an AC dimmer project and the triac gives me a deformed output signal whaterver the arduino code i upload .if anyone knows any trick to help with the ouput ptoblem please help , any help is appreciated .the exact problem is the amplitude of the negative alternation .the schematic and result are shown below .

author: bdunham7
author_rank: Super Contributor
timestamp: May 17, 2024, 07:09:09 pm
content: Your triac has a guaranteed senstivity of 50mA for quadrants I/II/III, but you are only giving it maybe 15mA peak. That might be enough to trigger it in quadrant I, but not III. So I'd suggest changing R3 to 220R or so.
Triac retriggering itself - Page 1
Forum section: electronics / beginners

author: LectroNoob
author_rank: Newbie
timestamp: June 29, 2020, 01:02:26 pm
content: Hi,I would like to know how can a triac retrigger itself.I already know about dV/dT or phase shift, but is there another way?It does that on a dimmer that I am working on and i don't understand why.There is a pull-down resistor on the gate in case, but does not seem to affect the problem.

author: capt bullshot
author_rank: Super Contributor
timestamp: June 29, 2020, 02:50:35 pm
content: The usual cause is dU/dt,Try adding a snubber network (series R / C, ballpark values 10nF / 22R) across the triac, if this solves the issue, dU/dt was the cause.In a dimmer circuit, look at what kind of load you've connected and wether the dimmer is suitable for the load. E.g. some (especially simple) dimmer circuits require the load to be mostly resistive (like a tungsten light bulb) and won't work well with a modern LED lamp.

author: LectroNoob
author_rank: Newbie
timestamp: June 29, 2020, 03:00:31 pm
content: I already have a snubber across the triac. Something around 10nF and 100R. Tried to remove it to see if it got worse, but didn't change anything.There is an inductor in line with the triac. I tried to short it with a wire but didn't seem to correct the problem.I'm out of ideas

author: capt bullshot
author_rank: Super Contributor
timestamp: June 29, 2020, 04:11:11 pm
content: Depending on your Triac and load, try a smaller R and larger C (e.g. 10R / 22n), sometime even larger C values will be required. Don't go for a too low R if you're using a small (less than a handful of Amps rated) triac.Some interesting literature:https://www.onsemi.com/pub/Collateral/AN-3008.pdf.pdfhttps://www.st.com/resource/en/application_note/cd00004096-rc-snubber-circuit-design-for-triacs-stmicroelectronics.pdf

author: LectroNoob
author_rank: Newbie
timestamp: June 29, 2020, 08:11:08 pm
content: I doubled the snubber capacitor and reduced the resistor to 10ohm, but no apparent change on the retriggerThank you for your inputs

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: June 30, 2020, 12:13:58 am
content: Also Fairchild AN-3008 and the appnotes from Teccor.