hybridfree/eevblog-posts huggingface dataset:
Triac seems to be always turned on - Page 1
Forum section: electronics / beginners

author: sujeshm3
author_rank: Newbie
timestamp: April 04, 2015, 07:58:27 pm
content: I've made a small Triac (BT136) based switching circuit, using MOC 3021 Opto Triac as the driver.The circuit seems to br working perfect with a 5W bulb as load, but when I tried connecting a LED bulb at the load, it was turned ON continuously even with no gate current.

author: wraper
author_rank: Unknown
timestamp: April 04, 2015, 08:14:06 pm
content: First of all, LED bulbs usually are not dimmable or are cheap Chinese crap containing just a capacitor as a ballast.Secondly if the load is reactive and mains voltage is 230V AC, MOC3021 is a very poor choice. It often triggers by by itself in such cases. MOC3051/3052 is much better. Thirdly, to cope with reactive load you need to use snubber circuit consisting of resistor and capacitor.And lastly, post the schematic and what LED bulb you are using.

author: wraper
author_rank: Unknown
timestamp: April 04, 2015, 08:20:07 pm
content: If you are not using this circuit as a dimmer, then you need different optocoupler with zero crossing.

author: sujeshm3
author_rank: Newbie
timestamp: April 04, 2015, 08:30:49 pm
content: Thanks for the reply,Yes, they are not cheap for sure.But as of now Im not planning to dim the bulb but just basic ON OFF control.I will do consider replacing the MOC3021.I'm not from a power electronics background so don't know much about TRIAC and other thyristor devices, so could you please let me know about the advantages of having a Triac based switch, does it make sense to have one in my project which for now is controlling home appliances. Does it have any substantial advantage over a relay...?

author: sujeshm3
author_rank: Newbie
timestamp: April 04, 2015, 08:32:59 pm
content: And yes my circuit does have a RC snubber.

author: Zero999
author_rank: Super Contributor
timestamp: April 04, 2015, 08:53:36 pm
content: Does the LED turn off if it's connected in parallel with a 5W bulb?Perhaps it's the leakage current lighting the LED?

author: wraper
author_rank: Unknown
timestamp: April 04, 2015, 09:06:49 pm
content: Quote from: Hero999 on April 04, 2015, 08:53:36 pmBTW yes, what is the power of this led bulb, does it light with the full brightness? Have you measured the voltage over the LED bulb? What is the value of the capacitor used in the snubber circuit?If you are going to just turn on/off once it a while, then relay would be a better choice. Triac will give any advantage only if you need to control power on something by dimming or need to switch very often, like every few seconds. Otherwise there will be mainly disadvantages over the simple relay, like 1-1.5V voltage drop across triac and therefore heating. If any significant power, you need to put it on the heatsink, additional parts which will give increased size and cost.If using Triac just for switching, then better to use something like MOC3061/2/3https://www.fairchildsemi.com/datasheets/MO/MOC3061M.pdfThis will give more robustness and less interference in the switching moment.
Trick to reflow for pads with component holes in them? - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: March 07, 2025, 03:09:22 pm
content: I'm researching QFN parts for a potential project, and I'm concerned about reflow soldering with these components. According to some datasheets, the exposed pad on the back of some QFNs have pad vias in them, mostly it seems for either heat dissipation or ground. They seem rather small (typical drill size of 0.254 mm diam.), but how would you make sure that the part holds and that solder doesn't flow to the other side? Are there any tricks to it, or is it not a problem if the holes are small?

author: PGPG
author_rank: Frequent Contributor
timestamp: March 07, 2025, 04:59:55 pm
content: I have read that holes have to be smaller than 0.3mm to not stole solder while reflow.To not put paste into holes the holes in stencil have to be in different places than holes in pad.I am using 0.3 diameter holes in these pads and it is accepted by contract manufacturer. I have never seen how it works regarding solder going into them.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: March 07, 2025, 05:47:33 pm
content: Thanks. Guess small holes are the way to go then.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: March 16, 2025, 08:07:18 am
content: There are many ways to Prevent Solder Wicking Through the Vias. Two common methods are via tenting and via plugging. You can also use smaller vias. If the vias are small enough and the solder paste volume is well controlled, surface tension will usually keep most of the solder on the top side. It is wise to reduce Solder Paste on the Exposed Pad. If too much solder paste is applied to the thermal pad, it can cause excessive solder flow, potentially pulling the QFN down unevenly or creating voids. The usual approach is to stencil small, distributed openings instead of a solid paste deposit. If you need optimal thermal dissipation and electrical grounding, a more advanced approach is via-in-pad with cap plating. This means vias are plated over and planarized, preventing solder from wicking while maintaining a flat surface.For small via sizes (~0.254 mm), solder wicking is usually not a major problem if the PCB manufacturer follows good design practices. However, for larger vias or when using a high amount of paste, wicking could cause solder starvation on the thermal pad or increase the risk of QFN floating. If you want to get further information about via- in- pad, you can see here:https://www.pcbway.com/blog/PCB_Basic_Information/Via_in_Pad_Design_PCB_Knowledge_177b607f.html
Tricking VAX BMS - Page 1
Forum section: electronics / beginners

author: un4tural
author_rank: Contributor
timestamp: November 14, 2023, 03:36:16 pm
content: Hello All,I can comfortable swap components/solder/cut etc. but the electric pixie magic I don't quite understand...I have a VAX battery charger go pop, PCB shorted, power brick dead, tried a rated power source, but it refuses to live... I cannot power the little VAC off another power source, cause it wants the secret handshake from battery, to confirm it is not about to go thermonuclear I assume...I've gutted the BMS off the 18650 cells, as I can no longer charge it, and wired in to try and hook up a Ryobi battery to the Vax "spot cleaner". it just thinks battery is kaput.Can I strap some resistors or something else, between cell balance terminals, to trick the BMS into thinking that battery is full/present? if it drops 4v between the terminals as it is around 20v fully charged, it would think it is "whole"? As it would likely not have current though, not really sure how to work out the resistor value assuming this would work?Plan after is to 3d print a little cap for Ryobi battery, so I can essentially have a little cable with connector, to hook up a Ryobi battery as I have a bunch of those knocking about...With spare 18650 cells I could build another Ryobi battery, as there seem to be options to purchase a bare BMS for Ryobi.Any recommendations? Seems a silly amount of waste to throw that spot cleaner out, and replacement chargers even used ones cost 1/3 of what i paid for the whole thing new few years back...Suppose I could use some small buck converters to give it voltages for those cell balance terminals, but that seems a bit overcomplicated?Tried a bit of a google, but I'm probably asking it wrong - I apologise in case I have any dumb ideas or missing something simple/obvious here?
Trying out the Riden RD6012P Power Supply - Page 1
Forum section: electronics / beginners

author: watchmaker
author_rank: Unknown
timestamp: April 12, 2024, 03:12:29 pm
content: I got this cheap (I think) from Ali. Powering it with a 70V Switching Power Supply for $30. $100 for all.The SET voltage is within mVs of my meters; the reported output is off by about 20mV though. The rotary control is very nice and it shows mV resolution.On my analog scope, with 10X probes and the V amp set to 5mV per division, I get 4 mV ripple whichI think comes down to .4mV of ripple; oops,multiply by 10! 40mV ripple. Came to me as I was falling asleep. If I am correct, this might be a useful supply for amateurs.I included a screen shot from my Siglent which I do not know how to interpret. Any guidance would be appreciated. Alos a pic showing the display against my Agilent 1252A (which agrees with HP and Fluke meters).

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: April 12, 2024, 05:23:53 pm
content: Also own this exact same model, love it.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: April 13, 2024, 06:16:44 am
content: These are popular supplies, there is even custom firmware for it.Bootloader and recovery info can be found on my git hub and the thread for custom f/w for device and wifi adapter is herehttps://www.eevblog.com/forum/testgear/ruideng-riden-rd6006-dc-power-supply/dont mix up power when connecting to batteries, use the battery center point or you risk doing damage (other users have done so and posted repair guides)Enjoy your new psu, I love mine and have used it almost daily for one task or another that am tempted to get anotherdarkspr1te

author: watchmaker
author_rank: Unknown
timestamp: April 13, 2024, 09:08:24 pm
content: Thanks! I am having trouble loading unisoft's firmware. Connects, shows the bin and the psu shows it is in boot mode. When I hit write it disconnects. Any thoughts? Found an old factory BIN; but can't figure out how to downgrade.Regards,Dewey
Trigger help needed - Page 1
Forum section: electronics / beginners

author: zaoka
author_rank: Frequent Contributor
timestamp: June 08, 2012, 06:31:04 pm
content: It would be nice if Dave make a video about Trigger feature for oscilloscope with examples for beginers.I have Agilent U1602A scope, I need to monitor 2 protection lines to find out which one is going high first thus turning ON protection circuit. I know other methods, however, I want to learn how to do this with scope.Also how to do single shot with it.Can anybody explain this?

author: MikeK
author_rank: Super Contributor
timestamp: June 08, 2012, 09:37:18 pm
content: See the sticky at the top of the Beginners area for Alan's oscilloscope video.
Trigger on a single rs232 character - Page 1
Forum section: electronics / beginners

author: handyguy
author_rank: Newbie
timestamp: March 07, 2020, 03:46:21 am
content: Hi,I am trying to trigger on a single key press of the DTE (my pc serial output port) and show the pattern on the oscilloscope. So far i can only see hits whiz by when I am in auto mode, and am unable to trigger on single. Is that possible? I can put it into roll or auto mode, and stop the trace after a key press and then search for the pulses. This I have to zoom in to see the ascii code. Using RS232 trigger and rs232 ascii decoding. my rigol ds1054 will not decode the characters (displays '.') until i zoom in sufficiently on the stopped trace, and then it decodes it - why is that?So two questions!Thanks all!
Trigger on leading edge question - Page 1
Forum section: electronics / beginners

author: lacosteaef
author_rank: Newbie
timestamp: March 23, 2015, 03:09:43 pm
content: Hello,I'm currently looking to build a front end to a ADC to capture short pulses (500ns) anywhere between 20mV to 1V in size. To implement this I was considering using the OPA615http://www.ti.com/lit/ds/symlink/opa615.pdfin the fast pulse peak detector configuration (pg 20).What i'm trying to figure out now is a elegant way to know when to sample the peak detect cap. The noise floor is around 30mV above ground and has around 1-5mV of noise present. I was thinking of using a fast comparator that will detect a rising edge and use the output to trigger my FPGA to know when to sample the ADC. Really though, my analog skills leave much to be desired and i was hoping I could reach out to see if someone could nudge me in a better direction. Ideally I would detect the rising edge of a pulse and then trigger the FPGA to read the ADC. Or perhaps triggering off of the falling edge would be ideal because the peak has already reached its maximum?Any thoughts or suggestions are appreciated. Thanks.

author: Marco
author_rank: Super Contributor
timestamp: March 23, 2015, 07:26:44 pm
content: What's the distance between the pulses?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2015, 08:03:33 pm
content: Using a suitably modified variant of the circuit, trigger pulses could be generated, in which case you could set flip-flops to record when a pulse is waiting (and optionally, count how many events have occurred, if not necessarily the values of any but the last of those events). This could be connected directly to an asynchronous or triggerable type ADC, or interfaced to an MCU.The trick is detecting when the input exceeds the peak, or when current flows into the holding capacitor, or something like that. Sometimes, it's nice to build the op-amp as discretes, just so you can tap off a convenient signal like this -- but tacking this on shouldn't be too much difficulty in this case.Tim
trigger option? - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: April 10, 2018, 02:21:13 pm
content: Hello, I have a Rigol DS1054Z, the question is, which trigger option to use in SINGLE mode, which is triggered, when the voltage exceeds a certain value?

author: TK
author_rank: Super Contributor
timestamp: April 10, 2018, 03:06:53 pm
content: Use edge trigger and set the trigger level to detect when voltage goes above the threshold.

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: April 10, 2018, 04:37:18 pm
content: sorry, that's the best choice the rigol has for simple voltage shot?

author: ebastler
author_rank: Super Contributor
timestamp: April 10, 2018, 07:00:19 pm
content: Quote from: Adrian_Arg. on April 10, 2018, 04:37:18 pmWhat is wrong with that "choice"? I.e. what would you like to achieve, and can't quite get done with Single Edge triggering?

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: April 10, 2018, 08:56:56 pm
content: I would like it to fire not on the edge, but at a voltage deterninado, that if I am working with 7volt and deciente at 6 volt will be triggered.

author: TK
author_rank: Super Contributor
timestamp: April 10, 2018, 09:00:29 pm
content: Quote from: Adrian_Arg. on April 10, 2018, 08:56:56 pmThat is what edge trigger is for. Set it descending, then threshold just above 6V, and the scope will trigger when voltage descends to around 6 V from a higher voltage
Trigger signal (logic high) from 32 analog signals - Page 1
Forum section: electronics / beginners

author: dk-001
author_rank: Newbie
timestamp: August 18, 2020, 11:03:38 am
content: Hi,In my project I have 32 analog signals produced from APDs (avalanche photo-diodes). These signals are amplified and split by two for further processing (one branch goes to ADC, other branch goes to trigger circuitry). They are very close to each other in time domain (rise times start very close relative to each others). I need to create a trigger logic based on a simple pattern: Trigger ifonly one channelis above a threshold, and reject all other cases. I can produce high/low signals for each channel by using comparators and then feed these to some cascaded digital logic elements to obtain the trigger signal. I was wondering if someone can suggest a simpler, faster way. I would prefer fewer number of processing to limit the propagation delays in logic ICs since since the ADC start/stop signal is based on trigger signal.Thanks...
Trigger the oscilloscope with digital signals - SHT15 serial data and Arduino - Page 1
Forum section: electronics / beginners

author: MattiaM
author_rank: Newbie
timestamp: December 01, 2018, 04:12:37 pm
content: I am a complete newbie with digital electronics, and I decided it was time to learn something new.I got an Arduino with a temperature and humidity sensor (SHT15, datasheethere).I thought that figuring how the sensor communicates with the microcontroller could be a good learning opportunity, so I took my scope and tried to see if I could identify the various communication steps described in the datasheet. And here is the problem: I think I am not triggering the oscilloscope correctly, and I have not been able to figure out how to show the signal properly.With a pulse width trigger set to 10us over a time span of one second, I get three pulses (in yellow the serial clock, in blue the data, first image attached) which look nothing like in the datasheet, although I figured the first one is to retrieve the temperature data, the second to retrieve humidity, and the third one again temperture (the third one is called from the humidity function in the library for the SHT15, because humidity values need to be adjusted taking into account temperature). I also figured that, with the 1s span, the sampling per second is not large enough to show any waveforms at the frequencies of the clock/data.With the same pulse width trigger set to 10us, over a time span of 1us I get something that seems the same as the first line in Fig. 17 in the datasheet: I can see the transmission start command, the '000' address, and the '00011' sequence indicating that the temperature measurement and, I believe, the ACK.However, I am not able to visualize the entirety of the trasmission: I can't visualize the data actually transmitted, the CRC-8 Checksum and all the other parts shown in Fig. 17. I am also not able to trigger on the humidity transmission either nor on the second call for temperature data transmission. What I see is just nothing. (2nd and 3rd images attached).What am I doing wrong? How can I visualize the entire span of bits?Thank you!Mattia

author: tsman
author_rank: Frequent Contributor
timestamp: December 01, 2018, 04:25:20 pm
content: Acheap USB logic analyser+sigrok PulseViewis going to more useful to see what is going on here. You can capture the entire communication and scroll through it at your leisure. PulseView won't know how to decode the data since the SHT15 uses its own protocol but you'll still be able to see it on screen. If it was a I2C sensor like a SHT31 then you'd see the decoded data as well.

author: rstofer
author_rank: Super Contributor
timestamp: December 01, 2018, 05:50:22 pm
content: The protocol looks a lot like I2C but I only just glanced at the datasheet.I sometimes use a digital pin that I can set just ahead of a transfer as a way to trigger the scope. True, these are usually for higher speed devices like FPGAs but the idea is the same. I can move the trigger point way over to the left if there is a lot of time lag between setting the output pin and the beginning of the transfer.
Triggering a 555 through a cap - Page 1
Forum section: electronics / beginners

author: Qmavam
author_rank: Regular Contributor
timestamp: February 24, 2020, 05:26:08 pm
content: I'm try to help the guy with the LDR triggering a 555.I'm slowly walking him through it and now just triggering it with a wire momentarily to grd, to pull Pin 2 low, through a capacitor.But it won't trigger.Here's the circuit, what is needed to make the circuit trigger properly.Thanks, Mikek

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 24, 2020, 11:14:41 pm
content: It should work. The problem may be that it is powering-up in the triggered state.Also, the values used for the trigger pulse are likely too large. If you don't have an oscilloscope then you should grab a simulator so that you can get a better idea about what the circuit is doing and how the component values effect the circuit's behavior.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 25, 2020, 03:41:24 am
content: This circuit here should do what you are wanting to do. It will avoid triggering on power-on.The only thing you will need to do is change the values of R1 and C1.

author: Jwillis
author_rank: Super Contributor
timestamp: February 25, 2020, 08:05:37 am
content: Try this revision of your circuit.
Triggering a touch screen with a microcontroller - Page 1
Forum section: electronics / beginners

author: mribble
author_rank: Regular Contributor
timestamp: October 16, 2018, 06:53:19 pm
content: Nearly all touch screens on phones are capacitive touch. These screens detect touch by a change in capacitance.There are several examples online of people taping a wire to the screen and then switching a relay to simulate a touch.I've verified a relay works. However, I was hoping I could switch to using a transistor or ideally just an IO line. I tried a quick test with Arduino by switching an IO line between high impedance and 0V. This didn't work. I suspect it's because of the parasitic capacitances you find in integrated circuits.I'm wondering if you guys know of a solid state device/transistor that has exceptionally low capacitance between the source/drain that I could try?

author: mribble
author_rank: Regular Contributor
timestamp: October 16, 2018, 11:12:24 pm
content: Basically what I'm looking for is some kind of really low capacitance switch that acts more like a relay than a mosfet.I've never used anything like this, but maybe something like this would work?http://www.ti.com/general/docs/suppproductinfo.tsp?distId=26&gotoUrl=http%3A%2F%2Fwww.ti.com%2Flit%2Fgpn%2Fts5a3166-q1Thanks in advance for any suggestions you guys have!
Triggering basics - Page 1
Forum section: electronics / beginners

author: Moeren
author_rank: Newbie
timestamp: January 26, 2015, 12:27:16 pm
content: Hi,I recently bought my first scope ( Rigol DS1054Z due to eevblog review ) and while I know most of the basics, I never had a DSO and am not familiar with the more advanced triggering types.I was wondering if it is possible to trigger based on the length of a pulse, and how such triggering would be found on the 1054. I found the pulse mode, but the icons don't really tell me much.I have some ws2812b and since the signal always starts with the >50us reset pulse, I thought there must be a way to trigger of of that, does somebody know how I can do that?Thanks for your time,Moeren

author: nanofrog
author_rank: Super Contributor
timestamp: January 26, 2015, 05:15:27 pm
content: Hopefully the following might be of some help.Basic and advanced oscilloscope triggeringOscilloscope tutorial and introduction
Triggering on Data Strobe encoding for eye pattern - Page 1
Forum section: electronics / beginners

author: bitbanger
author_rank: Regular Contributor
timestamp: December 21, 2018, 12:53:48 am
content: Hi Folks -I'd like to generate an eye pattern on a 100Mbps serial link, that features a data strobe clock.Unfortunately my scope doesn't feature any clock recovery functionality, technically no in-built eye functionality either, I'm just hoping to rely on persistence. I assume I can't simply trigger on this strobe? Or can I and just accept the reduced number of triggers?I keep reading mention of implicit triggering based on a fixed time base - how does this work? It sounds like this relies on auto sweep with the timebase set according to expected bit rate/unit interval? Even then, I don't see how the triggering is prevented from drifting.Would appreciate any insight you can offer.

author: tggzzz
author_rank: Super Contributor
timestamp: December 21, 2018, 08:29:42 am
content: There's no point in your scope having any clock recovery facility, since your circuits performance depends on its own clock recovery circuit.Use your circuits clock recover circuit, or simply trigger on a rising edge halfway between the high anf low voltages.
Triggerproblems? - Page 1
Forum section: electronics / beginners

author: hwj-d
author_rank: Frequent Contributor
timestamp: July 13, 2017, 03:26:46 pm
content: A 100hz sinus 0-2V is clipped by a normal SMD GW17 type Schottky-Diode. Can't trigger this at any level.It's a clean equal signal, bandwith limit 20Mhz, but doesn't matter, also holdoff. That's not a special problem from this scope. My Rigol 1054z 100Mhz shows same result.Do i overlook something?

author: w2aew
author_rank: Super Contributor
timestamp: July 13, 2017, 06:44:34 pm
content: There is likely some high frequency noise on the signal that the trigger circuit is seeing, causing a trigger on both the large rising and falling edges. Triggering on the rise in the "normal" sense, but also triggering on the falling edge due to a small noise-driven rising signal that crosses the trigger threshold. If your scope has a Trigger control to perform HF Rejection, try that.Here is a video of a similar triggering issue, due to a higher frequency signal riding along with the large low frequency signal:

author: hwj-d
author_rank: Frequent Contributor
timestamp: July 13, 2017, 08:35:18 pm
content: Yes, that's it!There is a trigger option "HF-Reject", that's helped. The signal coming from my SDG1025 isn't so clean as i thought. I didn't thought this could have that effect. Maybe that comes from cheap and/or wrong measurement with my rg58 cables connectors and it's termination.Thank you very much, to show it in your video. Have learned something...
trimmer cap color code? - Page 1
Forum section: electronics / beginners

author: ali6x944
author_rank: Frequent Contributor
timestamp: March 11, 2016, 09:00:27 am
content: hi everybody,i was dissembling old radios that stopped working, and i came across these trimmer caps that where in good condition, and i wont to know their values...i searched in google about them and i didn't see what I'm looking for, i did kinda find the value of the green trimmer caps but their are few left...some places that have info:https://en.wikipedia.org/wiki/Variable_capacitorhttp://electronics.stackexchange.com/questions/113102/what-does-it-mean-when-only-a-single-capacitance-is-specified-for-a-variable-cap
Trimmer pot in dummy load design - Page 1
Forum section: electronics / beginners

author: hot_wire
author_rank: Newbie
timestamp: June 30, 2013, 03:24:17 pm
content: HelloI have been looking into dummy loads recently and I came across the following design which has been on display on the EEVBlog:http://www.arachnidlabs.com/blog/2013/02/05/introducing-re-load/This appears to be the schematic corresponding to the load:https://github.com/arachnidlabs/reload/blob/v1/reload-schematic.pngI am trying to understand this design and most of it is rather straight forward, but I have one question. I noted that the SENSE voltage is fed into a second OpAmp stage (IC1$G2) which has a gain of 2. My guess is that this second stage serves the following purposes:1. 100 mV measurement output voltage corresponds to 1 A which is much nicer to read than 50 mV ~ 1 A.2. It is not possible to mess around directly with the SENSE node. (I.e. applying voltages by mistake, attaching a low-impedance meter or shorting it out, etc.)3. The trimmer can be used for calibration adjustment.I am however wondering whether it is relevant that the trimmer is part of the second stage or whether it could be designed into the feedback loop of the first stage just as well.Thank youMax

author: Odysseus
author_rank: Regular Contributor
timestamp: July 01, 2013, 07:52:18 am
content: It certainly can be added to the first stage by moving the entire resistive feedback network from the second opamp to the first, but just connect R4 to the sense node instead of the output of the opamp.However, this doesn't really accomplish quite the same function. Now, the current range of the dummy load will be increased by factor of 2, and measuring the real current draw must be done by measuring across the sense resistor itself.
LCR Trimmer Adjustment Tools - Page 1
Forum section: electronics / beginners

author: Teti
author_rank: Regular Contributor
timestamp: October 15, 2019, 08:21:20 pm
content: Hi guys, I got back to the electronics hobby after a couple of decades, please advise...Which one of these Trimmer Resistor Adjustment Tools would you choose? Does it matter? I can't really see any difference physically as long as they are non conductive?I guess I would choose Vishay for those bragging rights?https://uk.rs-online.com/web/c/passive-components/variable-resistors/trimmer-resistor-adjustment-tools/Thanks for your answers

author: MosherIV
author_rank: Super Contributor
timestamp: October 15, 2019, 10:10:54 pm
content: HiWelcome to the forum.Does not really matter which one, I have not used mine in god knows how long.Modern designs do not use pots any more, since everything went digital/microcontroller a lot of adjustments are done in sw and stored din Non volatile memory.Do not get me wrong, they are still used, just not as often/common.

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: October 15, 2019, 10:35:50 pm
content: Quote from: Teti on October 15, 2019, 08:21:20 pmUsually I use a dollar-store jeweler's screwdriver. Whether conductivity matters depends on what you're working with.

author: tkamiya
author_rank: Super Contributor
timestamp: October 16, 2019, 04:32:09 am
content: Most trimmer knob/screws are electrically isolated. It is a good idea to use isolated kind but not really necessary. They are typically low voltage anyway. I use any small screw driver I can find within my reach.Trimmer capacitor is a whole different thing though.

author: soldar
author_rank: Super Contributor
timestamp: October 16, 2019, 08:15:33 am
content: I don't think I have ever paid money for such a tool. For pots I just use a smallscrew driver and the rare occasions when I need something non-metal I just use something I made myself with a little plastic rod or whatever I have at hand. I have sometimes used the inner tube of a ballpoint pen but you can make one with any hard plastic.

author: Teti
author_rank: Regular Contributor
timestamp: October 22, 2019, 01:59:58 pm
content: Thanks for your answers, I might potentially need it for som RF stuff in the future. I've found some decent ceramic screwdrivers on Amazon, these are non magnetic, so shouldn't interfere with coils. I guess plastic would do the same jobbut again... those bragging rights ha hahttps://www.amazon.co.uk/s?k=frequency+screwdriver&ref=nb_sb_noss
trimmer test - Page 1
Forum section: electronics / beginners

author: rizoma
author_rank: Newbie
timestamp: March 14, 2014, 01:01:11 pm
content: Hi guys I got some chinese trimmers they look exactly like the bourns 3296 but instead are boater 3296 I would like test them to some degree... Basic stuff Any advice?Maybe that is the wrong section, sorry!Regards

author: mcinque
author_rank: Unknown
timestamp: March 14, 2014, 06:44:29 pm
content: I guess that a multimeter in Ohm scale would do the job.

author: Holograph
author_rank: Regular Contributor
timestamp: March 14, 2014, 06:50:14 pm
content: You can check with an ohmmeter (as mentioned) while turning them to see if the resistance change is smooth. But most likely if they are cheap quality it will wear out a lot quicker - it might not always be obvious when the parts are new if they are poor quality.What do you intend to trim with them? You could also check them with AC voltage of varying frequency to see if the resistance/impedance is stable.

author: robrenz
author_rank: Super Contributor
timestamp: March 14, 2014, 07:17:11 pm
content: Trimmers are designed for a very limited number of adjustment cycles anyway. Typical is in the 10 to 200 cycles.

author: deth502
author_rank: Frequent Contributor
timestamp: March 14, 2014, 07:29:10 pm
content: i use an analog meter to make sure they are qworking smoothly. good chance youll never notice a quick dip in the reading with a dmm.if you want to get real fancy, run some voltage through them and set your o-scope to .5 sec/div.

author: rizoma
author_rank: Newbie
timestamp: March 15, 2014, 02:46:18 am
content: I was taking about noise ratio, temperature stability, audio behavior thanks for the hints, the oscilloscope and feed a voltage seems a good idea, maybe I can compare before and after...The application it's for an Audio Vco

author: mcinque
author_rank: Unknown
timestamp: March 15, 2014, 07:02:07 am
content: Quote from: rizoma on March 15, 2014, 02:46:18 amIn that case a DSO is absolutely required, as suggested. You can try also to pass audio frequency to them and see their behaviour.
Trimming a LT1019_2.5v Voltage Reference - Page 1
Forum section: electronics / beginners

author: t1d
author_rank: Super Contributor
timestamp: August 25, 2018, 07:26:15 am
content: I would like to build the Dual Supply Dynamic Electronic load, that Jay_Diddy_B is developing. I want to use the VAC Supply Option. I have a LT1019_2.5v, in my stocks.- Do I need to trim the LT1019, at all, for the needed accuracy, for this circuit?- If not, how do I need to terminate the pin?- If so, could someone help me with the math, to do a three resistor trim, like the one shown for the 5.120v model, on page 9, top-left corner. Please. How important is it that the resistors are 1% Low TC Cermet?The LT6656 option is above $6. But, it may be easier to deal with?What about just a good old zener diode?I do not want to use the temp pin, for anything. Just terminate it to an unconnected pad?The device will be mounted in a big honking, Realistic, defunked (get it? <grin>), 100amp, stereo chassis. It uses one of the huge heat sinks and an 120vac computer case fan, for cooling.Thank you, for your help.

author: ogden
author_rank: Super Contributor
timestamp: August 25, 2018, 07:33:04 am
content: Quote from: t1d on August 25, 2018, 07:26:15 amNo. There's no point to have absolutely precise voltage reference in your device that needs current to be calibrated.

author: t1d
author_rank: Super Contributor
timestamp: August 25, 2018, 09:54:15 am
content: Thank you.
Trimpot adjustment range - Page 1
Forum section: electronics / beginners

author: Tj138waterboy
author_rank: Regular Contributor
timestamp: January 21, 2021, 01:06:01 pm
content: After combing through the forum I am still unable to see how to find a formula to calculate how much trim range you get with resistor divider. I stumbled upon article for building voltage reference for home lab and found the selected trim values odd being much higher than datasheet examples for ref102 voltage reference. The writer uses 3.6meg in line with 100k trimpot. Can anyone point me in the right direction to see why such high values are being used an or how much range this setup has? Schematic is on pg 11.

author: mvs
author_rank: Frequent Contributor
timestamp: January 21, 2021, 03:34:30 pm
content: Trimpot is used to supply 0-10V at wiper. Its resistance is quite low at end positions and does not really matter.If you look at internal schematic of REF102 in the datasheet, you will find internal resistor values.Trim range with 3.6M resistor should be around +/-29mV. You can approximate it with 5*(1-(x+50K)/(x+72K)), where x is 3.6M resistor.
Trio FJ 310 HF Receiver - Page 1
Forum section: electronics / beginners

author: Jazzman
author_rank: Contributor
timestamp: February 29, 2024, 08:17:52 pm
content: Hi guys, forgive my ignorance of what is probably a simple thing, but a capacitor has blown on this receiver and I'm. not sure what type it is.It sits across the primary of the mains transformer with a value of .01uF 630 volt and CP-C printed on the sleeve. What type of capacitor is this likely to be?For what ever reason it is shown on the circuit diagram but not listed in the component list.Help very much appreciated.

author: Manul
author_rank: Super Contributor
timestamp: February 29, 2024, 08:58:07 pm
content: Class-X capacitor. X1 or X2 capacitor of same value and voltage rating should be a good replacement.

author: Jazzman
author_rank: Contributor
timestamp: March 01, 2024, 03:25:09 pm
content: Thanks for the info Manul, I'll get one ordered straight away.Thanks again my friend.
Tron-Club Customer Service Issue/No Delivery/Forum Down - Page 1
Forum section: electronics / beginners

author: farlander762
author_rank: Contributor
timestamp: October 21, 2021, 12:22:13 am
content: Everyone seems to agree that Tron-Club's customer service is abysmal but overall a good service. I signed up for the full year in August and STILL have not received my first kit. They say they shipped it on 09.30 but it either got lost, or hasn't actually shipped yet. I notified them 3 days ago and still don't have a response. I'm very tempted to contact PayPal (they only accept PayPal) and see if they can help or get a refund.Additionally, I wasn't able to sign up for their forum due to the Register page being down. Now the entire forum is down and has been for at least a few days.Really starting to think this is a scam or that they've simply taken the money and run. It's really a shame, was looking forward to the hands-on education. Does anyone have any specific guidance?
trouble analog esr meter calibration - Page 1
Forum section: electronics / beginners

author: Savetheday
author_rank: Regular Contributor
timestamp: January 21, 2017, 08:21:57 pm
content: HiI bought a second hand analog esr meter. It doesn't have any instruction manual and I couldn't found it in internet. But I guess I need to do some calibrations.When I put two red test leads together moving pointer should go all the way right.But it doesn't.It goes up to middle.I have tried to adjust with potentiometer at the back and front even display reading underneath. I couldn't made it up to all the way right.Do you have any suggestions?Thanks.

author: Vtile
author_rank: Super Contributor
timestamp: January 21, 2017, 08:29:49 pm
content: I have no idea, but I must ask the obvious.. That Varta Super is a fresh battery is it.

author: Savetheday
author_rank: Regular Contributor
timestamp: January 21, 2017, 08:34:21 pm
content: Yes with multimeter I have read both 1.5Vs??Do I need to do something else?

author: Vtile
author_rank: Super Contributor
timestamp: January 21, 2017, 08:36:00 pm
content: I have more questions. What it does read while the probes aren't connected and how it do respond to the zeroing pot while leads are open? Some meters do have Infinity "zeroing"... Like I said, I have no idea, sorry.One thing might be that the meter movement is off.. So turning that black chisel screw really carefully do a mechanical zeroing for the meter..

author: Vtile
author_rank: Super Contributor
timestamp: January 21, 2017, 08:41:01 pm
content: Quote from: Savetheday on January 21, 2017, 08:34:21 pmDid you use any kind of load while measuring that 1.5V??? as it should be more like a 1.63V for a fresh alkaline measured with a modern high impedance (resistive) DMMs (with 1 to 10 MegaOhm input impedances).

author: kripton2035
author_rank: Super Contributor
timestamp: January 21, 2017, 08:43:58 pm
content: seems very close to the top right "capacitor esr tester" on my web page here :http://kripton2035.free.fr/analog%20esr/esr-multimeter.htmlQuoteso it could be a battery related problem.

author: Savetheday
author_rank: Regular Contributor
timestamp: January 21, 2017, 09:22:42 pm
content: Yes indeed, it was a battery problem. It works good with 3.3Vs powersupply.Thanks.

author: Vtile
author_rank: Super Contributor
timestamp: January 21, 2017, 10:18:15 pm
content: Good. Happy measuring.

author: kripton2035
author_rank: Super Contributor
timestamp: January 21, 2017, 10:18:46 pm
content: these batteries seems to be CR2 models ? so they must be 3v rated, and so you need some 6v nominal to make this esr meter to work normaly ?http://www.parts-express.com/varta-cr2-lithium-photo-battery--140-012

author: Savetheday
author_rank: Regular Contributor
timestamp: January 22, 2017, 02:19:00 pm
content: Quote from: kripton2035 on January 21, 2017, 10:18:46 pmNo, those are 1.5V not the lithium one. I measured with load 1.42V 1.44V.Quote from: kripton2035 on January 21, 2017, 08:43:58 pmI think this meter is different, it has 2 ICs and I'm not able to read IC codes.
Trouble finding low profile 12V supply for LED lighting  - Page 1
Forum section: electronics / beginners

author: Razor512
author_rank: Regular Contributor
timestamp: September 05, 2019, 02:22:10 am
content: Sorry if this is the wrong place to ask, but I was wondering if anyone has found any anything that can take 12V mains and output 12V but in a package that is 0.5 inches or thinner?Since many stores make it hard to search based on size, I was originally looking at taking a slim (but slightly over 1 inch) thick AC adapter, then taking the PCB out and removing and wiring taller components so that they could lay flatter, and then 3D printing a 0.5 inch junction box.The main reasoning for this, is to hard wire some under cabinet lighting for a kitchen, but virtually all of the common cabinet boxes sold now, have a base that is recessed by about 0.5 inches, things would have to be slim in order to keep the power supply and lights from being visible at normal viewing angles.The load at 12V will be less than 1 ampThe overall hope is to find an off the shelf product that can fit the thickness constraints before having to resort to taking apart 12V AC adapters and trying to get the thickness down to 0.5 inches.Much of what I have found so far has been 0.75+ thick.

author: LateLesley
author_rank: Frequent Contributor
timestamp: September 06, 2019, 07:43:42 am
content: So, I did a bit of googling. It thought it really was a hen's tooth you were looking for. Most were 16-20mm.https://www.alibaba.com/product-detail/LED-Light-Strip-20W-led-Driver_60691889145.htmlhttps://www.smarts-electronics.com/ultra-slim-constant-voltage-led-driver-12v-18w-15w_p595.html

author: Kjelt
author_rank: Super Contributor
timestamp: September 06, 2019, 10:06:36 am
content: 0,5 inch is 12.7mm, Govena makes kitchen led PSU's of 13mm, close enough ?https://www.tme.eu/gr/en/details/z-led-12w-12cv-sl/led-power-supplies/govena/z-led-12w-12cv-slim/https://www.tme.eu/gr/en/details/z-led-15w-12cv/led-power-supplies/govena/z-led-15w-12cv-slim/
Trouble finding replacement components - Page 1
Forum section: electronics / beginners

author: Sagescircuits
author_rank: Newbie
timestamp: November 10, 2023, 07:10:32 pm
content: So I’ve been working on this board for a massage chair from 2009 for a while now. It got wet twice 🤦‍♂️. The first time I was able to swap obviously blown capacitors and other random parts, and it worked great. The second time has been more difficult for sure.. I’ve swapped so many components and am starting to lose hope heh.I have some MOVs that I’m trying to find replacements for at the moment, but I’m just not having any luck finding exact replacements. I was wondering if anyone who knows more about it than I do could help me find equivalents to replace them with. They are yellow, 7mm, 2x with markings “7N470K” and 7x with markings “7N560K”. I’ve included some pics of them as well.Any help is appreciated 🙏.

author: kripton2035
author_rank: Super Contributor
timestamp: November 10, 2023, 09:07:33 pm
content: https://www.rapidonline.com/joyin-jvr07n470k65yu4-30v-1-8j-mo-varistor-7n470k-26-3140https://fr.aliexpress.com/item/32674323905.html

author: Sagescircuits
author_rank: Newbie
timestamp: November 11, 2023, 12:16:09 am
content: When I try the aliexpress link it says “no longer available”, but the other one works. Thank you! Now just gotta find the 1 heh.

author: kripton2035
author_rank: Super Contributor
timestamp: November 11, 2023, 08:22:45 am
content: found here, in germany, and you have to buy 50 ...https://www.schukat.com/schukat/schukat_cms_en.nsf/index/suchergebnisse?OpenDocument&query=JVZ07N560K

author: DavidAlfa
author_rank: Super Contributor
timestamp: November 11, 2023, 03:07:08 pm
content: Just check the datasheet specs and find a similar replacement, won't be hard.30VAC / 38VDC, 0.1mA @ 47V, 7mm disc.Digikeyparametric search results.
Trouble identifying a surface mount diode  - Page 1
Forum section: electronics / beginners

author: ddctechguy
author_rank: Newbie
timestamp: April 30, 2016, 01:45:26 am
content: Hi everyone. I hope someone can help me. I have a device in which someone applied the incorrect voltage and burnt a trace completely off of the board. They also blew a large surface mount diode. I have searched the internet endlessly in an attempt to identify this mysterious diode. From what I have been able to gather, it looks to be a Fairchild with the markings AE26-GGG. I have been to the Fairchild Semiconductor site in search of any info on this component, but have turned up nothing. Can someone please take a look at the picture and give me an idea of what I can use for an equivalent replacement?Thank You in advance!

author: amspire
author_rank: Super Contributor
timestamp: April 30, 2016, 02:07:04 am
content: GGG is the SMD code of a 1500W (1ms) transient voltage suppressor (TVS). Fairchild SMCJ58A or SMCJ58CA 58V standoff voltage. Clamping 93.6V at 16A.The package should be a DO-214AB. About 7mm long and 6mm wide.Not sure what the AE26 is.Other similar parts include TFMCJ58A, TV15C580J, CD214C-T58A, 1.5SMCJ58A.If the TVS shorted and blew out the PCB track, it probably saved the board from total destruction.

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 30, 2016, 02:09:38 am
content: AE26 could mean first number is rated current(2a) second number is rated reverse breakdown (60v), but usually they are like SS26 or SS110 rather than AE26...

author: ddctechguy
author_rank: Newbie
timestamp: April 30, 2016, 02:14:02 am
content: This device is powered by either a 24Vac or a 24Vdc supply. Unfortunately 120Vac was applied to the power input of the device. The rest of the components look good, only found the trace burnt off, and the diode shorted out.
Trouble identifying component in switch mode power supply - Page 1
Forum section: electronics / beginners

author: desertrout
author_rank: Contributor
timestamp: February 14, 2024, 02:50:36 am
content: I'm attempting to repair a power adapter for a Macintosh Portable, and can't identify this component, a TO-92 2L with the marking 'N10V':I can't find any datasheets. The marking on the PCB is 'PS', which I've never seen before and haven't found any reference to online.I believe the component is broken, as it measures OL both ways (if that means anything). It was sitting between the negative lead of the primary side filter cap and a SIP which then comes back to the gate of the power mosfet.I only have a vague grasp of switch mode power supplies, so I can't really sort this out. But also other examples I've seen (including other Apple power adapters of this sort and generation, but not specifically this model) don't have this component. So I'm hoping someone here might be able to help???

author: Jwillis
author_rank: Super Contributor
timestamp: February 14, 2024, 04:42:46 am
content: N10VTO92-2 0.4A/50V Circuit protection element. Also called a fuse.

author: desertrout
author_rank: Contributor
timestamp: February 14, 2024, 05:12:01 am
content: Huh - wow, interesting. Thanks!So, any idea what's with the 'PS' marking on the PCB?

author: Jwillis
author_rank: Super Contributor
timestamp: February 14, 2024, 06:56:01 am
content: Don't feel bad.It got me too

author: desertrout
author_rank: Contributor
timestamp: February 14, 2024, 01:17:42 pm
content: LOL I don't feel bad, I'm seriously wondering. Why wouldn't they mark it as F, like they did the mains fuse? PS from what I can tell is for 'Power Supply' but that's not the case here. Seems weird, no?

author: Jwillis
author_rank: Super Contributor
timestamp: February 14, 2024, 10:15:04 pm
content: Fixed the link. I suspect that a poly switch (PS) was substituted out. Just a guess.

author: desertrout
author_rank: Contributor
timestamp: February 15, 2024, 02:52:26 am
content: Huh! Cool - TIL polyswitches exist.