hybridfree/eevblog-posts huggingface dataset:
Use Peltier to heating - Page 1
Forum section: electronics / beginners

author: Jasonbit
author_rank: Regular Contributor
timestamp: October 21, 2018, 11:52:08 pm
content: Hello folks,I intend use Thermoelectric Cooler (Peltier) to heating a piece of copper (process PCB). I am reading this datasheet:http://peltiermodules.com/peltier.datasheet/TEC1-12706.pdfIn last page it is possible read this information: Max. Operating Temperature: 138ºC. This means which I can operate my Peltier without cooler provided that the temperature does not exceed 138ºC, right!?Thanks

author: Feliciano
author_rank: Frequent Contributor
timestamp: October 22, 2018, 01:06:57 am
content: You know, I'd think of a Peltier panel as a heat transfer device (with some % of efficiency) instead of a heating device. Wouldn't it be easier to use a ceramic resistor (or a transistor) attached to a heatsink? If you also attach a thermistor you can create a closed loop control circuit as well.

author: Jasonbit
author_rank: Regular Contributor
timestamp: October 22, 2018, 01:14:00 am
content: Quote from: Feliciano on October 22, 2018, 01:06:57 amYes, this is the best definition "Heat transfer Device"! ThanksThe goal is use the face hot of the peltier to warm the PCB cooper. According to what I've been reading on the internet I can use a simple PTC Sensor to create a closed circuit through PID control the temperature of the system.I will search about use ceramic resistor as a heat transfer device.Thanks

author: IanB
author_rank: Super Contributor
timestamp: October 22, 2018, 02:15:00 am
content: Quote from: Jasonbit on October 22, 2018, 01:14:00 amA resistor is not a heat transfer device, it is a heat source...
Use some computer Hard Drive help. - Page 1
Forum section: electronics / beginners

author: Crambone
author_rank: Frequent Contributor
timestamp: March 09, 2024, 09:04:12 pm
content: If you look at the picture hard drive 1 is being replaced with 2, I’m not sure what adapter or cables I will require to swap over. I’m a Computer idiot so be kind.Thanks , Drew

author: soldar
author_rank: Super Contributor
timestamp: March 09, 2024, 09:07:33 pm
content: Why?

author: tunk
author_rank: Super Contributor
timestamp: March 09, 2024, 09:20:43 pm
content: Drive 1 is SATA:https://en.wikipedia.org/wiki/SATADrive 2 most likely is 2.5" IDE:https://en.wikipedia.org/wiki/Parallel_ATA#IDE_and_ATA-1Even if an adapter exists, it may be cheaper (and simpler) to get a new SATA drive.

author: selcuk
author_rank: Frequent Contributor
timestamp: March 09, 2024, 09:29:33 pm
content: Looks like your mother board has both SATA and IDE connectors. If you have spare connector on that IDE cable (Normally they have 3 heads, 1 to mother board, 2 to devices), you can plug that and a spare power cable to the hard drive.I agree that new SATA drive may be better as IDE drive is probably old tech.

author: soldar
author_rank: Super Contributor
timestamp: March 09, 2024, 09:30:16 pm
content: Quote from: tunk on March 09, 2024, 09:20:43 pmI cannot imagine a scenario where it would make sense to install an old IDE drive today and much less as replacement for SATA.Probably the sensible thing to do is install an SSD if the SATA drive needs to be replaced.But we would need to know more and why.

author: AndyBeez
author_rank: Frequent Contributor
timestamp: March 09, 2024, 10:53:14 pm
content: If you have to install an IDE drive and, there is no IDE port on the motherboard, you can use an IDE(PATA) to SATA adapter card. See attached. The required cable is a 80 wire, 40 pin PATA IDE ribbon cable.Edit: For future finders, the adapter needs to be abi-directionalParallel ATA(IDE) to SATA type. That's SATA into the motherboard and PATA(IDE) out to the HDD. The HDD should be visible in the BIOS as a SATA HDD. Deployment of a Secondary IDE device, which is normally the legacy CD-ROM drive attached to the same ribbon cable, might not be available via your adapter. Generally, one adapter per IDE device.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 11, 2024, 05:26:31 pm
content: Those parallel interfaces (No 2) have been obsolete for 15 to 20 years, and it makes no sense whatsoever to use them. Those things are very slow, have little storage, and their age makes them unreliable. You can get second hand SATA drives for about the same price as an adapter. Those adapters also mostly make sense if you want to recover data from such an old drive.

author: soldar
author_rank: Super Contributor
timestamp: March 11, 2024, 10:19:40 pm
content: I have maybe 15 or more old IDE drives that I have taken from scrapped computers over the years. I have USB adapters so I can plug them in to a USB port and I use them for backups. They are good for that purpose. Plug 'n copy. Unplug 'n store.And they are free.
Use tiny solar panel in ambient light for DIY sensor project - Page 1
Forum section: electronics / beginners

author: mdijkens
author_rank: Regular Contributor
timestamp: October 01, 2020, 12:25:56 pm
content: I have built a small sensor project based on an ESP8266 that runs +7 months from a single 1000mAh lipo.How can I charge this lipo with a tiny solarpanel in ambient (indoor) light? I assume an average of 1 mW is already enough to keep it charged. (e.g. 3mW during the day, 0mW during the night)I was thinking of the same small solarpanels you see/saw in watches/calculators/clocks etc. Max a few cm^2Is it possible?What kind of solarpanel / charging circuit could I use to keep it efficient?

author: Ian.M
author_rank: Super Contributor
timestamp: October 01, 2020, 12:36:42 pm
content: Those small panels seen in cheap solar powered gadgets usually charge a nom. 1.2V NiMH battery. You'd need several in series or a boost converter designed for energy harvesting to get them to charge a LiPO.Perhaps look at panels with more cells in series for a higher output voltage?Googling:energy harvesting solar to LiPOreturns some useful results, including articles from Hackaday and various chip manufacturers.

author: mdijkens
author_rank: Regular Contributor
timestamp: October 01, 2020, 02:12:18 pm
content: Thanks for the link. I'll start reading into thatFirst article surprises me a bit, since it looks exactly like what I'm trying to achieve, but he's talking about direct sunlight.In direct sunlight I even get to 100+mA with a regular TP4056 and a 3x5cm solarpanel. This however won't charge anything without direct sunlight, so not suited for indoor use...I think I also need specific solarcells for ambient light?

author: Ian.M
author_rank: Super Contributor
timestamp: October 01, 2020, 03:06:11 pm
content: You'd need a high efficiency amorphous solar cell. e.g seehttps://panasonic.co.jp/ls/psam/en/products/pdf/Catalog_Amorton_ENG.pdfHowever in 200 Lux illumination (bright office) you'll have great difficulty finding anything smallish capable of delivering even 0.1mA, an order of magnitude less than you need.
Used Agilent E3641A - questions - Page 1
Forum section: electronics / beginners

author: vutt
author_rank: Contributor
timestamp: April 11, 2022, 06:52:03 pm
content: After being so impressed with HP 34401A DMM I decided to acquire second bench PSU from same HP lineage. With wider voltage range and perhaps more PRO hw than my current OWON clone (also seen on attached pic).Potential issue - while it works across all ranges and passes trough "hold [Display Limit] button while powering unit up" self test routine I'm concerned about6 mV voltage while output is off. As seen on attached pic.Another somewhat related behavior. When I'm doing same hold button power up self test routine it puts out 1V and that stays after self test is done. However 1V goes away after I turn output On-Off and it settles on 6mV. Hm...Also note to myself - Think twice before buying used PSU-s again. I had to deal with a lot of smelly dust bunnies grown in heavy smokers lab In Japan. Also fan is rattling a little annoyingly. I wonder if Noctua is making HP compatible replacement fans...

author: free_electron
author_rank: Super Contributor
timestamp: April 11, 2022, 06:59:19 pm
content: really ? 6 millivolts ? that's leakage !

author: vutt
author_rank: Contributor
timestamp: April 11, 2022, 07:44:20 pm
content: ...well my cheap Owon PSU shows only 290 nV with output off...

author: strawberry
author_rank: Super Contributor
timestamp: April 12, 2022, 02:47:10 pm
content: If it doesnt drift then should be fine.they tell something about 4wire and 5mV offset?? 10mV resolutionmy 34401a was drifting ohms range before repaired

author: vutt
author_rank: Contributor
timestamp: April 15, 2022, 10:15:25 am
content: @strawberry No drifting. So I should be fine. Thanks for replay.I have another observation/question not worth separate thread. Decided to observe V transients with scope. There is little ~5V voltage drop when I turn E3641A on (yellow trace) compared to switch on without load( grey reference trace). See attachmentI could not replicate this behavior with my OWON PSU so it cant be my DC load fault.Well PSU is 20+ years old.Could it be that something is starting to fail?User error - tested it with DC load CC mode...Otherwise I'm happy with performance. No voltage movements when switching load on/off. OWON has -20mV drift/drop. Also it turns on twice as fast than OWON.

author: strawberry
author_rank: Super Contributor
timestamp: April 15, 2022, 12:23:04 pm
content: dont know maybe, OVP trigeringif unregulated voltage drop as well, dry capacitor

author: vutt
author_rank: Contributor
timestamp: April 15, 2022, 12:34:19 pm
content: I edited my post.Well this was "user" error LOL. I tested it CC mode, of course DC Load will try to regulate everything else in order to keep current constant.I tested it in CV mode - no dipsE3641A is actually working as intended.
Used Fluke 87V with wild ACV readings - Page 1
Forum section: electronics / beginners

author: Freebie
author_rank: Newbie
timestamp: March 04, 2017, 12:50:31 am
content: I brought a used Fluke 87V off eBay and just received it today. All ranges are ok except AC volts. The issue is if you wave the connected leads (connected to COM and Volts and nothing else) around the right side of the meter, the voltage will jump all over the place. I get readings of 2 to over 400 volts. Is this normal behavior or is the meter defective?

author: med6753
author_rank: Super Contributor
timestamp: March 04, 2017, 01:39:21 am
content: That's not 400 volts. It's 400 millivolts or 0.4 volts. Normal operation. You are golden.

author: Freebie
author_rank: Newbie
timestamp: March 04, 2017, 02:14:04 am
content: It's my first Fluke and I didn't notice the range. Thanks.
Used some 8 pin DIP sockets for interchangable on oscillator prototype boards - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 04, 2017, 09:19:03 pm
content: I was making some permanent oscillator circuits, I'll get about 4 on the little borad I have. And I have lots of 8p DIP receptacles. So I wired it up so that I can replace the various transistors, capacitors, inductors, a crystal.For great in that function too
Useful PCB stuff, ideas to order from PCB manufacturers - Page 1
Forum section: electronics / beginners

author: honeybadger
author_rank: Contributor
timestamp: May 17, 2020, 11:43:39 pm
content: Hi,from time to time I need to order PCBs from Chinese PCB manufacturers for my clients. Every time I see the DHL shipping prices (and the ridiculous DHL customs declaration fee) I add my personal projects $2 PCBs to the shipment. The thing is I am out of personal project ideas and I have far too much "perma-proto" breadboards alreadyIt seems wasteful not to use the $2 offer with "free" shipping. Custom SMD->DIP boards will be next. Do you have any other ideas which are actually useful to the electronics lab?

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: May 18, 2020, 12:11:51 am
content: SOIC-8 to TO-99. Haven't seen those around.Not sure if footprints can be overlapped.
Useful Poster - Page 1
Forum section: electronics / beginners

author: danadak
author_rank: Super Contributor
timestamp: November 30, 2017, 12:10:04 pm
content: A useful poster on measurement errors.https://info.tek.com/www-four-step-error-checker-poster-em-ty.htmlhttp://download.tek.com/document/LowLevelHandbook_7Ed.pdfRegards, Dana.
Useing MAX1447 ADC - Page 1
Forum section: electronics / beginners

author: xoom
author_rank: Regular Contributor
timestamp: July 07, 2016, 05:12:58 pm
content: Hi, I made voltmeter with this chip, it measures correct, everything looks right, but there is one problem.. At least not found anything about that in datasheet..Problem is: When i turn it on it does something.. maybe calibration or smth and shows some numbers (like going up numbers from 0 to about 15000) when reaches some number then it blinks it once and then starts working normal. Anyone seen that? is is possible to disable that and make it get ready faster.. that counting takes about 2-3 seconds..Sorry for my English.Best Regards,xoom

author: MatthewEveritt
author_rank: Unknown
timestamp: July 07, 2016, 05:36:57 pm
content: From page 15 of thedatasheet:QuoteI've never used these parts, but it sounds like it's doing an offset calibration. I don't see any mention of being able to disable it, and by the sounds of it you probably don't want to.

author: xoom
author_rank: Regular Contributor
timestamp: July 07, 2016, 05:45:35 pm
content: I don't want to disable calibration. But i want to disable those showingsI'm considering maybe better use Atmega for that. Also O.T. question.. for current measurement if i use leads from shunt resistor to another board. Much noise can be picked up? or better is to amplify it near shunt resistor then wire up to another board?
Uses for A Function Generator - Page 1
Forum section: electronics / beginners

author: German_EE
author_rank: Super Contributor
timestamp: December 29, 2015, 03:21:02 pm
content: Once in a while we see a post from a beginner asking what use a function generator would be in a lab, after all, they are expensive pieces of kit. Well, today I saw a great use for one AND it also demonstrates what a well known circuit does to your signal.So, the question for you all is, What effect do the Bass and Treble controls have on an audio signal?We all know that these controls either attenuate or amplify the low and the high end of an audio signal but there's a better way to demonstrate it. Feed a 1 KHz square wave from a function generator into an audio amplifier and wire a scope across the output, if it's a decent amplifier you should see something resembling a square wave on your screen. Now start playing around with the tone controls and see what it does to the signal, increasing the bass will round off the edges of the square wave until it begins to look like a sine wave but increasing the treble introduces ringing to the start and end of the pulse along with lots of other alterations.What were we doing? A friend of mine had an audio amplifier which had different frequency responses on the left and right channels, the left side sounded muffled with way too much bass. By injecting a square wave into both channels then usingthe scope we were able to trace the signal through and find the faulty component, a cracked polycarbonate capacitor in the tone control circuit.

author: Fat
author_rank: Regular Contributor
timestamp: December 29, 2015, 04:04:48 pm
content: Interesting post. Thanks!

author: cobbler
author_rank: Unknown
timestamp: December 29, 2015, 10:38:33 pm
content: Thanks it is posts like this that help us learn when to use the right tool for the job.

author: German_EE
author_rank: Super Contributor
timestamp: December 30, 2015, 09:12:17 am
content: This is why I posted the story in 'Beginners' rather than 'Repairs'.

author: pmbrunelle
author_rank: Regular Contributor
timestamp: December 30, 2015, 09:16:06 am
content: I find the use of a square wave (containing many frequencies) rather than doing a sine sweep (which can take long) is clever.

author: owiecc
author_rank: Frequent Contributor
timestamp: December 30, 2015, 10:06:22 am
content: If you do a sweep you can do a poor man's spectrum analysis on the scope:
Uses of capacitor connected in series with Vdc - Page 1
Forum section: electronics / beginners

author: zzlong94
author_rank: Contributor
timestamp: November 21, 2017, 06:00:42 pm
content: Capacitor is connected in series with Vdc to clear off the ripple of Vdc.However, the value of capacitor is just 100 nano Farad .it is possible to clear off ripple of Vdc or its act as another function as well?

author: rstofer
author_rank: Super Contributor
timestamp: November 21, 2017, 06:13:26 pm
content: I guess I don't see the capacitor as 'in series' with anything but rather connected across the power supply and it is intended to absorb high frequency transients. This is commonly called a 'decoupling capacitor'. Dave has a video about this:

author: nugglix
author_rank: Regular Contributor
timestamp: November 22, 2017, 07:35:57 am
content: And Alan has one with experiment and the usual nice explanation.

author: Brumby
author_rank: Unknown
timestamp: November 22, 2017, 08:40:44 am
content: Quote from: zzlong94 on November 21, 2017, 06:00:42 pmIt absolutely is not. It is connected in parallel, commonly described as "across".Using multiple Earth symbols for all "ground" points is frequently done, but it takes away the visual cue of a single line running across the circuit diagram, which makes parallel connections much more obvious.
Using 0,3Vpk 20kHz signal to open transistor - Page 1
Forum section: electronics / beginners

author: Big Foot
author_rank: Newbie
timestamp: January 12, 2016, 10:38:19 am
content: Hello everybody, I'm a beginner at electronics and heard this is the place to get helpI want to make small circuit to release camera shutter.Conditions are:Input signal:ON: AC 0,3Vpk (0,6V peek to peek); 20kHzOFF: 0VI want to enable a transistor for the whole time of the signal being on.Camera is released by shorting its 2 pins (one is 5V other is GND)I can use 3V battery for this circuit.I was thinking about using opamp for this, but my knowledge fails when i try to smooth the output of the opamp to keep the transistor open for whole time of the signal.I attach a picture of my first thoughts.I hope you can help me.

author: Big Foot
author_rank: Newbie
timestamp: January 12, 2016, 10:50:08 am
content: Quote from: dom0 on January 12, 2016, 10:46:04 amI don't know the source resistance. It is audio jack output of mobile phone.

author: Zero999
author_rank: Super Contributor
timestamp: January 13, 2016, 04:40:53 pm
content: If that's the case, then the source resistance should be fairly low.There are plenty of ways to do this. Here's one using the CD4007.

author: Audioguru
author_rank: Super Contributor
timestamp: January 13, 2016, 05:39:35 pm
content: Were you planning to use a lousy old 741 opamp (its design is 47 years old) powered from 3V without looking at its datasheet? It shows it powered ONLY with a 30V supply because many do nothing if the supply is less than 10V.A door opens and closes. A transistor does not open, instead it turns on or it turns off and I do not know which one is your "open".Your signal is AC. It must be rectified and filtered so that the camera shutter does not turn on and turn off at 20kHz.
using 35 output MM5451 LED driver to build an LFSR noise generator? - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: January 25, 2017, 02:16:01 am
content: I've been simulating different Linear Feedback Shift Registers to create pseudo-random noise like they used in the old ETI Vocoder. I don't have a 4006 like ETI used but I've been messing with using two 74HC164 shift registers and an XOR for now.It all seems to work and creates noise if I clock it fast enough but I found that I have an old MM5451N LED driver which is a giant 35 output shift register but being a driver it sinks current unlike a 74164 or 74595 etc.Here's the datasheet.http://www.mouser.com/ds/2/268/mm5450-778453.pdfThe outputs will be connected to the inputs of an XOR so I need them at a known state at all times and hopefully 0V and 5V.From what I can see this chip doesn't look like it just has simple open collector/drain outputs (which I'm assuming would just need pull-up resistors to do what I want) so I'm not sure how I could use them for anything other than driving LEDs and mis-use it for inputting data into an XOR.

author: Ian.M
author_rank: Super Contributor
timestamp: January 25, 2017, 02:30:41 am
content: No chance. It uses a leading '1' start bit and only updates its output once every 36 clock pulses.

author: james_s
author_rank: Super Contributor
timestamp: January 25, 2017, 03:16:51 am
content: A number of classic arcade games use a LFSR made of a pair of 74LS164s and a few gates. Here is the one used to make the ship thrust sound in Asteroids. The output of this is passed through a simple low pass filter. Galaxian uses a nearly identical circuit to generate the scrolling starfield background.

author: dentaku
author_rank: Frequent Contributor
timestamp: January 25, 2017, 03:23:34 pm
content: Quote from: Ian.M on January 25, 2017, 02:30:41 amOh yeah, I was wondering about that leading one while reading the datasheet then forgot about it while trying to figure out what the outputs looked like.I remember testing it out with an Arduino quite a while ago and obviously the code I used took that into consideration.Oh well.

author: dentaku
author_rank: Frequent Contributor
timestamp: January 25, 2017, 03:28:08 pm
content: Quote from: james_s on January 25, 2017, 03:16:51 amNice. That's the kind of stuff from that past that I find interesting.

author: dentaku
author_rank: Frequent Contributor
timestamp: January 26, 2017, 01:31:16 am
content: I just built the circuit I attached to my first post and it sounds so much like the old Atari Games from when I was young, especially when I turn up and down the clock frequencyThe old game Dragster and Haunted House sounded just like this.At high enough speeds I can tell where it repeats.
Using 555 charge pump to boost the 11.1v lipo to 15 possible? - Page 1
Forum section: electronics / beginners

author: amateur_25
author_rank: Regular Contributor
timestamp: February 13, 2014, 04:57:52 pm
content: Hi Guys,I know the 555 can be used as a charge pump to obtain a higher voltage. What I need to do is boost 11.1v @ 4A (2 3 cells lipos) coming from my lipo to 15v so I can drive my leds properly. They're wired as 4 columns ( in series) by 7 rows ( in parallel) hence I need at least 12.4v to give each led equal power. Also AFAIK the 555timer isn't designed to power such a big load. How would I get more current at the higher voltage? Also can you safely wire 2 lipos in parallel. Prefer it not to blow up in my face.I have already built the matrix on veroboard it works. I just need a portable power source as it's a work light. The work light I have used very cheap leds. I also think the power source they've thrown together is lethal. No mains isolation and the capacitor/resistor combo used to reduce the voltage isn't a y capacitor. Not only that it's on the neutral side and not line. Isn't that dangerous? I think I'll convert it to a power brick instead. At least that will have a switch mode transformer in it.

author: amateur_25
author_rank: Regular Contributor
timestamp: February 13, 2014, 06:30:28 pm
content: not too bothered about efficiency. Well I would like around half an amp since I may make it bigger.So how do I wire this up to the timer? Sorry I have no experience of this sort of thing.Is the the arrangement in the image what am after?

author: Zero999
author_rank: Super Contributor
timestamp: February 16, 2014, 04:55:17 pm
content: A charge pump isn't the best option for 500mA. A boost converter is a better option.

author: amateur_25
author_rank: Regular Contributor
timestamp: February 16, 2014, 05:25:25 pm
content: ok Just out of curiosity if you were to use one, how many milliamps would you expect it to be good for? Just so that I know for next time. I've opted for a simple lm257 from ti.
Using 5V from the USBc port for the gate driver IR2302, is it reliable enough? - Page 1
Forum section: electronics / beginners

author: karakis
author_rank: Newbie
timestamp: May 05, 2025, 08:18:06 pm
content: Hi,I'm working on a synchronous buck converter with an input voltage of around 60V, and I'm planning to use the IR2302 gate driver (https://mou.sr/4jqqFSB) to drive the two MOSFETs. According to the datasheet, the minimum Vcc for the driver is 5V. I’m considering using the default 5V from the USB-C port as the Vcc for the gate driver. I tested this setup on a breadboard, and it seemed to work reasonably well, but I’m not fully confident that it's robust or reliable enough for the final PCB design. I’d prefer to use the default 5V from the USB port, because otherwise adding a separate boost converter would increase complexity in the PCB. I wanted to ask if anyone has experience with this approach or any suggestions that might help.Thanks!

author: radiolistener
author_rank: Super Contributor
timestamp: May 05, 2025, 11:04:33 pm
content: You cannot expect min 5V from USB. While on desktop PC powered from mains it can be 5.0..5.2 V, but on batterry powered devices (like notebooks, tablets, smartphones, etc) it will be often 4.5..4.9 V or even less

author: langwadt
author_rank: Super Contributor
timestamp: May 05, 2025, 11:13:34 pm
content: with a rising under voltage lockout of 5V is might never turn on, and 5V gate drive will limit the choice of transistors. Why not use a linear regulator to get ~10V from the 60V input? that'll also give you a much wider choice of gatedrivers

author: karakis
author_rank: Newbie
timestamp: May 05, 2025, 11:59:00 pm
content: Quote from: radiolistener on May 05, 2025, 11:04:33 pmI will be supplying it from the usb plug directly. I am planning to usehttps://www.mouser.de/datasheet/2/196/Infineon_DS_IPP030N10NF2S_1_0-3556281.pdfthis which says 3-3.8V Vgs. What would be your recommendation for my case?

author: karakis
author_rank: Newbie
timestamp: May 06, 2025, 12:00:14 am
content: Quote from: langwadt on May 05, 2025, 11:13:34 pmI will have a solar panel as an input so I dont want to use it as the reliable source. I tested this driver today on breadboard it was working actually but couldnt be sure if its robust enough

author: thm_w
author_rank: Super Contributor
timestamp: May 06, 2025, 12:45:03 am
content: The issue is not Vgs, langwadt is telling you the IR2302 requires minimum 5V Vcc supply.So find another driver with a lower Vcc if you can, or use the 60V supply.Its not clear what you are doing though, USB powered device with a 60V solar input? Why not power it from 12V or something instead.
using 7806 - Page 1
Forum section: electronics / beginners

author: nickeevblog10
author_rank: Contributor
timestamp: February 08, 2018, 01:56:23 am
content: Hi, I am a newbie so I better start at the beginning.I have an AS600 6V alkaline battery powered portable screwdriver and want to power it using an unused computer power supply.I want to connect the motor to a molex connector and wondering if simply splicing a 7806 voltage regulator between the motor and the molex connector from the computer power supply is going to be enough for the motor to work properly.I have included photos so you can see what I have done so far.First I tried to run the motor of 12V forgetting it is a 6V motor then began trying to find out what to do to make the motor run.I was told splicing the 7805 voltage regulator into the setup would work ok.I would like to know now not just to to guess, if someone can help me please.I hope I can get the photos I took to upload.

author: djacobow
author_rank: Super Contributor
timestamp: February 08, 2018, 02:24:06 am
content: This will probably not work. The 7806 is only good for up to 1.5A, and that only when power dissipation it's handled adequately.The drill motor might draw less than 1.5A when free-running, but when it's actually generating torque turning a screw, I suspect it pulls much more.Also, dropping 6V @ 1.5A means 9W dissipation in the regulator. Your little heat sink is likely not up to the task.Finally, you should have some capacitance in the input and output of that regulator.On the other hand, the 78xx are pretty robust little guys and are more likely to shut down when unhappy than just break, so you might get away with light intermittent use.

author: Nusa
author_rank: Super Contributor
timestamp: February 08, 2018, 02:24:39 am
content: It would depend on current requirements, which may be too high when the screwdriver is working hard. AA batteries are capable of delivering a lot more current than a 7806.I'd suggest trying it using the computers 5V supply first, since you've got that already. If the performance is adequate, you're done.

author: Brumby
author_rank: Unknown
timestamp: February 08, 2018, 02:33:05 am
content: +1 on trying the 5VThe voltage of batteries under load will sag a bit, but the 5V of computer PSUs will be regulated ... and they tend to offer a good chunk of current.

author: nickeevblog10
author_rank: Contributor
timestamp: February 08, 2018, 03:34:42 am
content: Using the computer power supply 5V worked well and when I applied pressure to the motor while driving the screwdriver it handled that really well.Thank you
Using "smart switches" in parallel to do load sharing? - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: August 10, 2017, 07:12:10 am
content: Does anyone know if it's OK to use devices such as the Infineon BTS432, in parallel to do load sharing?The data sheet is herehttps://www.infineon.com/dgdl/Infineon-BTS432E2-DS-v01_01-en.pdf?fileId=db3a304326623792012688c5622b6cb7I tried various Google searches for "high side smart switch" and parallel or load sharing but that didn't turn up much. What key words should I be searching for?If I were to run two in parallel would it be simply a case of checking the "on resistance" to make sure that they are reasonably balanced?

author: capt bullshot
author_rank: Super Contributor
timestamp: August 10, 2017, 08:10:28 am
content: It's quite unusual to do so, here one would just lookup and use the next larger switch.I don't see any general issue to do so, but you should not expect full double load capability. As the Rds_on rises with die temperature, the switches should do some basic current balancing on their own. Just don't expect it to be ideal. The inductive kickback clamping may not share the current, since the breakdown (avalanche) voltage is expected to have more tolerances between units. Better use an external catch diode.Status output and input can be paralled if the logic matches your needs.
Using a 3 terminal capacitor - Page 1
Forum section: electronics / beginners

author: revtintin
author_rank: Newbie
timestamp: October 08, 2017, 02:41:15 pm
content: Hi,I'm in the middle of building a PSU, and I ended up ordering a pair of 3 terminal capacitors (instead of the 2 I'm familiar with). I wired up and tested them just using one of the +ve terminals and the readings were as per the book I'm following.What's the extra +ve terminal for? Also, I'm supposed to have used "phenolic strips" to mount the capacitors, providing a "3 chassis mount insulated tie points" for them... but I don't quite understand. Does anyone know what kind of hardware these would be? A link to some actual parts in say Mouser/Digikey would be very helpful.Thanks!

author: David Hess
author_rank: Super Contributor
timestamp: October 08, 2017, 10:04:05 pm
content: Quote from: revtintin on October 08, 2017, 02:41:15 pmThe extra terminal is to make the capacitor polarity unambiguous; a three terminal capacitor can only be wired up one way.QuoteThat sounds like these. They mount to a chassis and provide several insulated terminals.http://www.mouser.com/Connectors/Terminals/_/N-5g5uZ1yzvvqx?P=1yztjf0&FS=True

author: Phoenix
author_rank: Frequent Contributor
timestamp: October 09, 2017, 05:36:08 am
content: Quote from: revtintin on October 08, 2017, 02:41:15 pmDo you have a link to what you ordered?

author: Zero999
author_rank: Super Contributor
timestamp: October 09, 2017, 08:36:45 am
content: What sort of capacitor is it? I can think of two types of capacitor which have three terminals.

author: revtintin
author_rank: Newbie
timestamp: October 09, 2017, 02:38:48 pm
content: The ones I ordered are:http://www.mouser.sg/Search/ProductDetail.aspx?R=401X442U050AK8virtualkey59850000virtualkey598-401X442U050AK8

author: wraper
author_rank: Unknown
timestamp: October 09, 2017, 02:44:29 pm
content: Did you ever open the datasheet at all? It obviously says "no internal connection" on 3rd pin, it's there solely for mounting robustness.

author: revtintin
author_rank: Newbie
timestamp: October 09, 2017, 02:50:21 pm
content: Quote from: wraper on October 09, 2017, 02:44:29 pmI'm ashamed to say I didn't! Thanks for pointing that out. I am still curious if this is the case for all 3 terminal capacitors .

author: wraper
author_rank: Unknown
timestamp: October 09, 2017, 02:58:43 pm
content: Not always, it may have 2 capacitors inside with one common connection. But this was common it the past, not nowadays. I cannot remember when I've seen such last time.

author: Zero999
author_rank: Super Contributor
timestamp: October 09, 2017, 03:01:49 pm
content: Quote from: wraper on October 09, 2017, 02:58:43 pmOr it could be one capacitor, with two pins to either the positive or negative, in which case they should be connected together. Always check the data sheet.

author: revtintin
author_rank: Newbie
timestamp: October 09, 2017, 04:36:02 pm
content: Thanks all. I will definitely study the data sheets more from now on.
Using a battery pack on dead internal - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: June 24, 2019, 02:21:07 pm
content: Hi All, I am thinking of buying an Oculus Quest wireless VR HEADSET. According to the manufacturer when the internal battery dies the device becomes disposable. Can one run a device with a practically dead battery, off a battery pack safely? Isn’t that just trying to charge a battery that won’t hold the charge? If you can still run the device even though your tethered to it that would be better than nothing if it works. I know Lithium’s can be unstable. What are the safety concerns with a setup like that?

author: Rerouter
author_rank: Super Contributor
timestamp: June 24, 2019, 02:38:29 pm
content: Generally running a device on a degraded battery wont cause any significant risk, the main point is the amount of energy it can chemically store has degraded significantly compared to the original capacity, the whole exploding into fite risk is generally from punctures or gross overcharging, and the size of that reaction is limited by how much energy is in there in the first place,Think of it like running a laptop off the wall charger for years after the battery has failed, depending on the design of the power system of the device it can cause stability issues, but in most cases it will still power on and work for however long it gives you.As for possibility of replacing the battery. I would expect places like ifixit will get around to working out how to replace the battery in it, there previous models where not outside the realm of general user with basic tools to open and service,

author: tony3d
author_rank: Frequent Contributor
timestamp: June 24, 2019, 03:19:01 pm
content: Well, if there is no fire risk, a battery pack slipped in your pocket would be a nice simple fix, and probably be able to run over 3 hours with a nice size pack. That would work for me.
Using a CM Choke from EMI Filter as Transformer - Page 1
Forum section: electronics / beginners

author: Frankentronics
author_rank: Regular Contributor
timestamp: April 12, 2020, 11:47:03 am
content: Greetings,A friend of mind wants me to make him an interface to tap a phone line. The device is described here:https://www.ranecommercial.com/legacy/note150.htmlThe schematic is here:He is a musician and he wants to use the phone line to send and receive audio.So, the device requires a 1:1 transformer and I like to use salvaged parts. Perhaps this is a crazy idea, but can I use a CM choke, salvaged from an EMI filter, to function as a transformer? Of course, it would have to be rotated 90 degrees, or wired "sideways", to be a transformer.But basically, might that work for this particular application?Thanks...

author: srb1954
author_rank: Super Contributor
timestamp: April 12, 2020, 11:58:18 pm
content: It won't work very well at all. A common mode choke won't have nearly enough inductance to work at audio frequencies unless you are prepared to suffer enormous signal loss through the circuit.A transformer designed for audio frequencies will have a winding inductance of at least several Henries whereas a common mode choke will typically be less than 1mH.

author: james_s
author_rank: Super Contributor
timestamp: April 13, 2020, 03:13:33 am
content: Small 600 ohm audio transformers are ridiculously cheap.https://www.ebay.com/itm/10Pcs-Audio-Transformer-600-600-Ohm-Europe-1-1-EI14-Isolation-Transformer-DIY/173610350428

author: Frankentronics
author_rank: Regular Contributor
timestamp: April 13, 2020, 04:28:21 am
content: Quote from: james_s on April 13, 2020, 03:13:33 amWell, that's clearly the solution.Thank you for taking the time to post the link.
Using a DAC to control small voltages - Page 1
Forum section: electronics / beginners

author: stevehendo
author_rank: Newbie
timestamp: May 03, 2018, 04:18:27 am
content: Hi All,First time using a DAC, so feel free to set me straight if I am going about this all the wrong way.I'm wanting to use a 12-bit DAC (MCP4725) to put out 5-50mV on the non-inverting input of an op amp (it's very low offset, so I think I'm ok in that regard). I'm currently using a precision 5v reference (REF02).I can see two options to get full resolution out of the DAC:1) Use a 100 to 1 voltage divider (eg. 99k and 1k). Is this reasonable or is there an upper limit to how high a voltage divider ratio can be?2) Use the full 0-5V from the DAC and multiply the inverting input by 100 using a precision op amp.Is there a preferred way to deal with this or am I way off track? Any advice much appreciated.Steve

author: ogden
author_rank: Super Contributor
timestamp: May 03, 2018, 07:13:35 am
content: Voltage divider is most common way of altering DAC voltage range. Just make sure divider does not load DAC output. In your case MCP4725 is buffered with opamp output stage and does not mind (100k) load on it's output.

author: stevehendo
author_rank: Newbie
timestamp: May 03, 2018, 10:29:48 am
content: Thanks very much for your help.
Using a DC-DC converter's "enable" pin as an "on" button or load switch - Page 1
Forum section: electronics / beginners

author: derGoldstein
author_rank: Regular Contributor
timestamp: July 07, 2017, 10:48:46 am
content: This seems to be a very simple question, but I've learned never to assume when it comes to electronics: Most DC-DC converters have an "enable" pin that you pull high to turn them on. Is it acceptable to use that as the "on" switch of the device? It has the benefit of being a near-zero-current pin, meaning you can use the tiniest switch you can find.It would also mean you can use an MCU to switch a potentially heavy load on and off.Is there a reason not to do this?

author: OiD
author_rank: Regular Contributor
timestamp: July 07, 2017, 02:38:54 pm
content: Nearly all modern DC-DC IC handle the on/off very elegantly if the circuit is properly designed. The enable pin is pretty much there for this very purpose.On older IC's you could get voltage/current overshoot. Some DC-DC's even have soft-on, where there is a ramp up during the on/off stage.

author: boz
author_rank: Regular Contributor
timestamp: July 07, 2017, 08:38:04 pm
content: Thats exactly what the enable pin is for

author: tablatronix
author_rank: Regular Contributor
timestamp: July 09, 2017, 07:24:19 pm
content: What sucks is that all these cheap chinese dc dc modules dont expose the enable pins, or pull it down up under the chip so you cant even mod them. Shame.
Using a differential ADC as unipolar - Page 1
Forum section: electronics / beginners

author: Axk
author_rank: Regular Contributor
timestamp: February 06, 2019, 08:53:23 pm
content: http://www.ti.com/product/ADS7945Can I use the differential version of this ADC (more cheaply available from aliexpress) as to measure an ebike battery voltage (13s6p battery) using a resistive divider or do I need the unipolar version?There are better options available from aliexpress or ebay I'm sure, but this is the first one I found through Digikey that is avilable on aliexpress and that has 2MSps and 14bit for my application.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 06, 2019, 09:14:19 pm
content: One can often use differential ADCs in a unipolar mode, with one input fixed at ground or a different fixed level. Depending on the model one may not be able to use the full range, but usually one polarity is OK. With some models there will be a slightly higher error due to nonlinearity, as the specified linearity of often for differential input with zero common mode voltage.The mentioned ADC is anyway not a good choice for measuring an accumulator - it's a rather fast one. No need for 2 MSPS on a battery. It's also an ADC in a small case and thus difficult to solder by hand. The input may need a buffer, but I have not checked the datasheet.I would more like consider something like MCP3421 - a slow 18 Bit ADC.

author: Axk
author_rank: Regular Contributor
timestamp: February 06, 2019, 09:21:43 pm
content: My reasoning of why I need this sampling rate is as follows.I've measured the current waveform between the ebike controller and the battery and it has components of several KHz for sure, and maybe more. Considering the high current in this application the voltage will also vary with the current.Measuring power I would need 2 ADCs so oversampling at a couple of MHz should give me a good margin for better integration of the consumed power.
Using a diode to make a capacitor drain in 1 direction? - Page 1
Forum section: electronics / beginners

author: MWisBest
author_rank: Contributor
timestamp: November 06, 2017, 06:10:22 pm
content: Just want to make sure this idea will actually work before I try it.The idea here is to have a capacitor that stabilizes voltage on the output without feeding back into the input. The application is an automobile, specifically the headlights. I have an audio amplifier that draws sudden surges of current, which causes a momentary voltage drop while the alternator regulator adjusts for the load (approximately 0.2V for 50-100ms). This is slightly visible with the headlights. I'd like a capacitor to "buffer" that so it's not noticeable, but if the capacitor drainsbackinto the rest of the car this will be fairly useless without an enormous capacitor because the headlights are just a fraction of the overall power usage. Will a diode work here?

author: jm_araujo
author_rank: Regular Contributor
timestamp: November 06, 2017, 06:16:29 pm
content: In theory, yes.In practice, the headlights are power hogs and you will need a beefy diode and a huge capacitor.

author: MWisBest
author_rank: Contributor
timestamp: November 06, 2017, 06:54:13 pm
content: Quote from: jm_araujo on November 06, 2017, 06:16:29 pmYes of course, it will take some beefy components. They use somewhere around 5A of current each. Each headlight will get its own diode+cap(s). Heatsinked TO-220 package diode and somewhere between 4,000 and 12,000 uF of caps should do the trick I think.

author: Psi
author_rank: Super Contributor
timestamp: November 06, 2017, 06:59:54 pm
content: From memory headlights are around 5A so i would spec a 20A continuous diode each.The cap has to be quite big, maybe supercap size. Thats not too much of a an issue. You can get them easy enough. Cost a bit through.The issue is when the system first powers up and the caps are empty it's going to draw huge current (30A+) and may burn out the diodes. So maybe add a series resistor that limits inrush current under the diodes pulse current.Your may get a better result just putting big caps at the amp though. I dunno

author: MWisBest
author_rank: Contributor
timestamp: November 06, 2017, 07:49:08 pm
content: Quote from: Psi on November 06, 2017, 06:59:54 pmThat's a good point about empty caps. I was already planning on having the relayafterthe capacitor rather than before it, so that there's no current surge every time the headlights turn on, but when the battery is first hooked up to this it could definitely be an issue. Perhaps I can add a switch for the resistor, so it can just be disconnected easily once the capacitor is charged.Quote from: Psi on November 06, 2017, 06:59:54 pmThat's what I'm trying to avoid. Those things scare me, anything off-the-shelf for that is very sketchy and stupid expensive.
Using a Fan Speed 12v controller..better with PWM fans or regular fans? - Page 1
Forum section: electronics / beginners

author: shaolin95
author_rank: Newbie
timestamp: July 02, 2025, 08:30:40 pm
content: Hi!I am swapping the fans of a Behringer amp to Noctua fans but connecting internally they only will run at around 5V thus too low CFM. I am using a 12v controller to power them externally instead:https://www.amazon.com/UMLIFE-Controller-100-240V-Adjustable-Connector/dp/B0DQL4LZL1/ref=sr_1_1?crid=RIIVPEBA7G8B&dib=eyJ2IjoiMSJ9.yG6TOYacSmjNn_wNVVnoFcSzGAtnSwUqWtYOPpNY8EWJu3aCC5i4G9HysY7L6Hoawr95KscBfaGX13oaa2rZXshPgsmD7OP860vpNMoQdRcXRDJ4jTGVvdYNblzWZLGNXt1zu6leTcaS7ukoJcELX7M5QkPP1G3RotNEJFyWOpd2AQVvwKdhLyQkmxs5_U0xW6QDMoymY_w_bXOTAbluiUz93-DudRx7md4NoAHgO-tVIN_cyOxwL-_318SLp4VVZRQk9F5hqYdpeZrfwR-t82IrZIei-5M7c1i0K7J9WrA.kqR6omTdqbV2swf_bQnCB3P1Z9U9imV62yhcDuBASP4&dib_tag=se&keywords=pwm+fan+controller&qid=1751485984&s=electronics&sprefix=pwm+contro%2Celectronics%2C141&sr=1-1It works great BUT I started to wonder, is it best to use this device with the PWM version of the fans or just the regular version? Or does it make any difference?Thanks!

author: JustMeHere
author_rank: Frequent Contributor
timestamp: July 02, 2025, 08:41:44 pm
content: That device only connects 2 wires.If you're asking if you should use a 3 or 4 pin fan, then it doesn't matter.

author: shaolin95
author_rank: Newbie
timestamp: July 02, 2025, 10:45:35 pm
content: Quote from: JustMeHere on July 02, 2025, 08:41:44 pmI was not sure if the PWM fan is designed differently than the regular fan and if that will somehow work better when controlled with that fan controller.But if it makes no difference then, I will keep what I gotthanks

author: David Hess
author_rank: Super Contributor
timestamp: July 03, 2025, 02:51:12 am
content: Quote from: shaolin95 on July 02, 2025, 10:45:35 pmIt makes no difference in the sense that a two wire controller will not support the PWM function of the fan. The PWM fan will not perform any differently without the proper controller.