hybridfree/eevblog-posts huggingface dataset:
Help with mosfet dying - Page 1
Forum section: electronics / projects

author: Loden
author_rank: Newbie
timestamp: May 15, 2025, 03:52:22 pm
content: Hi EEVblog forums, I'm hoping you can help me find a solution. I found a solenoid boost circuit (can't find the source anymore) that essentially acts as a voltage doubler by discharging a cap to ground and pulling the low side of the solenoid to -24v (in my case). This circuit worked pretty well for one of my solenoids, but for the other (a bigger one), it's started destroying the capacitor in charge of charging the cap.The circuit works by opening the mosfet that charges the capacitor once the mosfet below the solenoid is closed. This causes the voltage difference across the 10k resistor to the positive side of the mosfet to go to +24v, which then opens the mosfet, reducing the Vgs as the cap charges.I've run out of ideas on how to troubleshoot or fix this problem.I have a couple of ideas as to what might be causing the problem:- The gate voltage on the charging mosfet goes too high when the cap starts charging (Vgs is 24v for a short time, couldn't find a mosfet rated for that so far)- The gate voltage on the charging mosfet goes too low for too long while charging the cap, causing the mosfet to have a higher RdsON and overheating- The Ids is too high, even though the mosfet is rated for 65A continuous current- The current spike when the capacitor starts charging is too high? trace resistance and RdsON together is around 10mOhm, so that could be a problem.- The diode I have in place to stop the cap discharging through another version of this circuit on the same power supply is interfering with its functioning?Please help me understand how to debug this circuit or what to try. I don't know where to look anymore. Should I add a power resistor in series with the cap to stop it charging too fast?

author: Terry Bites
author_rank: Super Contributor
timestamp: May 15, 2025, 04:43:02 pm
content: Stephen Woodward of course!www.edn.com/relay-and-solenoid-driver-circuit-doubles-supply-voltage-to-conserve-sustaining-power/

author: MariuszD
author_rank: Regular Contributor
timestamp: May 16, 2025, 05:56:51 am
content: Do you need fast charging?Capacitor charging is only 50% efficient. Other 50% must be dissipated in Q9. IRFR7440 have very limited SOA. Q9 have high resistance in gate circuit so it can't cut off instantly, when Q1 turns on. Shoot-through current will flow.Add resistor in series with Q9 drainQuote from: Loden on May 15, 2025, 03:52:22 pmWith oscilloscope.
Help with my 7S BMS Circuit - Page 1
Forum section: electronics / projects

author: lja246
author_rank: Contributor
timestamp: November 22, 2022, 08:34:56 am
content: Hi all,I'm designing a handheld light that's battery powered using a 7s li-ion battery pack. I have attached an image of the current BMS circuit that I am planning to use. I created the circuit based off of datasheets for the IC's and I was wondering if someone could look over it and tell me if I am missing something or if it won't work because when ordering the PCB's they usually take a while to arrive and I'd rather ask for advice first before just experimenting and possibly wasting a lot of time.The max current that I am planning to draw from the pack is around 4 amps and it will be connected to a microcontroller that will monitor each cell anyway to provide diagnostic info and will cut the light if the overall voltage drops to low. Even though it will have a microcontroller attached I don't plan on having it control the cells e.g balancing.
help with obd 1  - Page 1
Forum section: electronics / projects

author: r
author_rank: Contributor
timestamp: March 14, 2014, 01:55:29 pm
content: I am after some info and hope that some one can help, I am doing a project on using the RASPBERRY PI and OBD 1. I am after the data sheets/technical spec for OBD 1 1997 nissan micra hope u lot can help as have a limited amout off time left to get it. I am trying to use a raspberry pi to read the binary data coming out the OBD port.from rikki
Help with obtaining M2M sim cards in the UK for hobbyist use. - Page 1
Forum section: electronics / projects

author: jusanother
author_rank: Contributor
timestamp: February 26, 2015, 05:40:02 pm
content: Hi,Has anyone got a any experience buying small quantities, (i.e one off) of M2M sim cards in the UK. I need one for a weather station project.All the web sites for M2M cards seem to extensively contain industry waffle and general padding BS. No prices. I have only found one quoting prices:http://m2msecuritysims.com/uk-m2m-sim-only-data/but they seem a little sketchy, TandC quotes different contract period to web site, paragraph numbers don't tie up, looks copy and pasted.Any others people have used ? good, bad, ugly, etc. ? I only need around 1MB a month and the lower the cost the better (£1-2 GBP would be good). No calls, no text, just data.I notice the newSpark Electronand may go for it if all else fails.Thanks. Cam.
Help with OP AMP Output - Page 1
Forum section: electronics / projects

author: dave_robinson_022
author_rank: Contributor
timestamp: October 15, 2021, 02:23:22 am
content: I have set up a basic circuit as shown. I am measuring voltage using differential input on a TLE2141 with a gain of 0.033. As expected I get the correct readings through various voltages up to 30V.However, when I try to change the voltage back to positive with a gain of 1 I seem to lose approx 68mV regardless of what the input voltage is. I can't for the life of me work out why this is happening?

author: David Hess
author_rank: Super Contributor
timestamp: October 15, 2021, 02:45:24 am
content: The input bias current of the TLE214 can be up to 2 microamps which into the 50 kilohm parallel resistance at the inverting input will produce an offset voltage of up to 100 millivolts.The TLE214 should be used with much lower values of resistance, however placing a 50 kilohm resistor in series with the non-inverting input will cancel out this error reducing it by about 20 times from the input offset current.

author: magic
author_rank: Super Contributor
timestamp: October 15, 2021, 06:18:03 am
content: You can also reduce it 100x by making the resistors 1kΩ or 2000x times by making them 1kΩ and putting 500Ω in front of IN+

author: dave_robinson_022
author_rank: Contributor
timestamp: October 15, 2021, 08:45:37 am
content: Awesome thank you.The original circuit came from a power supply design and the 100k resistors were to protect the inputs to the OP AMP should the current sense resistor and/or MOSFET short.Keeping this in mind I tried 10K and 330R which would still limit current to 6mV at 60V, and this worked. Oddly though there was a slight variation between 0.8mV at 15V to 5.7mV at 1V.I also tried 51K in series with ground as suggested and this fixed the error to within 1.1mV over the same range
Help with part identification - LED Momentary Pushbutton - Page 1
Forum section: electronics / projects

author: sdscotto
author_rank: Contributor
timestamp: June 12, 2012, 11:49:38 pm
content: Can anyone help identify this manufacturer/vendor?This is a green LED lighted momentary contact pushbutton.Thanks in advance!

author: free_electron
author_rank: Super Contributor
timestamp: June 13, 2012, 02:10:05 am
content: Schurter. Unmistakably the 's' in a square. Swiss company. Famous for fuse holders.

author: sdscotto
author_rank: Contributor
timestamp: June 13, 2012, 02:31:03 am
content: Thank you! I parametric and google searched myself silly looking for that switch!I was hoping for a direct replacement but after looking at their web page, it doesn't look like they make it anymore.Thanks again!scotto

author: codeboy2k
author_rank: Super Contributor
timestamp: June 13, 2012, 01:41:13 pm
content: I often use this page when I am looking at a logo I don't know. It's not complete.Schurter is NOT in there, by the way.http://freespace.virgin.net/matt.waite/resource/logos/index.htmmaybe we could all contribute on a wiki page here, and make our own logo database.
Help with pinout for a Rofin-Sinair SCx60 RF CO2 laser (with partial teardown) - Page 1
Forum section: electronics / projects

author: Another crazy Aussie
author_rank: Newbie
timestamp: July 08, 2025, 07:55:36 am
content: Hi everyone,I recently scored an old Rofin-Sinair SCx60 RF CO2 laser (now theLuxinar OEM 65iX) at auction (price was too good to resist), but while it came with its associated RF unit and cables, it didn't come with the control unit needed to operate the thingI couldn't find any manuals specifically for the SCx60. The new manufacturer Luxinar does have a decent manual but sadly doesn't list the laser or RF deck pinouts (they've got the user-facing pinouts of the control box butnotthe pinouts between the RF deck/laser and the control box).Does anyone happen to have an idea which pins on the laser head and RF deck are which? There's not a huge amount of electronics in both the laser of RF deck so it's probably a pretty basic interface (the SCx30 is mostly dumb analog so I imagine the SCx60 is the same), but it'd still be good to know which pins are which before I try powering it up.There's an interconnection diagram for an SCx30 laser on the forumhere, but unfortunately that model seems to have the control unit built into the laser whereas the larger SCx60 model seems to have the controller as a separate box (integrated with the 16kW 48V PSU). The SCx30 also uses what looks like a couple D-sub connectors whereas the SCx60 uses a single circular connector (there's two in the photo, but one has nothing wired to the other side). While I can probably hack it into a useable state, I'd rather operate it properly before I start ripping out and replacing bits...

author: Another crazy Aussie
author_rank: Newbie
timestamp: July 08, 2025, 07:58:51 am
content: And for anyone who just wants to look at laser art

author: Another crazy Aussie
author_rank: Newbie
timestamp: July 08, 2025, 08:00:05 am
content: And a bit of RF wizardry
Help with plasma cutter repair - Page 1
Forum section: electronics / projects

author: zupta82
author_rank: Regular Contributor
timestamp: December 06, 2020, 03:37:52 am
content: Hello everyone I figured I might get some hits from the more veteran guys on this forum here is a linkhttps://www.eevblog.com/forum/beginners/update!!-plasma-cutter-repair/

author: zupta82
author_rank: Regular Contributor
timestamp: December 06, 2020, 07:22:26 pm
content: Has anyone had trouble opening the link above that I posted , I clicked it on my iPhone and it gives me a 404 error

author: Gyro
author_rank: Super Contributor
timestamp: December 06, 2020, 07:29:25 pm
content: Quote from: zupta82 on December 06, 2020, 03:37:52 amPleasestop opening new threads on the same subject, this makes your third! You have plenty of responses on your other threads. If somebody can help you then they will already have seen them.

author: Simon
author_rank: Unknown
timestamp: December 06, 2020, 07:32:58 pm
content: Quote from: zupta82 on December 06, 2020, 07:22:26 pmwell that makes this thread doubly useless then so locked!
Help with Power Supply Noise Test - Page 1
Forum section: electronics / projects

author: RonFred2
author_rank: Contributor
timestamp: May 01, 2025, 10:48:28 pm
content: I am testing a few power supplies to determine which offers the best noise performance. First, I am testing my "known" good power supply on my test bench. But after testing it, the noise review does not seem that good. I seek help understanding my results and/or improving my test setup!Test Procedure:I set up my bench power supply (Keysight 36313A) for 12 Vdc and a maximum of 2 amps on output 2. I used coax cable test leads to connect to the scope's Channel 1 and 2 probes (MSO64B with TPP1000 1 GHz 10x Passive probes). I displayed the results of the two channels on the scope and the math channel for Ch1-Ch2. I was expecting results in line with the power supply performance factsheet. But my results, as shown in the scope photo measurement badges, are much higher.I then repeated the experiment with an 8-ohm 100-watt resistor and found that the noise results somewhat improved over the no-load results (opposite of what I expected).I have set the scope input channels to DC and 20 MHz bandwidth with no ground, Ch1 on the positive terminal, and Ch2 on the ground terminal for a "poor man's" differential test setup. I tried using an AC input, but the results seemed much worse.Do you folks think that these test results and this method will be useful in testing other power supplies - comparing them with this bench supply?Test ResultsKeysight E36313A Noise Test Result Summary:No Load Scope Differential (Ch1 - Ch2) MeasurementsVpp = 114 mVVrms - 20 mV1.5 Amp Load Scope Differential (Ch1 - Ch2) MeasurementsVpp = 91 mVVrms = 12 mVPower Supply DatasheetVpp < 5 mVVrms < 1 mVAttached is a segment of the Keysight datasheet showing noise performanceAttached are my test photos

author: mtwieg
author_rank: Frequent Contributor
timestamp: May 01, 2025, 11:34:59 pm
content: At a glance it looks like much of the signal power of the math trace is above 20MHz. If your intended measurement BW is 20MHz, why do you have horizontal scale set to 4ns/div?If the scope itself can't limit the bandwidth as required, you can make an external RC filter between the supply and scope.

author: RonFred2
author_rank: Contributor
timestamp: May 02, 2025, 09:15:24 pm
content: Thank you mtwiegI see your point. It looks like I was asleep at the sweep!I set up a few tests to ensure I don't repeat that mistake.Remedial ReviewTest Scope Results Waveform Frequency Generator1 / 4 ms/div * 2.6 div = 96 Hz1 / 10 ns/div * 5.2 div = 19 MHzEstimate Original Scope Horizontal Sweep Frequency1 / 4 ns/div * 4 div (estimated) = 62.5 MHzDesired Power Supply Noise Test Range20 Hz to 20 MHzNext StepRedo Power Supply RMS and P2P measurements on the scope using 4-ms to 10-ns sweep range
help with powerbank circuit - Page 1
Forum section: electronics / projects

author: micoud
author_rank: Newbie
timestamp: November 27, 2020, 01:05:28 pm
content: Hello friend , i would to make a custom powerbank ... this is the schematichttps://pasteboard.co/JChc1yR.pngi have received the pcb from jlcpcb (with smt service) but not works with batteryit seems to works only with usbc cable connected (charge the battery , power on the raspberry)Can you help me?
Help with product idea.  - Page 1
Forum section: electronics / projects

author: dominic.rose141
author_rank: Newbie
timestamp: May 24, 2015, 12:29:39 pm
content: Hi all, firstly want to shout out to Dave to say what a great YouTube channel.I'm new to the forum and wish to gain some helpful advice and information on an idea I have.I currently own a new company in which I make custom vivariums for reptiles.A couple of weeks ago a customer came to me asking for a thermostat that could control certain features.Currently from my understanding the features he is wanting, isn't a product. So I thought I'd make my own.New to EE I bought a arduino and learnt some code. Currently have a semi functioning breadboard and script.The next step is where I need help.I want to draw a schematic and PCB layout so that I can design the finished product and get some PCBs made. To hopefully throw it on kickstarter.The features are.A simple looking box with pluggable thermo probes and the option of wireless ones.It needs to power 240v ceramic heat bulbs, light limiting heat bulbs and heatmat/heat wire. Now I was going to have theses three as different products.The market currently calls theses. Pulse proportional, dimming and on/off thermostats.I currently only have a prototype for on/off using a SSR breakout for the arduino.The system also needs 12v dimming output for led strip lighting. As well as 12v fans.Of which I have figured out using a MOSFET.I was hoping to view the current and set temps using a phone app and Bluetooth. As well as having the option for a WiFi module which you'd use the Bluetooth to connect to. Which would let the device tweet the current temps.The lights and temps also change depending on time. Currently using a RTC arduino breakout.By now you might have figured out my problem. I have so many arduino based products. How do I make a schematic for a product without having to buy theses.Also if anyone has any advice on the Bluetooth, WiFi and 240v control for the dimming version as well as the 240v pulse proportional version.I hope I've given enough info if not please let me know and I'll do what I can.Thanks in advance.Dom.

author: dominic.rose141
author_rank: Newbie
timestamp: May 24, 2015, 01:01:15 pm
content: Thank you for the reply.I'm currently using a TIP-120 to do the pwm for the 12v LEDs and fans. Well the arduino is doing the pwm.I was going to buy a ESP8266 serial WiFi transceiver for the arduino and a serial BT RF transceiver module RS232. At least to begin with to write the code.
Help with RBA14B Diode Brige - Page 1
Forum section: electronics / projects

author: dmmguy
author_rank: Contributor
timestamp: January 19, 2024, 05:11:21 am
content: Hi there,Does somebody know where I can find the datasheet for RBA14B Diode Brige.It is the same that the one in this link:https://www.aliexpress.com/item/2047531365.htmlThanks a lot
Help with simple test of CC LED driver current limit? - Page 1
Forum section: electronics / projects

author: carl0s
author_rank: Unknown
timestamp: September 12, 2019, 11:15:00 am
content: Hi. I have these nice tiny boost LED constant current drivers. Perfect for lighting panel backlights from small microcontroller projects.As with most of them, there's a feedback resistor to set the current limit.What is an easy way for me to check what this is actually doing without burning up LEDs? Obviously I will connect my ammeter, but, the question is, can I just stick some big resistors in as the load, or will I not see the correct current thing? Will the current that I observe with a resistor load be the same limit that the driver would set for a series of LEDs ?This is the driver chip:http://pdf.dzsc.com/20090603/200903181710291452.pdfThe datasheet seems to suggest that a 1R resistor would set it to 100ma. Which makes sense and tallies with a Diodes Inc driver that I have previously used, where 5R resistor = 20mA. However the supplier of the board itself, say it is set to 300ma, yet there's a 1R resistor fitted. I'm inclined to trust the IC datasheet and say that the board is set for 100mA, but I'd like to test it with a suitable load.Thanks
Help with SMD battery or supercap replacement. - Page 1
Forum section: electronics / projects

author: georgian
author_rank: Regular Contributor
timestamp: July 07, 2025, 06:14:56 pm
content: Hello,Anybody know what kind of batery or super capacitor is this and where I can get an replacement?Many Thanks.

author: georgian
author_rank: Regular Contributor
timestamp: July 09, 2025, 07:19:00 pm
content: I found this super capacitor. It looks quite the same. I hope it works.https://www.reichelt.at/at/de/shop/produkt/supercap_smd_kondensator_0_22_f_3_3_v_6_8_x_1_4_mm-338051?PROVID=2807&gad_source=1&gad_campaignid=20946573290&gclid=CjwKCAjwprjDBhBTEiwA1m1d0oJi_Y7BFZ4055m4AuOcbv2jJhqG2nV56oMCbYJZMwAhFhJPf1ToSRoCGWsQAvD_BwEhttps://cdn-reichelt.de/documents/datenblatt/B300/STARCAP_SPEC_SHEET_DMS3R3224RF.pdf
Help with SMPS - Page 1
Forum section: electronics / projects

author: SashPlane
author_rank: Newbie
timestamp: November 21, 2024, 06:12:20 pm
content: Hello,I'm looking for help with what TR5 and TR6 are doing. I'm not quite sure as what they do ?? The Problem is TR5 BF 487 has gone Obsolete and we can no longer get.I tried a MPSA44 but it does not work like the BF487. When you use the MPSA44 , R41 Gets Supper Dupper HOT(Technical Term) SMPS works but TR5 HOTthe BF487 had a gain of Aprox 50 ish , the MPSA gain of 1Input voltage is 90 - 260 vac , outputs: 5v and 12vThanks for any help

author: Slh
author_rank: Regular Contributor
timestamp: November 21, 2024, 06:24:34 pm
content: Tr5 and tr6 are making a linear regulator to supply the controller IC. You should be able to substitute anything with similar voltage and power rating and gains. The current won't be very high.

author: xavier60
author_rank: Super Contributor
timestamp: November 22, 2024, 06:24:52 am
content: For an undamaged MPSA44 to have a current gain of 1, is likely due to E and C being swapped.

author: SashPlane
author_rank: Newbie
timestamp: November 22, 2024, 12:01:31 pm
content: OH Man...... you nailed itNow I feel like a Co-op again....lolThanks a bunch

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 24, 2024, 02:09:49 am
content: Hi!Let me be curious: who drew such a proper diagram with common bus wiring?

author: SashPlane
author_rank: Newbie
timestamp: November 24, 2024, 02:57:30 am
content: this drawing was done long before I took over this...the original was Hand drawn on vellum and then later converted to PDF.I still even have the Vellum PWB @ 4x F Size Artwork layout... of course i also have it converted to Gerber now also.Tape layout with stick-on pads - Good ole days of layout

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 24, 2024, 04:45:33 am
content: I have not yet seen that the current sense resistor at MOSFET source being bypassed by a capacitor.Is it possible to obtain traces from the current sense resistor at maximum load with C28 capacitor and without it?PSDo you have any transformer data? Dimensions, core material, air gap?
HELP WITH SPECS FOR TRANSFORMER - Page 1
Forum section: electronics / projects

author: soubitos
author_rank: Frequent Contributor
timestamp: January 03, 2018, 10:54:20 am
content: This is a transformer i got out of an old Abler VT-625P off-line UPS...I would like to use it for a bench power supply but got no idea how to use the windings.I am almost sure the secondary (low voltage) side is the yellow-orange-red cables but what on earth are the three cables in the primary for (white-blue-black) and where does the 220VAC go to?Transformer label reads VT-625P/220-230V KXP 0411 if that helps at all

author: duak
author_rank: Super Contributor
timestamp: January 03, 2018, 10:13:39 pm
content: I think the 220/230 VAC winding is two of the red, yellow and orange wires because they are smaller diameter, lesser current. The larger wires are lower voltage, higher current.Measure the resistance between the red, yellow and orange wires to find which is the highest. If you have low voltage AC available for test (eg. less than 30 VAC or so) apply it to those two wires and measure what the voltages are between the three large wires.If there are no major sparks, flames or smoke then try applying the full line voltage to the first two wires and measure what the voltages are between the three large wires. Note, for safety's sake wire a 20 to 75 watt incandescent bulb in series with the line voltage to limit current first.Cheers,

author: strawberry
author_rank: Super Contributor
timestamp: January 04, 2018, 03:07:41 am
content: Check with ohm meter. High resistance(~50..2000ohm) windings will be for higher voltages.
Help with STCS2A LED linear driver - Page 1
Forum section: electronics / projects

author: aiq25
author_rank: Regular Contributor
timestamp: July 12, 2014, 07:00:50 am
content: Hello. I'm trying to design an LED driver using the STCS2A chip from ST Micro. I would like to use this chip primarily because of it's size. I'm hoping with the bigger size I will be able to solder the chip myself. I'm designing a PCB using Eagle CAD and I just wanted to post my schematic to get some feedback on it since I'm still a newbie in electronics. I'm still learning how to use Eagle CAD, so I don't have the PCB ready yet. I had to add the chip package and symbol to Eagle CAD. I'm not sure if the chip package is modeled correctly, so I plan on printing out the PCB and checking the sizes before trying to get a PCB made.Attached is my schematic. I'm thinking of adding a fast-acting fuse to the LED+ line to protect the LED's from high current. I'm planning on using some 10W multichip LED's to test the board. The multichip LED's have a Vf of 9-12V and If of 1050mA. I'm planning on using 3 LED's per driver. I have 6 LED's I would like to use. The DC power supply I'm thinking of using the Genssi 36V DC 9.7A 350W Regulated Switching Power Supply (not sure if this is a good choice, the reviews on Amazon look positive).Ultimately I will be using these drivers for an LED lighting system I'm building for my saltwater aquarium. I will also replace the LED's with Cree or other quality LED's after testing the system. I ordered some Chinese LED's from eBay to do test on and see if the system works.I know I could buy the drivers and power supply but I would like to build my own driver to get some experience in getting a PCB made and in electronics in general.

author: mij59
author_rank: Frequent Contributor
timestamp: July 12, 2014, 07:48:43 am
content: Hi,The STCS2A is a linear regulator, dependent on the total Vf you'll need to dissipate at lot power.Worst case scenario: Vf =9 V, total voltage across the led's 27V , the voltage across the regulator is 9V.Power dissipation of the STCS2A (9V*1.05A) = 9.45 W, so you'll need a heat sink.If Vf =12V the regulator won't work because the voltage across the regulator needs to be 0.58 V (typical) or more.You may have a look at switch mode led drivers

author: aiq25
author_rank: Regular Contributor
timestamp: July 14, 2014, 04:11:40 am
content: Quote from: mij59 on July 12, 2014, 07:48:43 amI never really considered the power dissipation of the chip due to the total voltage across the LED's. I guess I will have to switch to a switch mode driver. I think I will go with the LM3406HV. The extra voltage input will be good, in case in the future I want to add more LED's to the array. I will need to change the schematic and the design. Thank you for replying.
help with TEC driver - Page 1
Forum section: electronics / projects

author: apraxophobia
author_rank: Contributor
timestamp: November 22, 2024, 02:15:54 am
content: Working on a basic TEC driver.Architecture shown in diagram- high side fet, sense resistor, before an H bridge.The parameters are nothing crazy. It's designed for 3A, 12V. Everything is in more-or-less working order; differential amp works well, setpoint, H-bridge, etc. There's a low-pass on the gate for stability, but that's not relevant (I think).It works well up to ~.5A-- Vset and Vsense are dead on-- above which it completely and suddenly overshoots the setpoint, maxing out the current. I've directly probed the op amp inputs while this happens; bizarrely, V+ (Vsense) > V- (Vset), and yet the op ampcontinues to decrease!?!?until it hits 0V (the bottom rail). It won't move again until the setpoint moves back to zero.Any ideas for what could cause this? I've replaced op amps, double checked gate capacitance, etc., and everything seems fine... I am completely out of ideas.

author: coppercone2
author_rank: Super Contributor
timestamp: November 22, 2024, 03:05:47 am
content: I recommend using this circuit insteadhttps://www.homemade-circuits.com/wp-content/uploads/2022/12/single-door-refrigerator-circuit.jpgless troublehttps://www.rigidhvac.com/mini-compressors

author: beenai2018
author_rank: Contributor
timestamp: November 22, 2024, 04:19:17 am
content: Im not sure if you had a chance to see this .https://www.ti.com/lit/an/snoaa72a/snoaa72a.pdf?ts=1732198622716It looks like the current is measured in line with load and is bidirectional for the implementation in the paper.

author: coppercone2
author_rank: Super Contributor
timestamp: November 22, 2024, 04:25:39 am
content: it also has a true H-bridgeThe first schematic is drawn 'funny'. I don't know what is going on there.If you have a odd circuit stability problem like this, chances are you don't wanna put a block diagram. A block diagram is for a working system. Why should we play mad libs with your block diagram?Things like your component choice might be important. I love how the power transistor is nameless and the H-bridge is nameless and some how the feedback loop is 'probobly not important' for a f eedback control circuit.

author: Andree Henkel
author_rank: Regular Contributor
timestamp: November 22, 2024, 01:07:09 pm
content: @ apraxophobiaYour control amplifier seems to be connected wrong:the control voltage needs to be at + input, the sense via resistor to - input,thus you get negative feedback around your control loop.additional you need a capacitor between output and - Input of your control amplifiersuch you get an integral regulator consisting of cap, amp and resistor to - Input

author: apraxophobia
author_rank: Contributor
timestamp: November 23, 2024, 03:20:36 pm
content: Are you sure? If Vset<Vsense (current too high), output increases, closing the fet, decreasing current? Maybe I am misunderstanding.
Help with this pulse stream encoding - Page 1
Forum section: electronics / projects

author: Back2Volts
author_rank: Unknown
timestamp: November 06, 2017, 03:01:57 am
content: I am trying to reverse engineer the transmission of an RF remote control for a sprinkler station. I have setup an RCR-315-RP receiverhttp://www.mouser.com/ds/2/238/rcr-rp_um-8864.pdfon a breadboard with a couple of trimmers to adjust the levels of the analog and digital outputs. Both outputs go to the scope and to a cheap LA with SIGROK. I use the remote control to turn a given valve# on (for a time preset in the remote) or off.I have captured the transmissions with PulseView, and I am a bit puzzled with the results. A command results in- Six pulse trains, which at first sight appear identical, separated by 220 milliseconds LOW.- The trains have a fix number of pulses.- There are three distinct pulse shapes.- Pulses start with a HI for 1 millisecond, followed by LO for 6, 10 or 14 milliseconds. ( Referred below as A,B,C )I have attached a screen shot of PulseView. Here are the sequences for zones 1, 2, 3, 4, 8, for 1 minute, ON and OFF:Z1 ON: ABBBBBBBBBBBCABBCABBBBCABBCZ2 ON: ABBBBBBBBBBCABBBCABBBCABBBCZ3 ON: ABBBBBBBBBBCBABBCABBBCBABBCZ4 ON: ABBBBBBBBBCABBBBCABBCABBBBCZ8 ON: ABBBBBBBBCABBBBBCABCABBBBBCZ1 OFF: ABBBBBBBBBBBCABBBBBBBBCABBBZ2 OFF: ABBBBBBBBBBCABBBBBBBBCABBBBZ3 OFF: ABBBBBBBBBBCBABBBBBBBCBABBBZ4 OFF: ABBBBBBBBBCABBBBBBBBCABBBBBZ8 OFF: ABBBBBBBBCABBBBBBBBCABBBBBBI know very little about ASK, but I don't think this is it because of the long LOW segments. I do not see how the underlying clock could be 1KHz, but I may be missing something.I would appreciate any tips to proceed or insights on what encoding protocol this might be.
Help with TIA output for SiPM sensor - Page 1
Forum section: electronics / projects

author: rsinghap
author_rank: Newbie
timestamp: July 18, 2023, 07:45:11 pm
content: Hello, I'm designing a transimpedance amplifier for a SiPM (Silicon Photo Multiplier Array Broadcom AFBR-S4N44C013) sensor. I want the output voltage to range between 0 and 3.2 V max so I can input it into an Arduino.I'm using a 36 V bias voltage from a custom 3.2 V to 36 V booster.The main issue I'm facing right now is that even though the output of the op-amp varies proportionally with the brightness, the range is in the millivolts (20 - 100 mV) when the power is on and 0 - 45 mV when the power is off. Changing the feedback resistor R5 to 100k fixed the opamp output at around 0 V. Any suggestions for how to fix this and amplify the output to the desired range?I've attached the schematic. Also, the buffer section of the circuit is not being used right now. If you have any suggestions for how to fix the issue that the buffer is powered by 3.3V but receives the full 36V, that would help too.Here's the datasheet of the SiPM:https://docs.broadcom.com/doc/AFBR-S4N44C013-DSThank you.

author: paul@yahrprobert.com
author_rank: Regular Contributor
timestamp: July 18, 2023, 09:17:42 pm
content: Didn't we go over this already? You have a positive signal going into your inverting op-amp stage, which now has no bias on the + input, and has no negative supply. So you're asking the op-amp output to go negative, but there's no negative supply, so it can't.

author: moffy
author_rank: Super Contributor
timestamp: July 18, 2023, 11:26:24 pm
content: Quote from: paul@yahrprobert.com on July 18, 2023, 09:17:42 pmYes and no correction to the schematic about the bias voltage amplifier, even though he says he isn't using it. If it's there it should be corrected.

author: Someone
author_rank: Super Contributor
timestamp: July 19, 2023, 12:22:57 am
content: Originating threadhttps://www.eevblog.com/forum/projects/need-help-with-tia-circuit-for-sipm-sensor/msg4899116/#msg4899116
Help with understanding the regulator on the Wemos D1 R2? - Page 1
Forum section: electronics / projects

author: msmyrk
author_rank: Newbie
timestamp: October 01, 2018, 12:58:52 am
content: Hi,I'm looking at a schematic for the Wemos D1 R2 (https://www.openhacks.com/uploadsproductos/wemos-d1-r2-schematic.pdf).As I understand it, Vin is somewhere up around 12V, so they've got some sort of pre-regulation on there to reduce the power dissipation of the linear regulator.The 3.3V regulator has a 250mV dropout, and that Q3 transistor has a 0.4-1.0V gate/source threshold. My guess is that this will keep the input to the linear regulator at somewhere between 3.7 and 4.3 volts, but I can't for the life of me work out the mechanism for it:- Could someone possibly explain the mechanism by which the opamp switches the transistor to get the right voltage?- Assuming my understanding is right, would this lead to a particularly noisy 3.3V line? Wouldn't the opamp keeping wanting to switch the transistor off until the regulator starts dropping off before switching the transistor back on, causing ripple of some sort?Cheers,Martin.P.S. I'm new here, so let me know if there's something I could improve about my post, or if there's a better place to put it.Edit: and off to an awesome start, I thought I had posted this to the Beginner forum (sorry mods)

author: bson
author_rank: Unknown
timestamp: October 01, 2018, 02:02:02 am
content: Q3 is just to switch between +5V derived from VIN and USBVCC - if the former isn't present it will feed USBVCC onto the +5V rail. IC1A is used as a comparator.

author: msmyrk
author_rank: Newbie
timestamp: October 01, 2018, 02:14:33 am
content: Oh, of course!Thank you both - makes sense to me now.
Help with Universal LVDS Driver Board MT561-B - Page 1
Forum section: electronics / projects

author: Spoogepk
author_rank: Newbie
timestamp: September 16, 2018, 07:25:23 am
content: Hi every one, I Had an old LCD lying around so I thought I’d give it a shot and see if I can turn it into a working monitor. So I ordered this inexpensive universal driver board MT561-B v2.1, unfortunately I could not get it to work properly. Please read below of what I have done so far. Any input will be highly appreciated.LCD panel: (LG) LP121X04-C2K2Specs: 12.1 1024x768 XGA (RGB) 6-Bit 1-Ch LVDS CCFL1. Set the board to 3.3V and resolution mode: 23 i.e. 1024x768 6*2-1 (I don’t understand what the 2 is for) I needed 6 Bit 1 Ch.2. Now the LVDS connections over on the driver board side has odds and evens, somewhere on the forums I read that it should be hooked up to the odd pins and leave the VCC_EDID, CLK_EDID, DATA_EDID alone as the board does not use that feature. I tried the following connection pairs (refer to the pictures).3. I have identified the pins on both ends, since I didn’t have the 20Pin unique connector I soldered the pins on the board directly, I double checked all connections for shorts. Pins start with A1M/A1P which I hooked up to O zero (-)/O zero (+) upto A3M/A3P…O2-/O2+. I also swapped the pins arrangement starting from A1M/A1P = O1-/O1+ upto A3M/A3P…O3-/O3+. And the clk-+ closer to Odd pins.All I get is a white line and a black screen (see image), no display. I was wondering if I missed out something. I might be close to something or totally far off. Can someone check this out for me and give an expert opinion please?Datasheet Link:(LG)LP121X04-C2K2.pdf

author: Spoogepk
author_rank: Newbie
timestamp: September 25, 2018, 11:20:40 am
content: No one around to help?
Help with USB extension cable - Page 1
Forum section: electronics / projects

author: alah
author_rank: Contributor
timestamp: May 07, 2020, 10:26:42 pm
content: Hi ALL; I sourced an USB ext, measures 4.5m. so with my USB mouse its about 6.5m.Works fine but if I use the ext with my smartphone it doesn´t.I know little about USB comm. but some say that the signals degrade over distancewhich I can understand. Some say that it works with Ethernet cable, which I haven´t tried yetDo You think it could be due to USB 5v supply?Why would the phone need it, it has it´s battery?If so, what do You think about the attatched circuit? It´s a youtube video, THANKs.OH, please don’t suggest self powered USB hubs or other gadgets, it´s IMPOSSIBLE for me.The following is a link to a video, do you thinkit works, helps? THANKsAdd_extra_power_to_any_USB_cable(youtube.com)

author: pigrew
author_rank: Frequent Contributor
timestamp: May 07, 2020, 10:38:14 pm
content: A standard USB cable is limited to 5m (seethis website). Latency (the amount of time it takes for the signal to get from one end of the cable to the other) actually is a major factor.Another issue, especially with a smartphone, would be voltage drop. The cable has some series resistance, and if the phone tries to start charging, it may pull the voltage lower than the minimum (about 4.5V).The YouTube video way probably isn't a good idea, though with better construction could work. Cutting the shield will introduce noise to the USB signal, and the diode will drop maybe 0.6V (more than USB spec allows).What to suggest? A USB hub (preferably powered). A long USB cable (not extension may work).Is the total USB cable length more than 5m?

author: coromonadalix
author_rank: Super Contributor
timestamp: May 08, 2020, 12:00:36 am
content: Why dont you use an usb wireless mouse ?? You have so many usb plug converters to fit almost everything on this earth ?And if you connect a mouse to your smartphone why not use a bluetooth mouse ?
Help with USB extension cable - Page 1
Forum section: electronics / projects

author: alah
author_rank: Contributor
timestamp: November 01, 2019, 03:36:50 pm
content: Hi AL; I finally got a BLU smartphone and by wifi I receive internet from my neighbour. The problem is that I have to move my desktop , monitor,.... to the balcony, which is really a deposit. So I bought a USB 5 meter extension but it doesnt work; found out afterwards that USB2.0 comm has 5m limit. Googled and found that with ethernet cable some people have solved this problem. I tried but the only device that works is my mouse. If I plug my USB to UART converter " device not recognized" When I connect my phone I dont get any error message but its not listed in devices and printers. Some say that I should use aself powered USB hub. If its due to the USB 5v power, can I disconnect it and try with an external 5v supply?Thanks, Alberto.

author: Hughieandrolf
author_rank: Newbie
timestamp: November 01, 2019, 03:59:27 pm
content: Hi. Ive been using one of these for various things over the years.https://cpc.farnell.com/pro-signal/psg08427/lead-usb-2-0-repeater-5m/dp/CS14520Works with a printer, plotter, arduino, keyboard, but not tried anything else.

author: viperidae
author_rank: Frequent Contributor
timestamp: November 01, 2019, 10:22:53 pm
content: A USB cable longer than 5m needs an active repeater. Like the one in the above post, it effectively has a single port USB hub on the end of it.If your cable doesn't show up as a USB hub, it's not an active cable.

author: alah
author_rank: Contributor
timestamp: November 28, 2019, 10:18:48 pm
content: Thanks, but our basic salary ere is 5 bucksA MONTH5n max, is that due to 5v power loss over the cable? If so can I disconnect USB 5v and use an external 5v supply? Any risk? Or is it due to loss of comm signals integrity? Any amplifier circuit? Thanks, Alberto.
Help with VEML6075 - Page 1
Forum section: electronics / projects

author: firstcolle
author_rank: Regular Contributor
timestamp: December 20, 2016, 11:01:09 am
content: Hi,i'm playing with a VEML6075 UVA/UVB sensor from vishay. i'm able to read out the raw data from the sensor but i have some doubt about the equation for convert the raw data into uva/uvb in uW/cm^2.nothing is reported in the datasheet. and the application note (linkhttp://www.vishay.com/docs/84339/designingveml6075.pdf) only reports the UVI calculation method..anyone could help me?thanks
Help with Vintage IC identification - Page 1
Forum section: electronics / projects

author: jsterEEvblog1
author_rank: Newbie
timestamp: May 09, 2025, 04:17:04 am
content: Hello,I have an old IC with the following markings and I don't know what type it is? Google search yields "nothing" and I hate to bother distributors because I just want to know what this chip does:DT μL909459F 7014The Mu in front of L909... looks like a backwards 4 so I'm guessing it's a Mu symbolLooking forward to reading what anybody might find...Thanks in advance

author: moffy
author_rank: Super Contributor
timestamp: May 09, 2025, 05:32:26 am
content: Post a photo of the chip magnified.

author: srb1954
author_rank: Super Contributor
timestamp: May 09, 2025, 05:50:16 am
content: Quote from: jsterEEvblog1 on May 09, 2025, 04:17:04 amThis is a Fairchild part number, possibly something from their DTL (diode-transistor-logic) product line. The date code (7014) indicates that is is from 1970.I can't find a reference to this particular part number in Fairchild catalogs dating back to 1975 so you will need to look for archived versions of older catalogs dated prior to 1970.

author: HalFoster
author_rank: Frequent Contributor
timestamp: May 09, 2025, 11:44:34 am
content: The DTuL 9094 is a dual J-K flip flop in a 14 pin package - the last two digits, "59", indicate the temperature range which would be 0-75 C

author: jsterEEvblog1
author_rank: Newbie
timestamp: June 05, 2025, 10:34:18 pm
content: Oh maan,,, this is great! Thank y'all so much. This is very helpful. Now off to study how this thing works in the loop of its larger circuit.And if it breaks I know what to replace it with now. I was really dreading popping this guy out of its DIP-14 socket,,, praying the pins didn't tear like foil,,, ufta. All worked out fine.Thanks again!!

author: bostonman
author_rank: Super Contributor
timestamp: June 06, 2025, 02:22:02 am
content: It may still be nice to post a photo for anyone who comes across this thread in the future.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: June 06, 2025, 03:03:09 am
content: Quote from: bostonman on June 06, 2025, 02:22:02 amI second this recommendation.Edit; DTL logic, you have got a museum piece in your hand, literally!
HELP With VOX AC100CPH - Page 1
Forum section: electronics / projects

author: angelothewolf
author_rank: Contributor
timestamp: May 11, 2013, 06:08:33 pm
content: http://www.ampix.org/albums/userpics...x_AC100CPH.pdfHi everyone!! ive got this VOX AC100CPH wich suffer some of those ^worst than before^ repairs.the amp came up with a very low output and stuck in the dirt channel. some hours later i get the schem and i realise that the TCN207 - CON7 / TCN9 - CON9 connections were inverted, so, the TCN9 with the TCN207 & the CON7 with CON9.after connecting everything in the right way the amp came to life again, sounds loud and the channel switch does his job too. BUT! an intermitent loud poping sounds appeared. so, its being difficult to get to the source of the POP. i try with new valves and the problem persist, all the voltages on the schem are normal. i think its an preamp issue couse trhough the return the pops goes away.today i got an oscilloscope so a little tips would be very appreciated!!

author: angelothewolf
author_rank: Contributor
timestamp: May 12, 2013, 03:50:54 pm
content: anyone__???

author: SeanB
author_rank: Super Contributor
timestamp: May 12, 2013, 04:18:31 pm
content: IC209,204 looks like a good candidate for having been crisped by 200V on the input, from the reversed connectors. Capacitors C205,206,217 are also candidates for having broken down. Disconnect con7 and see if the noise goes away ( output will go away as well, but the click should go as well) and if so do a blanket replacement of the components.

author: angelothewolf
author_rank: Contributor
timestamp: May 13, 2013, 02:54:38 pm
content: Quote from: SeanB on May 12, 2013, 04:18:31 pmdisconnect con7 and the noise remains the same, disconnect con7 and con9 and the noise still there. that means that the problem is not in the preamp stage>? when i disconnect CON16 the noise goes away!...when i pull out the first pre tube the noise disapears too....thanks for the replies!!
Help with wireless power, as well as power supply design - Page 1
Forum section: electronics / projects

author: Aerotusk
author_rank: Newbie
timestamp: November 07, 2017, 08:03:58 pm
content: I'm working on a project for school that will resemble this:Each of the tubes draws around 3 or 4 milliAmps at 140 to 150V, peaking at 170V for the strike voltage. Since I will be needing 16 of them, I had a few questions about how to power the entire thing.My first question is with the wireless power transfer to the tubes. I don't know too much about how to go about it, but I have come up with a few ideas.1. I was thinking I could pulse 150V through the coils, using a 555 timer to control the pulses, and a MOSFET to translate it to a higher voltage. The problem I had when I tried this at 10V was that the MOSFET got really hot, even when only powering an LED. I read some places that I was not using a high enough voltage on the gate of the MOSFET, and that I needed either a logic level MOSFET, or a bootstrap circuit. However, the logic level MOSFETs I looked at only had 30V max gate-to-source voltages, which, if I understand the datasheet correctly, means that I can only step up the voltage by 30V max.2. Another idea I had was to run around 10V through the transmitter coil, and have the receiver coil have around 15x as many turns as the transmitter. I'm pretty sure this would work (in theory), but I wanted to get the opinions of people with more experience.3. My last ditch option would be running 10V through the transmitter, and receiving it through a receiver with the same number of coils, then stepping up the voltage with a circuit inside of each piece. The problem with this is that it is a whole lot more work, and a lot more points of failure. (Here's the circuit I would use to do that:http://www.instructables.com/id/High-Voltage-Power-Supply-for-Nixie-and-Valve-Tube/).My second question pertains to powering the entire board:If I were to do my first idea, my original plan was to use the circuit linked above. However, this circuit drops dramatically in voltage and gets really hot when powering more than 4 tubes, and sometimes ends with a release of magic smoke. I feel like the dropping in voltage would be bad, since pieces get removed from the board as time goes on, so towards the end of the game it would be supplying over 200V to each of the tubes.1. Instead of using this circuit, would I be able to use a small transformer to take the 120V AC from the wall, and take it to around 150V, rectify it, smooth it with a capacitor, and run it through the MOSFET? I understand if this is a terrible idea, as I do not have much experience designing power supplies.2. If the above method wouldn't work, would running multiple of the aforementioned circuits in parallel work, so as to increase the max current?I have a few months to work on this project, so I am willing to take my time to get it working well. Any help is appreciated!Thanks in advance.
Help with wiring TIP31 transistor to run LED's on subwoofer? - Page 1
Forum section: electronics / projects

author: daleumad
author_rank: Newbie
timestamp: March 22, 2012, 08:14:18 am
content: I am wiring LEDs to my subwoofer to sync in beat of the music, to stop the bulbs from blowing, i am thinking of wiring a TIP31 transistor to it and plug in RCA and 12v in to run it using a rca out to the actual amp,in the attached picture please make sure i got all the wiring right and tell me if it would workhttp://i1245.photobucket.com/albums/gg589/daleumad/asdfghnh.pngid get a bigger picture but it wouldnt let me, just use like browser zoom or open in paintand sorry if this is in the wrong sectionedit:also should the LED's run in a series or parallel?

author: divelectservices
author_rank: Contributor
timestamp: March 23, 2012, 03:15:33 pm
content: ummmm....