hybridfree/eevblog-posts huggingface dataset:
How to switch 7kV to GND ? ( smd components ) - Page 1
Forum section: electronics / projects

author: smokeyjoe11112
author_rank: Newbie
timestamp: April 21, 2023, 05:31:06 am
content: I have an application where I need to switch the output of a voltage multiplier multiplier circuit generating 7kV to GND. Previous design switched 2kV to GND by stacking 3 x photo triacs ( VOT8024AM-VT ). The problem with switching 7kV is that the dv/dt over the triacs is too large causing them to trip prematurely. Even stacking 10 of them does not work. Any suggestions ? I have a height limit of 3.5mm which is a constraint complicating things further. Any suggestions would be greatly appreciated !

author: daqq
author_rank: Super Contributor
timestamp: April 21, 2023, 06:02:38 am
content: Try searching for "high voltage cascode".

author: smokeyjoe11112
author_rank: Newbie
timestamp: April 21, 2023, 06:58:20 am
content: Thanks this is interesting.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 21, 2023, 07:48:45 am
content: Stacking Optoisolators are going to be a problem as you need the 7kv ratingIxys do a 4.5kV MOSFET - could use two of these with a photovoltaic isolator or transformer to drive the top one.https://www.digikey.co.uk/en/products/detail/ixys/IXTT02N450HV/3737633A bit more than 3.5mm height but could you maybe the through-hole version and mount it in a cutout in the PCB ?Depending on your switching time requirements, it may be doable with a string of HV MOSFETS and capacitive level-shifting

author: jonpaul
author_rank: Super Contributor
timestamp: April 22, 2023, 10:09:33 pm
content: triggered spark gap,EG&G

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 22, 2023, 11:13:06 pm
content: Quote from: jonpaul on April 22, 2023, 10:09:33 pmMaybe a small xenon flash tube ? Not sure it will hold off 7kV though, and may be hard to find a low-profile trigger transformer.

author: jonpaul
author_rank: Super Contributor
timestamp: April 23, 2023, 06:10:03 am
content: mult crowbar use 7 kV spark gap, non triggered.try EGG, Siemens, CP CLARE, TTI. not cheap!Jon
'Loading' of a pin of an IC when running simulations? - Page 1
Forum section: electronics / projects

author: Yamin
author_rank: Frequent Contributor
timestamp: May 17, 2020, 10:19:53 pm
content: Hi guys,Random question, but it's been something that I have been wondering for sometime.I been trying to simulate the control circuitry for the 'mode' control function of the TDA8924 amplifier chip. I have to assume a value for the 'load' of that particular pin. In this case I use a 100K resistor. This is the only way to figure out what the voltage at the pin would be due to the external components.So my question is that is there a certain value I should be using for this pin 'load'? Different values for different kind of pins?Maybe a hint given on the datasheet? I can think of other instances where I might encounter the same issue, with different ICs I mean.Thanks in advance for the help
How to tent a few vias - Page 1
Forum section: electronics / projects

author: mriPaul
author_rank: Contributor
timestamp: May 30, 2020, 11:19:15 pm
content: I had a 4 layer PCB made and decided not to tent the vias. Now under an FFC connector, I get unwanted contact. I am getting new boards with tented vias made but it will take about 9 days due to the 4-layer design. Is there a quick fix I can use on a test board (today)? I was thinking about fingernail polish but it may be too thick. Any thoughts...

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 30, 2020, 11:23:56 pm
content: Preferably a high temperature enamel, legit soldermask stuff especially. Which isn't crazy or nasty, it's readily available, and sets with a UV LED flashlight.Also polyimide tape, which is probably still too thick. Nail polish is fine if it doesn't melt under soldering heat, which... I'd be weary about. Try it, see if it makes a mess. It may go on too thick, straight from the bottle yeah, but that's easily fixed with a little solvent, e.g. acetone, ethyl acetate.Spray paints of various sorts; maybe a high temperature one from the hardware store. Hm, beware of possible conductivity in black or metallic types I guess? Most should be ok though. Doesn't need to be the super temp enamel/ceramic kind, just something that doesn't melt as easily.Tim

author: mriPaul
author_rank: Contributor
timestamp: May 31, 2020, 01:08:00 am
content: Thank you very much. I like the high temperature paint idea. What happened is I have a via too close to a pad. There was no solder mask bridge between the two. The pins are .05mm spacing. My usual soldering method is to drag a solder blob over all the pins and solder wick if the solder spans two pins. I will try single pin soldering. Is that possible for this spacing?
How to test Ground Probe Circuit Board? - Page 1
Forum section: electronics / projects

author: JamesArthurHof
author_rank: Newbie
timestamp: March 20, 2021, 10:36:38 pm
content: I am an industrial electrician. I would like to start bench-testing these Ground Probe circuit boards. I tried setting something up, yet need help. The inputs on the board are wired to plunger switches that ground out on steel parts in a press—a part present indicator. The board’s outputs are wired to a Modicom True Low (TL) PLC Input card. I have supplied photos and schematics. I think it should be pretty simple for you electronics smart guys. I have supplied appropriate photos and schematics.

author: ajb
author_rank: Super Contributor
timestamp: March 21, 2021, 04:41:57 am
content: Just a functional test?The schematic shows a positive ground system, so the probe inputs are activated by connecting them to the positive side of the 24V supply. The outputs are open collector aka sinking outputs, meaning they will be pulled to the negative side of the 24V supply when active. So a test fixture could be a momentary pushbutton from each probe input to 24V+ and a 24V lamp between each output and 24V+. Press each button, check that the corresponding lamp illuminates. Of course you could do this with just jumper wires instead of switches and a voltmeter instead of lamps.The trim pots set the sensitivity of each probe input, presumably to account for resistance in the probe contact with the part. If you need to adjust those to a specific level then you could connect the probe inputs via a resistor of suitable value, but you'd need to identify what value that is based on the probe/part characteristics. Probably better to dial those in on the machine anyway.One other thing you could bench test would be to measure the voltage between pin 20 and the negative side of the supply. The pinout says that pin 20 is no connect, but the schematic shows that it's the reference point the card compares the inputs to. It should measure about 5.5V with a 24V supply. If not, then there's a problem with R17/R18 or U1/U2.It looks like there's probably a negative ground version of that board as well, for which you'd need to connect the probe inputs to the negative side of the 24V supply. The schematic makes it look like it could be the same PCB with different components fitted and some jumpers moved, but there are no jumpers apparent on the board in the photo so it's probably a different PCB but hard to be sure. Just something to watch out for if you have a bunch of boards of mixed or unknown provenance. I'm also a little suspicious of the schematic because D1 is clearly connected wrong--as drawn its pins are shorted making it entirely useless. I'm pretty sure that's just an error in the schematic drawing and the wire parallel to it isn't supposed to be there.
How to Test Stability on HP/Agilent E3611A Power Supply - Page 1
Forum section: electronics / projects

author: MillerKiller
author_rank: Newbie
timestamp: September 26, 2025, 07:14:35 pm
content: Hello everyone 😉I’m new here, and thanks to the community I’ve already made a lot of progress understanding the schematic of the well-known HP E3611A power supply, which some of you have tried to build yourselves or even improve upon.My question is about how to measure the stability of the power supply, specifically using a bode plot and phase margin.I have already watched this youtube video on how to measure the stability of an inverting amplifier:.In short: You break the feedback loop, inject a signal there, and measure at the output to get Vout/Vin_m and then the bode plot.But how exactly should I apply this to my power-supply circuit? Where exactly should I open the loop? For example, would the red-circled point in the current-control loop be the right place?I’d really appreciate any advice 🙂Thanks, Johannes

author: exe
author_rank: Unknown
timestamp: September 26, 2025, 09:12:44 pm
content: An easier option might be to measure pulse response and see slew rate, overshoot and ringing. This method is not as detailed as having a bode plot, but if the goal to measure stability it's my go-to method to do this.

author: JenniferJQueen
author_rank: Newbie
timestamp: September 29, 2025, 03:59:41 am
content: Quote from: MillerKiller on September 26, 2025, 07:14:35 pmThank you so much!
How to test the SNR, THD and Lifetime of a Cell Phone Speaker?        - Page 1
Forum section: electronics / projects

author: Redwan
author_rank: Newbie
timestamp: February 23, 2016, 03:45:23 am
content: Hello Everyone!I actually want to know the standard procedure of testing the SNR value, THD value and Lifetime of a Cell Phone Speaker. Like How long the speaker will last smoothly after manufacturing.I also intend to know the standard value of SNR, THD and Lifetime measurement of a 8 ohm, 0.8 watt speaker of a cell phone aka mobile phone. I Appreciate any types of testing procedure for testing the speaker of a cell phone in Details. It is needed for a Cell Phone manufacturing company, Urgently.Thanks in advance for your help!

author: DrGeoff
author_rank: Frequent Contributor
timestamp: February 23, 2016, 03:53:18 am
content: I doubt that a passive component like a speaker will have either SNR or harmonic distortion. There will be plenty of other non-linearities though, including mechanical and electrical resonances, impedance variations with frequency, excursion limitations etc.The lifetime of the speaker that is driven correctly will probably be determined by the weakest mechanical connection (ie moving parts). If it is not driven correctly then all bets are off.
How to test Voltage Regulators with Reset Function - Page 1
Forum section: electronics / projects

author: Megawilsound
author_rank: Contributor
timestamp: October 30, 2020, 11:59:24 am
content: HI, Brains trust.I would like to know how to test Voltage Regulators with Reset Functionpart number L78MR05.It is a Sanyo chip the data-sheet is attached.ThanksMegawilsound.

author: JoeyG
author_rank: Regular Contributor
timestamp: October 30, 2020, 01:08:07 pm
content: Looking at the data sheet .Which part?L78MR06 : 6V (Reset output ....... Open collector)L78MR08 : 8V (Reset output ....... Open collector)L78MR09 : 9V (Reset output ....... Open collector)L78MR12 : 12V (Reset output ....... Open collector)In the data sheet use theSpecified Application CircuitTest the regulator section first..Apply Vin = Regulator desired voltage + 2.5V(or more) , measure Vout it should be Regulator desired voltageEg for L78MR06Apply Vin = 6V + 2.5V = 8.5V so ~ 9V is OK >> Measure Vout and check it is 6V (if you vary Vin from 9V to 12V Vout shoukd be steady a 6V)Test the ResetEg for L78MR06Start at Vin = 9V then lower Vin to 6V-0.3 = 5.7 (drop below 5.7V) >> RESET pin should follow Vin until 5.7V threshold and then drop to zero volts

author: JoeyG
author_rank: Regular Contributor
timestamp: October 30, 2020, 01:21:55 pm
content: " alt="" class="bbc_img" />

author: Megawilsound
author_rank: Contributor
timestamp: October 30, 2020, 01:40:41 pm
content: HI JoeyGthe part number is L78MR05.Thanks

author: JoeyG
author_rank: Regular Contributor
timestamp: October 31, 2020, 10:42:45 am
content: In the data sheet use the Specified Application CircuitTest the regulator section first..Apply Vin = Regulator desired voltage + 2.5V(or more) , measure Vout it should be Regulator desired voltageEg for L78MR05Apply Vin = 5V + 2.5V = 7.5V so ~ 9V is OK >> Measure Vout and check it is 5V (if you vary Vin from 8V to 12V Vout shoukd be steady a 5V)Test the ResetEg for L78MR05Start at Vin = 9V then lower Vin to 5V-0.3 = 4.7 (drop below 547V) >> RESET pin should follow Vin until 4.7V threshold and then drop to zero volts

author: vignesh_shan
author_rank: Contributor
timestamp: October 31, 2020, 11:54:52 am
content: Reset thresold voltage (VRTH) is mentioned as Vo-0.3Vo-0.2 .Where is it mentioned Vo-0.3 = 6-0.3 = 5.7?I mean how did you get the 5.7V as the Vin min voltage that trigger the reset to low?ThanksVignesh.M

author: ledtester
author_rank: Super Contributor
timestamp: October 31, 2020, 02:47:52 pm
content: QuoteJoeyG was using the L78MR06(the 6V version) as an example:Quote

author: JoeyG
author_rank: Regular Contributor
timestamp: November 01, 2020, 04:57:27 am
content: CorrectThe RESET part of the regulator isonly triggeredwhen Vin isbelow the RESET threshold specified the data sheetfor the specific regulator.The data sheet allows the threshold tolerance you mentioned.The RESET threshold is different for each regulator part number.
How to test VQFN Power Management IC? - Page 1
Forum section: electronics / projects

author: samy03
author_rank: Contributor
timestamp: May 02, 2018, 02:12:16 pm
content: Hi All,I am using TPS65217 in my project but it only comes in VQFN package. Is there anyway I can get a VQFN to DIP adapter to test my circuit on a breadboard? I have a QFN to DIP adapter but pins don't align with VQFN.I would really appreciate your suggestions.Thank you

author: mbless
author_rank: Regular Contributor
timestamp: May 02, 2018, 02:30:42 pm
content: You can check websites likeProto AdvantageandSunRom, but it's probably not advised since you need a good ground plane to dissipate the heat the device will produce.

author: samy03
author_rank: Contributor
timestamp: May 02, 2018, 04:07:47 pm
content: Thanks for the suggestion, but both these sites only have QFN adapters, no VQFN!

author: Siwastaja
author_rank: Super Contributor
timestamp: May 02, 2018, 04:15:58 pm
content: It contains integrated DC/DC converters, running at 2.25MHz. Even though the complete integration of the power MOSFETs makes the layout work easier, it's still paramount to minimize the input capacitance loop (output C and L loops are important as well). See datasheet page 82. This is totally impossible to operate with a DIP adapter, even if such a thing existed, and even more impossible on a breadboard. You need to design a proper PCB, I strongly recommend 4-layer since it makes things easier than trying to get the layout right on two layers.

author: jbb
author_rank: Super Contributor
timestamp: May 02, 2018, 09:14:26 pm
content: Do they make an evaluation board? Those can be very helpful.

author: samy03
author_rank: Contributor
timestamp: May 02, 2018, 09:23:11 pm
content: Well this IC is used in Beagleboard but I am changing some configurations and wanted to test that.

author: jbb
author_rank: Super Contributor
timestamp: May 03, 2018, 06:14:19 am
content: Maybe you could modify a Beaglebone then. Remove the processor and solder on your own test leads. If that's too expensive then we return to your making a test board.

author: capt bullshot
author_rank: Super Contributor
timestamp: May 03, 2018, 07:55:01 am
content: TI sells an evaluation board for this chip. I'd recommend you to get one of these for your evaluation. Prototyping using an adapter board and a breadboard simply won't work (as others pointed out). If you have the equipment, you may want to layout and etch a simple board on your own, here (where I'm working) we do this on a regular basis, it's quicker than ordering a prototype board from a professional supplier, but quite limited in terms of technology. Soldering a VQFN to such a homebrew board is possible and works, but it's a royal PITA. So IMO the best way would be to go for the Eval board and modify its components.

author: samy03
author_rank: Contributor
timestamp: May 03, 2018, 09:06:00 pm
content: Thanks all! I will probably get the evaluation board for the IC.
How to track down a Chinese OEM - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: May 06, 2023, 04:26:16 pm
content: There's a slew of handheld multimeter/oscilloscopes being sold, like the one pictured below. They're sold under various brand names. I'd like to contact the actual manufacturer of them, and make a business deal for customizing the firmware, but there seems to be no way to identify the OEM.Any ideas on how I could track them down?Thank you.

author: wasedadoc
author_rank: Super Contributor
timestamp: May 06, 2023, 04:39:34 pm
content: Sometimes the OEM's name or their model number is on the PCB.

author: tunk
author_rank: Super Contributor
timestamp: May 06, 2023, 04:50:20 pm
content: There's a review and teardown here:https://lygte-info.dk/review/DMMMustool%20MDS8207%20UK.htmlThe PCB is marked eone, maybe this:www.e-one.net.cn/en/

author: rea5245
author_rank: Frequent Contributor
timestamp: May 06, 2023, 05:03:47 pm
content: Quote from: tunk on May 06, 2023, 04:50:20 pmWow! Thanks!
How to Transmit sound via bluetooth - Page 1
Forum section: electronics / projects

author: Avinash Somanathan
author_rank: Newbie
timestamp: February 08, 2015, 09:32:51 am
content: I wish to transmit sound over bluetooth using A2DP . So I wish to know alternatives to RN-52 module from Roving Network. Please suggest other modules that can directly transmit bluetooth sound to other standard bluetooth headsets.

author: lutkeveld
author_rank: Regular Contributor
timestamp: February 08, 2015, 09:39:43 am
content: Sure Hifi BT4.0 APT-X

author: Avinash Somanathan
author_rank: Newbie
timestamp: February 08, 2015, 11:15:47 am
content: I wanted more like a module not a ready made solution. Would be great if anyone can share knowledge on which bluetooth module is used in any standard cell phone

author: Kalvin
author_rank: Super Contributor
timestamp: February 08, 2015, 11:47:40 am
content: Maybe this will help you to get started:https://learn.sparkfun.com/tutorials/understanding-the-bc127-bluetooth-module"Another great use of the BC127 is device-to-device audio. You can use this to add Bluetooth streaming to any device with an audio output to another; for example, you can stream audio across the room from your PC to a stereo amplifier without running a cord.The process is a similar to pairing with a cell phone, as above, but requires that you pre-configure one of your BC127 modules to act as a source–they ship configured as sinks."There is a module, breakout board and software library available. I guess there are probably a few similar modules available in a nice price range.

author: Avinash Somanathan
author_rank: Newbie
timestamp: February 08, 2015, 03:35:28 pm
content: Thank you so much Kalvin. you practically solved my issue. Its my first question and got a prompt response. Thank you so much Dave Jones for hosting this. Hope that this thread gets more responses
How to troubleshoot RF output network? - Page 1
Forum section: electronics / projects

author: Boscoe
author_rank: Frequent Contributor
timestamp: September 06, 2021, 03:03:19 pm
content: Hi all,I'm a bit stuck in a project. I'm trying to implement a custom design for the STM32WLE5CC with a built in radio for LoRaWAN. I copied the ST reference design for the schematic and the values however this didn't work as ST listed completely incorrect values in the BoM for this design - the schematic was correct luckily.I found the STM32WLE5CC reference design and updated the values accordingly. However, the system still cannot send a LoRaWAN packet successfully. I know the code and backend is all good as it has been testing on the Nucleo reference board for the JC MCU variant.So, the PCB isn't working despite the schematic being good, the code being code and the component values being good. I'm using a very small RF switch for the RX/TX which is very difficult to solder, I removed this and soldered in a link to remove this as a potential issue. I'm only trying to transmit across the desk but nothing. I'm looking to buy a HackRF to see if anything is coming out. If not I'm still in this dead end situation.Can anyone give me any pointers on how to debug? FYI I only have a 1GS, 100MHz scope.Thanks!

author: Boscoe
author_rank: Frequent Contributor
timestamp: September 08, 2021, 05:39:09 am
content: Quote from: evb149 on September 07, 2021, 02:52:22 amHi evb149, thank you for your reply.I didn't know about the VNA, that's something I think look into. I think this is a good angle of attack.Power and grounding is good, I followed the ST app note and I believe it's good. All the pins are connected correctly (checked 100 times!). Yes I have several pF sized caps in the right places.Resets are good, code runs on the MCU.The diode circuit is very interesting, I will look into that also.I'm fairly convinced it isn't software as it works on the reference PCB.

author: Boscoe
author_rank: Frequent Contributor
timestamp: September 09, 2021, 10:48:33 am
content: The root cause of the issue we were experiencing was we fitted load capacitors onto the crystal generating the clock for the LoRa carrier frequency which are not needed as they are included in the MCU package. The capacitors pulled the crystal frequency low, making the carrier frequency out of spec. meaning transmission was not successfully received.

author: cstratton
author_rank: Regular Contributor
timestamp: October 24, 2021, 05:01:22 pm
content: Good catch!Worth noting that all the typical sub-GHz LoRa frequencies are within range of an RTL-SDR if you want a way to "see if there's anything there"

author: rfclown
author_rank: Frequent Contributor
timestamp: October 24, 2021, 08:15:47 pm
content: Quote from: cstratton on October 24, 2021, 05:01:22 pmGlad you found the problem, but I would second this suggestion of an RTL-SDR. Nothing comes close for low cost spectrum analyzer. The only thing cheaper is a diode detector (Schottky diode, resistor, capacitor) but that won't show you the frequency. The RTL-SDR with free software like SDR# is amazing.
How to turn on a pwm (SG6841, OB2268) - Page 1
Forum section: electronics / projects

author: status1
author_rank: Contributor
timestamp: February 25, 2021, 02:52:15 pm
content: I am working on a SMPS where the pwm blew up so I am not sure the exact replacement part number but from the pin out I narrowed it down to a certain type SG6841 or OB2268 both of which match the pin layout on the PCBWhile I replaced all the bad parts I still can't get the SMPS to work mainly because I can't get the PWM to start oscillating All I get is the input voltage to fluctuate around 20VSo I was thinking if there was a way to get the PWM to work by itself without the rest of the power supply if that is even possibleIn other words what is the minimum required to see any kind of oscillation on the output ?I attached the pin out and terminal assignments for the OB2268 that I am working withAs I mentioned with the ic installed I am getting a voltage fluctuation around 20V between VIN and GND so that is pins 3 and 1 but that voltage is coming from the bulk cap through a couple of 680k resistors so I measured 147V without the ic so I imagine there is another resistor or something that would regulate the voltage down to 20VSo the question is could I just apply 20V DC externally to pins 3 and 1 without the rest of the power supply ?Would that work the same way ?

author: status1
author_rank: Contributor
timestamp: February 25, 2021, 04:57:29 pm
content: Here is my first experimentI connected my 30 DC supply to pins 1 and 3 and slowly raised the voltage and measured the voltages on the pinsBelow 20V the only voltage it would measure was on pin 7 which is VDD which is supposed to be supplied by the Aux winding of the transformer but maybe it also gets supplied from pin 3At 20.6V I was getting a voltage on pin 4 RI which is the voltage setting frequencyOn my PS I have a 24k resistor from pin 4 to gnd so I substituted that with 25.1K on my breadboard and looked at it with my Hantek scope and I am getting this waveform that I attachedAt 20.6V I am also getting a waveform on top of the dc at pin 7 and also at pins 5 which is the temp control pinI am also getting a waveform on pin 2I am not getting anything on pins 6 and 8

author: status1
author_rank: Contributor
timestamp: February 25, 2021, 06:30:38 pm
content: The next thing I tried was to smooth out the voltage oscillation on top of the dc voltage at pin 7I added the same value cap that I have on the bd 22Uf/20v with the + to pin 7(VDD) and - to pin 1 gndNow the oscillation on top of the dc voltage on pin 7 is gone but now the actual dc voltage is going up and downThis is the same problem I was having when it was on the bdIs this normal ? I assume it's notSo how can I get rid of the oscillation coming from the ic without affecting the voltage on pin 7

author: AcM
author_rank: Contributor
timestamp: October 20, 2022, 01:24:44 pm
content: Hi status1,I've more or less the same situation and can't find any detailed information on how to power up that chip.Have you been able to solve it?Regards
How to turn on this server power supply? - Page 1
Forum section: electronics / projects

author: Hiemal
author_rank: Regular Contributor
timestamp: March 03, 2019, 12:06:11 am
content: I tried pulling each pin to ground with no success, as well as pulling each pin to the aux 12v rail too. It definitely works, as the auxiliary 12v supply rail is on but the main one is not.Any ideas? I know it's possible to turn this on without "talking" to it, as some bitcoin miner sites have this power supply with an ATX power supply cord coming off of it.Thank you!

author: sahko123
author_rank: Frequent Contributor
timestamp: March 03, 2019, 12:10:07 am
content: maybe just the main output isnt working. did you get it new or used and untested

author: Hiemal
author_rank: Regular Contributor
timestamp: March 03, 2019, 12:57:30 am
content: Used and working, so it should be fine...

author: syau
author_rank: Frequent Contributor
timestamp: March 03, 2019, 01:31:45 am
content: May be the following web site can helphttps://www.rcgroups.com/forums/showthread.php?1292514-How-to-convert-Server-Power-Supplies

author: coromonadalix
author_rank: Super Contributor
timestamp: March 03, 2019, 04:47:36 am
content: do a search in rcgroups as syau wrote if its there you'll know it. or post a thread there, they are ressourcefulIt worked for me with a few servers psu i had
How to turn on/off system using transistor or mosfet? - Page 1
Forum section: electronics / projects

author: Danesh_SA
author_rank: Contributor
timestamp: August 22, 2017, 07:34:06 pm
content: Hello!I started building a system and this system should always power on ,but when it connected to 5v DC power supply it should be turn off.the system is using 3.7v Lithium Polymer battery.im using simple PNP circuit and connect the Base of PNP to 5v input of charger,but it wasn't work!how should i design this circuit?is there any schematic?

author: Zero999
author_rank: Super Contributor
timestamp: August 22, 2017, 10:11:27 pm
content: Connect a pull-down resistor between R1 and 0V?How much current does the load draw?

author: Danesh_SA
author_rank: Contributor
timestamp: August 23, 2017, 04:14:44 am
content: Hello Hero999!Thank you for your reply.the current is about 300mA at peak.you mean i should have pull up and pull down resistor in this circuit?!

author: danadak
author_rank: Super Contributor
timestamp: August 23, 2017, 09:56:38 am
content: Something like this, you will have to adjust to your loadrequirements and power in PNP. Also drive R to sat thePNP, and the base to V+ to absorb the Zener leakagewhen supply has dropped to insure PNP fully off.Attached. Blue curve load current, the others Voltages.Regards, Dana.

author: danadak
author_rank: Super Contributor
timestamp: August 23, 2017, 10:00:04 am
content: If you want switch to function as a switch, either on or off,then a comparator might be more appropriate, one with areference in it in order to set accurately trip point.Regards, Dana.
How to understand range of RFID ?  - Page 1
Forum section: electronics / projects

author: Sai teja
author_rank: Regular Contributor
timestamp: October 09, 2018, 01:51:28 pm
content: Hi, I am planing to use MFRC522 based module in an application.http://www.hobbytronics.co.uk/mfrc522-readerAs per description, read range is 3 cm.1) Can anyone explain from which point I need to consider that 3 cm distance?2) And also please tell how much region of the card should be in that field?3) Can anyone tell how field is generated for this module?Please help me in this regard.
How to unlock a microsd that was in an Android? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: August 17, 2019, 06:23:53 pm
content: I have a 16G microsd that you can see the contents of and it looks like android OS file stuff, but I can't erase or format it. I've tried removing the read only attribute with diskpart and other things with no luck. I read that CMD27 can set or clear bits related to write protection, but I don't see any info about this. Has anyone else run into this and know of a tool that resets the card so it can be written to again? I've got a project going with fatfs on AVR so I can sent commands to it if I just knew the right one to send.

author: amyk
author_rank: Super Contributor
timestamp: August 17, 2019, 06:57:45 pm
content: Get the SD specification and read through it. There's various levels of protection that they have, hopefully the "permanent write protection" is not set.
How to upload a arduino bootloader for samd21 microcontroller - Page 1
Forum section: electronics / projects

author: drakejest
author_rank: Regular Contributor
timestamp: September 19, 2021, 08:23:46 am
content: Im making my own board based on the samd21 micro-controller and would like to place a boot loader into it preferebly arduinos so i can upload codes using their IDE. currently my computer does not detect the board via usb, and was hoping uploading a bootloader would also fix that as coding in arduino IDE and uploading using atmel studio through jlink mini edu is a very tedius process.I hooked up my board using a JLink mini edu and can confirm that atmel studio detects the device, but dont know what to do next, since my board does not exacltly use the same samd21 as any of the arduino board do i just choose a bootloader on any arduino samd21 ddevices?
How to use a 1602 LCD Displays Until My 2004 Arrives? - Page 1
Forum section: electronics / projects

author: t1d
author_rank: Super Contributor
timestamp: August 30, 2019, 04:55:35 am
content: I would think that it would only display two lines? Is there any danger of breaking anything?Here is the website:https://www.electronicwings.com/pic/gps-module-interfacing-with-pic18f4550Here is the schematic:

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 30, 2019, 05:01:54 am
content: Should work fine as long as the pinout is compatible. Any output outside the display boundary will simply not be viewable.

author: t1d
author_rank: Super Contributor
timestamp: August 30, 2019, 05:10:30 am
content: Yep, pins are compatible. Should work, as I see it. Just wanted an extra opinion. Thanks for the help.
How to use device and charge their batteries when the proper accessory is lost - Page 1
Forum section: electronics / projects

author: Merlysys
author_rank: Regular Contributor
timestamp: September 16, 2020, 03:14:07 pm
content: So many gadgets, when I need to use one the power adapter for them is often misplaced.Not a problem for most of you as you put the gadget away in a box after using it, along with the adapter and probably the manual too!Starting with this adapter (for SONY video camera DCR-HC21)...what is the 3rd pin for? Any idea how to use it with just any (batteries,power supply,etc) 7.2V source?Here is its battery, what are the middle 2 pins?Eventually I want to build something that will enable power to any low voltage gadget and charge their batteries. Maybe there is one already I can buy, but for now I need to get this SONY working.

author: MosherIV
author_rank: Super Contributor
timestamp: September 16, 2020, 04:23:57 pm
content: HiWhat 3rd pin? The cable shows the negative has a U shape metal tang.The positive is a sinlge tang.The easiest way is just look on Amazon with the model number and at least 2 suppliers will come up with 3rd party charger for your device.
How to use industrial SBC's CPU board? - Page 1
Forum section: electronics / projects

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 01:51:03 pm
content: Hello guys.As title says, they look like a PCI card...How can I connect power and other things to them?Thanks.

author: SL4P
author_rank: Super Contributor
timestamp: June 16, 2015, 02:02:45 pm
content: photos or link to manufacturer product page?

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 02:17:23 pm
content: Quote from: SL4P on June 16, 2015, 02:02:45 pmIt's not in my hand currently, but it looks likehttp://www.ebay.com/itm/INDUSTRIAL-SBC-PC-IPC-TEXAS-P54C-PENTIUM-WOLFHOUND-CPU-BOARD-P5133HX-CPU-133MHZ-/281662039051?orhttp://www.ebay.com/itm/ADVANTECH-PCA-6155V-SBC-W-CPU-MMX-233MHZ-32MB-SDRAM-681-/151248833029?

author: rollatorwieltje
author_rank: Unknown
timestamp: June 16, 2015, 02:27:05 pm
content: I had one with a Via CPU on it, it just took 5V on a standard 4 pin harddisk power connector. No backplane needed. It had standard IDE ports and a CF slot on the bottom for the operating system.

author: SL4P
author_rank: Super Contributor
timestamp: June 16, 2015, 02:30:41 pm
content: a good start, but you'll need to wait until you get your hands on it.it looks like a fully self-contained computer.If you can identify what peripherals are actually on the board itself, you may be able to add power, a serial console - and have a decent Linux computer.Add a backplane and video card, and the rest is in your hands, but it all depends on the card and installed options.
How to use JTAG bus transceivers? - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: March 09, 2017, 12:06:24 am
content: TI have a few bus transceiver chips that offers bus scanning through JTAG. How to use those on a home brew SBC project?My platform would be based on an 80C88. Where should I put the bus transceivers? How to debug the platform with those?

author: bson
author_rank: Unknown
timestamp: March 09, 2017, 08:34:19 pm
content: JTAG testing of a processor requires a processor with a JTAG module.
How to use LIN bus devices - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: July 08, 2011, 08:10:11 pm
content: ok so I've stumbled on the LIN Bus as a method of transmitting data/control signals around a 12V DC system on the power lines, I deal for my scalextric project. But how do I use it ? I've looked up a chip and read the datasheet and it is not really self explanatory.From an implementation point of view, what do i need to do to use a LIN bus transceiver to connect two micro-controllers together ? can I just connect the transceivers to either end of the power rail and assume that I can treat the i/o pins as direct connections or do i need to do anything else to get them talking properly ?

author: johnmx
author_rank: Frequent Contributor
timestamp: July 08, 2011, 10:49:36 pm
content: Check Microchip website, there's a lot of application notes, development board with schematics, software libraries, etc.What you want more??http://www.microchip.com/en_US/technology/lin/
How to use MCP2200 or MCP2221 USB Chip to send HID mouse data? - Page 1
Forum section: electronics / projects

author: milad1234
author_rank: Newbie
timestamp: June 15, 2016, 03:17:43 am
content: Hello all,I have been trying for 2 weeks to figure this out but no luck.I appreciate if anyone can help me figure this out.I am working on an open source USB project and I am trying to find an alternative way than using the onboard USB of PIC18F Microcontroller.(USB chips come with Vendor id and product id which solves the problem)My goal is to create a simple mouse using a PIC18 and a USB chip with HID support.Pic18 sends the mouse commands and then the HID USB chip uses the hid descriptor to move the cursor in host PC.So I bought a MCP2200 USB to UART Bridge but I can't get it working.The USBView software showed the USB descriptor is missing mouse report descriptor but there is no way to add it using MCP2200 utility software.It only lets you change Vendor id,product id,and name of company using string descriptor.So I am wondering if it's possible to do this using MCP2200 chip and if it is then how it's done!I also Bought a MCP2210 and MCP2221 and again same story..I would appreciate if you help me figure this out using the mentioned USB chips or any other USB chips!

author: Ian.M
author_rank: Super Contributor
timestamp: June 15, 2016, 04:16:32 am
content: The MCP22xx range are renumbered USB PICs. This has been positively confirmed for the MCP2200 by reading the device ID.The MCP2200 is a PIC18F14K50 chip with factory programmed CDC class UART bridge firmware.The MCP2210 is also a PIC18F14K50 chip with factory programmed custom HID to SPI master bridge firmware.The MCP2221 is believed to be a PIC16F1454 or '1455 chip with factory programmed composite device: CDC UART bridge and custom HID to I2C master bridge firmware.None of them can enumerate as a HID mouse or provide a bridge to any mouse chipset using standard HID mouse drivers.If you want to emulate a mouse using Microchip parts without running a USB stack in your main MCU, you'll have to take one of the above PICs(as reprogramming MCP2xxx series chips isn't advised - they may not meet all the specs for the PIC they are using even though they are within their own specs.),and the HID mouse in a circle demo for your chosen chip from the Microchip MLA, then hack on that till it can be controlled by your main MCU over your chosen serial interface.

author: laneboysrc
author_rank: Contributor
timestamp: June 15, 2016, 08:22:15 am
content: The OpenSource USB M-Stack by Signal 11 Software has a sample application that emulates a USB HID mouse. Works fine on a PIC16F1455.http://www.signal11.us/oss/m-stack/hope this helps, Werner
How to use Neutrik NADB15FF and what are computer sub-D screws size? - Page 1
Forum section: electronics / projects

author: Kjelt
author_rank: Super Contributor
timestamp: July 31, 2018, 08:30:20 pm
content: Double question:1) What is the metric/US norm for the sub-D connector screws? I measure 2,69mm outer size which makes it 0,1059 inch uhhhh ?2) I have bought some quite expensive Neutrik NADB15FF connectors see picture, but I am not very happy.Neutrik says to drill a 24mm hole which I did and the connector fits just through.The plate can be screwed to the chassis, great the plate is solid mounted BUT but the connector is not connected physically to the plate in any way.So it has like 1-2mm on both sides to keep it there. Doesn't look very solid to me.Am I supposed to buy extra screws type of question 1) and mount it from the inside also ? For €20 a piece they could have included themSomeone used these connectors?thanks

author: ajb
author_rank: Super Contributor
timestamp: July 31, 2018, 09:06:46 pm
content: The jack screws on D-sub connectors are typically 4-40 UNC thread with a nominal major diameter of 0.112" (and a pitch of 40 threads per inch). I've seen references to jack screws with M3 male threads and 4-40 sockets, but I think those are pretty rare in the wild.Neutrik's assembly doc shows that the ears of the connector are supposed to be outside of the panel, captured between the panel and the connector bezel:http://www.neutrik.com/zoolu-website/media/download/12281/Assembly+Instruction+-+D-SUB

author: Kjelt
author_rank: Super Contributor
timestamp: July 31, 2018, 09:48:46 pm
content: Thanks for the screw identification, gonna see if I can buy some short ones somewhere.The Neutrik server seems down (504) so will try tomorrow.The hole should be 23,6mm for which a roundholedrill is unobtainable. But I used a 23mm in steel which resulted in a 23,5mm hole so close enough I would say.Still it feels flunky, there is little "meat" for the connector to hold on to. I could use a metal epoxy glue that would suffice.Neutrik was always my number one they make great connectors , this is the first one I find a bit underwhelming, depending on a 2mm edge to keep it from falling out.
How to use RTDs at 400-700°C? (Connecting wires) - Page 1
Forum section: electronics / projects

author: jogri
author_rank: Frequent Contributor
timestamp: June 20, 2020, 08:53:26 pm
content: Hi guys,i have a question regarding high temperature measurements: I want to measure the temperature of a reaction vessel at different points while it is inside an oven. I choose RTDs because they are rather small and cheap, but i could also use thermocouples.Now i have a problem: How can i reliably connect the RTDs to wires? I can't solder them as the solder will just melt and twisting the wires together doesn't seem like a great idea either. Looking for RTDs with longer leads isn't an option either as they will be ~40cm deep inside the oven.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 20, 2020, 08:59:48 pm
content: Many options such as high-temperature solder alloys or spot welding, but I think, crimping will be by far the easiest.

author: 2N3055
author_rank: Super Contributor
timestamp: June 20, 2020, 10:04:53 pm
content: 700 C is a lot for RTD, at these temps thermocouples are usually used..

author: David Hess
author_rank: Super Contributor
timestamp: June 21, 2020, 07:16:32 pm
content: Thermocouples would be easier to use at that temperature however at high temperatures, the options are high temperature solder, crimping, and spot welding.

author: wizard69
author_rank: Super Contributor
timestamp: June 21, 2020, 07:58:27 pm
content: Quote from: jogri on June 20, 2020, 08:53:26 pmYou on the border for proper RTD operation so you might want to look at thermocouples. Thermocouples are just a welded joint between two different conductors so they are often smaller than RTD's.QuoteYou can order your leads in any length you want and this applies to both RTD's and thermocouples. Try companies that are focused on RTD's and thermocouples such aswww.omega.com. We always buy TC's at work that can be hooked up to a load and run through a port on the oven, to a recorder in one run. It is better to avoid splicing TC to avoid funky connections plus you don't want to accidentally create another junction that offsets you readings. Omega for example has a check box for 20 meter leads. Omegas web site seems to be totally screw up at the moment so you may have to call.
How to use SiT8103AC-22-33E-48.00000X ?  - Page 1
Forum section: electronics / projects

author: Sai teja
author_rank: Regular Contributor
timestamp: January 24, 2018, 10:20:33 am
content: Hello, I want to use SiT8103AC-22-33E-48.00000X crystal oscillator to generate 48 MHz clock. This is MEMS type crystal oscillator. Datasheet of this IC does not provide any application circuit. Am I suppose to use any capacitor at output of the IC. If yes, what should be its value and package ? Please help me in this regard.Link of the datasheethttps://www.mouser.com/ds/2/371/SiT8103-datasheet-351.pdf

author: ConKbot
author_rank: Super Contributor
timestamp: January 24, 2018, 01:13:16 pm
content: It's a plain ttl/cmos output, the same as what any plain logic or microcontroller would put out. The only thing the oscillator will need is appropriate decoupling, and the enable/standby pin to be in the correct state.

author: Sai teja
author_rank: Regular Contributor
timestamp: January 24, 2018, 02:01:21 pm
content: Thanks for your replyDatasheet describes rise and fall time changes with load capacitance. Does it mean I have to place a load capacitance at output.

author: ConKbot
author_rank: Super Contributor
timestamp: January 24, 2018, 05:20:19 pm
content: As you load the output more, the slew rate falls, and the rise and fall times get slower. The lower the slew rate, the more power supply noise gets converted into jitter. No capacitance is required on the output to operate, but a jitter-sensitive application would want a high slew rate to prevent this, and an EMI sensitive application would want a lower slew rate to reduce EMI.Also, the 15pF increments are a "typical" input capacitance with a bit of trace capacitance, so you can estimate your rise time if you're driving multiple inputs with the single oscillator.
How to use tactile switch as a ON-OFF button - Page 1
Forum section: electronics / projects

author: tapasxplore
author_rank: Contributor
timestamp: November 08, 2017, 12:54:03 pm
content: Hi,I am planning to use tactile switch to turn ON & OFF the circuit, can any one of you suggest IC for the same. I am not using any micro-controller in my circuit. I am thinking of using TPS3422 single channel push button controller, but after reading the datasheet, we can see there are two ports RST(invert) and Reset in the TPS3422, so how we can use TPS3422 without controller.Regards,Tapas

author: ebclr
author_rank: Super Contributor
timestamp: November 08, 2017, 12:57:52 pm
content: or

author: Bushougoma
author_rank: Regular Contributor
timestamp: November 10, 2017, 03:31:09 am
content: You can use an SR latch it just requires a single quad NAND gate IC (tie the 2 unused NAND gates inputs directly to power or ground). Pull the S input low with the R input high and the Q output will go high. Pull the R input low with the S input high and the Q output will go low. High = output connected to VCC or Logic 1. Low= output connected to GND or Logic 0. Note that NAND gates can't source or sink much current (25 mA max) for the TI SN74HC00 so be sure to check the datasheet. Driving larger loads will require an external transistor or MOSFET.The SR latch follows the following truth table:----------S R Q----------0 0 not allowed0 1 11 0 01 1 no changeYou could also use a 555 timer in bistable mode you can use two tactile switches one for ON and another for OFF (not shown) or a single tactile switch for ON and OFF as shown in this schematic. The 555 is capable of sourcing or sinking 200 mA max so you can drive larger loads without an external transistor or MOSFET.