hybridfree/eevblog-posts huggingface dataset:
Desperation charger - Page 1
Forum section: electronics / projects

author: TriodeTiger
author_rank: Regular Contributor
timestamp: June 02, 2012, 09:42:08 am
content: iPod died after months of hibernation (forgot), so rigged this up (solder free!) in 5 minutes before I had to leave. Spliced USB->iPod connector at bottom.Surely I'll think of something else to top up a charge when on my next flightDo I get points for desperation? It worked!(PS: Poor TO-220)

author: T4P
author_rank: Super Contributor
timestamp: June 02, 2012, 11:12:45 am
content: 10 Points For Gryffindor!Jokes aside, it worked well for a desperation charger ...It died after months of hibernation ... hah . China batteries
Detailed Colpitts design/operation criteria...? - Page 1
Forum section: electronics / projects

author: jimblair
author_rank: Newbie
timestamp: September 19, 2021, 04:29:51 pm
content: Hi, I am hoping to get a recommendation of a really detailed, and accurate, Colpitts BJT oscillator design/operation tutorial/description. I've read dozens of explanations online and on youtube, but I am struggling to find one that describes the transistor feedback. If you have found a detailed semiconductor level description of how the oscillator design works, I'd appreciate a pointer to that source. I am hoping for two specific explanations....(1) how does the oscillator tank incorporate the 2nd capacitor between the BJT collector and emitter, and (2) how the FM modulation works.thanks in advance for any recommendations.

author: iMo
author_rank: Super Contributor
timestamp: September 19, 2021, 04:48:48 pm
content: What aboutthis thesis?

author: bob91343
author_rank: Super Contributor
timestamp: September 19, 2021, 06:29:17 pm
content: A Colpitts oscillator relies on the voltage step-up you get when you apply a signal to the capacitive tap on the resonant circuit.FM occurs when you vary anything in the circuit. To make it controllable, a voltage variable capacitor is often used.
detailed description of a CANbus? - Page 1
Forum section: electronics / projects

author: k8943
author_rank: Regular Contributor
timestamp: February 03, 2019, 09:48:58 am
content: Anyone have a detailed description of a CANbus, for example from a German car?Am new to CAN, have studied the technical aspects but would like to read about how it's implemented in practice accross a wide variety of communication scenarios before jumping in.Particularly interested in seeing what people to do confirm messages have gone through, track errors, detect failed devices and so forth. Wondering if flags are set when waiting for responses or if blocking waits are used? Wondering if watchdog timers run all over the place to detect failed devices that haven't recently submitted information or if remote frames are preferred to request information instead? etc. etc. Also wondering if single message IDs are preferred for a class of recipient with device-specific information then contained in data fields; or if individual message IDs are used to target specific devices and offer the possibility of the ACK serving as reception confirmation. Etc. etc...No plans to badly reinvent the wheel!

author: Psi
author_rank: Super Contributor
timestamp: February 03, 2019, 09:52:59 am
content: Might help

author: k8943
author_rank: Regular Contributor
timestamp: February 04, 2019, 06:45:59 pm
content: Thanks Psi, enjoyed looking at those.Someone suggested reading about "Can Open" - a higher level set of principles for working with CAN for automation. Been googling and reading and has helped clarify some good working methods. Tx again.
Detect LIR2032 vs CR2032 Battery In Charge Circuit - Page 1
Forum section: electronics / projects

author: hal9001
author_rank: Regular Contributor
timestamp: December 06, 2023, 08:54:44 am
content: I want to use a TP4056 chip to charge a LIR2032 battery. The battery can be replaced since its in a battery holder. Is there a way to detect and not charge the battery if a CR2032 is replaced instead of LIR2032?Cheers!

author: ArdWar
author_rank: Frequent Contributor
timestamp: December 06, 2023, 09:12:25 am
content: Idk if it always holds true universally but CR2032 won't even allow you to charge them. Apply 4V across them and they'll probably only let ~40uA through. I guess you can detect the charge current and bail out if it's too low. You probably want to cut off LIR charging anyway if it goes below ~100uA.The problem is that this is not a guaranteed behavior.Theoretically you can check their voltage. A properly maintained LIR2032 should not go below 3V while a CR2032 won't go above 3V (save for brand new one with zero lead).The problem is that a deeply discharged LIR2032 can go below 3V too and still OK to charge.

author: tszaboo
author_rank: Super Contributor
timestamp: December 06, 2023, 09:31:47 am
content: This is where a sticker, user guide, and silicon sealant are a good candidate to solve a problem, instead of some electronics.

author: Peabody
author_rank: Super Contributor
timestamp: December 06, 2023, 03:46:19 pm
content: The popular SZ042 module for the DS3231 RTC has a 2032 holder onboard, and it has a "charging" circuit consisting of a 200R resistor and a 1N4148 diode in series. This is a holdover from the time when the holder was populated with an LIR2032. When powered from 5V, this circuit would apply about 4.4V to a CR2032 continuously. Many thousands of these modules have been sold with CR2032s, and you don't hear of batteries blowing up. I don't know how well the charging circuit actually works for an LIR2032. It doesn't follow the CC/CV algorithm, and never terminates, so it definitely doesn't follow the rules. But I don't know if that matters.But the question in my mind is what the TP4056 would do when attempting to charge a CR2032. If it applies full charging current, would voltage ever reach 4.2V? How much current would actually flow? If almost none did, would it terminate? It seems to me that you should give this a try. There may be no need to detect a CR if the TP4056 would refuse to charge it in the first place.Don't forget to replace the TP4056's default charge current setting resistor. I read that 33K (for 35mA) is the right one for an LIR2032.
Detect UART polarity..? - Page 1
Forum section: electronics / projects

author: dav888
author_rank: Regular Contributor
timestamp: December 30, 2024, 09:12:44 pm
content: Muxing UART via SBU1/2 in a Type-C connector. So if the cable is connected in reverse, UART TX on the device-side will go to UART TX on the host-side..Need a way to auto-detect this on the host side. Assuming there is no traffic, we could look at which pin is pulled-high. But lets assume there is traffic on the bus, how to achieve this in a safe way...!?---(fully aware that this is normally done on the device side, but don't want to add the IC's needed there for orientation/detection/muxing)

author: Zipdox
author_rank: Regular Contributor
timestamp: December 30, 2024, 10:12:37 pm
content: Well if there's traffic on the bus then that's obviously the TX pin on the other end...

author: dav888
author_rank: Regular Contributor
timestamp: December 30, 2024, 10:28:07 pm
content: guess I can just use a flip-flop that latches as soon as it has seen a logic-one on its inputthis can be used to both enable a mux to flip SBU1&2 + an OE pin to ensure its not exposed until known

author: PCB.Wiz
author_rank: Super Contributor
timestamp: December 31, 2024, 05:38:06 am
content: There are RS232 parts that detect valid RX, and that can disable TX, but their fixed interaction of those is not quite what you need here, pity.Maybe new parts will come that give direct user control ?Addit: maybe simpler parts with RX /EN and TX /SHDN can be used with simple external drive-present latched check.More complex level checks could catch contention allowing more live checks.
Detect when DC motor is running? - Page 1
Forum section: electronics / projects

author: Tom18991
author_rank: Contributor
timestamp: December 06, 2023, 05:37:51 pm
content: Looking for advice on how to detect if a DC motor is running, using only its ground wire? No current flows when the motor is off. I'd like to create a yes/no binary signal I can feed to a microcontroller -- high when the motor is running, low when it is not. Is there a tried and true way to do this?

author: soldar
author_rank: Super Contributor
timestamp: December 06, 2023, 05:41:44 pm
content: No current is ever flowing on the ground wire. You mean "neutral"?

author: themadhippy
author_rank: Super Contributor
timestamp: December 06, 2023, 05:58:44 pm
content: Quotetheres no neutral on DCQuotelow side current sensors and a comparator?

author: TimFox
author_rank: Super Contributor
timestamp: December 06, 2023, 06:06:27 pm
content: Do you need to check that the motor is not stalled?The current is higher than normal under stall conditions with power applied.

author: soldar
author_rank: Super Contributor
timestamp: December 06, 2023, 06:13:08 pm
content: Quote from: themadhippy on December 06, 2023, 05:58:44 pmI missed the DC part. My bad.

author: Benta
author_rank: Super Contributor
timestamp: December 06, 2023, 06:58:25 pm
content: A glass tube reed switch with a coil wound around it. That'll even double as noise filter.

author: rcjoy
author_rank: Regular Contributor
timestamp: December 06, 2023, 09:04:09 pm
content: For industrial use, a DC current switch:https://www.automationdirect.com/adc/shopping/catalog/sensors_-z-_encoders/current_-a-_voltage_sensors_(ac_-a-_dc)/dc_current_switches#
Detect wire break on LDR - long cable - Page 1
Forum section: electronics / projects

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 29, 2020, 03:16:14 pm
content: Hello everyone!I have a part of a project where I have an LDR, which I read through an ADC with a voltage divider configuration.LDR is connected to +5V and ADC, 4k7 to ADC and GND. Simple stuff.I have to detect the full range of the LDR, meaning from total dark to full light.Everything works, but I need a feature where I have to detect if the LDR is disconnected.By disconnected I mean disconnected from the +5V rail and the ADC rail, independently.The extra problem is that the LDR is connected with 2m, 3mm thick copper cable (4m because it is on both legs of the LDR, so back and forth it's 2x 2m).I have a 100nF cap on the ADC which is helping with the distortions.I had no luck, because when I'm detecting full darkness (Rdis 20M) I detect it as an open circuit.I have seen a lot of examples on the internet, but I need assurance on what should I try?Extra:http://www.farnell.com/datasheets/77395.pdfthe datasheet of the LDR usedWould a photodiode make the job easier? Something like a SFH203FA?Using an ATmega32u4

author: macboy
author_rank: Super Contributor
timestamp: January 29, 2020, 03:58:28 pm
content: Place a low leakage diode (1N4148?) across the LDR, reverse biased (so it normally does not conduct). Connect the LDR to a GPIO pin instead of to +5V, and place a high value (100 K to 1 MOhm) resistor to ground.To detect a break in the connection, set the ADC pin to digital and output high/one (5 V). Set the LDR output pin to digital input and read the value. If the connection is good, the diode and/or LDR will conduct, so the voltage will be at about 4.4 V which will measure as a high/one. If it is disconnected, the pin is pulled low by the resistor to ground, and it will read as a low/zero. It is not possible to detect the exact location of the break.

author: mrburnzie
author_rank: Regular Contributor
timestamp: January 29, 2020, 04:20:09 pm
content: I just ran a simulation on the configuration, and it should work!Thanks! Will get back to you with real life testingkudos!
Detecting bi-polar input using Arduino / MCU - Page 1
Forum section: electronics / projects

author: danners430
author_rank: Regular Contributor
timestamp: July 12, 2018, 03:15:38 pm
content: Afternoon folks,Yet another question regarding RC receivers, albeit loosely :-)I've discovered that the RC receiver I'm using outputs a bipolar PWM signal depending on user input. If the joystick is moved "forwards", we get a positive voltage, and if it's moved "backwards" we get a negative voltage.Since Arduinos and MCUs generally can't detect negative voltages, I thought of using a pair of optocouplers to detect the two signals - one for detecting the positive voltage, the other to detect the negative voltage. Does this sound like a reasonable solution?CheersDaniel

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: July 12, 2018, 03:41:50 pm
content: What receiver is this? This isn't like any RC radio I've ever heard of.Why not just couple the signal to 1/2 the rail with a resistive network?

author: Zero999
author_rank: Super Contributor
timestamp: July 13, 2018, 07:43:33 am
content: What voltages do you expect from the negative PWM signal?How about scaling the voltage to within the power supply rails of the MCU and using a comparator to detect the appropriate threshold voltage?

author: mikerj
author_rank: Super Contributor
timestamp: July 13, 2018, 07:44:48 am
content: Sounds like this receiver has a motor speed controller built in and the OP is looking at the voltage across the two outputs. If so them measuring each output with respect to ground should give a unipolar PWM signal.

author: danners430
author_rank: Regular Contributor
timestamp: July 13, 2018, 07:46:18 am
content: Hey guys,Sorry for the lack of response, I was about as busy as could get yesterday I've double checked with the manufacturer, and the info I was getting is wrong - it actually outputs a positive PWM signal, no negative voltages used... Problem solved by itself!Cheers anyway folks!Sent from my ONEPLUS A3003 using Tapatalk
Detecting current capacity of a USB cable? - Page 1
Forum section: electronics / projects

author: Pack34
author_rank: Frequent Contributor
timestamp: November 16, 2017, 04:26:33 pm
content: Here's the idea.On a project I want to use a USB-C connector to take advantage of the added current. The power budget of the device is going to be tight for the 500mA USB standard, which is why I'm looking at USB-C.Now, you can buy a USB-A to USB-C cable and charge at the 500mA. In this state I don't want to be able to charge while the device in ON. However I would like the ability to use a portable USB-C charger and use the device at the same time.How would you be able tell if the connected USB cable is cable of the 5V 1.5A of a USBC-USBC cable or the 5V 500mA of a USBA-USBC cable?

author: tszaboo
author_rank: Super Contributor
timestamp: November 16, 2017, 04:31:16 pm
content: USB can supply more current than .5A. Because they dont place fuses or current limit switches on them, because they cost money, and generally, nobody really cares about the standard. Also, your phone will charge with like 2A on a regular USB cable if it can.What they do is simple: Measure the voltage. If it drops below 4.4-4.5V it's bad, reduce the current. Simple as this.

author: Pack34
author_rank: Frequent Contributor
timestamp: November 16, 2017, 04:38:52 pm
content: So, just let the battery charge and the device operate at the same time but disable the charging circuit if VBUS dips? Sounds simple enough.Something like this would probably want to be under firmware control so I don't have the battery charging state oscillate...

author: tszaboo
author_rank: Super Contributor
timestamp: November 16, 2017, 04:47:49 pm
content: You dont disable the charging, you reduce the current.A chip like BQ25895M does everything for you, it is worth reading the datasheet, just to see what features it has, and what you might need.
Detecting if the AirCon is running... - Page 1
Forum section: electronics / projects

author: toftat
author_rank: Newbie
timestamp: August 11, 2010, 06:15:39 pm
content: I would like to optimize the setting of the thermostats in my house (I have programmable ones) to do this I need to detect if the AirCon is running. The idea being that a better setting will end up with lower runtimeI can't connect directly to either the AirCon or the thermostat so I need to observe the effect of it running, to this end I have come up with 2 ideas and am hunting for more1) measuring a thermal delta between the vent outlet and "somewhere else" in the room. Somewhere else probably being against the ceiling to make sure that there _is_ a delta2) measuring airflow. I have successfully done this using an old processor fan and measuring the voltage coming from the motor during hurricanes but I suspect the vent output is not forceful enough to generate anything significant...As this is a hobby project, cost is a significant consideration...Thanks for any further ideas!

author: Simon
author_rank: Unknown
timestamp: August 11, 2010, 06:44:03 pm
content: so you simply want to know when the AC is running ? do you have access to any low DC voltages in the AC unit ? if you want to detect the differnce in air temp putting a sensor on the top or in front of the intake and one in front of the outlet will certainly get you your delta C

author: tecman
author_rank: Frequent Contributor
timestamp: August 11, 2010, 10:32:42 pm
content: 1. Clamp on current sensor on air handler or compressor circuit2. Temp sensor on vapor line3. Airflow "sail" switchAll are relatively simple and cheap to use.paul

author: XynxNet
author_rank: Regular Contributor
timestamp: August 12, 2010, 09:58:48 am
content: 4. You could put a hall sensor near your aircondition fan.

author: gbowne1
author_rank: Contributor
timestamp: August 15, 2010, 05:45:53 am
content: I don't know but you could set up a small PLC to control this. AllenBradley Micrologix 1500's are nice for this.You can set up all kinds of things on it, relays, sensors, switches, etc.In my case, I'm adding a small GE FANUC 90-30 to my home control for the HVAC requirements of heating and cooling.Greg
Detecting media button presses on earbuds/headphones - Page 1
Forum section: electronics / projects

author: i509VCB
author_rank: Contributor
timestamp: April 18, 2025, 01:21:19 am
content: I am working on a project which has a 3.5mm headphone output. I would like to be able to detect the volume up/down and pause/play button presses.While this sounded as easy as a google search, I could not find any concrete info on how this would be implemented from the device side and not the headphone/earbud side. Is there some specification or good resource documenting this?

author: amyk
author_rank: Super Contributor
timestamp: April 18, 2025, 02:04:04 am
content: https://electronics.stackexchange.com/questions/242883/how-do-media-buttons-on-a-plain-wired-headset-workUsually sensed on the device side with an ADC in the mic bias circuit. See page 53 of this datasheet for an example:https://www.renesas.com/en/document/dst/da7219-datasheet?r=1563341
Detecting specific objects - Page 1
Forum section: electronics / projects

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 09, 2016, 06:21:31 am
content: I am building a project with a quadcopter. I want to be able to detect specific objects (such as keys or animals).My current thought is using an RF transmitter, however, I would like to have those transmitters last as long as possible and as small as possible.Does anyone know of any better ideas of how I can detect objects?

author: grifftech
author_rank: Frequent Contributor
timestamp: October 11, 2016, 03:18:03 pm
content: paint the objects a bright color

author: BFX
author_rank: Frequent Contributor
timestamp: October 12, 2016, 12:49:34 pm
content: If your drone are big enough you can implement object tracking using OpenCV on Raspberry Pi.If not you can send series of images by transmitter to computer on the ground, implement it there and after that send command "object identified" to quadcopter.But response of second solution is not too much quick.There is also possibility for best performance implement the same algorithm to an FPGA but it's not so easy.

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 15, 2016, 05:10:26 am
content: Quote from: grifftech on October 11, 2016, 03:18:03 pmOne of the problems is if a person is wearing that colour, it could get awkward, lol.

author: ziggyfish
author_rank: Regular Contributor
timestamp: October 15, 2016, 05:43:26 am
content: Quote from: BFX on October 12, 2016, 12:49:34 pmIts a 680 mm (motor to motor) frame, so it would be definitely big enough for the Pi. I am working on building a circuit board which will contain the sensors (MPU 9250 (i2C), LiDAR sensor (i2C), Motor PWM, and RC communication (UART)).As it requires a few connections and 6 PWM channels (it's a hexacopter), I am looking at using MK12DX256VLK5 (the MK10DN64VFM5 doesn't have the pin count), or MKV58F1M0VLL24 Microcontroller. The MK12D only runs at 50Mhz, however, should be ok if I use the Pi as the brains, while putting the basic higher lever motor control logic (actual motor control is done via the ESC, but requires PWM to communicate), i.e level flight, turning, etc.The MKV58 has a faster processor, however, I don't know if the algorithms would run well even with the faster processor (240 Mhz). However, may use the MKV58F1M0VLL24 for expansion reasons even if it can't handle the algorithms.
Detecting the Removal of an Input - Page 1
Forum section: electronics / projects

author: electosleepy
author_rank: Contributor
timestamp: October 03, 2016, 07:46:41 am
content: Hi,I have a device that is powered from 2 USB ports. I basically want to detect if one input has been removed so that I can put the system in a suspend mode. How can I do this?

author: Fungus
author_rank: Super Contributor
timestamp: October 03, 2016, 07:54:43 am
content: What's in the "device"?Is there a microcontroller? Is it just a light bulb? What?

author: wraper
author_rank: Unknown
timestamp: October 03, 2016, 08:03:23 am
content: Detect VBUS obviously.

author: Psi
author_rank: Super Contributor
timestamp: October 03, 2016, 08:08:00 am
content: VBUS detect plus some ORing diodes

author: German_EE
author_rank: Super Contributor
timestamp: October 03, 2016, 11:56:19 am
content: You can get various power monitoring chips, these are normally used to check a CPU power line and if a loss of power is detected then an interrupt is generated and settings are saved.So, use two of these chips, one for each USB plug, and if the supply fault pin changes state then it goes into suspend.
Detecting USB device connection while unpowered - Page 1
Forum section: electronics / projects

author: oliver602
author_rank: Regular Contributor
timestamp: October 03, 2011, 10:02:54 pm
content: I'm thinking about a USB charger that can be permanently installed in a car or motor home.I want to minimise current draw while no USB device is attached. Tens of micro amps.Perhaps by using a very low power circuit supplied by a linear regulator to disable the switching regulator when no device is attached. Id also like to include low input voltage shutdown, to avoid a flat car battery.Is there a reliable way to detect when a USB device is connected while it is unpowered, without any mechanical switches?

author: reagle
author_rank: Unknown
timestamp: October 04, 2011, 12:55:14 am
content: You might be able to just find one with very low quiescent current and rely on it for detecting load. Otherwise maybe inrush current of the device getting connected? Typically there would be a sizeable cap on the power line

author: Psi
author_rank: Super Contributor
timestamp: October 04, 2011, 12:56:54 am
content: The lowest idle power possible is zero, which you could do with a pushbutton to start the process.Or even a tiny solar panel and supercapacitor to store enough charge to latch a relay or pull the IC's enable pin high.However i'm sure there is an easy way to monitor for pullups/pulldowns present when a usb device is plugged in.That would meet your tens of micro amps target.Maybe get a few usb devices and see what resistance they have from D-/+ to ground.Have a read of the USB standard, there might be an official way to do this.

author: joelby
author_rank: Frequent Contributor
timestamp: October 04, 2011, 02:26:01 am
content: How about a microswitch in the USB socket?
Detection method for coilgun? - Page 1
Forum section: electronics / projects

author: JustClaire
author_rank: Contributor
timestamp: September 18, 2019, 06:50:44 am
content: Hello! I am currently thinking of making a coilgun as a project, and i have a question. What is better to use for projectile detection? As i need to disable the coil once the projectile is in the middle of it, I need some form of detection for the projectile. I was thinking of using IR sensors, however their responce time is quite slow and may be insufficient. What would be the best way to detect that the projectile is in the middle of the coil? Thank you for help)

author: Psi
author_rank: Super Contributor
timestamp: September 18, 2019, 06:52:51 am
content: Check out-Photodiodes-Phototransistors-LDRsi forget which is fastest but i know one is much better than the others when it comes to speed.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 18, 2019, 07:59:07 am
content: Doesn't much matter. The above differ by ~100us (give or take how an LDR would be used; they're an abomination), in which time the projectile has moved little. Even if you manage to achieve sonic speed, that's only ~0.3mm/us, enough to deserve some consideration with a bright LED and a good photodiode, say.Tim

author: JustClaire
author_rank: Contributor
timestamp: September 18, 2019, 08:09:25 am
content: Quote from: Psi on September 18, 2019, 06:52:51 amQuote from: T3sl4co1l on September 18, 2019, 07:59:07 amThanks guysIm new to this so its really helpful
Determine wheatstone bridge pinout - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: August 09, 2015, 12:43:53 am
content: I have a load cell I'm using for a project, but I'm not sure how to connect it. I'm sure it's a wheatstone bridge, but how do I determine which pins are which? In theory, the resistance between any two nodes in a bridge will be identical. Is there a simple method for finding opposite nodes?Here's the datasheet, for all the good it will do:http://www.omega.com/Pressure/pdf/LCDB.pdf

author: rs20
author_rank: Super Contributor
timestamp: August 09, 2015, 12:49:18 am
content: Your assumption isn't quite right -- the resistance between two opposite nodes will be equal to R (where R is the resistance of any one element in the bridge), but the resistance between two adjacent nodes will be 0.75R.Once you've found two opposite nodes that way, it doesn't really matter how you connect it up -- I believe you can connect a wheatstone bridge reflected upside down, side-to-side, and the worst that'll happen is positive loads will be reported as negatives. Which you can fix by reversing any two wires, or just adding a "-" in software

author: retrolefty
author_rank: Super Contributor
timestamp: August 09, 2015, 01:04:05 am
content: As told by rs20 an ohm meter will determine node arrangement. That aside Omega generally uses red (+) and black (-) wires as the excitation node, and green (+) and white (-) for the measurement node.

author: Rachie5272
author_rank: Regular Contributor
timestamp: August 09, 2015, 01:15:24 am
content: Ah, right you are. Never try to do resistor math while tired...

author: jtroyase7
author_rank: Newbie
timestamp: January 07, 2020, 01:18:59 pm
content: Hello,I have a similar problem and was wondering if you could help me.I want to use a Xtrans CODAN pressure transducer that I know it works with a wheatstone bridge configuration. As expected it has 4 pins (GND, Vsupply, Vright, Vleft), however I am not able to find any datasheet that can indicate me which pin corresponds to which type of signal and the company does not want to help me. I am a little bit new to electrical engineering and do not understand properly your explanations. However, I have measured resistance across the pins (please see attached image).I would like to know which letter (A,B,C,D) corresponds to which number (1,2,3,4).Thank you very much,

author: andy3055
author_rank: Super Contributor
timestamp: January 07, 2020, 06:02:22 pm
content: Long time since I studied these. Here is a useful site:https://www.electronicshub.org/wheatstone-bridge/

author: Kleinstein
author_rank: Super Contributor
timestamp: January 07, 2020, 06:25:12 pm
content: Those resistor values are not compatible with the simple 4 resistor bridge circuit. So there must be something else inside.

author: jtroyase7
author_rank: Newbie
timestamp: January 08, 2020, 05:50:00 pm
content: Thank you for you answers. I will keep pushing the company to obtain the information (seems like the only thing I can do) and I will post it here their answer so another person could benefy if he/she gets in the same situation as me.
Suggestions for debugging techniques for complex SMPS IC? - Page 1
Forum section: electronics / projects

author: dsg123456789
author_rank: Newbie
timestamp: September 03, 2021, 05:18:35 pm
content: Hello, I'm working on a board design using a MAX77960, which is a buck-boost converter for DC/DC power conversion and lithium battery charging.I've got the MAX77960 working on a board where I only stenciled & reflowed its circuit, leaving the rest unpopulated. I'm able to tie the MAX77960's power output to the correct place on a board that doesn't have the MAX77960 populated, and with that I'm able to power the 2nd board from the 1st via the MAX77960 (by tying the power outputs and grounds together).I also have a board that is fully populated. If I inject the 3.3V power rail via a bodge (disconnecting the board's 3.3V supply), I'm able to have my microcontroller communicate with the onboard MAX77960. Its status registers say it's healthy, but the switcher isn't switching, and the output voltage is very low (0.9V) even though it's configured to try to maintain 9V on the output. I can see that the MAX77960's internal LDOs are working--they're both reading 1.8V. And like I mentioned, I'm able to reliably communicate with it and program it via I2C.The fully populated board has 5 additional connection to the MAX77960:- 2 control signals from the uC to the MAX77960 that have 10kΩ pulldowns, and which I have disabled/left floating in the uC, so I don't think these have any effect- 1 open-drain signal from the MAX77960 to the uC with a 10kΩ pullup to a 3.3V rail that is downstream of the MAX77960. This 3.3V rail powers the uC.- An I2C bus, which has 5kΩ pullups to the aforementioned 3.3V railI'm not sure how to approach debugging this:- should I treat it like a switching power supply that's failing to bootstrap, and look into replacing/retesting passives that I may have damaged during soldering? I've spent a fair bit of time with my hot air station and fine tipped iron ensuring that MAX77960 is attached fully. Are there other approaches one can take to diagnose a non-working SMPS when you know that the circuit/PCB has had successful assemblies?- Should I treat it like a power design problem, where my I2C pullups are causing weird current paths and breaking stuff? How do I approach thinking that through?- Is this a partial failure mode that happens with SMPS controllers when cooked too much during assembly, where I should be trying solder a new one?- I don't think the problem lies in the digital logic space, since the comms seem to be working, but maybe someone has an idea for what else I should be looking into?Thank you for your ideas in how to approach debugging this! If it would be helpful, I can post a system diagram, simplified schematic, or the full schematic (but the board has 263 components organized in 15 modules, which isn't conducive to specific suggestions).
Determining Tech-Ohm Ceramic Resistor Current/Power Rating - Page 1
Forum section: electronics / projects

author: fuzzoli
author_rank: Regular Contributor
timestamp: April 18, 2023, 11:20:06 pm
content: I picked up a few Tech-Ohm ceramic resistors at an estate sale this past weekend. The resistance value is printed, but no current/power ratings. I looked for charts based on size, etc., but no luck. These particular ones are about an inch in diameter and about 10" long. Thoughts?Thanks!

author: WattsThat
author_rank: Frequent Contributor
timestamp: April 18, 2023, 11:35:20 pm
content: Size is consistent with the very common 225W rated ceramic power resistors. Google Ohmite 270 series for a generic equivalent.

author: fuzzoli
author_rank: Regular Contributor
timestamp: April 19, 2023, 12:23:51 am
content: Ah, silly me! Why didn't I think to look at the current manufacturers! I was so caught up on the tech-ohm! Thanks for the quick answer!

author: james_s
author_rank: Super Contributor
timestamp: April 19, 2023, 02:29:36 am
content: You can also load it up while monitoring the temperature, when you reach a power level where it settles at around 125C that's probably a reasonable place to stop.
Determining the die temperature of a power module - Page 1
Forum section: electronics / projects

author: macgeorge
author_rank: Newbie
timestamp: October 04, 2016, 07:31:58 pm
content: Hi all,I am experimenting with a setup to measure the die temperature of a power module under known power dissipation (to verify the thermal resistance of the datasheet).The test I thought to implement is as follows:1) Since the diode forward voltage is a linear function of the temperature, I used a low current source to measure this voltage drop in various temperatures (using a thermal oven).2) After that, I can use a high current supply, connected in series with the diode to heat it up and measure the dissipated power. If I stop the high current and use my low current source again, I can measure through an oscilloscope the voltage drop immediately after the high current cut out. By using the equation I extrapolated in the previous step, I could determine the diode die temperature.I completed the first step with very good results (the forward voltage vs temperature curve is fairly linear) and now I am building the second phase.The circuit I am going to implement is as follows:I am thinking of using a gas chamber relay switch because of the high current (>50A). Cables will also be made as short as possible to minimize inductance.The relay I am consideringcan withstand high voltage (I assume a voltage spike will occur during cut out). However, should any other protection be implemented to protect either the high current power supply or the low current source?Thanks in advance!

author: rfeecs
author_rank: Frequent Contributor
timestamp: October 04, 2016, 09:41:05 pm
content: This is a difficult measurement. There is a lot of literature on the subject. There is a MIL-STD that describes it.A big problem is that the temperature of the diode starts to change within microseconds. You need to separate the electrical transients from the thermal transient.Here's one reference that discusses it:http://samunet.hu/extfil/Temperature_saturation_voltage.pdf

author: rfeecs
author_rank: Frequent Contributor
timestamp: October 04, 2016, 10:03:56 pm
content: FYI, it is in the 3100 series of tests in MIL-STD-750.Download revision E from here:http://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=35927Interesting reading.There are various tests for diodes, BJTs, MOSFETs, etc.
Determining the voltage ratings of unmarked SMD ceramic capacitors? - Page 1
Forum section: electronics / projects

author: Dave8266
author_rank: Contributor
timestamp: November 01, 2021, 08:24:43 pm
content: Is there any reliable way to determine the voltage rating of unmarked SMD ceramic capacitors?I was handed a bag of them at work, which came in without a label, but had already been separated from the shipping box by the time it was discovered. I've measured the capacitance (22uF), and they are 1206 in size, so based on a quick DigiKey search, it looks like they could be anywhere between 4 and 35V.I have plenty to destructively test, but even so, is it reasonably possible to do so? From what I've read about the failure and wear mechanisms (such as:http://www.ieca-inc.com/images/Ceramic_capacitor_Failure_Mechanisms.pdf), it sounds like I might have to destructively test hundreds of them, for long periods of time, to have a good idea?This is mostly just a curiosity question. Without identification, we've already concluded that we wouldn't use these for production assemblies.Thanks

author: wraper
author_rank: Unknown
timestamp: November 01, 2021, 08:34:26 pm
content: QuoteNo. They easily survive 10-20 times of rated voltage short term. However may fail at increased voltage when left under such long term, like for a week. Capacitance drop under DC bias is not reliable metric either. Capacitors rated for different voltage often lose about as much capacitance under same DC bias. Or opposite, capacitors with the same capacitance and voltage rating from different series lose vastly different amount of capacitance under DC bias.

author: tggzzz
author_rank: Super Contributor
timestamp: November 01, 2021, 09:21:10 pm
content: Increase DC bias voltage until the capacitance falls to 10% of the capacitance at 0V bias. That's the rated voltage.Yes, that isslightlycynical.

author: wraper
author_rank: Unknown
timestamp: November 01, 2021, 10:03:51 pm
content: Quote from: tggzzz on November 01, 2021, 09:21:10 pmIt depends more on physical size rather than rated voltage.

author: David Hess
author_rank: Super Contributor
timestamp: November 02, 2021, 03:25:10 am
content: Would measuring the leakage current as the voltage is increased reveal anything about the rated voltage?

author: max-bit
author_rank: Frequent Contributor
timestamp: November 02, 2021, 06:47:22 am
content: NoYou could measure the breakthrough-damage threshold, but it will always be different.

author: Dave8266
author_rank: Contributor
timestamp: November 06, 2021, 06:51:43 pm
content: Thanks everyone, appreciate the replies and the confirmation on my suspicions.
Determining transformer current rating - Page 1
Forum section: electronics / projects

author: Jeff1946
author_rank: Regular Contributor
timestamp: April 30, 2012, 01:46:42 am
content: I have a few unmarked AC power transformers I have removed from various electronic devices. It's easy to measure the voltage. How to I determine the current. My thought-- put various loads on and note the voltage drop. My guess would be about 10% drop maximum. Then I would leave this load on and see how warm the transformer gets. Any other suggestions?

author: BravoV
author_rank: Super Contributor
timestamp: April 30, 2012, 02:00:43 am
content: Had similar question while a go at when I mod my isolation transformer, a fellow here pointed out few useful hints ->https://www.eevblog.com/forum/projects-designs-and-technical-stuff/modding-an-isolation-transformer-please-advise/msg80157/#msg80157Hope this helps.

author: IanB
author_rank: Super Contributor
timestamp: April 30, 2012, 02:10:12 am
content: To give you an idea, here is a load graph I plotted of a transformer marked 12 V 2 A. I think checking it doesn't get too warm after leaving it running for a while is the best option you have for figuring out the current rating.
deutsch compatible pcb plug - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: July 25, 2013, 10:41:40 am
content: I could do with a pcb and panel mount rectangular Deutsch plug (looks like a socket thought). Deutsch don't do them, does anyone do compatibles ?

author: notsob
author_rank: Frequent Contributor
timestamp: July 25, 2013, 11:03:44 am
content: Not sure which one you are considering, perhaps a diagram or picture would help. Anyway a quick google brought this -http://www.vanline.com.au/PDFs/Deutsch.pdf

author: Simon
author_rank: Unknown
timestamp: July 25, 2013, 11:22:22 am
content: I'm aware of the deutsch range but they don't make what I want. i was wondering if anyone made "compatible" parts
Dev kit memory vs number images stored - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: October 24, 2024, 01:45:25 am
content: Hi,looking at dev kits like this one (or similar ones)https://www.st.com/en/evaluation-tools/32f469idiscovery.html#overviewit comes with a 800x480 pixels display and the QSPI is "only" 128Mbit.Am I correct in saying that (without any compression) it can only store just over 10 full screen-sized images assuming 4 bytes per colour (1 layer with transparency)?128,000,000 / (800 x 480 x 32) = 10.4That also means no video can be stored (unless you just play a few frames)?Is that correct or am I missing something?Thank you
Developing a sine-to-pulse generator with fast and precise rise time - Page 1
Forum section: electronics / projects

author: Sariel
author_rank: Regular Contributor
timestamp: December 13, 2023, 11:41:26 am
content: Greetings,I'm exploring the possibility of introducing rectangular pulses with a rise time of 1ns (350MHz) into my existing circuits.Unfortunately, acquiring a sufficiently fast-function generator within my budget is challenging, as they tend to be priced at $2,000 and above.However, I do have access to an RF signal generator.My idea is to create a simple Sine to pulse generator. The plan involves injecting a 350MHz sine wave into a circuit, potentially composed of high slew rate opamps. This circuit should be capable of delivering repetitive pulses at the output, with a 50% duty cycle (although the ability to tune the duty cycle would be advantageous), and 1ns rise/fall times into a 50-ohm load.Do you have any recommended circuits for this purpose?My plan is to simulate the circuit in LTspice before moving on to the circuit board design phase.Thank you.

author: ch_scr
author_rank: Frequent Contributor
timestamp: December 13, 2023, 01:12:43 pm
content: I'd try and use a (P)ECL line reciever (e.g. MC100EL16). Reasonable price, easy to implement (if you follow high speed / transmission line layout considerations) and solid performance. If you needeven moreedge speed, change to MC100EP16. If you need more output swing, maybe put a balun on the output, too? In that case you could use the (noise-wise) preferred -5V circuit and get the ground reference level translations for the in/output via the baluns "for free".

author: tggzzz
author_rank: Super Contributor
timestamp: December 13, 2023, 06:20:32 pm
content: You don't mention important details, e.g. amplitude nor whether it has to be 1ns or could be faster.However, have a look at:https://www.eevblog.com/forum/testgear/show-us-your-square-wave/msg1902941/#msg1902941
Developing solution for audio playback - Page 1
Forum section: electronics / projects

author: tyguy2
author_rank: Unknown
timestamp: July 18, 2019, 05:37:29 am
content: I'm currently working on a project that needs to loop a few second audio clip every couple of minutes over a few hour period. I'd prefer to stay away from embedded computers, ie raspberry pi's and the like, since the project will be sent to production and needs a long battery-life. While researching solutions, I came across this on Adafruit:https://www.adafruit.com/product/2220This is essentially exactly what I need, the only issue is that I'm trying to integrate this into a production PCB, so the idea of spending $25 a piece for these, along with the fact I can't order the flash pre-programmed, is a bit of an issue. I know Adafruit offers the schematics to this board, so in theory I could just lift the design from there, but the main component isn't available on Digikey, and I'm not sure if they've flashed it with some custom, non-commercially licensed firmware. Does anyone have some ideas as to how I could proceed? Should I just use an imbedded Linux machine, something that consumes less power than an RPI, or is there an easier way?

author: tyguy2
author_rank: Unknown
timestamp: July 19, 2019, 12:16:19 am
content: Quote from: blueskull on July 18, 2019, 05:46:29 amIt seems that their programming software hasn't been updated since Windows Xp/7, and I can't find any information on their website about the SPI commands available. If I could find those SPI commands, specifically for their ISD3800, I think I could make it work, but as it stands I'm not sure. Are there any other chips able to do something similar to this? Maybe something similar to the ISD1700 but with a higher sample rate than 12khz?

author: edavid
author_rank: Super Contributor
timestamp: July 19, 2019, 04:50:32 am
content: ATMEGA328 + serial flash? That way you can use an Arduino audio player library.

author: tyguy2
author_rank: Unknown
timestamp: July 21, 2019, 05:59:21 pm
content: Quote from: edavid on July 19, 2019, 04:50:32 amI looked around, and the Arduino Audio library was ported to the SAMD21 line of chips (https://github.com/arduino-libraries/AudioZero/blob/master/examples/SimpleAudioPlayerZero/SimpleAudioPlayerZero.ino), which was cheap enough and would play back at a high enough quality to use. Thanks!
Development of a new electrolytic capacitor - Page 1
Forum section: electronics / projects

author: The Electrician
author_rank: Frequent Contributor
timestamp: February 15, 2014, 11:51:25 am
content: Here's a fascinating (but long) paper detailing the work that goes into improving an electrolytic capacitor:About new electrolytic

author: SeanB
author_rank: Super Contributor
timestamp: February 15, 2014, 12:46:32 pm
content: link does not render well with SMF, you just need to select the unhighlighted remainder and paste onto the URL.

author: Monkeh
author_rank: Super Contributor
timestamp: February 15, 2014, 01:29:26 pm
content: Or just, y'know..http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedbackFAQ/DECEF7F25203B33E852578A400584ECC/$file/2011-03%20CARTS%20-%20Low%20ESR%20Aluminum%20Electrolytic%20Capacitors%20for%20Mid-to-High%20Voltage%20Applications.pdf
Development tools for Wifi ? - Page 1
Forum section: electronics / projects

author: jk96
author_rank: Newbie
timestamp: February 12, 2013, 06:49:29 pm
content: I am working on a project to improve and alter OSI layers like MAC, Physical in WiFi.We found ns3 for simulation.Can we use the existing wifi module come with laptop for realtime working or we have to use a spectial wifi modules to alter the layers.what are the tools and hardware we want to test it in real time?

author: joelby
author_rank: Frequent Contributor
timestamp: February 12, 2013, 10:32:59 pm
content: I couldn't give a definitive answer, but I think it would be difficult to modify the low level behaviour of a commercial computer WiFI device as the internals are usually not documented publicly or well.You might want to consider investigating a software defined radio approach with some hardware such as the Ettus Research USRPs. As an example or starting point, there are some GNU Radio implementations of 802.11b:https://www.cgran.org/wiki/BBN80211andhttp://span.ece.utah.edu/pmwiki/pmwiki.php?n=Main.80211bReceiver

author: jk96
author_rank: Newbie
timestamp: February 12, 2013, 10:58:01 pm
content: Thank you joelbywhich Spectrum analyzer is idle for WiFi Development?please clarify does the MAC layer is written in hardware or OSif OS can we use linux kernal and edit?is there any Wifi Module allow to Custom OSI layer?

author: joelby
author_rank: Frequent Contributor
timestamp: February 12, 2013, 11:25:49 pm
content: I can't really think of a good reason to use a spectrum analyser unless you're designing your own radio hardware.I can't speak for all implementations, but MACs are usually hardware. You should certainly have a look at the Linux kernel source and see what is done in the wireless drivers.I've no idea about WiFi modules that allow that sort of customisability, but I would think that there are none. Computer WiFi cards are cheap, commodity devices that are not designed for extreme reconfigurability. That's why I'd recommend an SDR like the USRP family. Of course, they are not cheap.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 13, 2013, 03:25:05 am
content: Working with digital communications at that depth needs a Tiffany Yep level of knowledge.A cheap RF2500 module (or equivalent) can be used as a spectrum analyzer, and WiFi cards with good open source drivers are great for "hacking".