hybridfree/eevblog-posts huggingface dataset:
Multiple N-Channel logic-level Mosfet high-side switching with common GND - Page 1
Forum section: electronics / projects

author: philbx1
author_rank: Regular Contributor
timestamp: February 21, 2014, 09:17:03 am
content: Hi All,Still trying to get my head around mosfets, and yes, I should really be using P-channel fets here, butanyway N-channel is what I have.Is it possible to switch an N-channel fet through a positive supply?Here's a simple example of what I'd like to have, but I'm guessing it's in smoke territory :-)I've used a DC motor as an example, but the real-world use is for multiple RC glow plugs which all share a commonground to the engine body.PWM is a separate issue also re. frequency and switching, but I'll leave that for now.

author: Psi
author_rank: Super Contributor
timestamp: February 21, 2014, 09:19:51 am
content: There's some weird symbols in that diagramWhat is the top most connection?

author: philbx1
author_rank: Regular Contributor
timestamp: February 21, 2014, 09:26:24 am
content: Quote from: Psi on February 21, 2014, 09:19:51 amThe top connection is just an alternative pad I left in and possibly should have left outnot to distract from the motor (or glow-plug) which would normally be connected.The +7v and AGND are what I'm trying to show as the motor supply.Thanks for posting so quickly BTW.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 21, 2014, 09:36:33 am
content: The transistor is backwards, so it'll never turn off, but the diode shows supply going into the motor anyway...To get an NMOS high side turned on, you need a gate voltage at least 5V (logic level device) above the supply, i.e., 12V or more.If the output is always switching within a known period of time (such as PWM limited to <100%), a bootstrapped driver is usually used. Otherwise, a charge pump (internal to the driver, or external, e.g. ICL7660, or a 7555 and diodes) or switching converter is used to generate the +12V (give or take) supply.Tim

author: Psi
author_rank: Super Contributor
timestamp: February 21, 2014, 09:38:55 am
content: Quote from: philbx1 on February 21, 2014, 09:17:03 amYes you can switch positive with n channel but you need two voltages, on to run the motor/glowplug and another, which is 5V higher, to turn on the mosfet gate.The n channel mosfet in your diagram needs to have source connected to the load and not VCC

author: philbx1
author_rank: Regular Contributor
timestamp: February 21, 2014, 10:18:56 am
content: Thanks much T3sl4co1l and Psi.Looks like (not that I play golf) that I need a driver.
Multiple nFAULT DRV8803 - Page 1
Forum section: electronics / projects

author: mrburnzie
author_rank: Regular Contributor
timestamp: June 28, 2020, 08:20:59 am
content: Hi everyone!I'm working a project where I have multiple DRV8803 ICs for solenoid driving.The DRV8803 has a nFAULT pin, which is used for over temperature/current monitoring.I'm using 16 channel i2C MUX to control them from my MCU.I'm running out of pins when I add all the INPUT channels (4), plus the nFAULT pin.I'm controlling one solenoid at the time (the time difference between activation of two solenoids can be minutes to hours).Could I tie all nFAULT pins together (or group them into 4-8) and monitor that pin?By the datasheet nFAULT is "Logic low when in fault condition", so I think that it would work without a problem, because I know which solenoid is from which exact driver and I can determine where the fault is coming from.Datasheet:https://www.ti.com/lit/ds/symlink/drv8803.pdf?ts=1593275378760&ref_url=https%253A%252F%252Fwww.ti.com%252Fmotor-drivers%252Fsolenoid%252Foverview.htmlStay safe!

author: mikerj
author_rank: Super Contributor
timestamp: June 28, 2020, 08:31:25 am
content: The nFAULT output is open drain so you can safely tie all your nFAULT outputs together with a single pull-up resistor.

author: mrburnzie
author_rank: Regular Contributor
timestamp: June 28, 2020, 08:50:47 am
content: Thanks for confirming. Cheers!

author: Simon
author_rank: Unknown
timestamp: June 28, 2020, 04:14:34 pm
content: looks like someone goofed up on that datasheet copy and pasting from one of the many other DRV88xx drivers. I can't see how that driver woueli work for a stepper motor the way the show as the outputs are open drain not tri state totem-pole.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 28, 2020, 04:53:21 pm
content: Yes, fault output pins are almost always open-drain just because of this reason: you often want to save pins and ease routing by treating all faults equally, without needing to know where the fault is coming from. This is especially handy if your fault handling is a discrete logic circuitry and not an MCU, you don't then need a large OR gate.Just remember the pull-up resistor or it won't work!
multiple output isolated DC power supply - Page 1
Forum section: electronics / projects

author: mghitti
author_rank: Newbie
timestamp: May 29, 2023, 09:01:15 am
content: Hi,I need to build a 10x 12vDC 150mA isolated power supply with linear LDO, my question is: Is it a good idea of design using a single toroidal transformer 220V-15VAC and then a 1:1 pulse transformer on each output for isolation? For requirement we can't use isolated DC/DC converters.Thankss

author: moffy
author_rank: Super Contributor
timestamp: May 29, 2023, 11:21:44 am
content: Have a look at the SN6507, it might suit what you want:https://www.ti.com/lit/ds/symlink/sn6507.pdf?ts=1685300138186&ref_url=https%253A%252F%252Fwww.google.com%252F
Multiple power requirements - better way? - Page 1
Forum section: electronics / projects

author: ToBeFrank
author_rank: Regular Contributor
timestamp: July 05, 2011, 05:47:27 pm
content: I have a circuit that needs three different voltage levels - 8V, 5V, and 3.3V. The input is 12V. The current design is using 3 different linear regulators (12V->8V, 8V->5V, 5V->3.3V). The circuit needs less than 500mA. Is there a better way to do this than using 3 regulators? It works fine now, but I was wondering about smaller size, less cost. Since the load is not constant, I don't think I can use a voltage divider?

author: Zero999
author_rank: Super Contributor
timestamp: July 05, 2011, 05:54:32 pm
content: It's probably the best option.You've not said at what voltage you require the most power? If battery life is important, you could use a switching regulator for the voltage you require the most power from.

author: ToBeFrank
author_rank: Regular Contributor
timestamp: July 05, 2011, 05:59:40 pm
content: The most power is required at 3.3V, about 220mA at maximum load. This design is not battery powered so power efficiency (other than thermal management) is not a big concern.
Multiple push buttons - Raspberry - Page 1
Forum section: electronics / projects

author: XaviPacheco
author_rank: Regular Contributor
timestamp: August 27, 2018, 01:20:36 am
content: Hi,What is the best way to implement an algorithm to read 6 push buttons, debounce them, and do something according to the button pressed? Interrupts or polling mode? I would appreciate any resource you could provide.Thank you.

author: rs20
author_rank: Super Contributor
timestamp: August 27, 2018, 01:29:36 am
content: I'm going to leap in ahead of the crowd and say that anyone who flatly says "interrupts are better" or "polling is better" or "a button is an input event and interrupts are about responding to events so interrupts is the right choice" is giving bad advice. They both have their advantages and disadvantages.Given that your using a Raspberry Pi, it seems like power efficiency is a lost cause; so I'd recommend starting with polling for the sake of simplicity. It's much easier to reason about debouncing algorithms when your samplings happen on regular intervals, especially if you're new to this sort of thing. You can then think about interrupts as a later micro-optimization.
Multiple soft latches which turn other latches off - Page 1
Forum section: electronics / projects

author: Lazyboy
author_rank: Contributor
timestamp: February 09, 2022, 09:30:41 pm
content: I am a HW designer and programmer, using microcontrollers for everything, but the chip shortage is having me do everything the old way again. No micros. Only Jelly BeanI have 4 buttons, each of which turn on a different part of the circuit. I need "soft latch" on all of them, and the obvious answer is this very popular video:So this is pretty simple, but I also need the following. When one new button is pressed, it needs to "un-latch" the other one that is on (whichever that might be). So only one circuit can be active at one time.Imagine it with 4 buttons connected to 4 LEDs, only 1 LED can be latched on with its corresponding button. When a new button is pressed, the new corresponding LED is latched on, and the other LED is unlatched by that (turned off).Can anyone help?Thanks!

author: ledtester
author_rank: Super Contributor
timestamp: February 09, 2022, 10:19:53 pm
content: A recent related thread:https://www.eevblog.com/forum/projects/selector-switch-using-push-buttons-(e-g-like-source-selection-on-an-hifi-amp)/
multiple thermistors - get max value - Page 1
Forum section: electronics / projects

author: Chupacabras
author_rank: Regular Contributor
timestamp: December 21, 2015, 04:22:33 pm
content: Hi,I have several thermistors (NTC) to monitor temperature inside enclosure on different heatsinks.I want to control fan according to maximum value of those thermistors. Without MCU, just analog circuitry.But I don't know how to get the highest value (voltage) of those thermistors.I tried it with diodes, but it seems to be quite inaccurate.Is there any way how to get "max" value of several analog signals?

author: dmwahl
author_rank: Contributor
timestamp: December 21, 2015, 04:55:35 pm
content: Setting up an op-amp as an ideal diode (precision rectifier) will remove the error due to diode drop.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 21, 2015, 05:07:47 pm
content: Might be worth looking at the R-T curve of the thermistor around the temps you're interested, and how that influences the effect of just wiring them in parallel.You may find that simply wiring them in parallel will be close enough to achieve what you want. How much difference are you actually going to see between the 4 locations?

author: Seekonk
author_rank: Super Contributor
timestamp: December 21, 2015, 05:39:07 pm
content: I've done a similar thing with open collector LM339 outputs in parallel, you get the lowest value.

author: Chupacabras
author_rank: Regular Contributor
timestamp: December 21, 2015, 06:05:04 pm
content: Quote from: dmwahl on December 21, 2015, 04:55:35 pmThank you!That works perfectlyExactly as I need
Multiple thermocouples reading issues - Page 1
Forum section: electronics / projects

author: shamooooot
author_rank: Regular Contributor
timestamp: August 15, 2025, 07:28:47 am
content: Hi guysI need help tackling intermittent jitter / cross coupling on multiple transmitters thermocouple loops.- Multiple K-type thermocouples (, one per transmitter.- Transmitter SW-TK18https://www.aliexpress.us/item/3256804166845987.html?gatewayAdapt=glo2usa4itemAdapt: K input, 4–20mA output, specs: 12–24VDC supply, isolation 1500VAC/1min, accuracy 0.2%FS, temp drift ≤0.05%FS/°C, load 0–600Ω.- Power: all transmitters and displays fed from the same 24V supply.- Individual displays with 250Ω burden resistor to display readings.I am getting occasional jitter on readings. Sometimes one channel’s reading shifts when another channel or transmitter changes temperature.Apparently the best solution is using a 4–20 mA loop isolator, but for 8 sensors it would be out of budget and I don't have enough time to order them.
Multiplexed user interface ideas - Page 1
Forum section: electronics / projects

author: Pferd
author_rank: Contributor
timestamp: October 13, 2021, 06:17:57 pm
content: Hey there,I am in need of some clever help with my user interface. It consists of 5 seven segment displays plus a 2x8 button array with illuminated tactile switches. The Leds are on two channels each 8 just like the seven segments plus dot. The channels get multiplexed by a 4017 counter and BC517 Darlingtons. The low side is driven by a ULN2803. But I am struggling with the switches. Maybe somebody has a good and elegant way of wiring them up. Ideal would be, since this interface sits on a separate daughter-board, to utilize the same 8 lines the leds are using for the switches during the time the two switch-channels are active in the cycle. The last option as far as I can see is to use a whole separate port (PORTC) for the switches. In my schematic the 16pin connectors are meant to be together and the 10pin connectors are together.I wouldn´t mind using the PORTC for the switches, since I have many pins left, but I´m just wondering if there is a more elegant solution. But I can´t see a way of using only one port for the leds and switches without disrupting the led action.Thanks in advance!

author: Kleinstein
author_rank: Super Contributor
timestamp: October 13, 2021, 06:40:20 pm
content: If only 1 key at a time (one of each group) is pressed, one could connect the switches to the segment lines and use to seprate inputs for the µC. In an additional phase the µC would turn of all leds on the high side and than scan the 8 low sides 1 at a time.
Multiplexer or other analog switch with +30V analogue input - Page 1
Forum section: electronics / projects

author: willPowell
author_rank: Contributor
timestamp: May 09, 2022, 09:56:20 am
content: Hi everyone,I am looking to switch an analogue 30V signal across 4 channels to a load of around 10kOhms (30V / 10k = 3mA) at 30kHz+.I am currently using optically isolated solid state switches which are easy to implement but only got to around 7.5kHz.I previously tried with gate drivers and an H-Bridge configuration however this proved too difficult to implement for reasons out of my EE understanding.Multiplexers seem like a good solution, however most are designed with low analogue input voltages.Please only suggest IC's that do not require much additional circuitry!Thanks in advance,Will

author: Someone
author_rank: Super Contributor
timestamp: May 09, 2022, 10:42:23 am
content: There are many switches pretty much designed for exactly those specifications: TMUX7209

author: Terry Bites
author_rank: Super Contributor
timestamp: May 09, 2022, 12:21:36 pm
content: Microchip HV range.

author: Zero999
author_rank: Super Contributor
timestamp: May 09, 2022, 02:42:51 pm
content: DG303Bhttps://www.vishay.com/docs/71402/71402.pdf

author: willPowell
author_rank: Contributor
timestamp: May 10, 2022, 10:09:09 am
content: Thank you for all your answers. I think I will go with the TMUX7208 it looks like a nice and simple solution
Multiplexing different circuits to one output pin - isolation methods? - Page 1
Forum section: electronics / projects

author: max_torque
author_rank: Super Contributor
timestamp: September 06, 2020, 07:54:14 pm
content: I have a device that has multiple "channels" where each channel can be software selected as to what that channel's function.One function is a high side output, using a smart switch, this is a low impedance (50mOhm) output of system voltage, which is normally around 28v, but can be as much as aropund 45 volts under certain casesA second function is as a precision Thermistor, where there is a precision current source (at between 1 to 5 volts depending on thermistor used and the temperature of that thermistor)This means that the thermistor circuitry needs to be isolated from the high side switch circuitry, and the up to 45 volts that could sit on the pin due to that function. What i need is ideas for how to achieve this. Currently top of the list is using SSR's (60v & 100mA rated) that "hide" the thermistor circuitry behind those solid state devices. Are there any other options? Such as high voltage analogue multiplexers or similar? Cost is not that important, but i'd like to avoid a complex jumble of descretes and physical relays are a no-no due to the devices environment (high vibration). The SSR option also conviently means the switch on signal is not referenced to the voltages on the output pin and hence can be directly driven by the microtypical SSR:https://uk.farnell.com/vishay/vo1400aeftr/ssr-mosfet-60v-100ma-full-reel/dp/2369247The on state resistance and leakage needs to be reasonably well controlled between -40 and ideally 125 degC (i'd except 105 degC) to avoid messing up the thermistor drive current.Any other options / ideas to do this isolation / switching?
Multiplexing or using 431's for a more compact VU Meter? - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: August 22, 2023, 04:25:18 pm
content: Of course I know there's dedicated VU meter IC's with tons of comparators inside, but I was thinking. Why not just use TL431 voltage references instead of op amps? If you feed the signal into the Ref input, biasing it 2.5V above ground, it would work as a crude comparator, right?And another idea, couldn't you just multiplex one op amp, so have an electronic switch that grounds either the LED or a resistor divider network for the comparator voltage. This way you can just use one op amp and multiplex it trough each voltage level. Probably wouldn't be that much more compact when discrete but it should be more compact in an IC.

author: TimFox
author_rank: Super Contributor
timestamp: August 22, 2023, 05:36:32 pm
content: How would 431s be more compact than simple comparators?Interesting question: how to obtain the "ballistic" performance for arealVU meter?https://www.aes.org/aeshc/pdf/mcknight_qa-on-the-svi-6.pdf

author: TimFox
author_rank: Super Contributor
timestamp: August 22, 2023, 06:49:42 pm
content: Comparators are readily available packaged in quads.You still need resistors for both solutions.The ballistic properties ofrealVU meters, not the fraudulent ones in vulgar use, are covered in my citation and the Wikipedia article.See question 10 in my citation.For audio recording and broadcast modulation, peak-responding meters are probably better than “volume” meters (VU = volume unit).

author: Benta
author_rank: Super Contributor
timestamp: August 22, 2023, 07:03:07 pm
content: Quote from: TimFox on August 22, 2023, 06:49:42 pmSpot on. I believe this was pioneered by the BBC, who called them PPM or "peak programme meters".They were characterized by a very fast attack (rise time) and a slower, well-defined decay (fall time), and also by responding to both positive and negative peaks.All back in the analog meter times of course.

author: TimFox
author_rank: Super Contributor
timestamp: August 22, 2023, 09:10:52 pm
content: Iamreplying to your thread.Yousuggested replacing comparators with LM431s and I saw no reduction in complexity compared to quad comparators.Youare talking about "VU meters", and I pointed out thatrealVU meters have ballistic specifications.Youasked what that meant, and I referred you to the specific point in the article about VU meters.Youasked what this has to do with your thread, and I answered.

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 22, 2023, 10:36:06 pm
content: Quote from: ELS122 on August 22, 2023, 04:25:18 pmYou might if your VU meter only has one or two LEDs. (More of a max/min level check than anything else)As you mentioned, they make dedicated UV meter chips for a reason... They wouldn't if the other solutions were better/easier.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 23, 2023, 10:02:47 am
content: Making what you can buy is silly.
Multiplexing PT1000 with i.mx28 - Page 1
Forum section: electronics / projects

author: XaroRSA
author_rank: Contributor
timestamp: October 26, 2014, 07:29:08 pm
content: Howdi peeps.I am looking to multiplex numerous PT1000's thermometers using a Freescale i.mx28.I plan to run a single adc channel into the MUX(74HC4067), then out to the sensors.Do I need to use a input buffer before the MUX? Will the +-80ohms Ron from the MUX serious affect my readings?The adc max voltage is 1.8V.Cheers!

author: SeanB
author_rank: Super Contributor
timestamp: October 26, 2014, 07:58:31 pm
content: As it is a pt1000 sensor are you using a 2 wire or a 4 wire connection? With 2 wire you will need to cal out lead resistance or accept the temperature error, and for 4 wire you will need 2 switches per channel and buffer them both after the switch to feed the ADC. Best is to arrange any gain setting and filtering on the buffer stage as well, a low pass filter at the input to the amplifier will help, but remember the settling time for the filter after changing inputs to avoid reading the step change as an error.Use the switches from the same 4067 to switch the wiring from a single sensor, otherwise you will have errors from temperature differences between the IC's affecting readings. Buffer after the IC because the ADC input current will cause issues if you feed the input current through the poorly defined switch resistance. Low pasx filter because temperature is a slow signal. You might also want a low pass filter on each input to the switches, or at least a series resistor for ESD protection, and sample after a delay for settling, or use a series of readings till they settle to a value.

author: XaroRSA
author_rank: Contributor
timestamp: October 26, 2014, 08:22:50 pm
content: Its a 2-wire connection for all the sensors.Im using this diagram is a reference:http://openenergymonitor.org/emon/sites/default/files/rtdmodule.pngThe i.mx28 has a maximum of 1.8V on the adc channels.The accuracy is acceptable up to 0.5 degrees, and 1 degree when 100+.Do you have any examples or links I can check out SeanB?

author: SeanB
author_rank: Super Contributor
timestamp: October 26, 2014, 08:49:15 pm
content: No, just fixed a couple of multi input boards on equipment. Most used a buffer after the switch to drive the ADC and do the required gain, filtering and such, and used RC filtering on the inputs along with overvoltage protection ( making it do dual duty as well) to low pass signals in. You could get a stable reading even with a lot of mains nois on the signals.Are you switching the power to each sensor as well with an analogue switch as well, or just using lots of 1k 0.01% resistors fed from a 2.048V reference via a buffer stage?

author: XaroRSA
author_rank: Contributor
timestamp: October 26, 2014, 09:22:53 pm
content: Havant decided on the final design yet, but was leaning more to the many 1k 0.01% resistors.
Multiplexing scheme of an LCD module - Page 1
Forum section: electronics / projects

author: Miti
author_rank: Super Contributor
timestamp: August 28, 2019, 07:14:09 pm
content: I have a device with an LCD that is defective. I have no chance or will to repair it but I'm thinking of making my own board for it while using the case, the LCD, etc. How do you figure out the multiplexing scheme of a 7 segment LCD? I have no idea how many COMs it has.Thanks in advance!Edit: The device is defective, not the LCD.

author: TomS_
author_rank: Frequent Contributor
timestamp: August 31, 2019, 12:44:29 pm
content: Brute force.Hook a suitable power supply to pins 1 and 2, if no segment comes on try 1 and 3, and so on.Eventually you will find a common and can start to map pins to segments.Perhaps the datasheet for the original hardware used to drive the LCD could give some hints as to which pins are commons.

author: Miti
author_rank: Super Contributor
timestamp: September 07, 2019, 02:55:31 pm
content: Quote from: TomS_ on August 31, 2019, 12:44:29 pmThanks Tom!There's no chance to find a datasheet, just a blob of epoxy and few caps.Anyway, I was able to map it using the FY6600 generator set to 50Hz square wave and 3V amplitude. Higher voltage and I see ghosts, lower voltage and i don't see anything. 3V seems to be the sweet spot where only the correct segments turn on. This is the device that I want to make my own PCB for.https://www.banggood.com/WeiHeng-A08-50KG5g-Backlight-Digital-Handle-Luggage-Scale-Portable-p-954735.html?rmmds=myorder&cur_warehouse=CNIf you ask why, I bought one from BG and it was reading too high. I found the way to calibrate it, you attach the batteries while pressing both TARE and UNITS and it goes into calibration mode. You then set the temperature, the zero level and, I think, 20Kg but I'm not sure. Unfortunately while I was playing with the calibration mode and trying to figure out what's the upper calibration weight that it wants, it simply died. Probably it has bad code that overwrites some code area with the calibration constants in certain conditions, I'm just guessing. So now it won't power up.
Multiplexing stuff - Page 1
Forum section: electronics / projects

author: Veips
author_rank: Newbie
timestamp: December 20, 2016, 07:50:12 pm
content: I don't really have much experience with multiplexing but I wanted to know what is the difference between 16-multiplexing and 32-multiplexing because I was looking at LED drivers and in some of them there was 16-multiplexing support and or others 32-multiplexing or something else.

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: December 21, 2016, 11:33:11 am
content: Multiplexing means, like one to many -< , here you have one input and some bunch of control lines (lets say n) , you can direct that input to any of the 2^n output lines. Your 16 lines and 32 lines may be 1 to 16 or 1 to 32 mux.

author: Wilksey
author_rank: Super Contributor
timestamp: December 21, 2016, 12:43:51 pm
content: One can drive 16 channels, the other 32 channels.
Multipole magnetic encoder discs .. WHERE ? - Page 1
Forum section: electronics / projects

author: free_electron
author_rank: Super Contributor
timestamp: December 28, 2017, 06:16:27 pm
content: Anyone know where to buy those ?I am looking for multipole (11, 12 to 20 pole or more ) encoder discs like those used for speed/position sensors on motors.something in the 10mm to 14 mm range.Pololu sells those but i want a different source.

author: floobydust
author_rank: Super Contributor
timestamp: December 28, 2017, 06:45:29 pm
content: Try outK&J Magnetics.Usually at that small diameter, people go optical. With multipole magnets, I think the PPR is too low and flux is weak, if it's the usual fridge-magnet style.

author: mjkuwp
author_rank: Unknown
timestamp: December 28, 2017, 06:56:56 pm
content: I've ordered from this company.http://www.phoenixamerica.com/

author: jpanhalt
author_rank: Super Contributor
timestamp: December 28, 2017, 07:14:02 pm
content: Sounds like you want to build an encoder. If that is your purpose, my suggestion won't help.However if you just want a magnetic encoder, have you considered the AMS AS5048 encoder. It is 14-bit, fairly small, and robust. I have mounted one on the linkage of a farm tractor.John

author: free_electron
author_rank: Super Contributor
timestamp: December 28, 2017, 07:44:46 pm
content: Quote from: floobydust on December 28, 2017, 06:45:29 pmproblem again is finding encoder wheels...i basically need a little wheel that is the size of what they used for casette players to press the tape against the capstan. that would need to have the encoder disc in it.

author: free_electron
author_rank: Super Contributor
timestamp: December 28, 2017, 07:54:32 pm
content: Quote from: jpanhalt on December 28, 2017, 07:14:02 pmnot an encoder. just a motion sensor. ( basically if the magnetic disc is spinning. ) all i need is a pulse output. if the pulse train stops : no more motion

author: mjkuwp
author_rank: Unknown
timestamp: December 29, 2017, 01:28:04 pm
content: smallest here is 16mm diahttp://www.phoenixamerica.com/products/targets/magnetic/Magnet_Wheels/P10A_Magnet_Target_Wheel.html
Multipul DC power supplies in parallel on different breakers - Page 1
Forum section: electronics / projects

author: Plasmateur
author_rank: Regular Contributor
timestamp: August 19, 2019, 02:22:35 pm
content: Hello,I'm just looking for best practices when attempting to wire DC power supplies in parallel. I'm in need of 48V, 50A and I am in possession of QTY:3 48V 20A power supplies.I was going to connect each power supply to mains, and each power supply would be connected through a different 20A breaker. Could I use a mechanical switch to turn them all on at once?Also, should I be using diodes on each DC leg of the power supply to prevent any damage when switching them on?Together they are powering an inductive load.

author: capt bullshot
author_rank: Super Contributor
timestamp: August 19, 2019, 02:39:19 pm
content: In general, the answer is Yes (to both questions).You'd better look for the manual of your 48V supplies to see if there's a preferred way to run them in parallel (some power supplies offer this). Otherwise, the usage of diodes to decouple them is the way to go.By using diodes, the supplies are decoupled and protected, but current sharing might be unequal.

author: Plasmateur
author_rank: Regular Contributor
timestamp: August 19, 2019, 06:34:11 pm
content: Quote from: capt bullshot on August 19, 2019, 02:39:19 pmThank you for the reply! My intuition seemed almost correct - as you say, I should check the manual - they were cheap dudes I bought off amazon, maybe the seller has the manual on hand.
"Multipurpose" relay card with current measurement - Page 1
Forum section: electronics / projects

author: somlioy
author_rank: Regular Contributor
timestamp: January 10, 2019, 07:23:28 pm
content: HelloI'd like to make a relay card for my boat that is multipurpose, controlling multiple 24V loads. With multipurpose I mean that it can be used to control navigation lights and other higher current equipment.I'd like to have multiple channels on the relay card where each channel has a current measurement. Not high precision, but just an indication of current draw.Current draw for navigation lights isnt interessting, but I'd like to use it to decide wether theres a break or not in the circuit.So what I'm wondering is how I could manage the wide range of currents where the navigation lights are as low as approx. 100mA and other equipment ~16A?
Multitask Garden Robot, Emulator Prototype. - Page 1
Forum section: electronics / projects

author: libralect
author_rank: Contributor
timestamp: March 11, 2023, 04:22:03 pm
content: It's a 30kg garden robot that would save 12000 lbs of food packaging waste over a 20 year lifetime, and 4000 lbs of synthesized fertilizer.https://youtu.be/EYTiTh7_zO4I see the dev cost of this robot as being 100 times less than a self-driving car: single error fatality risk, unlimited chaotic cities, 90mph compute time limits, make self-driving cars unfeasible compared to multitask garden robots.Fruit-picking is very difficult using AI, but weeding, digging, sowing seeds, irrigation, are fairly easy tasks, and an experienced developer knows that anything is possible with logic.Millions of acres of farmland are chemically and brutally treated for food that is wrapped in plastic, shipped hundreds of miles, to supermarkets, so as an environmental chemist, rural processes analyst and EE dabbler, I have created an emulator prototype for a garden robot
muRata 1SJ LoRaWAN module - AT command reference document? - Page 1
Forum section: electronics / projects

author: TomS_
author_rank: Frequent Contributor
timestamp: June 12, 2022, 02:29:26 pm
content: Hi all.Im looking at building one of these modules into a project because they are smaller and cheaper than the Microchip RN2483A modules (and they are actually in-stock!).But muRata, in their infinite wisdom, requires you to have an eval kit to get a code that then lets you complete the registration process to get access to such document (yet the datasheet is publically available??)Im wondering if anyone would be able to share this with me as I dont plan to buy the eval kit - its quite a substantial cost for something that I cant later integrate into my project.Thanks.
EMI filters: Looking for second source - Page 1
Forum section: electronics / projects

author: AndersJ
author_rank: Frequent Contributor
timestamp: September 26, 2020, 09:23:04 am
content: I have the Murata DSS6 emi filters in production since 30 years back.They are no longer manufactured.They are the brown ones in the first picture below.Murata suggests the blue DSS1 series as replacements.Unfortunately they are wider, and cannot be stacked side by side as the original brown ones.I am looking for equivalent but thin EMI filters.Does anyone have a suggestion?

author: AndersJ
author_rank: Frequent Contributor
timestamp: October 02, 2020, 04:47:48 pm
content: Second source filter seems difficult to find.How about 3-pin through hole EMI filters in general?Any suggestions?

author: TimNJ
author_rank: Super Contributor
timestamp: October 02, 2020, 05:04:28 pm
content: Is there any way you can roll your own? Is this for a repair? Going into production with an old design, looking for a drop-in replacement?I'm not sure the exact details of the ferrite beads used, but I'd probably suggest a NiZn bead, using something like Fair-Rite 43 material. Slide onto two legs of a U-shaped wire. For the cap, an axial NP0 ceramic, soldered to horizontal wire. Obviously I'm not saying anything novel...that's just what it is.

author: AndersJ
author_rank: Frequent Contributor
timestamp: October 02, 2020, 06:26:08 pm
content: I’m trying to keep 25 year old products in production without upgrading the pcb’s to smd.I’ve been successful so far.This time, for the filters, it seems difficult.Perhaps physically large, 5 mm long, smd devices,if such filters exist, could be a workaround.

author: TimNJ
author_rank: Super Contributor
timestamp: October 02, 2020, 06:48:18 pm
content: Is your issue that you don't want to move to an SMD production line or that you don't want to modify the board layout?You could probably modify the layout to accept two ferrite "bead-on-leads" + ceramic capacitor. It would probably take more space than the existing parts though.

author: AndersJ
author_rank: Frequent Contributor
timestamp: October 02, 2020, 07:25:11 pm
content: "Issue" is a strong word.I have no big issue.If a change to SMD is necessary so be it,and a board layout change is no big deal,but I would prefer a pin compatible second source and move on.
Murata black box - Page 1
Forum section: electronics / projects

author: najrao
author_rank: Regular Contributor
timestamp: July 30, 2018, 10:20:03 am
content: Any idea what this is? And how to put it to use?

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2018, 10:25:09 am
content: Yes, it's a 24V to high voltage inverter. At a guess it's from a Laser printer.Edit: One possible use might be to make a high voltage insulation tester.

author: Zero999
author_rank: Super Contributor
timestamp: July 30, 2018, 10:34:27 am
content: Yes, it's a high voltage inverter and the 300V output is probably the most dangerous, as the current might not be limited to a safe level, as is the case with the high voltage outputs.

author: Gyro
author_rank: Super Contributor
timestamp: July 30, 2018, 11:32:24 am
content: BTW, I suspect the 5.4kV DC outputs are probably rectified and smoothed versions of the 3.75kV AC outputs.

author: najrao
author_rank: Regular Contributor
timestamp: July 30, 2018, 12:53:23 pm
content: Thank you, friends. There are three pcb's inside, and interconnections are not connectorized, wires soldered directly at the edges. The high voltage wires, all four of them, are terminated at each end with molded on 'boots', not allowing further dismantling. Everything is stuck in the case, so no way of studying the pcb and components. It would seem that there are no power devices at all, only ones limited to TO92. No smd, single sided through hole stuff.I have identified where the 24V dc goes in, a header with 7 pins in the top corner. The markings are obscure and applying controlled current limited dc to the two Vcc and GND pins produced no joy - no current whatever. Probably two are more of the remaining pins need to be set up.I did get to read that the unit is part of a Xerox printer of yester years. But no further hard facts. And I know nothing of Xerox printers. I need suggestions on how to crack this.
muRata help - Page 1
Forum section: electronics / projects

author: Cicada
author_rank: Regular Contributor
timestamp: February 24, 2018, 01:38:12 pm
content: HelloI am not sure if it would be better to put this post in the Manufacturing & Assembly board. If so can you guys give your opinion and then I can maybe post it there.Attached is a photo of the sticker on a reel of capacitors from muRata. I have searched high and low. I cannot find a way to decode the lot no. provided on the sticker to determine the date code (manufacturing year) of the capacitors. Does someone know how to do it or can you point me to a documents that shows how.The lot no. on this photo is IA7825FP5. Based on other reels that I have my suspicion is that the 7 in IA(7)825FP5 indicates the year 2007.I would be really glad if someone can help me.Cicada
Murata NXE1 - any good? - Page 1
Forum section: electronics / projects

author: dobsonr741
author_rank: Frequent Contributor
timestamp: June 14, 2023, 01:18:08 am
content: I wonder if you’ve used the Murata NXE1 series - it’s an isolated DCDC converter with PCB coil construction. I wonder if it’s an EMI mess or just fine.Teardown video:https://youtu.be/K6om51cr8Mk

author: spostma
author_rank: Regular Contributor
timestamp: June 14, 2023, 10:53:25 am
content: Murata's DC-DC converters are excellent!the isolation capacitance is just 3pF, which implies that perimary to secundary coupled common mode switching noise must be low.You can even use them for medical applications; the datasheet says:SAFETY APPROVALANSI/AAMI ES60601-1The NXE1 series is recognised by Underwriters Laboratory (UL) to ANSI/AAMI ES60601-1and provides 1 MOOP (operator protection) based upon a working voltage of 250 Vrms max, between Primary and Secondary.UL 60950The NXE1 series has been recognised by Underwriters Laboratory (UL) to UL 60950for reinforced insulation to a working voltage of 125Vrmsand for basic insulation to a working voltage of 250Vrms.Creepage is 2.5mm and clearance is 2mm---The Murata NXF1 series has even better specs:1W SMD 5.2KV Medical IEC60601 1MOPP (Patient protection) @ 250VAC
MuRata passive component SPICE models - Page 1
Forum section: electronics / projects

author: Cerebus
author_rank: Super Contributor
timestamp: August 12, 2016, 11:11:39 am
content: I thought that I'd just point up something I found the other day. MuRata have really comprehensive libraries of SPICE models available for their passive components, tailored to various SPICE simulators including LTSpice. Just look under the "Design Tools" tab on their website.These include things such as modelling parasitics and, for the capacitors, voltage dependence of the dielectric for ceramic capacitors. The latter has a significant effect on the non-ideal behaviour of MLCCs versus their DC bias voltage and can make quite a difference in some circuits. Dave's done a video on this.Here's an example of the effect feeding a 5V 500Hz square wave through 1K to a 100nF capacitor with different DC biases using both the MuRata model of a 100 nF 50V MLCC and the default LTSpice capacitor model.Quite a significant effect. Not important all the time but it'll bite you on the bum on occasions. I wouldn't suggest using the detailed models of passives for every simulation - they slow things down significantly - but where you're relying on details such as filter and timing circuits it's well worth the effort.

author: mikerj
author_rank: Super Contributor
timestamp: August 12, 2016, 02:34:59 pm
content: I recently discovered this very useful resource when I needed to model a specific Murata ferrite bead; trying to create a model based on the impedance plots on the datasheet was becoming very tedious.The voltage dependence of ceramic caps is probably larger than most people realise!http://www.murata.com/en-eu/tool
Murata THT inductor polarity - Page 1
Forum section: electronics / projects

author: Zeyneb
author_rank: Regular Contributor
timestamp: June 22, 2022, 05:14:26 pm
content: Hi there,As I have bad faith in asking Murata tech support a question for my 1 piece a year applicationI hope someone here have experience with the 1300R, 1800R and 2200R series of general purpose THT inductors. In this case the 18R104C part for a dc-dc converter application.Alright, so these parts have a polarity indicated by a short and a long lead length. I might vaguely remember getting informed about something like reducing EMI by connecting the noisy switching transistor on one lead and having the "quiet" node on the other lead.Is there someone here who can provide clarity on this.Many thanks,Zeyneb

author: thm_w
author_rank: Super Contributor
timestamp: June 22, 2022, 09:57:25 pm
content: https://www.mouser.ca/datasheet/2/281/1/kmp_1800r-2936251.pdfhttps://article.murata.com/en-global/article/basic-facts-about-inductors-lesson-6According to this guy the longer lead is the inner/bottom of the coil, but I don't see any references from murata to confirm:https://forum.allaboutcircuits.com/threads/different-length-legs-on-radial-through-hole-inductor.159165/If it does actually matter you could also consider a shielded inductor as well.

author: Zeyneb
author_rank: Regular Contributor
timestamp: June 22, 2022, 11:11:21 pm
content: I have these inductors at home. Would it make sense to build the dc-dc converter on a breadboard and thenmoving another inductor around the one on the breadboard to see in which orientation I have the least signal pick-up?For this other inductor connecting 10 mOhm resistor between the leads and test leads to an oscilloscope? I've not much experience with this. I hope it makes sense.I hope I communicated this clearly.

author: trobbins
author_rank: Frequent Contributor
timestamp: June 22, 2022, 11:12:46 pm
content: If you have sufficient quantity, and can sacrifice one unit, then do a tear-down assessment to identify the lead going to the outermost layer.

author: thm_w
author_rank: Super Contributor
timestamp: June 22, 2022, 11:35:20 pm
content: Quote from: Zeyneb on June 22, 2022, 11:11:21 pmIts unlikely you'll measure a large difference, but yes, you could measure using an oscilloscope then flip the inductor around and measure again.To do this you can connect the oscilloscope ground lead to the probe tip to form a loop. Or buy/make your own field probes:

author: coppercone2
author_rank: Super Contributor
timestamp: June 23, 2022, 05:03:49 am
content: that's fascinating, I thought it would be symetric enough to be basically really hard to measure. 5% really surprised me.What does this, like a non isotropic core and coupling to nearby parts?Maybe it has to do with the test fixture.. you would imagine if its on a bare PCB away from anything, 5 % seems crazy for machine made or film parts.I heard about this phenomena before and I thought maybe 0.5% max error
Music industry Side Gig - Looking For An Embedded Systems Engineer - Page 1
Forum section: electronics / projects

author: barry@azimuthlive.ai
author_rank: Newbie
timestamp: July 01, 2025, 01:58:29 pm
content: Building an industry defining system for capturing live music content. Currently have devices that collect music data that are deployed in 3 US markets.We are a bootstrapped startup looking for someone who has a deep love for music, that can take over the engineering of this network so that we can build for scale. This would be side gig to begin with and hopefully full time down the road.If this interest you, please DM me, if it does not, then I thank you for your time and wish you the best!
Musical Alarm Clock - Page 1
Forum section: electronics / projects

author: frank26080115
author_rank: Regular Contributor
timestamp: February 14, 2011, 05:49:51 pm
content: Video and instructions athttp://www.instructables.com/id/Music-Playing-Alarm-Clock/I know most of you will simply glance at the first page and maybe skim through the rest. This Instructable has 18 steps (with demo examples for each building block) and 5 appendices, with about 90 files and pictures, including logic analyzer files/screencaps, expected terminal output, USB device dumps. I sincerely hope you explore all my efforts. I covered everything from SD cards, FAT file system, USB mass storage, IR remote control, LCDs, RTCs, and decoding MP3s. It's built using a Teensy++ and encased into a SparkFun shipping box.

author: Unknown
author_rank: Unknown
timestamp: February 14, 2011, 07:39:13 pm
content: Great work, I am worried it will break into pieces on a Saturday morning though. Consider a proper box for this nice project!

author: sonicj
author_rank: Frequent Contributor
timestamp: February 14, 2011, 09:59:44 pm
content: looks like a very nice clock. i like the big numbers! definitely deserves a proper enclosure.-sj

author: williefleete
author_rank: Regular Contributor
timestamp: February 15, 2011, 06:28:25 am
content: nice.at one stage i modded a clock radio to turn on an MP3 player and play music when the alarm pin on it went highused an 08M to control the MP3 players play button and connected to the clock's alarm pin via optoisolatorkinda removed it afterward though, i have made my own clock using a few picaxe 08M's the main one has a 1 pulse per second ticker triggering an interrupt and sending out serial to some 7 segment displays being controlled with another 08M and shift registers

author: johnwa
author_rank: Frequent Contributor
timestamp: February 19, 2011, 11:32:48 pm
content: That's a nice display you have there williefleete!I see you prefer 24h format as well. Here is Australia, we seem to get thrown in with the US market sector, and all of the clock radios are 12h format. But, I took mine apart, looked up the datasheet for the clock chip, and found a 12/24h control pin, so I was able to modify it to my liking.Actually, my current alarm clock is the Linux 'cron' command on the file server running an mp3 player. This way, you can automatically have different alarm times on weekends...

author: williefleete
author_rank: Regular Contributor
timestamp: February 20, 2011, 05:02:19 am
content: i used 24 hour as it uses slightly less code space on the 08M's im using and i dont need to use a display to indicate AM or PMi do however have it beep the number of hours in 12 hour format on the hour using the display's "PC speaker" which is controlled via serial, replacing the colon positions with bell characters.
Musical Tesla Coil - Page 1
Forum section: electronics / projects

author: Saitama
author_rank: Contributor
timestamp: July 07, 2019, 09:46:02 pm
content: Hello! I have built a tesla coil and now I'm trying to make a driver circuit for it. I am planning to use 2xG4PC50FD in a half-bridge circuit, but the problem is that I don't have much time left, because I'm going to a different country and I don't have MOSFET driver ICs (I couldn't find any in the local stores). I already built an interupter and I was wandering if i could use couple of transistor as amplifier and NOT gates to drive the GATEs of the IGBTs that way. I don't have much time to research, so that's why I came here.I will appreciate every reply.Thanks in advance!

author: magic
author_rank: Super Contributor
timestamp: July 08, 2019, 08:28:15 am
content: Like this?https://microcontrollerslab.com/totem-pole-tutorial/Q4 is an inverter, Q1 and Q2 are a buffer which could drive a FET if sufficiently powerful transistors are chosen. Divide FET gate charge by intended rise/fall time and see how much current you need. Note that R2 must be low enough to provide sufficient Q1 base current and high enough that it doesn't fry Q4 or itself.The hardest part is pushing the gate through the threshold voltage region, usually 3~4V. This is where R2/Q1 need to work effectively if the FET is to turn-on quickly.Also, if Q4 is powerful enough, Q2 can be replaced with a diode. Then you only need two transistors of the same kind.