hybridfree/eevblog-posts huggingface dataset:
How to reduce noise in VCC line... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: August 28, 2013, 10:31:43 pm
content: Hi,I've got a temperature sensor MCP9701A in today. I noticed that it is very sensitive to noise. If I hook it to my bench power supply the output is correct around 0.9V, but if I power it from my frequency counter breadboard with a 150 MHz oscillator being measured, it pushes the voltage higher, 1.2V or so.I've tried a low pass filter with a 270 ohm resistor and various capacitors and this wasn't very helpful. What other ideas should I try? This is mostly a learning exercise...The data sheet does say this:4.3 Layout ConsiderationsThe MCP9700/9700A and MCP9701/9701A familydoes not require any additional components to operate.However, it is recommended that a decouplingcapacitor of 0.1 ?F to 1 ?F be used between the VDDand GND pins. In high-noise applications, connect thepower supply voltage to the VDD pin using a 200?resistor with a 1 ?F decoupling capacitor. A highfrequency ceramic capacitor is recommended. It isnecessary for the capacitor to be located as close aspossible to the VDD and GND pins in order to provideeffective noise protection. In addition, avoid tracingdigital lines in close proximity to the sensor.

author: Unknown
author_rank: Unknown
timestamp: August 28, 2013, 10:46:10 pm
content: Solderless breadboards with their long wires aren't exactly the most favorable for EMI. Making wires shorter, reducing coupling between wires (no large loops or parallel runs), twisting positive and negative wires and increasing the distance between sections might help. Note that there is about 10pF of capacitance between the rows in a breadboard that might capacitively couple the signals. A 10 pF capacitor has an impedance of only 100 ohm at 150 MHz. You can try grounding rows in between the high frequency signals and power rails. 150 MHz is much higher than I would ever go with solderless breadboards, since building circuits with 10 pF capacitors spread around the circuit gets quite tricky at those frequencies.Try veroboard or even better soldering the components involving high frequencies to a piece of copperclad (that acts as a ground plane) to reduce the noise emitted from the frequency counter.If it's just noise conducted via Vcc, then you can try cleaning it up with an inductor or ferrite bead that's effective at those frequencies.
How to reduce pin count on a 3.2" TFT LCD w/HX8347 Controller - Page 1
Forum section: electronics / projects

author: thakidd
author_rank: Regular Contributor
timestamp: October 28, 2010, 11:51:40 pm
content: Another forum member recently posted a link to this LCD screen as a killer deal:http://iteadstudio.com/store/index.php?main_page=product_info&cPath=3&products_id=54I decided to purchase one to play with. It comes with a 3.2" TFT LCD screen, HX8347-A controller, touch screen, and SD card reader. I would like to interface this device between various Atmel AVR products but I see one road block. Apparently the board requires 40 pins for the LCD control. This would blow a lot of my development board out of the water if the device was plugged directly in. Some would not have enough pins to operate the LCD + touch and others would be able to operate the device but provide no room for additional sensors.My question therefore is...Does a chip exist (such as a shift register or something) that would limit the pins? Could I possibly take this design and convert it to a serial/spi interface? Should I instead incorporate one MCU that would handle the user interface and pair it with another that would perform the other needed functions?I am concerned about which route to take. I do not want to degrade performance of the screen, touch, sd etc. I do not want to use all of my mcu pins. Nor do I want to over complicate and under utilize components in my design.Note: I am currently looking at 8-bit all the way up to arm for potential solutions for this and other projects as I would like to possibly make this screen part of my dev kit for any projects that might warrant a touch screen LCD.As always, thx in advance for your suggestions.

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 29, 2010, 12:44:12 am
content: some discussion here. you can get the spi ready lcd, and my suggestion, get the touchscreen, that can be a nice project to build

author: thakidd
author_rank: Regular Contributor
timestamp: October 29, 2010, 12:52:40 am
content: Ahh, that is the thread I found the Itead LCD screen linked in my OP. The Itead screen was only $27.50 and I already ordered it. At this point, instead of ordering another screen, I would like to figure out how to setup the one I ordered. I figure that route may save some cash and will also be a great learning experience...I just need a pointer in the right direction on this project. Pretty Please?!?

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 29, 2010, 01:00:38 am
content: then i think you should get the Duemilanove too as in the link... for just driving it. i once thought the same as you, if there is simple way to drive dot matrix LEDs, but there is no magic unless you buy another supporting chip just for thatand you are not gonna use all the 40 pins, some are used for SD and touch interface, its going to be like 16 to 30 only, you check it. but nothing as simple as 2-3 wires spi or i2c. so you can get the Duemilanove programmed as driver that accept serial data from another chip. i never done this yet, but this is what i understand. Cheers.
How to reduce speed of air conditioner AC fan motor? - Page 1
Forum section: electronics / projects

author: brunoaduarte
author_rank: Newbie
timestamp: October 29, 2024, 03:22:04 pm
content: The LOW setting of my Hisense 10,000 BTU window air conditioner rotation is very fast and noisy.I'm trying to reduce the speed for the LOW setting.The fan motor has 3 wires that set the rotation speed: red (high), yellow (medium), white (low)How can I modify the circuit of the low speed to reduce the rotation a little bit?Icing is not an issue because i'll not use the ar conditioner at the lowest temperature (16°C).I'll set it to 20~22°C, and also I just would like to reduce the fan speed a little bit, not stop it.

author: schmitt trigger
author_rank: Super Contributor
timestamp: October 29, 2024, 03:46:30 pm
content: Is the connector which I circled in red in the schematic, the same as the one I circled in red on the board?

author: Marco
author_rank: Super Contributor
timestamp: October 29, 2024, 05:36:27 pm
content: Yeah, that's probably the connector ... but you disconnected it, shouldn't you know?It's a 3 speed PSC motor, so that's hostile to additional speed control in multiple ways.There's a youtube video on how to wire a PSC with a VFD by disconnecting the capacitor. That might work if you simply ignore the mid/low speed connections and let the VFD do all the speed control. Or the motor might catch fire, it's a hack.PS. in another thread it was said simply putting a run capacitor in series with the low speed winding worked ... that seems slightly easierhttps://www.eevblog.com/forum/projects/how-to-control-ac-fan-speed/

author: brunoaduarte
author_rank: Newbie
timestamp: October 29, 2024, 06:31:50 pm
content: Exactly.

author: brunoaduarte
author_rank: Newbie
timestamp: October 29, 2024, 06:47:20 pm
content: Quote from: Marco on October 29, 2024, 05:36:27 pmAny downsides with the capacitor trick?

author: Randy222
author_rank: Frequent Contributor
timestamp: October 29, 2024, 09:10:40 pm
content: Just inline a speed control with the low speed wire.

author: Marco
author_rank: Super Contributor
timestamp: October 29, 2024, 10:15:45 pm
content: Quote from: brunoaduarte on October 29, 2024, 06:47:20 pmJust like triac control it might not work, or not work well for low speed control. Everything except VFD is an extremely hacky way to do smooth speed control on an AC motor.You could also try to bodge in some cheap BLDC/inverter airconditioning motor, cheap ones seem to take a 0-6V DC control input with an integrated BLDC driver.PS. oh all the cheap DC motors are 310V ... no good in Brazil I guess.

author: moffy
author_rank: Super Contributor
timestamp: October 29, 2024, 10:21:54 pm
content: Quote from: Randy222 on October 29, 2024, 09:10:40 pmThis motor is not a universal motor(DC motor with a series field) and would probably object to having DC put through it.

author: Randy222
author_rank: Frequent Contributor
timestamp: October 30, 2024, 06:57:04 pm
content: So then just inline a inductive "ballast", which is nothing more than an inductor. Adding some inductance increases Z (ohms) which lowers the amps and slows the motor.
How to reduce the time taken to reach desired current ?  - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: March 11, 2024, 06:34:25 am
content: Hello everyone, I would like to ask how to decrease the time to reach my desired output current which is around 0.35A? my output voltage is 60V and my output power is 21W. Thank you in advance guys. The simulation is given below.
How to register an account in Hantek website?  - Page 1
Forum section: electronics / projects

author: beauty2003tt
author_rank: Contributor
timestamp: January 28, 2016, 09:07:19 am
content: I was trying to download some software for my MSO5062D, and the site requires registration (which is silly in the first place). So I try to register, and the registration form is rejecting valid address, "btt.bk+hantek@gmail.com". Does someone know what's the problem here? Thanks.

author: cdev
author_rank: Super Contributor
timestamp: January 28, 2016, 04:47:29 pm
content: The username part (the part before the domain name) of any email address should just have alphanumeric characters and underscores, dashes, etc. A valid Unix username is the traditional thing to put there, but it can be longer, but it should not have spaces or other punctuation marks especially unless they are there for special reasons. The IETF (http://ietf.org) determines things like that in a process which results, eventually in what are called Internet standards - memorialized in a formalized structure called RFCs.

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 28, 2016, 04:49:54 pm
content: The + is killing it. Sucks but most people don't allow this.
How to remove only metal layer of IC chip not polysilicon layer? - Page 1
Forum section: electronics / projects

author: lakot18326
author_rank: Newbie
timestamp: September 12, 2024, 03:38:03 pm
content: Due to the presence of the metal layer on the IC chip, it is very difficult to determine how polysilicon layer is connected to the metal layer (first image).I decided to remove the metal layer of the chip using a low concentration of hydrofluoric acid.The second image provide useful information about the diffusion layer, but unfortunately, the polysilicon layer was also etched.What material should I use to selectively etch only the metal layer?

author: magic
author_rank: Super Contributor
timestamp: September 12, 2024, 06:03:00 pm
content: You need to remove some oxide that the metal is embedded in and you have just learned the hard way that stuff which attacks oxide attacks silicon too. I haven't done such things, but AFAIK people who do rely on careful timing to avoid overetching.You could lookhere, but again, it's just one source I know about, I haven't done it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 12, 2024, 10:40:26 pm
content: The metal is aluminum; anything which attacks it will do. HCl and KOH are likely candidates, with KOH discouraged as it can attack SiO2.If the full chip (minus bond pads, fuses, etc.) is passivated, this may not be very effective, and you'll have to carefully dose (time and concentration) HF to etch the passivation.AFAIK, HF without oxidizing power (no excess nitrate, chlorine, O2, etc. dissolved) doesn't attack Si, or at least anywhere near as fast, so maybe you left it on much too long, or had too much oxidation available. Doing a little bit at a time, and maybe adding a few granules of a reducing agent (sulfite, thiosulfate) to the solution, might help.Tim

author: lakot18326
author_rank: Newbie
timestamp: September 12, 2024, 11:43:32 pm
content: As expected, the right timing and concentration was the answer. Thank you for the good information.
How to reprogram APM 2.8 Flight Controller ? - Page 1
Forum section: electronics / projects

author: Swaroop 21
author_rank: Regular Contributor
timestamp: July 15, 2024, 01:00:30 pm
content: How do I program the APM 2.8 Flight controller with Arduino IDE to basically make the onboard AT2560 Chip act as an Arduino Mega. I have no use for it as a flight controller with its "Mission Planner" application. I tried to connect it to a PC it detects as a Mega2560 in Arduino IDE but I can't upload a program it says timeout. So is there any jumper setting that I need to change or perhaps I need to erase the 2560 and burn a new bootloader using ArduinoISP ?? As it would be a nice board with the sensors built in.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: July 15, 2024, 01:13:36 pm
content: you might have to change which upload method is used, thats found under Tools/programmer menu.I dont have a apm 2.8 around anymore but am sure it used it's own bootloader (non arduino) so you may have to either burn a bootloader or use external programmer (e.g another arduino device as the avrdude programmer)darkspr1te

author: Swaroop 21
author_rank: Regular Contributor
timestamp: July 15, 2024, 01:41:51 pm
content: Okay, Thanks
How to? Reusing LED Driver and LEDs (Backlight) from an LCD panel - Page 1
Forum section: electronics / projects

author: Eheran
author_rank: Regular Contributor
timestamp: October 24, 2024, 01:12:47 pm
content: I have an LCD panel (LP156WF6, datasheet) that I would like to convert to a "lamp". The datasheet shows connections from LED Driver to LED Backlight, but to nothing else. So I assume I do not need anything else to make the backlight turn on. The datasheet specs V_LED, PWM and EN on page 7. I applied 12 V to V_LED while feeding 500 Hz PWM with 50 % duty cycle and EN pulled high. But nothing happens. No current draw (<0.2 mA). I also tried to use 100 % duty cycle, as per the specs, with a DC signal with logic high (3 to 5 V) but also nothing. There is a timing diagram on page 15, but there is no easy way for me to get the +12V to ramp up within 0.5 to 10 ms (using a RD6006P). Is that critical? Time between V_LED to PWM and then EN are listed as min=0 and max nothing. I made an ESP32 script (code below) to turn on PWM and then the EN signal at reasonable timings after V_LED is present, but still nothing happens.How can I get the LED driver to turn on? Any ideas? What am I missing?Code:#define LEDC_TIMER_BIT 8#define LEDC_BASE_FREQ 500 // PWM frequency in Hz#define LEDC_TIMER_BIT_2 8#define LEDC_BASE_FREQ_2 20 // PWM frequency in Hz#define LED_PIN 15#define EN_PIN 18#define V_LED_PIN 19#define onboard_LED 27void setup() {pinMode(EN_PIN, OUTPUT);pinMode(V_LED_PIN, INPUT);digitalWrite(EN_PIN, LOW);ledcAttachChannel(LED_PIN, LEDC_BASE_FREQ, LEDC_TIMER_BIT, 0);ledcWrite(LED_PIN, 0);ledcAttachChannel(onboard_LED, LEDC_BASE_FREQ_2, LEDC_TIMER_BIT_2, 2); //channel 0 and 1 are together, must be 2 for 2 frequenciesledcWrite(onboard_LED, 0);}void loop() {int V_LED_PIN_state = digitalRead(V_LED_PIN);if (V_LED_PIN_state) {delay(1);// Set duty cycle to 50%ledcWrite(LED_PIN, 128);delay(10);digitalWrite(EN_PIN, HIGH);ledcWrite(onboard_LED, 128);} else {delay(1);// Set duty cycle to 0%ledcWrite(LED_PIN, 0);delay(10);digitalWrite(EN_PIN, LOW);ledcWrite(onboard_LED, 0);}}

author: Eheran
author_rank: Regular Contributor
timestamp: October 28, 2024, 05:14:03 am
content: Got it to work. I had to also apply 3.3 V to Vcc (pin 12+13) and then it worked right away.
How to run a galvanometer? - Page 1
Forum section: electronics / projects

author: somlioy
author_rank: Regular Contributor
timestamp: May 22, 2013, 07:41:18 pm
content: I got one oftheseinsulation monitors at work, and I want to replace the electronics in it with some custom stuff for another application. But I'm not quite sure how to drive the galvanometer , does anyone have a clue? Resistance measurements shows about 60ohms when the pointer is held still. Jumping up if moving.

author: qno
author_rank: Frequent Contributor
timestamp: May 22, 2013, 08:45:22 pm
content: Usually they are controlled with current anywhere in the 0 to 100 uA range to 0-10 mA.Ad a current meter in series and you can measure the full deflection current.Its a galvanometer (wiki ) a coil that rotates in a magnetic field.

author: somlioy
author_rank: Regular Contributor
timestamp: May 23, 2013, 01:32:34 pm
content: So thats what they're called. Easier to get some results ongoogle then.
How to safely test exposed-board style mains power supply? - Page 1
Forum section: electronics / projects

author: technix
author_rank: Super Contributor
timestamp: May 14, 2017, 04:31:33 pm
content: I recently bought two mains power supply boards sold as NOS (although it looks more like used but thoroughly cleaned.) Those boards are rated for 19V 65W, and comes with onboard IEC power connector and power switch. Before I plan anything for those boards, I need to test them. Here are my questions:How do I test the exposed-board style mains SMPS safely? I need to measure the actual output voltage and ripple. I have a true RMS multimeter (UT61E,) the DS1054Z oscilloscope and a few 10 ohm 10W resistors.Do I need to re-cap the board unconditionally? Or should I leave the old caps in if the ripple is low enough under load?How do I integrate this board into my own project? The screw holes on this board does not line up with the holes on the project case I have, can my own PCB contain holes matching this board so I can use brass stand-offs to mount the module on my PCB?How do I isolate the primary side of the module from my low-voltage circuit board? Can I put low-voltage circuitry directly below the power module with some isolation in place? If so, how to install the isolation material in between the boards? Will cardboard sandwiched between the power module and the main PCB work, with the cardboard held in place using the stand-offs?

author: David Hess
author_rank: Super Contributor
timestamp: May 14, 2017, 09:34:43 pm
content: Check the date codes on the capacitors. Are they a known good brand? If they are old or some no name brand then I would change them.Use fishpaper instead of cardboard.I would probably use plastic standoffs instead of brass but brass will work if creepage and clearance requirements are still met.
How to search for Multi Rail Different Voltage output SMPS - Page 1
Forum section: electronics / projects

author: RoadRunner
author_rank: Frequent Contributor
timestamp: March 30, 2020, 01:11:20 pm
content: For a Project I am doing I need 100 to 150W Mains SMPS preferably with +8V -8V, +24 -24 all around roughly 1A or even +24 -24 both 2A will work.Meanwell has many 2 to 4 rail SMPS but either they lack negative rail or voltage on negative rail does not blow -12V.Any reputable manufacture like mean well will do. But I just does not seem to find even +/- 24V SMPS anywhere at all.Does any one have any idea how to look for this type of SMPS? Or I will have to Use two sperate power supply?
how to see from lab results the PID amplifier which needs to be used - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: December 11, 2024, 06:44:54 pm
content: Hello, I have built a PLL system based on the article attached.In the scope photos we see the IF signal of the mixer.When the servo amplifier is ON as shown in photo 3 then the error signal ripple is much much smaller then photo 5.but the VCO keeps moving decreasing the frequency.So ripple wise the amplifier is good but the DC shift is not getting fix.My only spec is getting a lock on the resonant frequency of the resonator shown in the diagram below.We drive the FM coil of the YIG for VCO functionality.My YIG(VCO) FM coil has the following carachteristics:sensitivity 400(Khz/mA)3dB BW 2MHzresistance 1ohminductance 1.5uHHow can I see what kind of PID needed in my situation?What do you think the PID needs to be to lock in resonant frequency?
How to select a miniature geared dc motor for a project?  - Page 1
Forum section: electronics / projects

author: Fflint
author_rank: Frequent Contributor
timestamp: January 31, 2021, 03:17:27 pm
content: I've spent lots of time searching, but I found nothing so perhaps someone here will be able to help.Occasionally I look for a tiny/cheap geared dc motor or stepper to select it for a hobby project. Good examples of those motors are S30k (12v 14rpm dc motor, or 24byj48 (tiny stepper with 1:64 gearbox). Currently the way I do it is I go to aliexpress and search for miniature gearbox dc motor etc. I find one priced right and order it. No doubt this is not the best way to find generally available parts for projects others could make as well.So I thought there must be some catalogue with all those motors that would make the selection process better. Unfortunately all I can find are expensive higher wattage motors with all metal gearboxes etc. It seems I'm unable to find any catalogue that would feature really cheap tiny hardware like those I mentioned.Does anyone know if such catalogue exists?

author: fcb
author_rank: Super Contributor
timestamp: January 31, 2021, 06:44:34 pm
content: Mabuchi (also Canon, Maxon Motor, Portescap) have on-line catalogues, but for really low-cost (shite) motors you'll be getting production overruns from toys, at best overruns from automotive and HVAC so unlikely to have catalogues. The online robot shops seem to get hold of some of these overruns reliably.

author: wizard69
author_rank: Super Contributor
timestamp: February 01, 2021, 02:02:34 am
content: Maxon Motors: Some really amazing tiny Motors. They have an excellent on line catalog. However you may be appalled by the prices those jewels of a motor have on them.Oriental Motors: An excellent source of small motors. They have AC motors designed for 1 watt of power that can run all day for years. Very high quality stuff.Bodine Motors: also have a very good reputation for small motors. Again online is the place to go for catalog and standard parts.Parker / Compumotor: Really nice steppers and controllers.Pittman: (haydonkerkpittman) make really nice DC motors.Kollmorgen: Towards the large end but still have some nice cataloged small motors.The short list off the top of my head. Note they all sell to the industrial markets so prices might seem steep. However all of these can be found from time to time on the surplus or used market. Frankly I'm familiar with these names because all of them are used at work.There are literally hundreds of motor manufactures out there so the above list is at best a start. New motors are going to cost you if you want quality. Always look at the surplus market for the good deals. Also salvage from industrial machinery is always an option.
How to select the correct ESD immunity class for a device? - Page 1
Forum section: electronics / projects

author: TileSeeker
author_rank: Newbie
timestamp: October 15, 2024, 07:08:53 pm
content: I have a question regarding how to select the correct ESD immunity classification when working on a project.ESD protection s very common to add to PCB to protect sensitive components from large ESD voltages. There are many blogs, articles and application notes that talk about ESD and how to select an appropriate ESD diode, but they always fall short of providing a guideline for how to select an appropriate immunity classification for the specific application.https://www.ti.com/lit/an/slvae37/slvae37.pdf?ts=1728370750697&ref_url=https%253A%252F%252Fwww.google.com%252FIs a good application report that gives a step by step guide for selecting ESD diodes, but when it comes to the ESD class it only says that they select 1kV because that is what IEC 60601 specifies. Is the correct procedure to select an appropriate standard and what those requirements say? Or is there a more detailed analysis that one should do? E.g. I know that the device will likely be used by non-technical people in a non-ESD protected area and i know that I like in a place that can have a very dry environment. Should those factors be taken into account when selecting what ESD class to design for.Do any of the geniuses here have any experience with this?Ideally I would like a looking for a decision making guideline, flowchart, good practice or guide that I can use as a reference. Do you know if something like this exists?

author: PGPG
author_rank: Frequent Contributor
timestamp: October 15, 2024, 07:58:15 pm
content: Quote from: TileSeeker on October 15, 2024, 07:08:53 pmThe procedure looks something like this:EMC directive has a list of harmonized with it standards (updated from time to time).1. In this list you have to find the standard covering your product.2. In this standard there should be listed standards to be used to measure resistance for each disturbance and levels/class to be used in these standards for your product.3. You then use the right standard to check resistance for ESD, Burst, Surge, EM fields, magnetic fields, supply dips and may be other I don't remember.
How to select the right capacitor for this application? - Page 1
Forum section: electronics / projects

author: XaviPacheco
author_rank: Regular Contributor
timestamp: May 29, 2018, 03:29:28 am
content: I attach a picture found on the web as further reference. It's from a motor controller, the AC input goes through a relay and feed the rectifier. The rectifier output goes to capacitors and then to PMDC motor. The point is that I'm making my own controller. I've made several modifications, for example, instead of relay, I'm using solid state device (triac) with zero crossing detection. My question is regarding the big capacitors needed in the rectifier output. According to the image attached, they are two capacitors 1500uF/200V in parallel and a tvs diode. I don't know how they chose them. As I'm making my own design, I want to determine the capacitors that I need. How can I determine the capacitance needed? I will control a PMDC motor of 4 HP @120VDC using PWM. So I know the capacitors voltage rating should be at least 200V. Also, is that TVS diode relevant there?

author: JS
author_rank: Frequent Contributor
timestamp: May 29, 2018, 03:48:52 am
content: To determine bulk capacitance you need to account the current consumption and your allowable ripple, with those two you can choose the value you need. The type, for the size you are pretty much left with electrolytic ones, it doesn't make much sense anything else.The TVS is there for protection, what is it protecting against, I need to see more of the circuit, but some transient or PS failure probably.In parallel with all this also can go an extra power transistor and a braking resistor to discharge the caps when the voltage goes over the specified limit, as it's braking the current will flow from the motor to the driver overcharging the caps. I don't thing the TVS has something to do with this as it seems to have a much higher voltage and they are usually good for very short high current spikes, rather than dissipating a lot of energy from slowing down a motor.JS

author: David Hess
author_rank: Super Contributor
timestamp: May 29, 2018, 04:01:31 pm
content: I agree with JS.The usual rule of thumb for bulk input capacitors is 8200uF per (amp of current)/(peak-to-peak voltage ripple) based on a line frequency of 60Hz and a full wave rectifier which produces 120Hz.

author: Benta
author_rank: Super Contributor
timestamp: May 29, 2018, 06:36:47 pm
content: You don't need the caps at all. The PMDC motor will be perfectly happy running on rectified AC alone. Only downside is that your AC supply is 110 V and the motor is rated 120 V, so you'll lose ~9% speed.With the caps, you'll be supplying the motor with ~150 V.

author: JS
author_rank: Frequent Contributor
timestamp: May 30, 2018, 02:37:02 am
content: Quote from: Benta on May 29, 2018, 06:36:47 pmThe motor might be but the power transistors not so much, one walk-around would be to control the level with SCR instead of power transistors on DC. Still you need to be careful of over-voltage as the kickback of an inductive load can be enough to break the coil insulation.JS
How to send a power impuls - Page 1
Forum section: electronics / projects

author: Jane
author_rank: Frequent Contributor
timestamp: January 07, 2023, 11:28:00 am
content: I would like to start tumble dryer (Miele T8861WP) over internet.To begin the dryer requires START/STOP button to be pushed - it sends an impuls.My idea is that I would use WiFi socket and connect the dryer there. Then, over internet ,I open electricity connection to the dryer.But how can I send an impuls to act like pushing START/STOP button by hand?What hardware modification to make?Thank you for help

author: Psi
author_rank: Super Contributor
timestamp: January 07, 2023, 11:40:11 am
content: You can get remote button pushers.They are like smart lights or whatever, but instead of a light they have a mechanical pusher that will push when commanded to.Just google for "button pusher IOT'

author: Terry Bites
author_rank: Super Contributor
timestamp: January 08, 2023, 03:08:26 pm
content: If the start stop button is a real switch (it looks like it is) you can use a relay. Control the relay with some IOT thing.It would be sensible to monitor the LED status on that switch too. Check the voltages on the LED and design a comparator circuit to suit.I'd pull the control panel pcb and have a sneaky look.Slide the top off by undoing the two screws at the back and have look see. Heres a video showing you how to get in to the machine. Easy.
how to send mms with gsm/gprs shield? - Page 1
Forum section: electronics / projects

author: guy1802
author_rank: Newbie
timestamp: January 01, 2015, 04:20:27 pm
content: Hi all.I am working on my first project and i am trying to send a picture as MMS with arduino uno connected to tinysine gsm/gprs shield(http://www.ebay.com/itm/GSM-GPRS-Shield-For-Arduino-/230911052682).i am using SD and i cant figure out how to send the picturei really appreciate your help:)thank in advence.Guy

author: PChi
author_rank: Frequent Contributor
timestamp: January 02, 2015, 09:51:48 am
content: I don't know how but it may be possible using AT commands to the GSM?GPRS Shield. I suggest looking at the ETSI standards GSM 07.07 & 07.05 | Enhanced Commands available on line and the module specific SIMCOM AT Commands to see if it supports MMS.Does the Arduino Uno come with software to run the SD Card protocol? If not could the board be changed to one with an SD Card socket and software. Some of the SD Card protocol specification is available on line.

author: itdontgo
author_rank: Regular Contributor
timestamp: January 04, 2015, 03:10:20 pm
content: What you're looking for I believe is module specific. The standard AT GSM commands do not cover it. You'll need to find the MMS command manual for the SIM module you have there. I have the command for Quectel but they definitely won't work on a SIM module.It's not trivial what you are trying to achieve... it might be hard!

author: pyrohaz
author_rank: Regular Contributor
timestamp: January 05, 2015, 01:47:39 am
content: http://mt-system.ru/sites/default/files/sim900_mms_at_command_manual_v1.02_0.pdfHere is the AT command datasheet for your module. Hope it helps!
How to set and measure the loop Response of a Flyback using the Bode 100 - Page 1
Forum section: electronics / projects

author: rbola35618
author_rank: Frequent Contributor
timestamp: January 19, 2021, 03:25:12 pm
content: In this video, I show how to set and measure the loop response of a discontinuous Flyback converter. I show how to validate the spice model, how to use Zero-Pole canceling to set the loop. I also show how to used the Bode 100 to measure the transfer function of the Output Filter, the Error Amp, and then take the Open Loop response. Questions and comments can be sent to rbola35618@aol.com or posted here on YouTube.

author: gae_31
author_rank: Contributor
timestamp: January 19, 2021, 05:20:00 pm
content: Would be great if you could show the difference in frequency response between the Bode 100 and the Cleverscope.
How to set the output voltage for the TPS92201 - Page 1
Forum section: electronics / projects

author: mangoByte
author_rank: Newbie
timestamp: September 30, 2025, 12:14:12 pm
content: Hello everyone.This is my first post. I am working on a LED lamp project for which I have chosen the TPS92201 as the LED driver. I would like the output current to be 800mA. So according to the datasheet I have chosen a 0.125m ohm resistor. What I do not understand is how to set the output voltage. In section 8.2.2.2, there is a formula given, which says that a R2 resistor needs to be used. There is no R2 resistor shown in the schematic. Confusingly in the equation in 8.2.2.2 V_FB=0.6V but in section 7.3.5, it says that V_FB is typically 0.1V.I would like to know how to correctly use this IC for an output current of 0.8A and ouput voltage of 3V. This is my first project with such a complexity, so please excuse me for being a noob. I appreciate any help.This is the datasheet:https://www.ti.com/lit/ds/symlink/tps92201.pdf

author: Zero999
author_rank: Super Contributor
timestamp: September 30, 2025, 12:25:39 pm
content: You don't. The output voltage is the forward voltage of the LED(s) plus the feedback voltage. The feedback volage is typically 0.1V, so for 400mA:V = 0.1VI = 0.4AR = V/I = 0.1/0.4 = 0.25R.It's a constant current power supply. It regulates the current not the voltage. The voltage is determined by the characteristics of the LEDs, which depend on the temperature and current. I have only skimmed the data sheet, but if there's a calculation involving the output votlage, just use the nominal forward voltage given on the LED data sheet, plus the reference voltage.

author: mangoByte
author_rank: Newbie
timestamp: September 30, 2025, 12:43:33 pm
content: Oh that makes total sense. I was just confused because the datasheet has section that mentions setting the output voltage with the R2 resistor, that is not shown in the schematic. Thank you very much

author: SiliconWizard
author_rank: Super Contributor
timestamp: September 30, 2025, 02:10:07 pm
content: Quote from: mangoByte on September 30, 2025, 12:43:33 pmThat's something others have noticed with those datasheets from TI. Many of their buck LED drivers have similar confusing paragraphs which appear C/C from other datasheets for conventional buck converters.

author: Zero999
author_rank: Super Contributor
timestamp: September 30, 2025, 02:10:56 pm
content: Quote from: SiliconWizard on September 30, 2025, 02:10:07 pmCould they be using AI to generate them?

author: Nominal Animal
author_rank: Super Contributor
timestamp: October 01, 2025, 09:51:17 am
content: I described the issues with the TPS92201 datasheetin this post here, and reported it to TIhere; the corrected datasheet should be available in a few weeks.
How to simulate a power surge on USB Flash drive? - Page 1
Forum section: electronics / projects

author: komatsu
author_rank: Contributor
timestamp: July 30, 2014, 10:06:46 pm
content: As an experiment, how would one simulate a power surge on a USB flash drive.(nothing nefarious here btw just trying to hone my electronics skills by engineering a fault in a crappy old 2gb stick and then try to rectify it)

author: microbug
author_rank: Frequent Contributor
timestamp: July 31, 2014, 11:44:09 am
content: Hook GND to neutral and 5V to your mains supply(Please don't)

author: Rerouter
author_rank: Super Contributor
timestamp: July 31, 2014, 12:00:42 pm
content: use a big coupling capacitor and a pulse generator / AWG that can output into a short without dying (5V power rail can look very low impedance)you then isolate out the 5V supply from your computer so that it doesnt suffer the tests, and power the usb from another source, couple in the pulse and watch how it reacts,
How to simulate sensor signals? - Page 1
Forum section: electronics / projects

author: aju11
author_rank: Contributor
timestamp: April 22, 2019, 07:10:08 am
content: I am working on a project that involves 26PC-series Honeywell pressure sensors (linked below) interfaced to Filtering, ADC and microcontroller.https://www.mouser.in/datasheet/2/187/honeywell-sensing-26pc-series-miniature-low-pressu-1143546.pdfThe 1 psi part of the 26pc series has output voltage range of 0 V to 16 mV.It is not practically possible to have a full setup (pumps, valves, pipes, sensors, etc) at the desk while software is being developed.I want to have a quick and simple solution that could generate a 0 to 16mV DC signal and can be controlled by a pot to simulate the sensor.May be like some opamp circuitCan anyone help please?

author: DaJMasta
author_rank: Super Contributor
timestamp: April 22, 2019, 08:32:14 am
content: Provided your measuring circuit is pretty high impedance, you could just do it with a voltage divider and a supply rail. Either a fixed divider and a variable supply, or a divider with a pot (probably on the low side so you can go to 0mV) and if you're feeling fancy maybe a small capacitor to stabilize it.If output impedance of the sensor is a problem (your measurement system needs a bit of current), then something like a divider with an opamp follower through a suitable output resistor would do the job.

author: David Hess
author_rank: Super Contributor
timestamp: April 22, 2019, 05:14:19 pm
content: Build or buy a bridge transducer simulator.It would be easier to describe what is needed to build one if the schematic shown in the datasheet was not wrong; based on the numbers given, there is obviously a large modulus (series) resistor which is not shown.In practice, a simple bridge will give the proper results however. Use 4 precision resistors to make a bridge, about 7.5 kilohms) and then use resistors from one output to either supply to create various calibrated output levels. No active devices are required.I could not find any example schematics of a simulator online. It might be considered too trivial. Real simulators tend to be pretty expensive because of the precision requirements although that pressure sensor is not particularly demanding in this regard.
How to solder PC104+ connectors? - Page 1
Forum section: electronics / projects

author: dmendesf
author_rank: Frequent Contributor
timestamp: June 18, 2023, 10:26:59 pm
content: I'm a happy user of PC-104 stackthrough connectors: 2 rows of pins with 2.54mm spacing that can be easily soldered and then boards stacked. Now I decided to try PC-104+ because they're denser (2mm spacing, 4 rows). Just when I got the connectors I noticed the difficulty of soldering them: A soldering iron cannot approach the inner rows of pins, and a solder crucible would put a crust over the entire pins. Does anyone sees a homebrew option to solder these? Thank you.Daniel Mendes

author: Buriedcode
author_rank: Super Contributor
timestamp: June 18, 2023, 10:57:44 pm
content: I would use solder paste and hot air. I'm unaware of any iron tip that would be able to get close enough to solder an inner row. At least a solder paste syringe would be able to get on every pin.

author: Benta
author_rank: Super Contributor
timestamp: June 18, 2023, 11:19:14 pm
content: Mount and fix the connectors on your PCB (eg, solder the four corner pins by hand to hold it).Dip the connector pins in a protective paste, except for the last 1...2 mm. Gypsum, Calcium, synthetic compounds will work.Wave solder the PCB.Clean the pins. Done.

author: dmendesf
author_rank: Frequent Contributor
timestamp: June 18, 2023, 11:25:15 pm
content: Thank both of you. I found this machine that seems designed just for this case:https://zeph.com/pc104.htmlNot that i'll buy one... but seems that solder paste in a syringe + hot air is the way to go. Maybe even a thin solder wire + hot air will work.

author: Marsupilami
author_rank: Frequent Contributor
timestamp: June 19, 2023, 02:07:47 am
content: Aren’t these supposed to be press-fit? Or at least exist in a version that’s press fit?
How to specify a bypass device within a JTAG chain using J-Flash? - Page 1
Forum section: electronics / projects

author: bhj99
author_rank: Contributor
timestamp: July 22, 2025, 03:26:13 am
content: Hi all, I am hoping someone here has experience with Segger J Link and J Flash.I have a custom PCB design that involves a JTAG chain between two STM32U585AII6Q microcontrollers and one Microchip MPF100T PolarFire FPGA.I am attempting to use the J-Link PRO and J-Flash for first-time JTAG programming with the chain sequence as follows: J-Link PRO TDI -> MPF100T -> First STM32U585AII6Q -> Second STM32U585AII6Q -> J-Link PRO TDO.From what I can tell, the MPF100T is not supported by J-Flash. How can I specify the MPF100T as bypass device to shift all 1's to the instruction register? I do know the IR Length is 8 for the MPF100T and the device ID is 0x0F8111CF from its BSDL file.Any help with the J-Flash Project setup would be greatly appreciated. Thanks in advance.
How to spice up my ultrasonic cleaner? - Page 1
Forum section: electronics / projects

author: Hank
author_rank: Newbie
timestamp: December 18, 2024, 05:58:22 pm
content: I've got an Emmi-5 Us cleaner, it's got a small transducer epoxied to the tub, and I want more cleaning power!The output stage consists of 2 X IRF830, and the transducer is fed via a transformer, so by the looks of it.I've got a 60W transducer from Aliand I was wondering if this will do the trick, but my knowledge about these things does not really suffice, hence me posting over here.So the question is: does a transducer of 10 W have the same reactance as one of 20 W, and do I need to double the output voltage, or how does it exactly work, don't want to let the magic smoke out yet!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: December 20, 2024, 05:31:52 am
content: A driver for a 10W transducer is not going to drive a 60W transducer properly.And because the driver + transducer is probably more exensive or similar cost to a whole new ultrasonic cleaner, you're probably better off to buy a decent complete one. Attempting to remove the transducer to replace it with another will be another headache.
How to split one audio input in two and have volume control? - Page 1
Forum section: electronics / projects

author: vini_i
author_rank: Regular Contributor
timestamp: October 04, 2016, 07:53:32 pm
content: I want to build myself a headphone amplifier with a dual independent outputs.The chip i want to use is the PAM8403.The recommended input circuit from the data sheet is attached.Attached is also my suggestion for how to wire one input to two PAM8403s with volume control.Is my suggested circuit viable or did i miss something?

author: Zero999
author_rank: Super Contributor
timestamp: October 04, 2016, 08:13:05 pm
content: Quote from: vini_i on October 04, 2016, 07:53:32 pmWhy? It's probably hard to find a less suitable IC.It's a class D amplifier with a bridged output. Headphones typically have a common connection to both transducers and often have a higher impedance than the PAM8403 is specified for.How about using an IC specifically designed for driving headphones, such as the TDA8559T?

author: vini_i
author_rank: Regular Contributor
timestamp: October 04, 2016, 08:29:07 pm
content: QuoteIt's a great chip, but it's obsolete.What other chips would work well?Would my proposed circuit work with them?

author: Zero999
author_rank: Super Contributor
timestamp: October 04, 2016, 09:18:21 pm
content: There are plenty of other headphone amplifier ICs. There's the TPA6130A2 which is still made and many more. For a headphone amplifier, you need a class AB amplifier.Yes, the circuit you posted should work for other amplifier ICs.

author: Someone
author_rank: Super Contributor
timestamp: October 05, 2016, 12:06:01 am
content: Quote from: Hero999 on October 04, 2016, 09:18:21 pmExcept its a very poor extrapolation from a single circuit to a dual attenuated design, the high pass filter corner is moved by changing the load impedance from 18k (+ 18k internal? minimum for that chip) to a variable impedance based on the settings of the potentiometers, and without buffering the signals then present a varying impedance to the amplifier input.

author: vini_i
author_rank: Regular Contributor
timestamp: October 05, 2016, 12:31:46 am
content: QuoteHow would you suggest to split the input in two?

author: Someone
author_rank: Super Contributor
timestamp: October 05, 2016, 12:55:06 am
content: Quote from: vini_i on October 05, 2016, 12:31:46 amThis depends on the input impedance of the amplifier block you choose to use and the impedance of the source and if you need to include the filtering. You will likely need an opamp buffer match the impedances unless the input impedance of the amplifier is much larger (100000x or more) than the source impedance. Start with something that is known to work and then play with it in simulation or the real world:http://www.eeweb.com/blog/circuit_projects/efficient-pocket-headphone-amplifier-by-opa2227p
How to stabilize a linear power supply using Ltspice? - Page 1
Forum section: electronics / projects

author: Datguy123
author_rank: Contributor
timestamp: August 15, 2020, 08:54:46 am
content: Hi, I am building a linear power supply. I am unsure if my method of analyzing the open-loop gain on LTspice is correct because the magnitudes on the bode plot did not seem right (with a FB of 6.8k/750, the low-frequency gain should be around 20dB). I have sufficient phase margin for this DC operating point, but once I apply voltage with V3, the circuit starts to oscillate. Does that mean that I need to attain the bode plots of many DC operating points to ensure the supply is always stable?
how to stick 2 boards together (panel + board) - Page 1
Forum section: electronics / projects

author: VEGETA
author_rank: Super Contributor
timestamp: June 20, 2023, 08:58:41 pm
content: Hello,I have a small board 100x90mm with its top panel as seen in attachments, not final placement but dimensions will be similar.I want to use Matte Black PCB since it looks good and cheap.I have couple of options to do it:Option 1:make the board using regular black to be cheap then make 2 matte black pcbs; one for top panel and one for bottom panel.to stick them together, I use the following:stand-offs:Wurth 970300361 M3 30mm -> between top panel and board.Wurth 970050354 M3 5mm -> between board and bottom panel.would need 4 of each for each unit.screw:Keystone 29316 M3 L=16mm -> need 8 per unit.Option 2:use same Wurth 970300361 M3 30mm stand-off (female-female) and 2 screws per standoff without making a bottom panel, here pcb itself will be matte black and will ditch the bottom panel.will be low clearance in bottom since just screw head is there.Option 3:use a non-threaded stand-off like:https://www.digikey.com/en/products/detail/essentra-components/005298059905/4104020with rivet like these (with suitable hole diameter):https://www.digikey.com/en/products/detail/essentra-components/167205069902/7794369https://www.digikey.com/en/products/detail/essentra-components/QTPF-1BK/3814563same as option 2, with the pcb board itself + top panel, no bottom panel.Option 4:similar to 2 and 3 but instead of rivets and screws... something like rubber feet so that it looks more neat especially on bottom to have better sitting (not so important).Option 1 is more complicated and expensive, so what do you think?