hybridfree/eevblog-posts huggingface dataset:
Electrically noisy ATX PC power supply - Page 1
Forum section: electronics / projects

author: rea5245
author_rank: Frequent Contributor
timestamp: April 15, 2025, 03:36:26 pm
content: Hi,I'm using an ATX power supply to power my project. I was struggling with spurious (but oddly regular) glitches on some signal lines. After eliminating everything else, I finally disconnected the power supply and put a scope on its unloaded 5V line. The image below is what I saw. (This is even with the PSU's fan not running, because there's so little load.)It looks like the the same frequency as the glitches on my signals.Should I just put big capacitors on it, or is there no hope for this PSU?Thank you.

author: tunk
author_rank: Super Contributor
timestamp: April 15, 2025, 04:34:48 pm
content: I think the ATX specs says max 50mV ripple.You could try to put some load on it.Or, either you have a low quality PSU, and/or there's something wrong with it.You could open it and test the output capacitors.

author: Niklas
author_rank: Frequent Contributor
timestamp: April 15, 2025, 10:21:04 pm
content: It is probably both more effective and easier to put a ferrite clip on around the wires between the power supply and your electronics. If you have single wires it would also be possible to wind them in opposite directions on a ferrite toroid. Both options would form a common mode choke and it can work together with capacitors on the input of your electronics to filter this noise.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 15, 2025, 10:38:23 pm
content: What brand is it? Many of the off brands are very poor quality.

author: rea5245
author_rank: Frequent Contributor
timestamp: April 15, 2025, 11:32:26 pm
content: Quote from: NiHaoMike on April 15, 2025, 10:38:23 pmThe brand is GameMax. I bought it through Amazon. I contacted Amazon, and they're replacing it under warranty.
Electrobalance - Page 1
Forum section: electronics / projects

author: Gluon
author_rank: Newbie
timestamp: August 11, 2014, 09:10:07 pm
content: I have been thinking of how to make a nice useable electrobalence from an old voltmeter or maybe a VU meter. Although i HATE to wreck a nice meter, i have a small collection and i consider many of them to be works of art. I doubt man will ever again achieve that kind of mechanical craftsmanship. I LOVE old switches and meters, haha. Don't get me on a rant about how garbage pots and switches feel these days. Anyway... I might try to make my own galvanometer, since the less sensitive it is the easier it will be to measure voltage/current. I would love to a 10 gram range, which would surly burn out the coils of most delicate meters. I will have to experiment with this.In terms of the electronics i figure i need either a precision voltage ref or a precision current ref so provide stability so i don't need to calibrate every time i use the thing. Probably use an ADC, a pic (maybe use inbuilt ADC), and a simple lcd readout. My biggest question is how to get a stable reference, cheap and easy. 5volts 0.1% should do it. I've never done a project requiring this kind of stability before. I watched Dave's precision current source video, that is a bit overkill i think. I will be hand trimming as well, unlike Dave's non-trimmed design. Just wondering what my options are. Any other advise would be appreciated.tl:dr how would you design a simple digital 0-5V 0.1% accuracy voltmeter with a pic? 0.5% would be acceptable if 0.1% is too hard. Also i think i want at least a 16bit ADC, recommendations?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 11, 2014, 10:33:17 pm
content: I wouldn't use a PIC, I'd use one half an LM358.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: August 12, 2014, 12:14:16 am
content: Ben Krasnow, with the you-tube channel Applied Science has just done such a project, non cpu:youtube:http://youtu.be/ta7nlkI5K5g?list=UUivA7_KLKWo43tFcCkFvydw
Electroluminescent Material Light Sensitivity - Page 1
Forum section: electronics / projects

author: Drjaymz
author_rank: Contributor
timestamp: December 06, 2024, 12:28:50 pm
content: I bought some EL paper from eBay which comes with a cheapy EL driver, so cheap you can hear it singing away and something like 4khz.What I didn't expect was that when I came out of my dark shed the frequency of that singing changes. I covered it up and it goes back. I went to my desk lamp and sure enough the freqency of the circuit changes when light falls on the EL strip. I was not expecting that.I haven't mangled the driver yet, but its probably a self-resonant super cheapy thing, I think it produces AC. so just a couple of transistors and maybe a transformer or something even more crude.I googled it and didn't find much. I would image some property of the material changes with light exposure. Its unlikely to be temperature because its instant, capacitance or resistance maybe.

author: Drjaymz
author_rank: Contributor
timestamp: December 06, 2024, 12:57:41 pm
content: Ok, because I'm meant to be working I don't have all my kit with me, but I have got a chinese component tester. I checked and the frequency reduces when its light.It thinks the panel is a capacitor with an ESR of 17R.In the Dark it thinks its 11nFIn the Light it thinks its 22nFSo its a light sensitive capacitor - thats pretty groovy, its not a slight effect either, it doubles its capacitance.I did open the driver and its a centre tap inductor (looks like mini transformer) there are two SMD transistors and a 5pin package which might be a double fet or diode jobby, not sure its so small I cannot see a thing, but I imagine its a push pull oscilator thing.So I didn't know that and I guess if I searched properly I'd probably find it mentioned online somewhere.I'm going to guess there is a photodialetric effect? Never heard of it.
Electrolyitic Capacitor Ageing - Page 1
Forum section: electronics / projects

author: Glenn0010
author_rank: Regular Contributor
timestamp: February 25, 2020, 09:35:48 am
content: Hi All,I need to calculate my expected lifetime for an Elec Cap.I am looking at thehttps://www.mouser.co.uk/ProductDetail/Wurth-Elektronik/865080442004?qs=sGAEpiMZZMsh%252B1woXyUXj4jKQI6sNRw6szAjfBEpelo%3DI can use Arrhenius’s Law to determine the liftime with regards to temprature. However what about DC operating point. Say you have a 25 V cap at 16 V. I remember hearing that that also improves life time.Can anyone point me in the right directionThanksGlenn

author: wraper
author_rank: Unknown
timestamp: February 25, 2020, 09:44:35 am
content: Don't forget that lifetime figure is given under maximum ripple current spec. Voltage does not matter that much

author: MagicSmoker
author_rank: Super Contributor
timestamp: February 25, 2020, 01:22:40 pm
content: Quote from: Glenn0010 on February 25, 2020, 09:35:48 amThere's conflicting evidence (and mostly anecdotal at that, unfortunately) on how much longer an elko will last for a given percentage of voltage derating. Basically, there seems to be little benefit from operating at less than 75% of the WVDC rating, and if you need really a long (decades long) working life then you'd probably be better off with film capacitors.edit - added missing "need" in last sentence.

author: splin
author_rank: Frequent Contributor
timestamp: February 25, 2020, 05:53:17 pm
content: Seehttp://www.rubycon.co.jp/en/products/alumi/pdf/Life.pdf It would be interesting to know why they only apply voltage derrating to the screw terminal capacitors - perhaps they aren't as well sealed?[EDIT 2]: Also look at:https://www.illinoiscapacitor.com/tech-center/life-calculators.aspx
Electrolytic capacitor with corroded through shell - Page 1
Forum section: electronics / projects

author: turbo!
author_rank: Regular Contributor
timestamp: April 17, 2014, 02:29:33 pm
content: Anyone seen anything like this?I can't tell if it leaked out due to corrosive environment or if it corroded from inside. Whatever fluid they used in this thing is beyond stinky I can smell it from feet away. This was in a pair with identical one in parallel. The other one tests fine capacitance and current capacity wise. This one is of course completely flat.There's no bulging but it looks like there's signs of heat damage to the shrinkwrap on the interior side. I peeled off the shell so I can see what was going on.

author: SeanB
author_rank: Super Contributor
timestamp: April 17, 2014, 03:20:44 pm
content: It did do quite a few years of service though. Looks more like it was damaged during pick and place or during assembly which dented the can and pierced the side, and the effects of time and electrical stress eventually led to the electrolyte blowing out into the sleeve. It is quite possible the sleeve would survive an impact or clamping that punctured the can, and then during soldering the can got hot enough that it flattened out and hid the puncture until it got brittle from years of heat and corrosive attack. Those caps are quite old, I have not seen them for quite a long time unless you have old electronics made in the 1980' to early 2000's in either Germany or Holland, where they were quite popular. they are not known to fail from any thing other than old age mostly as seals degrade.
Electrolytic Decade Capacitor - Low Budget Project ^__^ - Page 1
Forum section: electronics / projects

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 11, 2012, 09:04:24 pm
content: Hello everyone!!!I've been repairing things for many years now and especially in the last 3 or so years blown caps (in computers/monitors/etc) have seemed to increase. I'm getting more and more computers that have silly blown caps in them!Well... normally they are in parallel and if I end up replacing them, and then testing the computer only to find out something else is damaged too... then I loose those caps that I put on. (I never like to remove them because re-using them too many times will cause them to damage.)SO! I thought I would make a Electrolytic Decade Capacitor in order to set the value, and solder on a couple/few wires to the board and then test it before I waste caps just to find out its still broken.I wanted to share this idea with you all and also show pictures of my project.All together it was only about $5.00 or so.(I used salvaged caps and scrap wire! New caps and wire might make the cost higher but I'd imagine still be under $10 or at least under $15)Anyway!!! So far I'm loving it, and its a great tool to have! ^__^The cable(last picture) is so that I can plug in my oscilloscope to the project/tests as a bonus! I also have a "normal" screw terminal plug (a old 75/300 ohm converter that I removed the coil from.)PS: My cap tester is a cheap crap one but it works pretty good for higher values. (under uF its really off) And Idid not yet add the "discharge" resistorto the project yet, I wanted to get some opinions and do some math before just adding any old resistor to it, lol.

author: PhynixViking
author_rank: Regular Contributor
timestamp: December 11, 2012, 09:10:38 pm
content: OHHHH I also... yea... I didn't label the switches yet, LOLthey are...(to the far right)10,000uF5,000uF3,200uF2,200uF1,000uF660uF330uF(off at the top left)47uf 100uF Resistor On/Off(then bottom left)To Cord
Electrolytics with organic (non water) electrolytes - Page 1
Forum section: electronics / projects

author: dom0
author_rank: Super Contributor
timestamp: November 04, 2019, 09:41:42 pm
content: Here's what I think I learned so far:- Water-based electrolytes give you higher CV, lower ESR- Water-based electrolytes are chemically aggressive (ie corrosive)So essentially all 85 °C and 105 °C (boiling point of the water-based electrolyte has to be higher than 100 °C?) capacitors use water-based electrolytes. Old capacitors (pre-mid80s) use electrolytes based on organic solvents like GBL.Organic electrolytes are chemically not nearly as aggressive, but result in lower CV, so poorer density.Now, from a hobbyist's "I want stuff to last" perspective non-water electros seem to be the better choice. But they seem to be relatively rare. However, it seems like 125 °C and higher capacitors cannot be made using water-based electrolytes. For example, the Rifa/Kemet PEG124 series use GBL electrolyte. They don't advertise it, butthis paperconfirms it. These capacitors would seem like a perfect fit to replace wet slug tantalums sometimes found in older test gear, among other things.=> Are organic electrolytes truly superior in terms of reliability than water-based electrolytes?=> Which are commonly available cap series using organic electrolytes?
Electromagnet driving and current sensing - Page 1
Forum section: electronics / projects

author: tomislav.babich
author_rank: Newbie
timestamp: November 21, 2015, 01:21:23 pm
content: I am doing a project which involves controlling current going through electromagnet and measuring the currents value. This is what I came up with so far: There will be L298 connected to Arduino and driving the electromagnet. For current regulation I will use PWM and for current measurement current I will use sense pin from L298+shunt resistor+op-amp. I have a few questions about this circuit:Is PWM adequate method for controlling current going through coil? Some places on the web suggest it but I am not sure.If PWM is adequate can L298 current sense pin+shunt+op-amp be used for measuring current? How would I do it in the code, maybe measure peak voltage?Do I need RC low-pass filter?I am looking forward to your answers.

author: MagicSmoker
author_rank: Super Contributor
timestamp: November 21, 2015, 03:44:15 pm
content: Quote from: tomislav.babich on November 21, 2015, 01:21:23 pm1. Yes, an inductor will integrate the PWM'ed current pulses drawn from the input capacitor (said capacitor is required) into DC + a sawtooth ripple component, depending on PWM frequency and inductance of the electromagnet (also whether ferrous metal is in close proximity to the electromagnet).2. Sure. Use a single op-amp difference amplifier and a non-inductive metal foil resistor specifically for current sensing applications. Whether you should work with the peak voltage (current) or the average depends on what you are trying to do, but most of the time you want to measure/regulate the average current.3. Yes, always use an RC filter to integrate away any voltage noise/spikes caused by stray inductance in the sense resistor and the wiring between it and the switch and ground. Note that if you use a single op-amp differential amplifier you can put the noise-filtering capacitor from the (+) input of the op-amp to ground (see attached picture). The value of this shunt capacitor is set so that the time constant formed between it and the resistor in series with the (+) input is the same as that of the inductive time constant of the shunt. For example, a 0.1R shunt with 10nH of inductance has a time constant (t) of 10nH/0.1R = 100ns; if the series resistance to the (+) terminal of the diff. amp is 1k then C = 100ns / 1000R = 100pF. All that said, it is usually impractical to measure the inductance of a shunt, so plan on tweaking the value of the capacitor once the circuit is built.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 21, 2015, 03:55:57 pm
content: Don't forget the freewheeling diode. Without it, the principle will not work at all and the thing will self-destruct.

author: tomislav.babich
author_rank: Newbie
timestamp: November 21, 2015, 09:26:05 pm
content: Thank you for your replies!
Electromagnetic coil and electromagnetic field - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: December 19, 2020, 03:15:27 am
content: Hi,a moving charge creates an electromagnetic field. i.e. a field which has a magnetic field/component running along one plane and an electric field/component running along a plane at 90 degrees.From that concept then a solenoid driven so that both ends are connected to an AC source should emit an electromagnetic field but antennas are not made with solenoids driven that why. Why?Also a solenoid (again driven with both ends connected to a generator) emits mostly magnetic field and no or very little electric field. Why?Thank you

author: bob91343
author_rank: Super Contributor
timestamp: December 19, 2020, 06:32:53 pm
content: The electric field depends on the voltage and most ordinary solenoids run at low voltage. Of course they emit fields but the amplitudes are small.The only difference between what you have and most antennas is the frequency or, more specifically, the ratio of the wavelength to the dimensions of the device. Ideally that ratio should be not far from unity.

author: ricko_uk
author_rank: Super Contributor
timestamp: December 20, 2020, 06:52:46 pm
content: Thank you both!
Electromagnetic interferences - how to handle? - Page 1
Forum section: electronics / projects

author: reptkeu
author_rank: Newbie
timestamp: January 26, 2020, 03:32:22 pm
content: Hi everyone,I'm working on a little DIY lamp project with a capacitive switch.The kit consists of a breadboard with some components, a battery and its charging PCB, and a 20cm-long electric wire that leads to the aluminium foil used as capacitive sensor.The lamp switch on and off randomly when in proximity of things, particularly as it nears other electronic devices.I believe this is due to electromagnetic interferences (EMI) affecting the electronic components.I'm wondering how I could fix the problem. I know EMC is a bit of black magic, but perhaps there are simple steps to address the issue, at least partially?I don't think I'm confident enough to delve into active shielding, so I'm looking for simpler passive options. Perhaps someone can help me find a good solution?Would it work to wrap my breadboard with aluminium foil?Is it possible to use a shielded cable for the 20cm cable leading to the capacitive sensor (aluminium foil)?Also, I have found electronic PCB using capacitive switches. Some parts seem to be covered with a yellow paste. Could this paste be a shield? Could I use something similar?Thanks in advance for your help!

author: 741
author_rank: Frequent Contributor
timestamp: January 26, 2020, 09:57:27 pm
content: Perhaps use thin shielded wire, the PCB-side braid tied to Vss?Also, maybe reduce capacitance by inserting a series capacitor of similar value to the sensor (wild guess: 22pF, I've no idea really though)
Electromagnetic shielding for DC-DC converter - Page 1
Forum section: electronics / projects

author: han
author_rank: Frequent Contributor
timestamp: February 26, 2014, 06:26:11 am
content: hi all,i'm on DIY differential probe project and have to use dc-dc converter due the size constrain.The diferential probe work very well, but have a large noise (100 mVpp).I probe the circuit and found the noise came from DC-DC converter. and it EM radiation,i have put many capacitor decoupling near the DC-DC converter, and it didn't helpis make cage from FR4 pcb to isolate the DC-DC converter will help?anybody have a experience for eliminating transient noise from DC-DC converter?thanks

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 26, 2014, 06:34:52 am
content: Sounds like an EMC problem to me.I'd have to see your circuit and layout to offer much help. And $50/hr...

author: Psi
author_rank: Super Contributor
timestamp: February 26, 2014, 06:36:10 am
content: Try an LC filter on the output of the DC-DC.I find this works really well for DC-DC powersupplys on my RC plane to eliminating switchmode noise that gets into the camera picture.RC filter would work too but the voltage loss across the resistor will vary with current and effect regulation, so its not ideal.

author: han
author_rank: Frequent Contributor
timestamp: February 26, 2014, 08:44:04 am
content: Quote from: T3sl4co1l on February 26, 2014, 06:34:52 amunfortunately the device it self less then $50 ...

author: han
author_rank: Frequent Contributor
timestamp: February 26, 2014, 08:50:54 am
content: Quote from: Psi on February 26, 2014, 06:36:10 ami have clean the signal with RC filter and have a clean signal on +/- Vsupply if i probe using coax soldered to circuit, the problem is the rest of circuit behave like antenna.the frequency is 500KHz but i doubt FR4 shielding will work, so anyone try it before?

author: DaveW
author_rank: Frequent Contributor
timestamp: February 26, 2014, 01:45:21 pm
content: You can LC filter the input and output (on the output making a pi filter) which works quite well. If you LC filter the input, it can help to add an RC snubber to compensate the the source inductance that has been added.Layout for SMPSs is pretty critical-something like this is helpful, but you are basically keeping the size of any loops down which are carrying pulsed high currentshttp://www.edn.com/design/components-and-packaging/4390811/PCB-layout-considerations-for-non-isolated-switching-power-suppliesAlso have a look at the slew rates that your controller is using. You can sometimes slow the switching of the FET which will reduce emissions quite dramatically/If things require more effort than that, metal cans over the analog input side can help. Also Wurth make ferrite tiles which fit over the critical part of the SMPS which reduces noise
Electromagnetism comic? - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: May 08, 2016, 02:06:32 am
content: Can anyone help me find a comic about the stranger properties of electromagnetism? I remember it from years ago, but I can't find it again.It started off explaining how a coil of wire wrapped around an iron ring could produce magnetic flux, but then it started doing weird things like stretching the iron ring, and using it as an analogue of wire. It demonstrated some very peculiar properties of electromagnets.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 08, 2016, 05:28:00 am
content: Ohh yeah, I vaguely remember that -- was probably mid 2000s? Damned if I know any keywords though..Tim

author: matseng
author_rank: Frequent Contributor
timestamp: May 08, 2016, 10:11:05 am
content: This?http://www.larrygonick.com/titles/science/the-cartoon-guide-to-physics/

author: Rachie5272
author_rank: Regular Contributor
timestamp: May 08, 2016, 04:43:30 pm
content: No, it was a webcomic, or something viewable online.

author: JacobPilsen
author_rank: Regular Contributor
timestamp: May 08, 2016, 06:06:04 pm
content: Maybe this???http://www-ucjf.troja.mff.cuni.cz/scheirich/wp-content/uploads/2015/06/mff_life_01.jpg/mff_life_02.jpg.../mff_life_89.jpg

author: Rachie5272
author_rank: Regular Contributor
timestamp: May 08, 2016, 07:22:32 pm
content: Still no. It had diagrams of transformer windings, along with explanations. Then the transformer core is used as a "winding". No characters or panels. It was one long page. Less of a traditional "comic" I suppose, but the format was befitting of a science comic like Abstruse Goose. Unfortunately my searches still yield nothing.

author: mikerj
author_rank: Super Contributor
timestamp: May 09, 2016, 08:36:28 am
content: This maybe?http://www.alchemical.org/em/cartoonphysics/index.html

author: Rachie5272
author_rank: Regular Contributor
timestamp: May 10, 2016, 10:08:34 pm
content: Nope. I guess it's been lost to time.
Electronic Assembly Demo Video (BGA/EQFP design) - Page 1
Forum section: electronics / projects

author: Sarcarean
author_rank: Contributor
timestamp: February 02, 2019, 06:27:00 am
content: Hi everyone! I am not really a video maker per se, but I get a lot of requests to show my process for electronic production and thought I would share it with everyone on here too! (Please forgive me if the production quality is not up to your standards).I made the above video to hopefully show some younger players a semi-low cost method of doing SMD assembly themselves.So for those of you who do not know me, I run EmbeddedComputers.net and I specialize in producing non-vol memory programmers (SPI, I2C, NOR/NAND, EPROM, HyperFlash, S93, 1-wire, CFI/SPI over JTAG etc.). I do everything myself (PCB gerber design layout, prototyping, assembling, firmware programming, and software programming). My software library which includes Flash definitions and programming interfaces/algorithms is open source (I have published new updates nearly every month for 10 years).Some details about this board: Its a 4-layer PCB with high-speed data design (for 480MHz USB) and 16-bit PIO bus for slave logic controller (160LE CPLD). The main MCU is an Atmel SAM3U (yes, fanboy) in a BGA-100 package (0.8mm ball spacing) and the logic IC is EQFP-64 with 0.4mm pin spacing. Some quick clarifications: I do have a large framed stencil printer, but it currently has a very large frame in with another board, so I opted to use the smaller proto stenciler instead. For BGA placement, I usually place these by hands, while my PnP can do them, I would need to replace one of the nozzles (which takes a while) so by hand is much faster for me, plus I like a little flux on my balls to help during reflow.I hope you like the video and I would be glad to answer any questions you might have. Thanks for watching!
Electronic Combination Lock Circuit - Page 1
Forum section: electronics / projects

author: gevv
author_rank: Contributor
timestamp: October 07, 2022, 08:59:16 am
content: Hello, It is simpler and easier to implement than systems with indicators. User password can be changed with administrator password.https://youtu.be/w_iUIGGLtmI07:00 General explanation of the circuit (required)03:06 Circuit test04:13 Changing user password with admin password06:23 New hex file, changing password, setting and compiling source code with Mplab program08:30 Circuit diagram08:34 PCB drawing08:38 👍
Electronic Component Help - Page 1
Forum section: electronics / projects

author: Lacasse
author_rank: Newbie
timestamp: July 10, 2017, 12:09:59 am
content: There is the schematic. This is an oscillator using a inductor and a resistor. So when the switch (SW1) is not pressed the 555 is reseted the output is low so the MOSFET Q1 is conducting pulling high the gate of the MOSFET Q2 so it is not conducting. When the switch (SW1) is pressed the output of the 555 become high because TRIG (0V at the beginning) is < 1/2 CV which is 2/3 of VCC. So the output of the 555 being high the MOSFET Q1 is not conducting the pull down resistor pull down the gate of the MOSFET Q2 so it is conducting. Then the inductor (L1) is being charged and it impedance is decreasing so the voltage of THRS is increasing until THRS > CV. When THRS > CV the output of the 555 became low so the MOSFET Q1 is conducting pulling high the gate of the MOSFET Q2 so it is not conducting. Then the impedance of the inductor (L1) is increasing and the voltage of TRIG is decreasing until TRIG < 1/2 CV and then the cycle restart again. My question was: Is there a single electronic component that can replace both MOSFET?Thank you

author: Lacasse
author_rank: Newbie
timestamp: July 10, 2017, 12:42:43 am
content: This is basically the same thing but in one package. The problem I have with this setup is that the second MOSFET Q2 won't switch fast enough because of the pull down resistor at the gate. The gate of the MOSFET have some capacitance and pulling the gate low using a pull down resistor take some time. I could use a smaller pull down resistor but I already tried it, it worked kind of good with a 100 ohm resistor but I'm wasting energy when the first MOSFET Q1 is conducting. I did some research and I found something called a thyristor I never used them would it work?Thank you

author: Lacasse
author_rank: Newbie
timestamp: July 10, 2017, 12:59:32 am
content: I appreciate your help but I want to have only one component to make the circuit as less complex as possible. And instead of adding a BJT pair I could add an op amp setup as a follower to boost the second MOSFET Q2 gate current.

author: Andy Watson
author_rank: Super Contributor
timestamp: July 10, 2017, 01:14:31 am
content: Quote from: Lacasse on July 10, 2017, 12:59:32 amA piece of wire ? The output of a 555 should be able sink and source enough current to drive the inductor directly. Look-up "metal detector 555"

author: Lacasse
author_rank: Newbie
timestamp: July 10, 2017, 02:22:35 am
content: The output of the 555 is a push pull output so the voltage spike of the inductor are wasted directly in the IC that is the reason why I used a MOSFET. When the MOSFET is not conducting the drain impedance is in theory infinite so the voltage spike of the inductor have no where to go if I'm right.
Electronic Design and PC Board prototype - Page 1
Forum section: electronics / projects

author: mkwifly
author_rank: Newbie
timestamp: February 26, 2016, 10:36:13 pm
content: I have a very simple electronic circuit I need designed and a PCB built so I can test a new product. Its a simple sound activated switch on certain frequencies and db output with a battery charger. Anyone give me a good direction to go? Looking for contact information and suggestions.Thanks

author: tggzzz
author_rank: Super Contributor
timestamp: February 26, 2016, 11:08:06 pm
content: Quote from: mkwifly on February 26, 2016, 10:36:13 pmSo, you have an idea and you want someone to design and implement it for you.It would help if you said where you live, so that you can sort out a spec face to face, and give an idea of how much you will be paying.

author: uncle_bob
author_rank: Unknown
timestamp: February 26, 2016, 11:34:11 pm
content: HiOne important question on anything like this ---- do you already have it protected by a patent?Bob

author: Eric_the_EE
author_rank: Contributor
timestamp: March 01, 2016, 06:03:12 pm
content: I'd be happy to look into it for you, free of charge. Depending on complexity, I can't guarantee that I can finish it for you immediately (I'm a senior Electrical Engineering student in the middle of a semester), but I would look into it free of charge. It sounds like a fun project opportunity, and I love any chance to design PCBs.email: eoberholzer@liberty.eduCheers

author: Audioguru
author_rank: Super Contributor
timestamp: March 01, 2016, 06:24:24 pm
content: "A simple sound activated switch on certain frequencies and db output" is a keys finder product sold at The Dollar Store. You whistle and it beeps. Its battery is cheap and lasts for a long time so it does not need to be rechargeable.
Electronic dice project. This guy needs some more likes and attention  - Page 1
Forum section: electronics / projects

author: b_force
author_rank: Super Contributor
timestamp: July 02, 2018, 11:38:08 pm
content: A friend send me this link.I couldn't find any other information here on the forum.RGB dice with remote control, wireless charging and accelerometers.Really well thought out and extra bonus points for the tiny flat flex PCBshttps://youtu.be/EerooKKX93w

author: s8548a
author_rank: Regular Contributor
timestamp: July 03, 2018, 05:02:45 am
content: This is pretty awesome...Thanks for sharing.

author: Haatveit
author_rank: Regular Contributor
timestamp: July 03, 2018, 05:59:07 pm
content: Jeez. That's quite impressive. I had a project also involving small cubes with LEDs on each face, and accelerometers and such, although it was not dice. But this guy has taken the miniaturization to a whole new level.Will have to keep my eyes on this project!

author: a59d1
author_rank: Regular Contributor
timestamp: July 03, 2018, 06:09:52 pm
content: Fantastic integration, but how well are they balanced?

author: apblog
author_rank: Regular Contributor
timestamp: July 03, 2018, 08:24:11 pm
content: This is amazing.We’ve really come a long way since the old magazine article electronic dice projects of the 70s.
Electronic Display Design Question - Page 1
Forum section: electronics / projects

author: DonBsquared
author_rank: Newbie
timestamp: November 07, 2023, 05:22:34 pm
content: Hi all,I'm an industrial design student and am extremely new to electronics. I'm looking to create a simple display similar to my attached image, but am not sure what components are at play to create such a result. I imagine there is some sort of display or perhaps an LED matrix behind the rounded black screen, but I can't figure out what. Would I be able to simply place such a display behind the black glass screen or would these be two connected parts?Any advice or part identification would be greatly appreciated, Thanks.More images here:https://www.behance.net/gallery/82015019/Beaner-parenting-education-robot-

author: ataradov
author_rank: Super Contributor
timestamp: November 07, 2023, 05:45:10 pm
content: Given all the pictures, it would not be practical to have this many individual LEDs. It is likely a round "watch" display like thishttps://www.buydisplay.com/1-32-inch-color-360x360-round-circle-screen-ips-tft-display-panel-gc9c01But all the pictures there seemed to be 3D reneders, I would not expect it to look that sharp and high contrast in practice. You can get close though.And there is no size reference, so it might just be a simple single color OLED display like thishttps://www.buydisplay.com/square-white-0-96-inch-96x96-oled-display-screen-ssd1317

author: coromonadalix
author_rank: Super Contributor
timestamp: November 07, 2023, 06:12:36 pm
content: woah nice ones
electronic drum brain. - Page 1
Forum section: electronics / projects

author: Hobgoblin_612
author_rank: Newbie
timestamp: October 11, 2011, 11:47:40 am
content: I am investigating the viability of making an electronic drum synthesizer. I want to be able to load custom .wav or .mp3 files in for each trigger and have them played when the pezio sensors are hit. I'll need about 10-16 separate channels, each with a few seconds of high sample rate audio.The sensor side of things is well documented and can be as simple as a zener diode and a 1M resistor connected to the ADC input of a micro. The main problem is that I need to play many samples at once (many drums are often played at once) so while there are many audio modules out there, none that I can find play more than one file at a time. Sparkfun has a breakout for a MIDI synthesizer chip which has a maximum polyphony of about 30 sounds but I can't load custom samples into it. I should add that i wnt the unit to be stand-alone.(no computers once completed)My current idea is complex but may work. It uses a series of ram chips and DAC's to play each of the samples which are loaded into them at start-up from an SD card by a micro.The outputs of each DAC are then mixed together and fed to the output. this of course requires address and clock signals for every channel and may even need a main micro and slave micros on each channel.I have considered using those sound recorder chips but I don't know of any that allow sounds to be "programmed" in (as opposed to recorded)It would be interesting to know how commercial "drum brains" work if anyone knows.Any ideas(or reasons my current scheme won't work) are welcome as this project is still in the ideas stage.ps. I am a drummer

author: bilko
author_rank: Frequent Contributor
timestamp: October 11, 2011, 12:21:33 pm
content: I would have thought a wavetable sound chip is what you may be looking for, remember the old Creative AWE32 with wavetable, you could record samples and play back. Take a look herehttp://www.creative.com/oem/resources/Chips/EMU8030.pdf
Electronic Enclosures with 1602 LCD Cutout - Page 1
Forum section: electronics / projects

author: NY2KW
author_rank: Regular Contributor
timestamp: October 14, 2023, 09:50:29 pm
content: There are so many small projects on my list but it seems no one makes any nice enclosures with a front panel precut for a standard 1602 or 2004 LCD. I hate the hole drilling then nibbling and with nice solid aluminum front panels, the cutout always looks crappy. I have used Front Panel Express for some of my higher end project but does anyone know of any supplier for nice metal enclosures precut for front LCDs?Jerry

author: Benta
author_rank: Super Contributor
timestamp: October 14, 2023, 10:11:02 pm
content: Cutting rectangular holes is always a challenge.Why not just use a bezel for your displays? No one will see your cutout then.Like this:https://www.ebay.co.uk/itm/353054663105

author: ataradov
author_rank: Super Contributor
timestamp: October 14, 2023, 10:14:49 pm
content: Last time I've searched, the selection was limited to thishttps://www.aliexpress.us/item/2251832529131136.htmlFor one-off projects custom 3D printed enclosures are a way to go.

author: abeyer
author_rank: Frequent Contributor
timestamp: October 15, 2023, 08:07:00 am
content: Why not just a pcb front panel for any of many aluminum extrusion options?
Electronic Firecracker - Page 1
Forum section: electronics / projects

author: FlyMario
author_rank: Contributor
timestamp: August 23, 2018, 06:09:42 pm
content: Hi,It is getting near for me to start working on Halloween props. One thing that has always interested me is these electronic firecrackers that you can get from frightprops. They are pretty expensive for what the are. They sound to me like a Capacitor being discharged very quickly. I am not sure if that is really what is going on so I thought maybe you guys might have an idea. I would like to make a few though I am not that great at creating electronic circuits.Any ideas?thanks,Pete

author: mikerj
author_rank: Super Contributor
timestamp: August 23, 2018, 06:46:36 pm
content: Sounds like a high voltage/ high current discharge. I guess an inverter/voltage multiplier ladder with sufficient low ESR output capacitance that when the spark gap gets ionised the resulting discharge current is very high and very short. Certainly wouldn't want to be getting fingers inside those things.
Electronic Fuse - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 08, 2014, 11:11:47 pm
content: I've hinted at this a bit in recent posts, and I see there's some interest in such a thing.So, without further ado, allow me to announce the humble Electronic Fuse:http://seventransistorlabs.com/Fuse/index.htmlAvailability: nada, still working on it.More updates to come!I ordered the PCBs from ITead Studio, and got a dozen. So I have a few extra prototypes to pass around...Tim
Electronic, key powered tumbler lock - Page 1
Forum section: electronics / projects

author: D4no0
author_rank: Contributor
timestamp: January 24, 2020, 11:12:35 pm
content: Today I was told that there is a company that makes electronic tumbler locks.The selling point of this thing is that the key presumably powers the circuitry located in the tumbler, checking the validity of the key and allowing to unlock the door based on the exchange. In theory the part where you power a chip using a key is not so hard, you just have to isolate a part of the tumbler so that you won't have a short. The part that is interesting is how do they move a mechanical part (I suppose is still a pin, or maybe more) in such a confined space. At first I was thinking that you can use an electro-magnet, however I'm not sure it would do the job, since there should be some kind of springs so that you won't be able to turn the lock when it's not powered.What is your opinion on this topic, what would be the most reliable way to build such a thing?PS: sadly I won't be able to get my hands on it anytime soon since it costs 260 euro/piece and it is out of my budget.
Observe electronic light bulbs disturbances with a SA/SDR - Page 1
Forum section: electronics / projects

author: mcinque
author_rank: Unknown
timestamp: March 11, 2017, 07:58:07 pm
content: Hi,I'd like to do some tests on various light bulbs (led and fluorescent) to see with a SA how much noise they inject on mains.I found this video with a simply solutionhttps://youtu.be/o8zMhjXcmoAI replicated on LTspice and bluesim the schematic shown in the video (except the EMI filter on mains) and simulated it, obtaining an output which is compatibile with a SA input frontend.What do you think about the circuit?There is any special precaution that I should observe selecting components (except voltage ratings)?Since we're dealing with mains and SA, I'd like to preserve the integrity of the instrument

author: mmagin
author_rank: Frequent Contributor
timestamp: March 11, 2017, 08:12:58 pm
content: Those capacitors better be Y-rated. And the paranoid part of me would use a DC block between this circuit and the SA.I think what you're looking to make is ahttps://en.wikipedia.org/wiki/Line_Impedance_Stabilization_NetworkSee alsohttps://www.eevblog.com/forum/testgear/emc-pre-compliance-testing-with-home-made-lisn/

author: mcinque
author_rank: Unknown
timestamp: March 12, 2017, 10:26:34 am
content: Yes, indeed caps must be Y rated. Metalized paper should be better because they tend to go open when they fail.But I was wondering what kind of protection I can include to prevent any catastrophic failure other than this.
Electronic Load - Page 1
Forum section: electronics / projects

author: EntropyWizard
author_rank: Contributor
timestamp: October 28, 2015, 08:28:05 pm
content: I built a small electronic load based initially off Dave's video on the subject (EEVblog #102)as well as some extentions by others around the internet. The final is pretty much unique though (I haven't seen a version with a gate input) so I thought I'd post it here in case anyone else wants to build a similar one. It's a no-frills, manually controlled load up to 2.5A, can dissipate about 25W, and has thermal overload protection and a gate input. I also welcome idea's for improvements, I'm thinking of building a larger one at some point.This version is built on protoboard and housed in an old DB-25 port switcher box from a thrift store. The heatsink is from some older model CPU I guessed could handle 20-30W. The MOSFET (Toshiba 2SK3561) is from a scrapped tube TV switchmode supply, but most any power MOSFET should work since this is only hitting about 2.5A. The thermistor is epoxied to the heatsink next to the MOSFET and the thermal overload circuit tuned via RV1 in operation to trigger at about 25W. The gate schmitt trigger has threshholds at 1 and 2 volts approx. and is held high (on) if nothing is connected.I've attached comparison traces using the load on a simple linear (7805 based I think) lab supply and a switched (old PC) power supply at 5V. The electronic load gate is driven with a 200Hz square wave from a signal generator and average load was set at 1A. The scope settings were 0.1V/div, 1ms/div.

author: German_EE
author_rank: Super Contributor
timestamp: October 28, 2015, 08:33:05 pm
content: Nice to see that I'm not the only one building one-off projects on protoboard, and extra marks for reusing that case which is too good to throw away.How about posting your schematic as well?

author: EntropyWizard
author_rank: Contributor
timestamp: October 28, 2015, 08:36:36 pm
content: The schematic should be there now -- I was swapping it from pdf which doesn't preview to jpg.
Electronic load analog part - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: May 18, 2021, 04:11:48 pm
content: Hi guys,I tried to build a Electronic load . I have attached the analog part of the schematic. My question is how do i calculate the damping factor of the analog part and damping resistors for pulse load.Thanks in advanceBaskaran

author: Zero999
author_rank: Super Contributor
timestamp: May 18, 2021, 04:25:45 pm
content: Why are there so many op-amps? Normally only one is required to ensure the voltage across the sense resistor, matchs the reference. If the reference voltage is too high, then add a potential divider to attenuate it.

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 19, 2021, 01:38:00 am
content: What is a 'damping factor of an analog part'? And what is a 'damping resistor'?
electronic load dought - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: October 26, 2014, 09:56:12 am
content: Hi guys,I have this dought , what happen when a constant power mode in the electronic load is set and hookup to power supply that is not capable of deliver that power.

author: Strada916
author_rank: Frequent Contributor
timestamp: October 26, 2014, 11:08:13 am
content: Simple the power supply will only apply what it can and no more. If the other way round then the power supply is limited by the electronic load. Provided the psu output is within the eload parameters.
Electronic load for battery cell testing - Page 1
Forum section: electronics / projects

author: m.k
author_rank: Newbie
timestamp: May 04, 2017, 11:00:28 pm
content: New project, i want do build a battery discharge tester for single cell testing.Specs:-voltage range: 0-4,5V (full current sink should be available down to 2V, maybe 25-30A down to 1V if possible)-current range: 50mA-75A (would be cool to have an universal setup that can either test an AAA NiMH battery for capacity and really push smaller Li-Ion -cells like 18650, 21700 and 26650 to their limits.) Should be able to switch off the current flow so the battery in test doesn't get overdischarged.-data logging via a arduino and a computer (because i can't do proper uCs yet)-temperature measurement and cutout-input should be floating so you can test an 3,3V earthed powersupply with an earthed data logging/showing computer.I never layed out an PCB before and have small electronic design experience (hey, i built a lab power supply with 2 LM317) so i may ask some rather dumb questions down the road when I'm at the board layout stage. But eventually I end up with a nice battery cell tester and share my design which may is helpful to anyoneFor now i did search for components and started with the schematic, next up is ordering the parts and doing some breadbording as well as figuring SPI out. Then think a litte about decoupling and component values and finally layout.

author: nctnico
author_rank: Super Contributor
timestamp: May 04, 2017, 11:05:05 pm
content: I'm missing a fuse in case the MOSFETs short due to a failure.

author: m.k
author_rank: Newbie
timestamp: May 04, 2017, 11:15:15 pm
content: I had a look at some automotive style fuses and already found some nice ones with low enough voltage drop to keep the internal impedance of the thing down. Going to definitely use a fuseI thought about reverse Polarity protection, because i guess the MOSFETs would act like a short if one does reverse the polarity, but keeping the internal resistance down makes this not fully trivial. Goes in the "nice to have" category.

author: VoltJesus
author_rank: Contributor
timestamp: May 05, 2017, 09:43:30 am
content: I started researching info on building one of these as well. Got a bunch of cells I need to test.I'll be watching this thread to see how your project goes.

author: MarkF
author_rank: Super Contributor
timestamp: May 05, 2017, 10:10:15 am
content: I'm building an Electronic Load (no microcontroller) based on designs put forth by Peter Oakesand Dave Jones.Mine is low power but you should see Peter's design and how he blew it up because your load section is very similar.