hybridfree/eevblog-posts huggingface dataset:
Simple PWM Wireless Transfer Transmitter - Page 1
Forum section: electronics / projects

author: Cirro
author_rank: Newbie
timestamp: November 28, 2022, 01:44:01 pm
content: Hi All,I am currently building a simple wireless transmitter coil so that I can later play with the receiver coil output. I am making a PWM based transmitter fixed at 85kHz with a 14uH coil. This is being achieved through use of a half bridge. I am implementing a Series--Series resonant inductive method for transferring energy over both loosely coupled inductors. The capacitors have been tuned for the fixed inductance value, however I am faced with the issue of current limiting.I am restricting myself to a 1A power supply so to get around this I am adding a series resistance to the load of 10R (ontop of the .2Ohm of the inductors series resistance). However this causes distortion in the inductor voltage. Below I have shown waveforms with and without this added resistance. As this added resistance will be influencing the impedance of the load - creating the distortion how can I go about limiting the current that the coil draws, whilst maintaining sinusoidal voltage across the inductor?PS - I do not believe this issue to be related to a lack of deadtime in the simulation as I am measuring the inductor voltage and additionally, I have built this circuit in person, using a gate driver with a deadtime and am getting the same waveform (with the addition of some resonance from the practical circuit)EDIT: I have since determined this issue to be no longer relevantCheers,Cirro
simple radio not working - Page 1
Forum section: electronics / projects

author: xchip
author_rank: Regular Contributor
timestamp: October 22, 2013, 12:18:04 am
content: Hi guys.I put together a LC tank tunned to a freq of 77.5Khz, then I connected it to an op amp and then to my oscilloscope. I was expecting to see some oscillations at the output, after all the antenna should bring some 'white' noise to the LC and the LC should just resonate at its resonance freq. I was expecting to see a nice wave in my oscilloscope but its all flat.[See pic for circuit] (edit: NOTE that the pic has wrong values for the LC resonator but the rest is OK)I bet something in fundamentally wrong in my design... Any ideas on what is wrong?

author: wraper
author_rank: Unknown
timestamp: October 22, 2013, 12:48:28 am
content: ...50Hz resonance frequency of lc circuit.

author: Circlotron
author_rank: Super Contributor
timestamp: October 22, 2013, 01:55:32 am
content: Yep, cap and inductor values are way to large.Also, make the opamp cct non-inverting rather than inverting like it is now. The input impedance is only 1k and this will damp any resonance of the tuned cct. Non-inverting is much higher impedance.

author: xchip
author_rank: Regular Contributor
timestamp: October 22, 2013, 10:03:25 am
content: Yep, forgive em for the 50hz LC I forgot to update the circuit with proper values.I never thought an inverting op amp would have a low impedance(which now that you said it loos pretty obvious)I'll give it a go and will post my results. I'm pretty excited

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: October 22, 2013, 10:44:12 am
content: Depending on what you are trying to do, then building a gyrator receiver may be the better way to a DCF77 receiver.If you are just looking for an excuse to learn about LC circuits and basic radio techniques, then please disregard this comment.

author: xchip
author_rank: Regular Contributor
timestamp: October 22, 2013, 01:44:40 pm
content: eheh, yes this is just an excuse to learn something about LC circuits, but I do appreciate your pdf, I will build it as soon as I get the LC thing working! thanks!Another question though. I am using a virtual ground at 2.5 volts, I presume that LC circuits wont like that and prefer to resonate around 0V. I guess I have to put decoupling caps, where would you place the caps?

author: xchip
author_rank: Regular Contributor
timestamp: October 23, 2013, 12:13:44 am
content: Got it, there is my resonator amplified by an op amp, I used a non inverting configuration so the high input impedance of the op amp doesn't damp the oscillation as Circlotron suggestedI have a DDS 9850 doing a freq sweep and I'm getting a nice spike at 54.9KhzThanks to everyone, I am so happy!
Simple reference for use with MCP3208 ADC and ESP32 MCU - Page 1
Forum section: electronics / projects

author: djsb
author_rank: Super Contributor
timestamp: September 18, 2025, 08:30:29 pm
content: I need a simple reference to use with a 12 bit MCP3208 ADC. I'm using it with an ESP32. I've tried connecting the VREF pin of the ADC to the 5V pin of the ESP32, but as the 5V measures approx 4.6v this is not ideal. I don't want to use the 3.3v pin of the ESP32. I've thought of using a TL431 as a reference, but I'm not sure how to use it properly. I'd like to use some kind of 4.096v or 2.048v reference if possible. Can the TL431 be adjusted for 4.096v easily? Are there any standard ways of doing this? Thanks.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: September 19, 2025, 03:50:59 pm
content: MCP1501-40 looks suitable for your application.CheersAlex

author: Buriedcode
author_rank: Super Contributor
timestamp: September 19, 2025, 06:47:48 pm
content: You can certainly use an adjustable voltage reference to generate 2.048/4.096 for easier calculations - they are set with resistors, so for production would require precision resistors (0.1% aren't that expensive) or for one-offs/low volume, 1% resistors + multiturn trimpot to trim. I have a draw in my parts tray with a bunch of LM4041 "modules" each trimmed and calibrated to a specific voltage.With that said, 4.096V/2.048V references are pretty common. LM4040 has a range of voltages. TL431 has a reference of ~2.495V so can't be set below that, a TLV431 has ~1.24 so can be set to 2.048V.Another option would be to use a standard regulator as the reference, along with a voltage divider (with trimmer) to get a reference - should be fairly low impedance for the reference, and bypassed with a 100nF cap. But you might as well go with a proper reference, it'll be more stable.
Simple reliable 96 LED capacitor dropper desktop lamp - Page 1
Forum section: electronics / projects

author: Victorman222
author_rank: Regular Contributor
timestamp: March 16, 2023, 11:31:13 pm
content: Warning, this project involves mains voltage. So my fluorescent tube lamp began playing up, and being the conscientious person i am, i wanted to go to the next level of energysaviness, LED!! The primary goals of the design is to be reliable: the capacitor and resistors are big to absorb inrush current, and easily fixable (hand solderable smd led footprints).I made the PCB with toner transfer method, soldered some used LEDs from broken lamps (what?? didn't i say i want it to be reliable?)... Well it worked after a few sessions of troubleshooting. Maybe a better layout would be not two strings in parallel, but a string of leds with two in parallel, so one LED failing doesn't stop half the lamp from working (however i haven't the slightest idea how to implement balancing resistors in that kind of circuit). Some back of the napkin calculations suggest that its power is about 8 watts (the resistance before the diodes is about 2.6 k, and the voltage clamped by 48 diodes is 3*48=144, so the current is 144/2600=0.055, then 0.055*144=7.975(W), I'm not sure that this is the correct way to calculate this kind of power supply, just my assumptions.)For the mechanical construction i had to take care in making it in such a way that the mains voltage is not easily touchable. I took my old lamps case, and by luck found a piece of acrylic the same width as lamp, cut it to length, made appropriate holes in lamp body to hold it with a cutout and two bolts and that was it. To finish off i glued a piece of steel to rear side of the PCB where the diodes are, trying to emulate aluminum backed PCB.I have used it for a month and it is relatively nice.Attached are some photographs, schematic and the Kicad files.

author: Victorman222
author_rank: Regular Contributor
timestamp: March 16, 2023, 11:33:48 pm
content: Some image and Kicad files failed to upload
Simple Resetable buzzer/LED circuit - Page 1
Forum section: electronics / projects

author: challie2
author_rank: Contributor
timestamp: June 11, 2019, 04:49:18 pm
content: Hi there I am trying too get into circuits, and I have a project I want to build.What I am trying to achieve is make either a simple relay or simple IC/transistor circuit that has primary function of being an alarm in the form of a buzzer and LED that must be acknowledged and reset by a button press. it has too be a 12 Volt circuit and cheap.How I want it too work as follows there are too rooms that I want too have a simple alert and acknowledgment circuit using a buzzer and an LED, In each room there is an operator who has too press a button, Button 1 in Room A starts the circuit. Button 2 in Room B acknowledges the buzzer and LED and resets the circuit. But button 2 cannot start the circuit likewise button 1 cannot reset the circuit. This is very similar to the disabled toilet alarm but it is not for that otherwise I would buy a kit for that.12Volts and cheap.I appreciate any help.Have a nice dayMany ThanksJamie Newman

author: Zero999
author_rank: Super Contributor
timestamp: June 11, 2019, 05:06:52 pm
content: You need a latching relay circuit.
Simple RF test set described - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: August 28, 2012, 01:04:01 pm
content: Just some forewarning of a piece of test gear of interest to RF tinkerers that could be a good project. The general concept is a 'swiss army knife'. It's small, cheap and does a lot. But not necessarily particularly well.Anyway it's described in the September 2012 Amateur Radio magazine available at many newsagents. I manage to get 8 RF test functions from an instrument that uses just one IC, one transistor, one meter (and lots of switches). As it stands it can measure RF power output, field strength (relative indication), CW, AM and SSB transmission quality and even generate signals on a few spot frequencies. Ideas on additional functions appreciated.In that same issue is a simple ESR meter that will also interest a lot of people. This uses an analogue meter and has a PCB layout (boards also available).

author: kg4arn
author_rank: Unknown
timestamp: August 28, 2012, 09:11:03 pm
content: Is it your circuit design?

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: August 29, 2012, 11:02:04 am
content: Quote from: kg4arn on August 28, 2012, 09:11:03 pmThe unit is, but the stages are stock standard.It's amazing how many things you can do with 3 or 4 stages.An LM386 is used as either a DC amplifier (to drive a meter movement) or an audio amplifier (for a small speaker). The latter is used for the signal monitor or audio signal tracer.A diode rectifies RF to DC (or in some cases audio).A crystal oscillator switched between a few frequencies provides some spot frequencies for receiver testing and a local oscillator for the SSB transmission monitor/WWV receiver.A tuned circuit (variable over a couple of common HF ranges) is good for the absorbtion wavemeter and receiver.And the meter movement gets use for the RF power meter/dummy load, field strength meter and absorbtion wavemeter.About the hardest challenge was switching all these without too many switches and there were some compromises.Though not the main subject of these videos, it get some use in them:
Simple short-circuit protection - Page 1
Forum section: electronics / projects

author: Analog Kid
author_rank: Super Contributor
timestamp: May 01, 2025, 10:56:34 pm
content: I just saw this idea for how to protect a power supply from short-circuit currents:This is in the Jan. 2008 issue ofModel Railroader. The application is a setup to drive Tortoise switch motors.The problem is that with the configuration used in the article, it's possible for there to be a momentary short circuit between the switch-motor contacts, which would pop the power supply circuit breaker.Since the setup uses low current, they solved the problem by just sticking an incandescent lamp in series with the load. (They used a no. 93 lamp, rated at 12.8 V and ~1A.) When the circuit is operating normally the bulb doesn't even glow.Seems like a pretty elegant solution to me. Of course, this wouldn't work in all cases, but for this model railroad application it seems perfect.

author: moffy
author_rank: Super Contributor
timestamp: May 02, 2025, 12:25:52 am
content: It's a very common method used in testing mains supply units, to prevent blowing fuses:https://www.eevblog.com/forum/projects/isolation-and-current-limit-project/

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 02, 2025, 03:01:54 am
content: It was also commonly used during repair of CRT's and other household equipment. Also, the first signal oscilator that HP ever made used a weinbridge oscillator, and that was stabilized by a small lightbulb used as a PTC.

author: Terry Bites
author_rank: Super Contributor
timestamp: May 03, 2025, 06:42:33 pm
content: Old school and used to be very common. Makes an appearance on many may repair/restoration benches. Usually needed when working on old tube devices.Mr Carlsons lab, Menditmark etc... make good use of this limiter.

author: MarkF
author_rank: Super Contributor
timestamp: May 03, 2025, 07:08:12 pm
content: More variations of the "Dim Bulb Current Limiter":https://www.eevblog.com/forum/beginners/dim-bulb-current-limiter-prototype/?all
Simple Solar charge controller, any issues? - Page 1
Forum section: electronics / projects

author: rickey1990
author_rank: Regular Contributor
timestamp: November 04, 2022, 01:32:07 am
content: Hi I am wanting to make a simple Solar charge controller for a DIY power pack. I am wondering if this design is okay.Link to online circuit simulatorhttps://lushprojects.com/circuitjs/circuitjs.html?ctz=CQAgjCAMB0l5BOJyWoSB0DsAOAzEjgCwCseAbDgExh7ggkhF0kCmAtGGAFAAuIVIpHAIqIPJCIixwiJzCxcYBJEo4s5SiXJRoJbVXJgsCMFRyU8OHEzggAJqwBmAQwCuAG17cA7uMngGv5SYOTCkL7ilBg6ElIIOhF+cTECgqkRxjZcYjmBOnmyumLsMJBUkLRUWHgkFuQIWOVSZYxg8PC65QJJIDiyRFJE2YNQ3HhSAF6sAHasAE6cVNBg7Lng2GDMJObKu-BUHFhQArAd5x3E4MsQPJNMw9IPNgkCINNzi2Yra9zzz09BjZzDZhCQOn8AXsGKNobIIX4SLDRDCpHgKmNEaM8BQBEJxLjekDxBiwjZ0eFuMYxGTUuRtBkQMdvkZwHRwrpGAA1AD2XhcAHNWNwBSBaRSxekJZS-HkqOk8qEZbZhK8KC9EpEhKqdMTXkS7FshnZ9Vq7BUbNr8pjwGE0sbhPKWmbHekrRaxsY0bjBMIcbEArdOjAiGFtRcOnQAEqsADOAEtY7wXDMAMbC5IBD3+nqgyJItEYgsEzV+YkggEpXo530l3M24kSxsBas7ARYMRWKTVGSRLvtztXaV9ocYxsY3rGWIY-okyn2JjZO2zpVvMAAORIWC4WqXwkeRptTtSU4ykWh0NrcPPKJr+Jzk7M9ttrudeCaANetNeEGVK9hT6Hr0K52oqdpEuSM5+hO3ALuQISAYhYhiI4rieN4sq3riF4opOQQSv2w5+NB+6QZSABuIDsI8ErUXuJz7rIxwcjAJCRCRVE0TBAAeVGvIYOjyAIDRMOAIRUORAA6sYAMoAArSQAAsY5HcLxEzHIIjBWIwgiWmJ4AANbSQADjy3i8VwdD4AI7R9LqeLXFJsbzKwHguAAnmpkp0EEDToCYonpAAQi4vC8AsXnvqReIxRWv5jPw6oviqKXCJw4AKGQRBmPotQ9nANilNA5A1DQjREFgeW0Ei4B2Kh7heJEdEpS1hSQikq7Jau8JwB1gZ2ik+oMBC-ynmY2T4ROdW7gI1iLnODbAviB7gZE8GZSUB5PhE-yyDtz69X1oQyIdi0oc4jW8OwHisAuCXhLAPDEZtnHZDtkKHh6X34kdk6jN9yK9rKQPWtespBBekPmDap4Soew4nWJ3b4gjGIXWhXg3XdJwPU93BAA.Kind regards, Rick

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 04, 2022, 01:12:45 pm
content: Just use an adjustable LDO with reverse current blocking.
Simple soldering station (temperature only) - Page 1
Forum section: electronics / projects

author: toribird
author_rank: Newbie
timestamp: May 16, 2024, 09:54:10 pm
content: Hello. This is a completely different product, but I would like to create a soldering station that looks like this.It is sufficient to be able to display the temperature of the tip on the display like the "QUICKO T12-951". I prefer a simple look.So my question is, do you think it is possible to obtain the temperature from a commercially available T12 or C245 station and display it on another LCD?I don't have the skills to use Arduino, etc., and I would like to obtain the temperature of the tip from the existing station controller.I would be happy to receive your advice or ideas. Thank you in advance!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 19, 2024, 09:50:59 am
content: Sure it's possible. But you would need some microcontroller programming skills. There are lots of code repositories on github that are compatible with the chinese soldering station controllers.You can also have a look at:https://hackaday.io/search?term=soldering+stationYou can probably find both source code and PCB layouts.
Simple spot permeability meter? - Page 1
Forum section: electronics / projects

author: rs20
author_rank: Super Contributor
timestamp: January 16, 2015, 09:56:10 pm
content: I found some magnetite stones on the beach, and I'd like to make a simple device to measure the variations of the stone's permeability over its surface. I'm not after calibrated values, just some uncalibrated value that is some mostly monotonic function of the true permeability. My initial concept was to take a nail, bend it like so, and use it as the core of the L in a Colpitts oscillator:However, as pointed out inother thread, the nail's conductivity will introduce crippling eddy currents and the magnetic flux will never reach the "region of interest". So I need to use a different core -- perhaps if I get a toroidal inductor core designed with SMPS's in mind, and then cut a tiny slot in it and place the stone up against that slot, that might work?My question -- can anyone foresee any issues with abusing a toroidal core this way? Or is my entire approach ridiculous/am I missing an easier way? Any critiques or suggestions most welcome!EDIT: Fixed broken image link.

author: tymm
author_rank: Contributor
timestamp: January 16, 2015, 11:30:15 pm
content: dunno if this might be useful:http://softsolder.com/2013/01/21/slitting-a-ferrite-toroid/Ed Nisley used a slit torroid for a hall effect sensor based current measuring device (final writeup for Circuit Cellar).Different application but seems like there's some overlap.i'm not really a magnetics guy, but i would expect there to be minimal effect with the DUT being outside the toroid.have you thought about trying a tape head?
Simple system PSU for a robot - Page 1
Forum section: electronics / projects

author: AleRoss
author_rank: Newbie
timestamp: April 16, 2016, 06:25:25 pm
content: Hi guys!First off, this is my first post so, hello worldI make robots in my school, we design them from the very basics stuff so i was thinking about the power supply unit. The robot should be made of four boards, three of which, stacked together: the bottom unit (which has many sensors and signals), the power supply unit and the logic unit (we use an FPGA module to develop on a zynq platform).Since we use many expensive components on each of theese two boards, and change often the fourth board (which is on the front), i'd like to make the power supply smart enough to detect shorts and rail voltage. I'd also like to branch the 5v rail in multiple ones, and monitor them.It is a very ambitious project, especially for a beginner like me, anyone that want's to follow me in this adventure?So here is what i've thought so far:The FPGA Module (Microzed) has already all the linear, low-dropout regulators the fpga needs so i don't need to desing such a complicated stuff.If i make this smart enough, i can report back to the FPGA the status of the rails, so i was thinking about implementing a standalone TI TM4C123GH6PM microcontroller which has plenty fo processing power and memory to accomodate my needs, plus i already own a developement board for it. This uC has a 12bit 12channel ADC that would be sufficient to read rail voltage and maybe to read the .1 Ohms sense resistors i want to try. About sense resistors, i would really like to avoid opamps, while easy and logic to use here, they would add complexity to the whole thing and i am really trying to to keep it simple. To detect overcurrent i just need to sense .5, 1 and 2 amps on the rails and with a 1v reference, i can go far beyond that. I've made some math on thisThe battery im going to use will depend on the voltage of the motors, but i'm planning to use a 3 cell lipo with a voltage of 11.1v. I need 4 rails of 5v@1.5A, so i need to handle 7.5W!!I really like the easy of use, stability, of the noise-free 78XX regulators, howerver a bit of math reveals to me that i can't power 3 servomotors (for a grabber on top of the robot), the FPGA and all the sensors with thoose. I can source 300mA at 30 °C, 11.1 v in, 5v out, without heatsink. The room for the board is not small, so i can count on a bit of surface, however i might also consider to seal this power supply and i will enclose it for sure, so little airflow is granted.I don't want to mess around with components i'm not confident about, so i won't design a switching supply. Sparkfun sells a DCDC Converter (https://www.sparkfun.com/products/9370), i might use that, any advice? any other solutions? where can i buy more reliable dcdc converters?I'm asking myself how to switch the rails when there's a fault condition, maybe i'll have something for tomorrow.. Let me know if this project is interesting and excuse me for the chinglish, i have made tons of errors for sure.Alessandro,Italy
Simple test of DC charge point (electrical vehicule) - Page 1
Forum section: electronics / projects

author: Lunasix
author_rank: Regular Contributor
timestamp: February 05, 2021, 07:36:03 pm
content: Do you have any ideas to do some simple test on DC charge point ? It is easy for AC charge point, but for DC charge point, commercial tester are very expensive, few models and over complicated if we just want to do rapid test.

author: uer166
author_rank: Super Contributor
timestamp: February 05, 2021, 07:38:09 pm
content: Yes, simply grab a car and plug it in, see if it charges. Everything else is either obscenely expensive or obscenely complex to make.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 06, 2021, 05:06:57 pm
content: Lots of DC fast charge hacking here:https://openinverter.org/forum/viewforum.php?f=17For some test load, two 240V stove elements in series should be good up to 480V. Not sure what would be the most economical load to do a sustained full power test for even a few minutes, probably can't get any cheaper than two scrap metal electrodes in a large container of salt water but there would be too many safety issues to list.

author: Lunasix
author_rank: Regular Contributor
timestamp: February 06, 2021, 06:19:08 pm
content: Thank you, I did not know this site.

author: Gyro
author_rank: Super Contributor
timestamp: February 06, 2021, 07:46:09 pm
content: Quote from: Lunasix on February 05, 2021, 07:36:03 pmWhen you say you just want to do rapid test, don't you still need to test safety aspects like earth leakage protection? I would have though that these were just as important as checking that there is a DC output and ought not to be skipped. I'm pretty sure the commercial testers verify these.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 06, 2021, 07:49:31 pm
content: Quote from: Gyro on February 06, 2021, 07:46:09 pmThat one is easy, connect a resistor from one of the lines to ground with a value that gives a current just above the trip threshold.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 06, 2021, 08:10:41 pm
content: CCS or Chademo ?

author: Lunasix
author_rank: Regular Contributor
timestamp: February 07, 2021, 09:22:45 am
content: QuoteYess.It is for CCS, for rapid test (ok / ko), models I have found are above 10000$.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 07, 2021, 11:52:53 pm
content: The problem you have is that CCS is an insanely ( and unnecessarily) complex protocol, so getting the controller to think there is a car connected will be a lot of work.For a 1-off it will almost certainly be cheapest to just buy the cheapest CCS car you can find and use that.Alternatively look at re-purposing the charge controller from a CCS car. There is work being actively done on that using Tesla m3 and BMW i3 controllers here :https://openinverter.org/forum/viewforum.php?f=17
Simple thermostat timer - Page 1
Forum section: electronics / projects

author: Rachie5272
author_rank: Regular Contributor
timestamp: January 29, 2015, 11:10:04 pm
content: I'm building an oven for curing polymers, and I'm trying to find a nice simple thermostat timer controller. Ebay is awash with cheap programmable PID thermostats, but they lack the time component. I want to be able to bake the polymers for a couple hours at a specific temperature, then turn off.Any suggestions? My temperature range is around 20-200 C.

author: tautech
author_rank: Super Contributor
timestamp: January 29, 2015, 11:36:09 pm
content: Quote from: Rachie5272 on January 29, 2015, 11:10:04 pmBreak it into 2 components; timer and thermostat

author: Rachie5272
author_rank: Regular Contributor
timestamp: February 13, 2015, 11:36:26 pm
content: This project just got a bit more complicated. It looks like I'll be needing a fully programmable ramp/soak controller, not unlike what solder reflow ovens use.Does anyone have suggestions on where to get such a controller?

author: KM4FER
author_rank: Regular Contributor
timestamp: February 14, 2015, 02:28:36 pm
content: Rachie5272,One of my other hobbies is making pottery and for that I have an electric kiln to which I have added a Bartlett Instrument Co V6-CF Kiln Controller which may work for your application.http://www.bartinst.com/KILN/v6cf.htmlWith this controller I can program in temperature ramps and hold times and could easily duplicate a reflow soldering profile. (Note to self: I should do that with some old scrap boards just for fun.) The list price on their web site is $219 US for the controller but you would need a few extra parts including a power transformer, relays, thermocouple, connectors and a box to mount it.Another company that makes a similar product is Orton.For those who are interested from the sound of the relays clicking on and off I am pretty sure the Bartlett controller uses fuzzy logic.Need to know more, let me know.earl...
Simple two range LED Capacitor Meter for R.F. Work? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 26, 2025, 01:55:38 am
content: Hi!. . .A year or two ago I found a simple two–range R.F. Capacitor Meter that could be built readily available parts and I don't think it required any form of programmed Microcontroller to build it either!. . .Trouble is, I've downloaded so many tons of stuff recently I can't find the details for the life of me now, and I would like to find it again and get the appropriate Chapter of my T & M Theory Book started before the project disappears into an outer space black hole for evermore!Does anyone recall a two range LED Capacitance Meter Project? The only clue I have is that I THINK it worked by adding the unknown capacitor in parallel with a known one and measuring the change of resonant frequency of a tuned circuit!Chris Williams

author: Sensorcat
author_rank: Regular Contributor
timestamp: February 27, 2025, 12:51:25 am
content: Do I understand correctly that you downloaded a description of that meter, but cannot find it among your downloads? If that is the case, you perhaps need a desktop search tool, something that does on your HDD what Google does with the internet. I use one for my large 'electronic library', and it is often amazing how helpful this is. It may appear pointless at first, because Google provides much more hits for any search phrase, but what you downloaded is a great filter (because you were interested in the stuff found), hence the average quality of the hits is much better. After some research, I settled with this program, and I am happy with it:https://docfetcher.sourceforge.io/en/index.html
Simple uCurrent case - Page 1
Forum section: electronics / projects

author: gobo207
author_rank: Contributor
timestamp: April 08, 2020, 12:04:40 pm
content: Hi all,Here are two uCurrent case designs. No screws, simple to print and just one part. All you need to change the battery is a fingernail.https://www.thingiverse.com/thing:4267006I eventually got sick of changing the battery and decided the extra current range could be useful so I made a AA battery version as well.https://www.thingiverse.com/thing:4267016Hope someone can also find these useful.Cheers!
Simple ultra low power switching light sensor - Page 1
Forum section: electronics / projects

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 07, 2023, 12:48:45 pm
content: Nothing-to-do Sunday, so time for tinkering!Some hogs are destroying a friend's crop, he got nice results by spreading some cheap FM radios over the field.However, having to go there everyday to turn them on/off is a PITA, he tried to make some battery-friendly switching circuit to turn the radios only at night, but he just knows relays and little else, so he asked me.The circuit must work at 2.5-3.2V (The autonomy of two AA batteries).I came with the idea of using a single 74HC14, which can work down to 2V, using one gate as a comparator, other as a low-freq oscillator and the rest as a charge pump to turn on a N-Fet.So far it looks pretty good, generating 12V at 500Hz while consuming 200uA.When the comparator stops the pump stage, it only takes 30uA (Due the loading the 100K resistor, I might change it for a higher value).The bad side is it lacks the tweaking capability of a comparator / op-amp.

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 09, 2023, 04:51:43 am
content: It seems to work nice, but I won't make any more by hand-soldering on prototype board (It takes ages lol), specially when I can make 60 pcbs for 6€Anyone interested in the gerbers just tell me and I'll upload them.
Simple upgrade to a TC1 Multi-Function Tester - Page 1
Forum section: electronics / projects

author: intabits
author_rank: Frequent Contributor
timestamp: March 21, 2018, 04:32:27 am
content: A simple, but quite useful upgrade to my TC1 Multi-Function Tester.I added a 3mm stereo jack, connected to the test socket pins 1,2, and 3.Then made a few test leads with 3mm plugs and various probe clips to use with it.It adds a few pF capacitance, but that can be allowed for.(Just don't use a metal plug like I dumbarsedly did.)A video about it:-
simple USB charging - Page 1
Forum section: electronics / projects

author: vini_i
author_rank: Regular Contributor
timestamp: July 22, 2015, 03:36:01 pm
content: i'm making myself a set of battery powered speakers that double as dual headphone amplifiers. i've got the audio side nailed down and now i'm working out the battery side. i want to charge the battery (single cell lithium polymer) using USB. what i've done in the past with these projects is use a charging IC and limit the current to less than 100mA that way i can plug it into a computer (without enumeration) to charge and not shut down the ports do to over current. another solution i've used is an FTDI chip ft230x. this chip can enumerate requesting 500mA and then turn on a FET to feed the charge IC which was set to 370mA. this worked well as a solution because there was a micro on the board and i used the FTDI for debugging purposes. the speaker board won't have a micro of any kind so the FTDI won't be a good fit.i want to charge at between 200mA and 300mA and i want to be compatible with both computer USB ports and wall chargers. is there a chip that will enumerate, enable power and be able to detect wall chargers without any other thrills?during some googling i came across the MAX8895 which will not only enumerate, detect a stand alone usb charger, but also has battery charging built in. unfortunately it only comes in a BGA package and costs over $3.
Simple vertical support for power strips - Page 1
Forum section: electronics / projects

author: calzap
author_rank: Frequent Contributor
timestamp: January 13, 2025, 03:04:17 am
content: In our office, my wife’s computer desk and my computer desk are back-to-back. At one end is a wall with a quad 20A outlet; at the other end is a table with a printer and scanner. For years, there’s been an incredible jungle of cables and power strips on the floor between the computer desks. Anytime something had a problem or needed to be added or removed, it was crawl underneath with a flashlight and try to decipher the mess. By the time the problem was resolved, it was often 4 or 5 dives under. So, I needed something to organize the power strips and things plugged-in to them and get the mess off the floor.I decided that a sheet of plywood on a clothes rack of suitable height and width would solve the problem. It would be thin enough to fit between the desks and high enough for the power strips to be off the floor. The clothes rack, as obtained from Amazon, is in the first pic. I replaced the casters with rubber feet, cut back the “wings” sticking sideways from the top, and shortened the vertical supports so the power strips would be about 30 cm above the desktops. One of the bottom horizontal spacers was moved to the middle so a pair of the shorter spars could stick under a desk. Then cut a sheet of plywood to fit, finished it and bolted it to the rack. See result in second pic.Finally, bolted power strips to the plywood. Was able to find power strips with 8 widely spaced outlets. You’d think a pair of 8-outlet strips would be enough for 2 people. Nope, needed more, so a 4-outlet strip was bolted to one side and plugged into an 8-outlet strip. I installed a few cup hooks to support cords with warts. Make a loop with the cord near the wart, secure the loop with a twist tie, hang loop on hook. Last two pics show the strips in use.Could have used Wiremold surface mount hardware to assemble strips. But the ones I bought work fine and were much less work to install than Wiremold and cheaper too.Mike

author: Poroit
author_rank: Frequent Contributor
timestamp: January 13, 2025, 05:47:30 am
content: Nice job....well done.

author: ledtester
author_rank: Super Contributor
timestamp: January 13, 2025, 06:48:53 am
content: I've done something similar using 3d printed brackets. You can find various designs on sites like thingiverse:https://www.thingiverse.com/search?q=power+brick+bracket&page=1Another idea using aluminum ties comes from the 8-bit Guy:How to wall mount virtually anything! -- The 8-bit Guyhttps://youtu.be/Xa8IrMWXtYc?t=1m40s
Simple radio transceiver circuit walkthrough - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: November 13, 2012, 09:17:10 am
content: Occasionally people ask about low power transmitters etc. FM bugs are great fun but most only go several hundred metres. What I love about this stuff is you don't need to go too much more complex to make transmitters (in an HF amateur band) that easily go several hundred kilometres.Plus if you go direct conversion making it a transceiver is as easy as adding an LM386, with the other parts shared with the transmitter. I wouldn't say the thing's finished - there's a few minor refinements that would make it more pleasant to use but the results are still good.Part 1:Part 2:Feel free to draw along as I sketch out the schematic!

author: poptones
author_rank: Frequent Contributor
timestamp: November 13, 2012, 03:39:23 pm
content: How do you mount an IC on such a circuit? Glue it dead bug style?

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: November 13, 2012, 06:49:13 pm
content: Quote from: poptones on November 13, 2012, 03:39:23 pmYou could, although you don't necessarily need to glue.If you know you don't want to use the chip again (and if you're game!) bend pins 2 & 4 90 degrees to be flush with the board with the chip mounted up side down.However I just built the amplifier and surrounding parts on a small bit of blank matrix board (approx 3 x 3 cm). Must have been feeling rich that day as I used an IC socket!

author: Prizmatic
author_rank: Regular Contributor
timestamp: November 15, 2012, 09:50:08 am
content: Great work Peter. Enjoyed the pen & paper walkthrough a lot.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: November 15, 2012, 06:51:17 pm
content: Quote from: Prizmatic on November 15, 2012, 09:50:08 amThanks Prizmatic glad you liked it. Another circuit walkthrough has been added - this time a crystal oscillator that pulls 2 x 7 MHz crystals over a huge >50kHz range. It's been added to the transceiver and is listed as Part 3.
Simple voltage level shifter questions... - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: October 27, 2017, 08:38:52 pm
content: I am trying to interface a single bidirectional data pin cheaply and with as little components as possible.On each side I have an AVR, so I can use the pullup on its GPIO pin if that helps/eliminates any external components.One AVR will be running 5V from USB, the other AVR might be 2.5V-5V.The thing is that I only want a 2 pin connection to the 2.5V-5V AVR. Ground and data. I found this BSS138 shifter, but it shows LV coming from the lower voltage device which would be 3 pins which I don't want.Any ideas?

author: alank2
author_rank: Super Contributor
timestamp: October 27, 2017, 08:45:53 pm
content: I should add that I plan on having each AVR switch between input with pullup enabled OR output ground.

author: alank2
author_rank: Super Contributor
timestamp: October 28, 2017, 02:36:11 pm
content: Any ideas or suggestions?
Simplest circuits for 3 voltage levels output from 2 logic inputs - Page 1
Forum section: electronics / projects

author: DigitalDesigner
author_rank: Contributor
timestamp: February 20, 2022, 02:48:25 pm
content: Hello,what are the two simplest (separate) circuits for the following two tables (please note that one output in each circuit is mid of the supply voltage (1V5)?Input A Input B Output3V3 3V3 0V3V3 0V 0V0V 3V3 3V30V 0V 1V5Input A Input B Output3V3 3V3 0V3V3 0V 0V0V 3V3 1V50V 0V 3V3Thank you

author: MarkF
author_rank: Super Contributor
timestamp: February 20, 2022, 03:12:40 pm
content: I believe this circuit will implement the 2nd table.I'm sure the 1st table can be done with P-channel MOSFETs to reverse the logic.

author: DigitalDesigner
author_rank: Contributor
timestamp: February 21, 2022, 12:24:49 am
content: Thank you Mark

author: Someone
author_rank: Super Contributor
timestamp: February 21, 2022, 01:01:52 am
content: Smells like a homework question, why is this circuit interesting? where is it used?P.S. 1 fet, 2 resistors

author: Damianos
author_rank: Frequent Contributor
timestamp: February 21, 2022, 10:58:35 pm
content: Quote from: MarkF on February 20, 2022, 03:12:40 pmDon't complicate it. The effect of A-input is the same. The B-input is inverted, so, removing the inversion of it (Q1) gives the asked result (I mean B to R2). AsSomeonesays.
Simplest design for a PCB reverse pulse plating control ? - Page 1
Forum section: electronics / projects

author: charliex
author_rank: Frequent Contributor
timestamp: August 28, 2012, 06:54:05 pm
content: We've been plating PCB's for a while with the normal pulsed plater, they don't work that great, you get unevenness in the copper distribution and it makes it hard to CNC afterwards.So looking to do reverse pulse instead. Already have the PSU to do the forward/reverse pulse supply but looking for a simple way to switch them. I was thinking about using some large SSR's controlled via a uC. The pulses would be about 20ms forward, 1ms reverse, with about 12v/10A for the forward and 20A-30A reversed.Thoughts?cheers

author: shanes1007
author_rank: Newbie
timestamp: February 11, 2014, 05:19:48 pm
content: Here's a solution for reverse pulse plating:http://www.lpkfusa.com/RapidPCB/ThroughHolePlating/minicontac_rs.htm

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 11, 2014, 06:15:04 pm
content: A few years ago when I had a basement to do electrochemistry in, I built a one of those (a polarity switcher, that is). Variable frequency and duty cycle, 5-20V supply, 5A capacity H bridge output (logic supply has to be a few volts above the load supply voltage, not a problem for most plating cells under 5V or so). I had made a PCB (compact, like 3x4"), but never really got a chance to use it.With bigger transistors and some small modifications (cut a trace for different forward/reverse currents), it should be able to do that. Interested?Tim

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 11, 2014, 07:36:28 pm
content: A brush DC motor driver (often used for wheelchairs and large R/C cars) can do what you're looking for.
Simplest Remote Controlled Latching LED - Page 1
Forum section: electronics / projects

author: Kedar264
author_rank: Regular Contributor
timestamp: February 11, 2015, 07:34:07 am
content: here i made simplest remote controlled latching led see the videoi installed led in front of photodiode and conected led in seris with photodiode ,this forms receiver circuitfor remote circuit , i used infrared led with some ressistor and pus button.simple circuit but works awesome in dark or meduim light condition,but when placed in very high lihgt conditions enviormental light triggers and latches the circuit.
Simplifying FT260 peripheral USB connection - Page 1
Forum section: electronics / projects

author: dkonigs
author_rank: Regular Contributor
timestamp: August 22, 2024, 05:13:55 pm
content: So I'm working on a few devices that use theFTDI FT260IC, and would like to try and reduce the number of components between the USB connector and the IC.The recommended connection is as follows:Basically it consists of TVS diodes, a pair of 47pF capacitors, and a pair of 33R resistors. For the TVS diodes, I'm currently using an ST USBLC6-2SC6 and for the other parts I'm just using individual passives.On some designs, this takes up a tad more board space than I'd like. And regardless, I wish I could do all of this in one component instead of 5.I've noticed that some companies make combo parts that put everything into a single component, but they all seem to have issues making me a little uncomfortable using them as a drop-in alternative. For example:ST USBUF01W6- Almost perfect, but it has a pull-up resistor on a USB data line. I don't think I need that, and am worried it would get in the way.ST USBDF01W5- No pull-up, but its designed for downstream ports. It doesn't have a TVS diode for VBUS, and has some additional pull-down resistors I might not want.onsemi NUF2042XV6T1G- Configuration is exactly what I think I want, but the capacitors are 42pF and the resistors are 22R.I know its possible that the specific resistor and capacitor values listed in all the FTDI datasheets, app notes, and eval board schematics may have some wiggle room on their values, but I'm not sure I'm willing to trust that assumption on blind faith.So does anyone have any specific recommendations here? Perhaps parts I haven't considered yet? Or perhaps experience using one of the parts I'm currently hesitant about using?Thanks.
Simulate power circuits in LTSpice. Using variable load in Watts. - Page 1
Forum section: electronics / projects

author: conducteur
author_rank: Regular Contributor
timestamp: February 03, 2016, 08:46:32 am
content: I'm currently simulating power supply circuits with LT SPICE. I want to simulate different parameters in function of the load. My load is currently a resistor with a changing value. (from 1 to 20 ohm).Can i define a load in Watts so i have the power in watts on the x-axis?Rian

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: February 03, 2016, 11:49:49 pm
content: I know that if you hold ALT and click your load resistor you would get a plot for the power dissipated by it. You can then hold CTRL and click on the plot name to get the average & rms values for the dissipated power. Not sure if this helps as I assume you are automatically varying the load, but give it a try.

author: Mj12
author_rank: Contributor
timestamp: February 04, 2016, 10:52:33 pm
content: You can create controllable constant power load by using arbitrary behaviour current source (bi) and define its current to something like I=v(control)/v(load) where load is net name for net that is being loaded and control is net name for voltage source that defines load power. You can also replace v(control) with for example {power} that allows you to define power level with ".param power=10" statement elsewhere in simulation or power can be variable in .step simulation
Simulated Arcing for Frankenstein style switches.  - Page 1
Forum section: electronics / projects

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 22, 2016, 12:36:38 am
content: I have come across some old switches that I want to use to switch real stuff but only at low voltage and with simulated arcing.12V to Drive contactor for switching.LEDs and peizos for simulated arcing, via a small micro.Anyone got any ideas on how to make this as cool as possible?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 22, 2016, 12:37:46 am
content: More pics

author: Rerouter
author_rank: Super Contributor
timestamp: July 22, 2016, 02:44:43 am
content: I would imagine using a disposable camera flash for the the main effect and some green / white leds for the full effect, , led's dont quite look the part, copper arcing has a hue of green, , and for the sound, it shouldnt be hard to record a good few arcs to cycle through,

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 22, 2016, 02:50:11 am
content: Camera flash, yes that sounds just like what I want. thanks.But not disposable, I'll look up some flash units, whatever they are.

author: Delta
author_rank: Super Contributor
timestamp: July 22, 2016, 02:55:50 am
content: Simply significantly increase the voltage and current you are switching. Hey presto, highly realistic "simulated" arcs!(One minor drawback is that this method might destroy your vintage switches and / or kill the operator)

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 22, 2016, 03:04:34 am
content: So u suggest a full realism mode.In summary.ProsSuper ScaryFast track evolutionLovely smell.Pre built DC arc extinguisher included.ConsPolice visitsPower bill.
Simulating a key press - Page 1
Forum section: electronics / projects

author: ganaps2
author_rank: Newbie
timestamp: May 28, 2017, 04:13:21 am
content: I have a system that has membrane switches with contact pads on PCB connected to the microcontroller in a matrix fashion. Need to simulate the key press without the actual switches from an external microcontroller. Any idea of how to do this?

author: Paul Moir
author_rank: Frequent Contributor
timestamp: May 28, 2017, 04:19:12 am
content: A bunch of opto-FETs too expensive?

author: Ian.M
author_rank: Super Contributor
timestamp: May 28, 2017, 04:27:48 am
content: That's the general approach, but if you have a common ground you can also use analog switches, and if its a regular matrix, an analog crosspoint switch can be a one-chip solution with a simple SPI interface.

author: KL27x
author_rank: Super Contributor
timestamp: May 28, 2017, 08:22:32 pm
content: Done this with keyboard... Bog standard BJT output optocouplers work fine in this case. Zero voltage drop of opto FET not necessarily needed.