hybridfree/eevblog-posts huggingface dataset:
10nF 63V Axial Electrolytic Capacitor KiCAD footprint - Page 1
Forum section: electronics / projects

author: electrovanga
author_rank: Contributor
timestamp: January 09, 2024, 07:39:29 pm
content: Hello,I am searching a 10nF 63V Axial Electrolytic Capacitor to make a footprint in Kicad but I really can't find it. Could you please help me to find one or about the dimensions?Note: Probably I opened this topic to the wrong section. Please delete this topic.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 09, 2024, 07:41:53 pm
content: 10nF electrolytic capacitors do not exist.Generally, follow this process:1) choose suitable component based on availability of distributors,2) read the datasheet carefully to confirm suitability3) open the footprint drawing page on the datasheet4) create the footprint in your EDA software

author: wraper
author_rank: Unknown
timestamp: January 09, 2024, 07:42:27 pm
content: QuoteSuch part does not exist. Not to say footprint is created for particular part, not its specifications.

author: Someone
author_rank: Super Contributor
timestamp: January 09, 2024, 09:16:46 pm
content: If you cannot find the part, why do you need a footprint?I shall make an entrance door for unicorns.

author: TimFox
author_rank: Super Contributor
timestamp: January 09, 2024, 09:31:41 pm
content: Forgive us our typos, as we forgive our neighbors’ typos.I assume he meant microfarads.
10V Boost Converter - Page 1
Forum section: electronics / projects

author: dotcom.com
author_rank: Contributor
timestamp: May 03, 2023, 11:32:48 pm
content: I am currently working on a design for a 10V Boost converter and wanted to ask for advice on my schematic, especially the oscillator and comparator.I am relatively new at this and want to ask for advice to meet my design requirements where the Input voltage Vin=5V, Maximum load current = 250mA, Output voltage ripple < 50mV, LIR under 20%, Clock frequency=100KHz and Power efficiency >90%. Everything is done in the transistor level.Currently I am having issues with my oscillator not producing the correct waveform. It's like a ln graph going into a vertical line. Does my schematics look even remotely correct or could the issue be with parts.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 04, 2023, 02:42:19 am
content: What’s the role of Q1 and Q2? IMO the schematics is incomplete and by the look of it, my gut tells it does not work.Can I suggest a ready made converter, like this:https://www.ti.com/lit/ds/symlink/tlv61048.pdf($1.50 in single quantity)

author: dotcom.com
author_rank: Contributor
timestamp: May 04, 2023, 03:39:10 am
content: Yea it was incomplete, i just updated it. Also I don't want to use a IC I am trying to create everything in the transistor level.So Q1 is a NPN BJT used in the relaxation oscillator (triangular waveform generator) circuit to generate a triangular waveform that will be used as a reference signal for the comparator circuit. Q2 is a NPN BJT used in the comparator circuit to compare the feedback voltage (Vfb) with the triangular waveform generated by Q1. The comparator circuit produces a PWM signal based on the comparison of the Vfb signal and the triangular waveform to control the switching of the MOSFET.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: May 04, 2023, 04:50:19 am
content: A step up converter is a complicated business. First, try to get the oscillator up and running in simulation. Nothing else. Hint: it will not start from 5V.

author: dotcom.com
author_rank: Contributor
timestamp: May 04, 2023, 06:25:19 am
content: So i changed my Voltage source parameter and applied a pulse to help the oscillator but this is what i get at my collector current of Q1. What could be causing this?
11 ?App sinusoidal encoder signal generator - Page 1
Forum section: electronics / projects

author: jyrki.j.koivisto
author_rank: Newbie
timestamp: January 25, 2017, 08:51:15 am
content: Hi,I happen to have a Bridgeport CNC milling machine (Interact 1 MK 2) from the 80's. It can control 4-axes but at the moment it only has 3 fitted (XYZ) I'd like to install fourth axis to it but the problem is finding suitable cheap encoder for it.Controller on the machine is Heidenhain TNC155A and it uses those 11 ?App encoders. I have some sort of understanding of the signals.Original Heidenhain encoders use a slotted disk at the end of the motor (125 slots per revolution) there is one lamp shining through and then for every signal line there are two photocells connected back to back. Photocells are mounted such that they produce current at different time phase of each slot in the disk. For example looking at the datasheet below positive current for I1 is produced by cell number 1 and the negative portion by cell 2.CNC Controller interpolates the signal to five different signal levels via comparators and produces square wave output which in turn is decoded 4x giving a resolution of 2500 ppr for rest of the controller.https://www.google.fi/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=0ahUKEwj0p9eq7tzRAhVBuSwKHX1WD44QFggXMAA&url=http%3A%2F%2Fwww.heidenhain.de%2Ffileadmin%2Fpdb%2Fmedia%2Fimg%2F1078628-21_Interfaces_en.pdf&usg=AFQjCNESmRHOJaAI5lX3Udl_syE_gIrNEg&sig2=HQluno5Q7AChm76m4yLPrA&bvm=bv.145063293,d.bGg&cad=rjaNow what I'd like to do is to use some digital encoders (for example AS5048A) and read them via some microcontroller and produce suitable current signal via some lookup table.Encoder interface on the TNC controller drives the I1, I2, I0 signal lines with +8v and the current is sensed via operational amplifier.Now the question is for all you analog guys is: How can I produce such a small current signal? Can I take D213E2 optocoupler and connect the outputs back to back and use some high resolution PWM to drive it? Will the photo transistor produce current when driven that way?https://www.google.fi/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=0ahUKEwiT-tms-NzRAhVCCiwKHRE5D6cQFggfMAE&url=http%3A%2F%2Fwww.vishay.com%2Fdoc%3F83647&usg=AFQjCNGH1ZcetBkciDrm0Q823voOeHnFew&sig2=sKUER1EsEAoGzK8xdr5jAQ&bvm=bv.145063293,d.bGgI have little knowledge for analog circuits and thus I ask for obscure use of transistors and if they have some alternative use modes and how they can be used differently or can they at all. Optocoupler would be ideal as it isolates the rest of the encoder from the current signal lines (+8v). Controller drives the lamp with +5v and that could be used for the micro.+8v is present on all the current signal lines,http://www.mycncuk.com/attachment.php?attachmentid=6205&d=1340922165also on the negative counterparts of the signal. I'm not sure but I think the photocels drive the +8v sense line up, not sure if they try to pull it to lower voltage.More info for my machine is at my YouTube channel:https://www.youtube.com/user/JyrkiKoivisto
110v -> 220v switching power supply conversion - Page 1
Forum section: electronics / projects

author: 17844
author_rank: Newbie
timestamp: August 04, 2017, 01:08:03 pm
content: Hello all,I want to learn more about switched power supply in general and a conversion of a 110v food saver vacuum bag sealer in particular. I have spent some time understanding the schematics and drawn a few (maybe incorrect conclusions):1. This is a 110v model but it seems to be somewhat prepared for a 220v version. Some caps are 400v in the 110v section. The 224J (.22 mF 250v) caps have previsions in the circuit for a larger casing, which could be a 470v version. Fairly straight forward2. I found the switching frequency to be about 50Khz but at the same time I am confused about the transformer as I dont find good input or output voltages (or likely they are below 1V).3. the two NPN fast switching transistors are BUL381D. They work in tandem somehow and I dont know how they are controlled with the coil/magnet thing in between the heat sinks. I am confused as I dont find a microcontroller och oscilliator to control the switching.4. I have not found any feedback from the two sides to control the voltage.5. On the output side I measure 5V (from a voltage regulator transistor) which goes to the control board, and the rest of that side seems to work on 20V (operates a pump to suck out air and a heating element to melt the plastic bag).Questions:1. My goal is to understand the power supply part and convert it to run on 220V. The BUL381D seems to run fine up to 900V but I am not sure what happens with the design when I double the input. I would assume all voltage is doubled all the way to some voltage regulator circut, but I am not sure where that happens in the first place. In the HF part voltages are confusing. After the rectifying on the output side I have 20V but not really sure how it is produced. Any ideas?2. I understand the normal procedure is to change the fuse and caps to work with the higher voltage. But normally guides I find dont replace the transformer, would this not be required as we double the input voltage?Any ideas and questions are welcome!

author: fourtytwo42
author_rank: Super Contributor
timestamp: August 04, 2017, 03:18:21 pm
content: If you have the schematics it may be useful to post them here. This looks like a self oscillating push-pull.Going by the input components it looks like a bridge followed by a single cap so no classic voltage doubler involved meaning the DC input to the push pull stage is ~1.4x110V or ~150Vdc, applying 220Vac will double this. Bear in mind for a push pull converter each switch is subjected to twice the supply plus any ringing spike.The transformer turns ratio will depend upon the required output voltage and the supply voltage so you would have to re-design and rewind the transformer for twice the supply voltage.....sorryAll best guesses of course.
115.2k 3.3 UART, 50cm cable OK? - Page 1
Forum section: electronics / projects

author: Emil
author_rank: Regular Contributor
timestamp: June 05, 2021, 05:53:41 pm
content: Is 3.3V UART at 115200 baud likely to work reliably over a ~50cm cable?(Connection between MCU and a Nextion HMI.)

author: rvalente
author_rank: Frequent Contributor
timestamp: June 05, 2021, 06:25:03 pm
content: Well, depends on the environment. I'd say for the majority of cases yes. Maybe adding a ferrite core to the cable just for sake of the mind

author: Siwastaja
author_rank: Super Contributor
timestamp: June 05, 2021, 06:46:14 pm
content: Very likely yes because UART receivers have multi-point sampling. At 115.2kbaud/s, there's a lot of time for the signal to settle despite ringing or slower rise/fall.UART being push-pull, slow rise or fall likely isn't a problem like in I2C.A small-value (like 22R) series resistor at the TX pin reduces ringing and EMI.It's a good idea to route alternatively GND - TX - GND - RX - GND if you can afford a few extra lines.
12 hr digital clock with an alarm - Page 1
Forum section: electronics / projects

author: Sangharsh Sharma
author_rank: Contributor
timestamp: July 17, 2019, 01:41:29 pm
content: Hello everyone. I've been trying to design a 12 hr format digital clock with AM/PM and an alarm setting. The problem that I always encounter is that the count always starts from random values. And, it continues to do so. What should I do so that when I connect the power supply it starts from 00:00:00? Also, I've used two push buttons to increase count of minute and hour. Sometimes, the circuit works and it doesn't. The count gets all random in the hour clock all of a sudden. I've got to demonstrate this project in 2 days. What do I do? I haven't been able to diagnose the error.I've used 7490, 7447 ICs. For the alarm, I've used DIP switches and 7485 ICs. I've attached an image below. This is how it starts when I give the power supply.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 17, 2019, 01:56:04 pm
content: Hold reset on the counters for a while at start-up. Traditionally a 555 timer would be used for this purpose

author: JagV12
author_rank: Contributor
timestamp: July 18, 2019, 04:45:39 pm
content: That large screen capture of your screen displaying a picture of the breadboard assembly is pure waste. We believe you.Pin 2 & 3 of every 7490 counter should be pulled high for a few ms at startup (NE555 or equivalent or capacitor (or reset button) connected to V+ rail with resistor to GND) while pin 6 or 7 (or both) is (are) held low all the time.By the way, real AM/PM clock start at 12:00 and end at 11:59 as per the big mess endianness... (and I'm sure you can do that !)
120-480V 60hz Power Supply - Page 1
Forum section: electronics / projects

author: twilliamson
author_rank: Newbie
timestamp: November 27, 2018, 02:59:51 pm
content: Looking for recommended designs / silicon for a low current 10watt Powersupply. 120-480vac 60hz Input (for a IOT thingy). Anybody seen any cleaver designs?

author: Wolfram
author_rank: Frequent Contributor
timestamp: November 27, 2018, 03:18:52 pm
content: SiC MOSFET flyback converters are a clean solution to this problem. There are a few published reference designs, check out TI PMP10416http://www.ti.com/tool/PMP10416, Cree CRD-060DD17P-2https://www.mouser.com/pdfdocs/Wolfspeed_evaluation_board_for_c2m1000170j.pdfand this article by Rohmhttps://www.powerelectronicsnews.com/technology/a-look-at-silicon-carbide-in-industrial-auxiliary-power.
120 Watt 10 Cell Lithium Ion Battery Charger Build or Buy - Page 1
Forum section: electronics / projects

author: spiritofsc
author_rank: Newbie
timestamp: March 18, 2016, 08:59:10 pm
content: I've been digging around trying to make a decision on building or buying the subject line charger. I don't mind paying for a premium product (cost isn't a concern). Searches turn up Tenergy / Turnigy / IMax. I've had bad experiences with Tenergy cells. Don't know much about the others.I have good tools but am a novice with electronics.I would like to be able to do a balanced charging of a configurable number of cells. I'd also like to be able to measure the capacity of those cells with the device I buy if that's an option.Thanks much for any pointers.Cheers,SC

author: firehopper
author_rank: Frequent Contributor
timestamp: March 18, 2016, 09:15:13 pm
content: also revolectrix has some nice chargers.http://www.revolectrix.com/
120 watt / 30 watt constant current load. - Page 1
Forum section: electronics / projects

author: kc9qvl
author_rank: Regular Contributor
timestamp: April 08, 2014, 01:59:50 am
content: I originally asked for information in the beginner forum. After a couple false starts making some real headway. Decided to build a dual input one high wattage and another low wattage. Panel meters will only do amps. Not going to worry about volt measurement I'll just use a multimeter.Built a custom aluminum resistor block from ceramic resistors. One section 0.25 ohm can handle 150 watts at C. Tested this connected the 4 1 ohm resistors in series Ran 25 volts 6 amps into the resistor for 2 days didn't fail. No looks good no cracking in the fire cement. The 1 ohm section 50 watts input didn't even heat up. The 2 fets are bolted right to the heat pipe. So the heatpipe itself is insulated. More to follow.

author: mjkuwp
author_rank: Unknown
timestamp: April 08, 2014, 02:48:37 am
content: cool! What is it for?

author: kc9qvl
author_rank: Regular Contributor
timestamp: April 08, 2014, 02:57:03 am
content: Constant current dc load.

author: Towger
author_rank: Super Contributor
timestamp: April 09, 2014, 08:54:17 pm
content: Low tech version:
1200 Amp. computer backplane - Page 1
Forum section: electronics / projects

author: compet17
author_rank: Regular Contributor
timestamp: May 09, 2015, 10:28:11 am
content: Did you ever wanted to know what a 1200 Amp. power backplane (midplane) from a HP c7000 blade enclosure is made of? Then looka here:Some specs? 12V 1200A / 5 Terabit/s data throughput / board thickness 8mm / 6 layers / US$3500

author: max666
author_rank: Frequent Contributor
timestamp: May 09, 2015, 06:50:50 pm
content: nice

author: Fsck
author_rank: Super Contributor
timestamp: May 09, 2015, 06:57:05 pm
content: as expect of the power output, some hellishly thick power planes for a computer board.

author: eneuro
author_rank: Super Contributor
timestamp: May 09, 2015, 07:04:51 pm
content: Sometimes any enclosures are... useless and all we need are fans... a lot of huge fansA look inside America's largest Bitcoin mining operationLonger version there:

author: eas
author_rank: Frequent Contributor
timestamp: May 12, 2015, 03:43:29 am
content: I see your dick-waving and raise you one gigantic phallic equipment enclosure, and on prime manhattan real estate, at that.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 12, 2015, 04:57:48 am
content: Quote from: eas on May 12, 2015, 03:43:29 amhttp://en.wikipedia.org/wiki/33_Thomas_Street, for anyone wondering. So, it really is a fair statement.Tim
120V LED Bulbs at 220V - Page 1
Forum section: electronics / projects

author: PabloF
author_rank: Newbie
timestamp: October 13, 2017, 01:58:11 pm
content: Hi,I'm thinking of buying 6 of these vintage looking LED bulbs in the US and bringing them to argentina.The problem is that here we use 220v instead of 120v.The obvious answer is to put a transformer, but the problem is that I also would like to use a dimmer (they are dimmable LED bulbs),Dimmers create hard edges in the current that could damage the transformer.So now the other obvious answer is to put 2 bulbs in series... this sounds to simple to be true.Does anybody think it could work with this type of LED bulbs?https://goo.gl/zvoDFyThanks in advance.

author: schmitt trigger
author_rank: Super Contributor
timestamp: October 13, 2017, 02:09:48 pm
content: You did not add a website link or file or photo to your post.But anyways...because of the non-linear load characteristic of the lamps AND the required dimming, I don't think the voltage will divide equally.Use a transformer instead.If the dimmer is located AFTER the stepdown transformer, there will be absolutely no harm done to it.

author: TK
author_rank: Super Contributor
timestamp: October 13, 2017, 02:51:39 pm
content: If the dimmer is a wall mounted unit, it will be difficult to add it after the transformer as the whole house wiring is 220V and also the dimmer needs to be 120V if added after. If it is for a permanent mount, do not mess with transformers as they can heat, fail and it is a fire hazard. Is is better to get 12V LEDs and use 220V to 12V DC power adapter that are certified in Argentina.

author: PabloF
author_rank: Newbie
timestamp: October 13, 2017, 04:00:01 pm
content: Unfortunately this type of LED bulbs don't come in 12v.Connecting the dimmer on the 110V side of the transformer is a risk I'm not willing to take, unless I could make some sort of low pass filter to smooth out the current spikes.Should I discard the 2 bulbs in series simple solution?

author: capt bullshot
author_rank: Super Contributor
timestamp: October 13, 2017, 04:16:56 pm
content: I'd give the series connection a try - worst thing to happen is two defective bulbs.These filament kind LED bulbs have a quite simple circuit inside - basically a ballast capacitor in series to the AC input and a rectifier. Connecting them in series should work IMO - but don't blame me if it doesn't. Take precautions in case it doesn't, try it in a safe place, not the final place where they shall be installed.

author: edavid
author_rank: Super Contributor
timestamp: October 13, 2017, 05:16:44 pm
content: Why not order 220V bulbs directly from China? I'm sure you could find the style you want.https://www.aliexpress.com/item/Antique-Retro-Vintage-LED-Edison-Bulb-E27-LED-Bulb-E14-Filament-Light-220V-Glass-Bulb-Lamp/32611960105.html

author: PabloF
author_rank: Newbie
timestamp: October 13, 2017, 06:43:00 pm
content: edavid, I think that's the safest option, thanks for the advice everybody.
121 Ton eDumper Electric dump truck  - Page 1
Forum section: electronics / projects

author: TK
author_rank: Super Contributor
timestamp: August 25, 2019, 09:59:32 pm
content: Interesting...https://www.businessinsider.com/edumper-121-ton-electric-dump-truck-2019-8

author: Mr. Scram
author_rank: Super Contributor
timestamp: August 25, 2019, 10:10:38 pm
content: That’s actually quite neat. I guess it won’t work for pit mining but when conditions are right it makes sense and saves a buck too. The best way of getting companies aboard is saving them money.

author: LeoTech
author_rank: Regular Contributor
timestamp: August 28, 2019, 07:05:03 am
content: QuoteUhmmm, did I miss something in my physics class?Ohh, wait, as it turns out - not surprisingly - it only generates more energy than it uses SOMETIMES.Okay, to be fair, after reading the article they do have a valid point, but it will only work if the unloading point is further down than the mine.Now I am curious to know, how did they manage to convert the potential energy into electric energy via the brakes. A lot of heat? And Seebeck converters?Leo

author: tautech
author_rank: Super Contributor
timestamp: August 28, 2019, 07:46:14 am
content: Quote from: LeoTech on August 28, 2019, 07:05:03 amIt's called regenerative braking.....it turns the drive motor into a generator.

author: aheid
author_rank: Regular Contributor
timestamp: August 28, 2019, 08:43:19 am
content: Using rocks as battery, neat! But yeah, money talks, hence why electric cars are such a hit in Norway.

author: Dubbie
author_rank: Unknown
timestamp: August 28, 2019, 09:39:23 am
content: Obviously, this truck is custom made for this particular mine which happens to be situated on top of a mountain.That fact coupled with the fact that they intend to operate the mine for many years makes this a very nice project. It should pay for itself over the lifetime of the machine.Nobody is suggesting that all dump trucks all over the world will run on "free energy" that's ridiculous.
125Khz RFID Proximity Card Number Confusion - Page 1
Forum section: electronics / projects

author: palpurul
author_rank: Regular Contributor
timestamp: April 05, 2022, 04:55:26 am
content: Hello,I've been working on integrating RFID readers to payment systems that I developed for vending machines. When a card is read with a RFID reader, the reader sends 26-bit data (2 parity bit, 8-bit facility code, 16-bit card number) via wiegand protocol.Here is the card that I have if you google "RFID Proximity Clamshell Cards" that's a very typical card.When I try to read use card with a card reader I get 0x79, 0x6457 which is 121, 25687 if you convert it to decimal.I am curious about the left part (0007955543), does anyone know what it is and how it relates to the card number of the facility code?Recently, we contacted a factory and we're planning to setup 10 of our payment systems there. To our surprise they sent us the numberon the left (0007955543) which is not what we read with RFID. They are not going send us the facility and card number on the left because there are about 450 of them, so we have to figure out what it is. They also say that they use this number for their turnstile, so there must be a way to read this number or there must be a way to relate these two numbers.Has anyone ever worked with these type of RFID cards and had to deal with these two numbers? I have two card readers, one of them is a single reader, it can only read 125kHz RFID cards with 26-bit wiegand protocol. The other one is a multi function card reader that has more features.Thanks!

author: palpurul
author_rank: Regular Contributor
timestamp: April 05, 2022, 07:11:35 am
content: As it turns out if you treat the the whole 26-bit as a decimal number (assuming parity bits are 0) and divide the number by 2 you get the number o the left.
125kHz transmitter design - Page 1
Forum section: electronics / projects

author: fedimakni
author_rank: Regular Contributor
timestamp: December 17, 2021, 12:51:53 pm
content: Hello,My target is to build a 125kHz transmitter. As you can see in the picture below this is a schematic for a 125kHz transmitter from sciosense. I didn't understand well how it works (transmission side) but i think that they are controling the gate of the mosfet and switch it on/off to send the data.I would like to understand more how it works in term of hardware and especially in the software side. What's the logic behind the state of the mosfet to send specific data?Are there document which provide informations about that?Any open hardware/software project about it?I prefer to use the same schematic but just by changing the microcontroller to another one but if there are other suggestions i will be very thankful.Thanks

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 17, 2021, 01:23:44 pm
content: It looks like they're using a phase shift PWM topology with a series resonant antenna circuit.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 17, 2021, 01:46:28 pm
content: Well, software side is whatever it's doing there, you'll have to look that up. Hardware is just an H-bridge driving a series resonant tank, or so it appears. Power level can be controlled by phase shift between sides, or duty cycle; so that gets AM, ASK, etc., and by varying timing, phase or frequency modulation (PSK, FSK, etc.).And, for... whatever it's for. If it's like RFID tags then that'll be ASK, and, Idunno what else, there's no receiving on that circuit...Tim

author: fedimakni
author_rank: Regular Contributor
timestamp: December 17, 2021, 02:49:19 pm
content: @NiHaoMikeYes i think that's correct, but what about the software side, i think it's the most important right?

author: fedimakni
author_rank: Regular Contributor
timestamp: December 17, 2021, 02:51:44 pm
content: @T3sl4co1lThanks for the reply,depending on what i saw in the datasheet it's not RFIDthey also use manchester encoded in their product description, but what about the software there's no document which can explain similar thing?Also what's AM ASK? Thanks

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 17, 2021, 08:00:00 pm
content: AM, amplitude modulation. Varying the pulse width or phase shift varies the square-wave area driven into the load, and thus the amplitude of the 125kHz component (fundamental). Harmonics can be mostly ignored due to the filtering effect of the resonant load. ASK is the special case where the amplitude is shifted between levels (amplitude shift keying). As opposed to full on-off (like old school Morse code keying). Similarly, PSK and FSK are digital modes but shifting phase or frequency between two states.I don't think you'd use Manchester to drive the coil directly, but that can be used on the signal, applying whatever modulation scheme after.Tim

author: David_1
author_rank: Newbie
timestamp: December 27, 2021, 02:20:31 am
content: is this a Transmitter or a reader ? for door entry / dog tags ?
128x64 LCD Contrast Question - Page 1
Forum section: electronics / projects

author: @rt
author_rank: Super Contributor
timestamp: August 14, 2016, 04:02:38 am
content: Hi GuysI’m making a breadboard to try using a graphic LCD display for the first time.The LCD I’ve chosen is this one:https://www.sparkfun.com/products/710... and here is it’s pinout from the data sheet:I’m familiar with all other pins from using character LCDs, but hoping someone can better explain the purpose of pins 3 & 18.Usually, pin 3 is for a variable voltage to adjust LCD contrast with a pot used as a voltage divider, but then what is pin 18 for?The product page on the Sparkfun site has a Pong Clock project, and I see this in the schematic:Is that a mistake? Because that’s just a fixed 10k resistor with the wiper connected to nothing.Cheers, Art.

author: bktemp
author_rank: Super Contributor
timestamp: August 14, 2016, 05:53:26 am
content: 128x64 LCDs require around 8V to operate.Vee is the output of an inverting chargepump: Vee = -Vdd = -5V.The voltage is taken from Vee and divided using the contrast pot between Vee and +5V so you can adjast the contrast voltage at pin 3 to around -3-4V.The pot at the Pong Clock is connected wrong.

author: @rt
author_rank: Super Contributor
timestamp: August 14, 2016, 08:51:53 am
content: Thanks for the clarificationSome other schematics on the net suggest the same.

author: @rt
author_rank: Super Contributor
timestamp: August 14, 2016, 11:10:53 am
content: The two 4k7 resistors top left is my potso far I have it wrongOther than that, the two supplies are good, and the backlight works,so I think tomorrow I get to program.

author: MickM
author_rank: Regular Contributor
timestamp: August 15, 2016, 03:03:27 am
content: Here is a good reference for these, they have several pinouts:http://playground.arduino.cc/Code/GLCDks0108It has some of the various pinouts.I have a couple of displays that use the KS0108 controller chip.The Vee pin on my modules is a negative voltage input, not output.It was from Amazon.com by NKC.This explains why they were cheap, external -Vee required.I needed a 9V battery connected "backwards" to Vee and the contrast pot.Most don't.

author: @rt
author_rank: Super Contributor
timestamp: August 15, 2016, 04:12:33 am
content: I’m trying to make a fixed resistor divider that works. For now, 4k7 + 390R is working.Hopefully later, the dsPic can make a PWM output to adjust contrast digitally.

author: @rt
author_rank: Super Contributor
timestamp: August 15, 2016, 01:03:43 pm
content: It’s fun to catch up after these LCDs have been out for years!Just the character data I’ll have to rotate once at startup.I figure I need to up the value of both resistors, because there’s supposed to be at least 10k resistance from VEE to the supply,but I have a total just over 5k.
128x64 lcd indentification problem  - Page 1
Forum section: electronics / projects

author: ykurban
author_rank: Contributor
timestamp: October 04, 2016, 01:31:39 pm
content: hey guys,i have this LCD, (possibly 128x64 i don't remember buying it)free photo hostingthere's no model number on pcb, only ICL7660 which is a cmos voltage converterI want to control it via arduino mega, so can anybody identify this board or suggest arduino library to interface it?

author: bktemp
author_rank: Super Contributor
timestamp: October 04, 2016, 01:44:16 pm
content: It is most likely KS0108/0107 based, similar to this one:https://www.adafruit.com/product/188

author: ykurban
author_rank: Contributor
timestamp: October 04, 2016, 01:52:11 pm
content: i also find this,ST7920http://www.buydisplay.com/default/glcd-128x64-st7920-serial-lcd-module-built-in-chinese-character

author: bktemp
author_rank: Super Contributor
timestamp: October 04, 2016, 02:18:27 pm
content: Your LCD has 2 CS pins (CS1, CS2). That's typical for KS0108 because it can drive only 64 columns. Therefore 2 ICs each with its own CS pin.

author: ykurban
author_rank: Contributor
timestamp: October 04, 2016, 06:54:40 pm
content: but there's 3 ic s on the board

author: bktemp
author_rank: Super Contributor
timestamp: October 04, 2016, 07:41:35 pm
content: 2x KS0108 for driving the columns, 1x KS0107 for driving the rows.
12kV tester compare 1980 version with 1960 version same product - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: December 16, 2022, 09:27:36 am
content: lets compare how the same product looks like in 1960 and in 1980it is a 12kV tester from the same companyDanbridge 12kV non-destructive insulation tester JP2 1960 test teardownhttps://youtu.be/x20jRbn7-JIDanbridge 12kV non-destructive insulation tester JP12A test teardown 1985https://youtu.be/Y6SCZ8J5XeQhere is their 2022 model sold todayhttps://danbridge.com/product_detail.php?indexs=46by the way: the old tube one still works :-)the design is far more simple, but it is also much harder to wear down

author: HighVoltage
author_rank: Super Contributor
timestamp: December 16, 2022, 09:40:58 am
content: Nice tear down of these two instruments, thanks!You are missing the tear down video of the 2022 version.Would be nice to see inside the new one as well.

author: oz2cpu
author_rank: Frequent Contributor
timestamp: December 16, 2022, 11:22:56 am
content: thanks mate, i dont have a huge budget to go purchase brand new instruments,but could have been cool if :-)for now i have to stick with used stuff, it is cheap and easy to get

author: jonpaul
author_rank: Super Contributor
timestamp: December 16, 2022, 08:01:10 pm
content: Bonjour, we Danbridge JP 30A since 1980s, as we built and designed HV transformers and Multilpliers and PSU.0....30 kV, huge RG6/U cable and probe, 0-1,10, 100 uA meter and speaker.Ranges 1,3,10, 30 KV.great instrument, HIGHLY RECCOMENDED!But the IEEE Schadow switches are a weaknessJon

author: oz2cpu
author_rank: Frequent Contributor
timestamp: December 18, 2022, 05:52:02 pm
content: anyone know where i can get a schematic of JP12A ?the 1980 model please contact mei got a few details i like to fix

author: jonpaul
author_rank: Super Contributor
timestamp: December 18, 2022, 10:00:45 pm
content: have the Dandridge JP 30 manual, somewhere a schematicà may be similar to JP12, perhaps less stages in HV multiplierContact me PMJon

author: oz2cpu
author_rank: Frequent Contributor
timestamp: December 19, 2022, 10:53:42 am
content: i have found schematic of JP15herehttp://peel.dk/Danbridge/it smells a lot like the same basis designBUT the high voltage part of it is clearly far from the same design as JP12,this means i cant use this schematic as much help for the type of problem i have in mine,so i send you a PM Jon :-) merci :-)

author: stowwest
author_rank: Newbie
timestamp: January 09, 2023, 07:14:09 am
content: Quote from: oz2cpu on December 19, 2022, 10:53:42 amThanks bro. It's useful for me.
12V (car) to USB charger port with current measurement - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: October 02, 2022, 01:47:59 pm
content: The title says it allI want to implement a USB charger on a project I'm working on for my car (I'm designing everything from scratch).I was thinking a simple buck, but I would also like to measure voltage/current also. And even better a current limiter (either component or software controlled).And if the IC has some arduino library (or easy to read datasheet). I'll be using a STM32F103.Any tips a good IC (I'm open to both serious suppliers and common Aliexpress chips)? I'm not space limited at all, so it doesn't have to be one chip.

author: tooki
author_rank: Super Contributor
timestamp: October 02, 2022, 01:51:16 pm
content: For current and voltage measurement, look at the TI INA226 (or the even cheaper INA219).For the buck converter, what’s stopping you from using a parametric search to find models with configurable current limits? Or looking for reference designs from IC manufacturers?You’ll want to look into USB charger designs, because reliable USB charging requires properly identifying the charger’s capability to the load.I’d highly suggest looking for reference designs for automotive applications, because they’ll give you a good idea of the kinds of circuit protection that is necessary in a car (one of the electrically worst environments).

author: okw
author_rank: Frequent Contributor
timestamp: October 02, 2022, 01:53:39 pm
content: Thanks for the amazingly fast reply. You're right, nothing is stoping me - and I have lot of buck experience, so I have some I prefer over others. But I was hoping there was some cheap buck options with integrated limter + V/A sense.
-12v, +12v , 0v GND Power supply - Page 1
Forum section: electronics / projects

author: itsanjan
author_rank: Newbie
timestamp: February 14, 2014, 01:34:05 pm
content: I have a current sensor that requires voltages -12V , +12V and a 0V Ground. How can make my own circuit to get a constant voltage -12v source (preferably DC input). I have made a +12 V and GND using Texas 7812 IC.

author: electronics technician
author_rank: Regular Contributor
timestamp: February 14, 2014, 01:48:25 pm
content: you will need a 7912 for the negative rail since you have the positive already NOW the capacitors are to be put in series with each other positive on top negative on the bottom and the leads of the capacitors that join together (negative to positive) go straight to the (CT) center tap of the transformer as well as the ground pin of the regulators enjoy

author: sleemanj
author_rank: Super Contributor
timestamp: February 14, 2014, 09:42:05 pm
content: OP, what you need is a voltage inverter, but you're going to want more than 12v+ to invert so that you can get your -12v out of it.Dave did a video on simple low current voltage inverters you can slap together with say a 555, a sensor probably doesn't need a lot of current.Anyway, voltage inverter is the term to search for if you're looking for an integrated device, there are some small ones that require minimal external components.Quote from: electronics technician on February 14, 2014, 01:48:25 pm7912 is a regulator, not an inverter, he has +12, but no negative voltage to give to the 7912 (let alone a negative with sufficient headroom).

author: grumpydoc
author_rank: Super Contributor
timestamp: February 14, 2014, 10:04:36 pm
content: Depending on how much current the -12V will draw an ICL7660A might do the trick.As this is a switched capacitor regulator no "headroom" is needed - it just turns a positive supply into a negative one.They can only supply maybe 10mA though

author: mariush
author_rank: Super Contributor
timestamp: February 14, 2014, 10:24:18 pm
content: You can also use a MC34063 to generate a negative voltage from a positive voltage. There are online calculators for the formulas and Dave also has a video explaining the formulas and doing the math for the "boost" mode (inverter mode is just as easy).Calculators:http://dics.voicecontrol.ro/tutorials/mc34063/http://www.bobtech.ro/tutoriale/componente-electronice/43-calculator-online-mc34063a-mc34063-step-down-step-up-inverterhttp://www.nomad.ee/micros/mc34063a/http://sourceforge.net/projects/mc34063uc/EEVblog #110 – Let’s Design a DC to DC Switchmode Converterhttp://www.eevblog.com/2010/09/10/eevblog-110-lets-design-a-dc-to-dc-switchmode-converter/If you want really smooth -12v, you can configure MC34063 to output -14v and then use a 7912 to get -12v.Be careful when you connect capacitors, might blow in your face if you don't get the polarity right.
12V - 48V, 250W Boost Converter project - Page 1
Forum section: electronics / projects

author: LatvianOnJuice
author_rank: Contributor
timestamp: December 16, 2014, 10:40:52 pm
content: Hello, everyone! Currently I am working on a boost converter project in my school.So I have gotten to the point, of finally putting my schematic on a PCB. I know there are several reasonable options of approach, however, they seem fairly limited. (For example, multisim -> ultiboard has certain issues of limited libraries (or maybe I just don't know how to properly use the program lol - with which you could also help me)).Anyway, my design currently sits in LTSpice. Is there any software, which you could recommend me to use, to proceed to the PCB layout design?Thanks in advance, any help is appreciated, as I am just a beginner!LatvianOnJuice

author: moffy
author_rank: Super Contributor
timestamp: December 16, 2014, 11:16:53 pm
content: Design Spark is free. Eagle CAD is also popular.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 17, 2014, 12:25:55 am
content: If school gives you Multisim, you might as well. I used it in school; it's geared more towards simulation (it used to be Electronics Workbench, simulation), which it does well enough. Project control (e.g., designators, BOM entry) and Ultiboard integration is rather tacked on. It's about as easy to use as you'd expect for its price point. But it's possible to do real work in.In my opinion, the libraries are vast (at least in v.10-11), complete with SPICE models (which something like Altium can't even begin to approach) and footprints. Many are better with some tweaking, or alternates chosen from the PCB library, but that's true of any suite.Tim

author: LatvianOnJuice
author_rank: Contributor
timestamp: December 18, 2014, 12:42:48 am
content: Thank you, guys, for your suggestions. Today I played around with Eagle and finally got kind of used to it. So I re-created my schematic, and transferred it to the board layout design, which is where I seem to be relatively clueless.After watching several instructional videos on youtube, I got some morr knowledge, although, I don't feel confident about the pcb layout design. From what I can imagine, I must have all kinds of EMC problems there (I just started this class in school, so I dont know much about it just yet).Are there any general rules of thumb on how and where to place specifix components, in order to avoid problems / have the circuit working more efficiently?Thanks once again in advance! This forums is packed with intelligent ppl. Hopefully one day I will be the one giving the advice, instead of asking...

author: juanfermed
author_rank: Regular Contributor
timestamp: December 18, 2014, 05:22:09 am
content: I have used DesignSpark before and is quite good. Yes, you will probably have to build your own footprint library for some parts but they also have a vast library. I have seen its PCB capabilities and they are good, maybe you should give it a try.
12V 6V 19V Regulation from Battery for Flight Camera - Page 1
Forum section: electronics / projects

author: mechknoll
author_rank: Contributor
timestamp: February 03, 2016, 02:30:23 pm
content: Good Day All,I am integrating 3 camera systems in a large fixed wing UAV and am having trouble finding the perfect solution for power. I have 3 cameras. 2 are powered by 6V and the last is 12V, then there is an onboard flight computer, it is an intel NUC and needs 19V. Is there a simple way to use one Lithium Ion battery and regulate 4 outputs? I have found several solutions but I want something that is VERY lightweight and reliable! any help on this?

author: KMoffett
author_rank: Regular Contributor
timestamp: February 03, 2016, 08:14:41 pm
content: What you want is a switch mode buck converter for each lower voltage...like:http://www.seeedstudio.com/depot/Adjustable-StepDown-DCDC-Converter-10V-17V18A-p-1717.htmlKen
12v adapted mod as 12v battery charger?  - Page 1
Forum section: electronics / projects

author: dave_j_fan
author_rank: Regular Contributor
timestamp: June 14, 2023, 05:42:36 am
content: I have modified 12v adapter to give 14.2 vBy changing feedback part in smps.I use it as cheap charger deviceAnd gave given to village people.Is it best way to do lead acid battery charger?It works.. But I want to know if there is any impact on battery?

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 14, 2023, 05:06:21 pm
content: It isn't the textbook charge curve, but assuming the operator has some skill/understanding (disconnect after full charge is reached) it's no worse than how cars and trucks charged their batteries for decades. Certainly beats nothing.That said that is assuming we're talking about flooded batteries one can easily add water to, the sealed types aren't as abuse tolerant.
+/- 12V DC DC Converters - Page 1
Forum section: electronics / projects

author: German_EE
author_rank: Super Contributor
timestamp: May 24, 2016, 04:34:59 pm
content: Sorry folks but my Ebay search skills are failing me. I'm looking for some DC-DC converters that can take a nominal 20V input and output +/- 12v @ 200mA per channel. Does anybody have a favorite supplier on Ebay that might have these in stock?

author: mariush
author_rank: Super Contributor
timestamp: May 24, 2016, 05:19:36 pm
content: Why not quickly make them on a prototyping board using two MC34063 ICs and basic components... it gets even cheaper if you buy 10-25 pcs of each component.Farnell has a lot of them in stock, here's a few through hole ones easy to solder on proto boards:1.http://de.farnell.com/texas-instruments/mc34063ap/ic-dc-dc-controller-34063-dip8/dp/10535792.http://de.farnell.com/texas-instruments/mc33063ape4/ic-dc-dc-converter-33063-dip8/dp/1053584Calculator software is here (even shows you how to connect things):https://sourceforge.net/projects/mc34063uc/Just pay attention to the inductor when you choose it .. for example you may see minimum 80 uH with Ipeak of 0.5a for 20->12v @ 0.25a and you may see minimum 105 uH with Ipeak of 0.8 , you could go with a standard 120uH for both and Ipeak of 1A or something like that... buying same inductor in bigger quantity saves money. For examplehttp://de.farnell.com/multicomp/mcsch895-121ku/induktivit-t-120-h-10-radial-bedr/dp/1864383would work and it's cheap in quantity.And for weird resistors you could put two or three in parallel to get the value you want (like three 1 ohm resistors in parallel to get 0.33-0.39 ohm)

author: Buriedcode
author_rank: Super Contributor
timestamp: May 24, 2016, 08:49:32 pm
content: Why not use a standard buck converter, with a coupled inductor? 1:1 inductors are plentiful on Farnell and can provide a negative rail, albeit not fully regulated. It'll require two extra components (diode and output cap for the second rail) and its regulation tends to track the positive rail, whilst being able to provide more current than a charge pump.
12V DC fans with built in speed controller. - Page 1
Forum section: electronics / projects

author: rfdes
author_rank: Regular Contributor
timestamp: June 14, 2021, 04:12:55 pm
content: Hi -I'm curious if anyone has technical information (schematics, theory of operation, etc.) regarding the genre of DC fans that have an additional set of input contacts that allow a thermistor to be attached giving the fan a built in speed controller. I have been searching and have had no luck in how they are accomplishing this functionality. I am speculating it is quite straight forward but would like to see a schematic or a block diagram. I'm guessing these fans are not particularly popular and PWM style fans are the current 'go-to' style.If anyone would please point me to some technical info, it would be appreciated.ThanksJim
12V DC Motor Controller, Schematic review - Page 1
Forum section: electronics / projects

author: lemm
author_rank: Contributor
timestamp: September 09, 2025, 08:04:49 am
content: Hi everyone,I'm excited to share the schematic for a new motor controller project I'm working on. My primary goal for this design is to ensure it is safe, efficient, and robust.Before I proceed to the PCB layout stage, I would be very grateful if you could review my schematic (I will attach the image in the post) and share your feedback. I'm open to any suggestions for improvement or pointers on potential issues you might spot.Project Overview:MCU: ESP32-C3-MINI-1Power Supply: A single-stage MP2315 for a direct 12V to 3.3V conversion.Motor Driver: DRV8871 with a hardware current limit set to approximately 2A.Protection: The circuit includes a fuse, reverse polarity protection diode, a TVS diode, and all recommended decoupling capacitors.Battery: The project is powered by a 3S battery pack (12.6V max).Motor: It's designed to drive a 12V N20 Mini DC motor with an integrated encoder.Thank you for your time and valuable input! 😊

author: youngda9
author_rank: Regular Contributor
timestamp: September 09, 2025, 11:11:44 am
content: Duplicate post from 2 days ago.https://www.eevblog.com/forum/projects/seeking-feedback-on-new-esp32-motor-controller-schematic

author: lemm
author_rank: Contributor
timestamp: September 14, 2025, 09:16:43 am
content: Oh right! I apologize, I couldn't find the previous post anymore and thought it had been deleted.