hybridfree/eevblog-posts huggingface dataset:
CAN/j1708/j1939 all in one chip? - Page 1
Forum section: electronics / projects

author: Stonent
author_rank: Super Contributor
timestamp: April 05, 2013, 07:13:50 pm
content: Does anyone know of an all in one chip that can speak all the major vehicle CAN protocols as well as j1939 and j1708?The ELM 327 covers CAN nicely but lacks support for the others. They have a few other chips in the 32x range but none that can do all.I contacted them about it and they said there wasn't enough room on the die for everything. Bummer.

author: JVR
author_rank: Regular Contributor
timestamp: April 05, 2013, 07:45:01 pm
content: DIY on an MCU.Most of the protocol bits that you would need are available, the rest as either a free registration, or an NDA away.

author: Stonent
author_rank: Super Contributor
timestamp: April 06, 2013, 07:20:04 pm
content: Yeah but that's a lot more work than I'm wanting to do. Many of those protocols have different baud rates anywhere from 9600 up to 500kbps.Getting the protocol specs and writing the application is about 90% more work than what I wanted to do intended.The ELM327 does everything I want except J1708.

author: Stonent
author_rank: Super Contributor
timestamp: April 06, 2013, 07:46:20 pm
content: Ok just found out that an ELM 327 is a PIC 18 series chip with an application on it.
Cannibalising a minidisc for parts for a automaton - Page 1
Forum section: electronics / projects

author: banjobill
author_rank: Newbie
timestamp: April 18, 2024, 01:37:05 pm
content: Hi, I'm new to the forum and new to electronics so apologies if I ask dumb questions.I have an old Sharp Minidisc and before binning it I looked for anything I could re-use - I'm interested in making automatons. There is a tiny motor and worm gear that positions the laser read/write head which looks like it could be useful.Any suggestions on how to decode where power should be applied, how much, tracking down datasheets (next to no part numbers). Or am I wasting my time?Cheers

author: ajb
author_rank: Super Contributor
timestamp: April 18, 2024, 02:28:41 pm
content: Welcome to the forum! Automatons are cool, would be neat to see what you come up with. There's an art museum near me that has a whole exhibit of wooden mechanical gadgets, that's my favorite part of their collection.Mass produced consumer goods like this will use a lot of custom (or semi-custom) mechanical parts, so are are not likely to find any datasheets. You'll have to do some reverse engineering. The motor will almost certainly be either a simple brushed DC motor or a stepper motor. The former will have two leads, the latter will have 3-5 leads. There might be an encoder attached, which will have 3+ leads, or they might rely on the read head to provide position feedback to the motor relative to the data track. Beyond that, we'd probably need to see some pictures to help figure out what's going on.FYI, I've seen similar mechanisms to what you're describing out of CD/DVD drives being sold separately on Amazon/ebay as small linear actuators. I can't find the right search terms now, but you might be able to find more of those mechanisms without having to cannibalize them yourself.

author: banjobill
author_rank: Newbie
timestamp: April 18, 2024, 03:53:52 pm
content: Thanks for the info. The motor is tiny - 14mm in diameter, 2mm thick. It has 3 pins so I guess it's a stepper. The biggest problem is attaching wires to the thingAny idea what voltage would be required?

author: coromonadalix
author_rank: Super Contributor
timestamp: April 18, 2024, 04:10:56 pm
content: i would say in a sense you loose your time, you would need to practice on bigger parts ....anywayto automate any moving sliders, rotating gears etc ... you need to find if there is a limit switch, an encoder wheel etc ...the system needs to know where it is mechanically ... if your are at a position limit, and can only do a reverse or only do a forward etc ...that's what we call feedback, position sensing, rotation speed sensing, rotation positioning with stepped motors, torque sensing etc ..

author: banjobill
author_rank: Newbie
timestamp: April 18, 2024, 04:28:01 pm
content: Good point!
Cannon Pixma MG2960 image sensor reverse engineering - CIS datasheet request. - Page 1
Forum section: electronics / projects

author: Majorstrain
author_rank: Contributor
timestamp: February 24, 2018, 01:56:48 pm
content: Hi all,I've been reverse engineering a Cannon CIS from their Pixma MG2960 multi function inkjet range.Previously I've used a Rhom CIS but I'm modifying my project to use the Cannon CIS.The Rhom was a 300 DPI single analog output, and used a simple clock and start pulse.The Cannon is a dual 300/600 DPI with the resolution selected by the number of clock cycles the start pulse is high for. 4clk's -300DPI / 6clk's 600DPIThe pin out's, reference voltage (0.9V) and timing I have determined from probing the printer.But I'm missing something.The output stays at 1.8V (equivalent to full light sense) during the active part of the cycle.It doesn't change with dark or light objects placed in contact with the sensor and with the LED's off and ambient light, shading the sensor gives no change in results either.The preceding started pulse and black level outputs seem to be correct.I was wondering if anyone had a datasheet for a Cannon 2 or 3 analog output CIS that might give me some ideas.The other option is a datasheet for the driving chip so I can probe that effectively.Number on the side of the sensor - R QK1-8992 08 06 517 (***New Edit***)Sensor PCB numbers are - 7H6-0748 and CHT BAAOThe chip numbers are A4102 , TI 721 , AJLH , G4 with and under scoreThanks,Phil

author: Majorstrain
author_rank: Contributor
timestamp: February 25, 2018, 08:19:15 am
content: Some progress has been made on nutting out the signals and clock rate that I have to feed the contact image sensor.The issue with not getting any change on the output is effected by the sensor scan rate.By scan rate, I mean how long the interval is between full scans. The sensitivity is grater with a faster scan rate. Rhom was unaffected but the rate. You could scan it once a day if you wished.If I scan once a second the output seams to saturate, but if I scan at 1000 times a second the output operates as it should. The clock speed is the same for each variation.I'm still getting unreliable output though.Obviously haven't got the number of clocks and other signals quite right.The sensor clocks out the light level of each pixel to the analog output pins each clock cycle.There is always dummy clocks before and after the active part of the sequence though.Rohm operates slightly differently in the number of dummy clocks and the start trigger signal.Still hoping someone has some leads or information.Cheers,Phil
Cannot export to *.dsn from KiCad. - Page 1
Forum section: electronics / projects

author: Chumanista
author_rank: Contributor
timestamp: March 01, 2015, 05:39:11 pm
content: The error:The .kicad_pcb file attached.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 01, 2015, 05:52:11 pm
content: Read the error message!Run a DRC on your schematic.How did you generate a netlist in the first place, as you cannot generate the netlist if not all components are annotated?
cannot identify this optocoupler - Page 1
Forum section: electronics / projects

author: Eliminateur
author_rank: Regular Contributor
timestamp: February 21, 2011, 07:16:35 pm
content: i've been searching for quite some time for the datasheet for an optocoupler i have here, the markings are:L 0625817AYi've searched 0625, L0625, 817, 817A, 817Y, nothing...any ideas?

author: Simon
author_rank: Unknown
timestamp: February 21, 2011, 07:21:30 pm
content: do you know the origin the the dvice it is in.For example i have a medical device mad in Russia many years ago, It had some weird named DIP14 chips in it that turned out to be the russian version of the 7400

author: Zero999
author_rank: Super Contributor
timestamp: February 21, 2011, 07:29:22 pm
content: Yes the Russians copied many ICs from the US, including those used in some electronic games which amusingly exhibited the same bugs.Do you have a picture of the PCB or a schematic?

author: Bored@Work
author_rank: Super Contributor
timestamp: February 21, 2011, 08:00:51 pm
content: http://www.us.liteon.com/downloads/LTV-817-827-847.PDF

author: Eliminateur
author_rank: Regular Contributor
timestamp: February 21, 2011, 08:19:06 pm
content: Bored takes the jackpot!, i found a similar device datasheet but wasn't convinced, so yeah... run-of-the-mill optocoupler...i wish i had an schematic!, it's from a Dell AC brick(which incidentally i have opened in another thread) that's misbehaving and i have no idea why

author: Zero999
author_rank: Super Contributor
timestamp: February 21, 2011, 09:15:57 pm
content: It's there to provide an isolated feedback path from the secondary to primary side and is unlikely to have failed so check out the other components before replacing it.
Canon Laser printer i-sense MF633C toner 045H chips protocol - Page 1
Forum section: electronics / projects

author: Wiljan
author_rank: Regular Contributor
timestamp: August 15, 2019, 01:55:17 pm
content: HiAfter being tired of clocked heads in several Inkjet printer after irregular use, I bought a Canon Laser printer MF633C which works very well.I comes with a starter kit of toner Black, Cyan, Magenta, YellowNow it starts nagging that the Toner needs to be replaced and that is based on a counter on numbers of print in BW, Color and BW +Color.I know or sure it has not been printing much color... mayby some logo on now and then so I pretty confiden that there are a lot of toner left.On each Toner there are a small chip (2pin) and I can read on the net that the printer reads those chips and the after a print save a new counter number back in the chip to keep track of the toner (so the numbers are NOT saved in the Printer but on each toner unit.I can see that it's possible to buy chip on Ebay saying the toner are brand new (always), but I then was wondering how the protocol was working and I have not found any info yet on the web.So I have soldered 2 wires on the Black Toner and hooked a scope onto it 2 see what's going on.Each time I print a page then when the print are done you get a beep from the printer and right after there are some data traffic.It I measure Ohm in power off the 1 pin have 1K to ground on a USB chassis in the printer and the other pin about 15K.I have taken a few photos of the Scope showing the idle level are about 0v and the it rise to about 3 volt and have data to 5 volt1-wire normal use the whole 0-5 voltSo what kind of data is this?Are the protocol know public?I would like to add in a small PIC or so to the the printer that all the tones are full, so I can wait to change the toner until it's actually used.I you continue printing you have to "accept" the Toner are in a low status and quality are nit guarantied.
canon selphy dye sublimation as pcb printer  - Page 1
Forum section: electronics / projects

author: rizoma
author_rank: Newbie
timestamp: May 20, 2014, 09:54:55 pm
content: I found this printer abandoned, it prints on 10X15cm(same size of my fr4) sheets, kind of planar way, so I thought maybe it can be used to print direcly on pcbs, anyone tried?If someone is interested maybe I can do a teardown post some pictures/videos and possibly we could try to see if that idea it's possible.Any Advice?

author: SeanB
author_rank: Super Contributor
timestamp: May 21, 2014, 04:48:44 am
content: It will not work, as it is basically a thermal printer that covers the paper with dye from a sheet. Similar to inkjet but a little more water resistant. Will not protect against etchant though, as it is a very thin and porous layer. If you try to print onto glossy transparency it will simply wipe off, it works best on paper where it gives brilliant colour.Only drawback of these is the high cost of consumables, as you use the same amount on a white page as on a full colour page.

author: rizoma
author_rank: Newbie
timestamp: May 21, 2014, 08:11:02 am
content: thanks, so at least I will not waste my time...cheers

author: zapta
author_rank: Super Contributor
timestamp: May 21, 2014, 08:46:21 am
content: Quote from: rizoma on May 20, 2014, 09:54:55 pmIt worth trying. The spleeny prints hold very well in water with zero 'dry' time. Am not sure how you will fit the hard and think PCB instead of the picture and how well the dye will stick to the copper but it worth trying.BTW, these printer are security/privacy hazard, the empty cartridge that you through away contains negatives of all pictures you printers.

author: rizoma
author_rank: Newbie
timestamp: May 21, 2014, 10:04:10 am
content: So far 1 negative and 1 positive opinion, I'm waiting some more to decide to dig into it or not, this can really be a time consuming project, so thanks to who spent a bit of his time arguing a bit about itRegards
CANopen, change NodeID on joystick - Page 1
Forum section: electronics / projects

author: tru3533
author_rank: Regular Contributor
timestamp: September 08, 2023, 08:37:00 am
content: I have a joystick who is running CANopenNodeID is 33h and I need it to be 34hAny idea how to set the joystick in configuration services and write the setting?Joystick boots upI can start it in (Operational mode)Trying to program it and get this answerAfter power powering it up again same result, no change.NodeID is located at 100Bh index 0 and is 1 byte
Can't communicate with MCP39F511 power monitor via UART - Page 1
Forum section: electronics / projects

author: Brathahn
author_rank: Contributor
timestamp: November 28, 2020, 12:48:11 am
content: Hi,im trying to communicate with an MCP39F511 power monitor IC but its not responding.i have connected a ftdi uart/usb converter to it and the ftdi chip is sending the data correctly but its just wont give me aything back.i think i am doing something wrong here but i cannot spot the error in my setup.i have tested 3 IC's so far and none of them responded anything back. i doubt that 3 out of 3 chips are dead.here is my setup:an ftdi uart converter is connected to a logic analyzer and the MCP39F511 (the logic analyzer is mostly a sanity check)when sending some commands with hterm, the logic analyzer confirms the correct transmission. but neiter an ack or nack is sent back from the MCP:so what am i missing?thanks in advance!

author: HalfSpace
author_rank: Regular Contributor
timestamp: November 28, 2020, 03:45:02 am
content: Hi Brathahn,The MCP39F511 should respond with a CSFAIL 0x51 even if the checksum is incorrect, but getting no response could be an incorrect baud rate setting. If the MCP39F511's were removed from something else or pre-programmed by a supplier, they may have been set to another baud rate than 115.2kbps. Try to send the commands at a lower baud rate and see if you get a response.Also do a search on this forum for the MCP39F521 which is a I2C version of the MCP39F511. The discussion regarding the MCP39F521 is similar to the problems you are having.HalfSpace

author: Brathahn
author_rank: Contributor
timestamp: November 28, 2020, 07:33:35 am
content: Thank you for the quick reply!well, this fixed my problem:https://www.eevblog.com/forum/microcontrollers/mcp39f521-i2c-power-monitor/msg1101038/#msg1101038the datasheet declares an optional 4MHz oscillator on pins OSCI and OSCO. if it detects none, it will switch to the internal oscillator.so i hooked up my function generator to it, and i could immediately communicate with it.also tying the OSCI pin to GND worked properly too.i think the chip measures the capacitance on the OSCI pin to check if there is an oscillator or not.. and the long trace of the breakout board and the breadboard may be the problem.edit: all three chips are working fine now.
cant control speed of motor driver - Page 1
Forum section: electronics / projects

author: beesnuts
author_rank: Newbie
timestamp: August 20, 2018, 03:04:52 pm
content: I'm connecting Tb-6612FNG (motor driver) with arduino mega 2560 R3The problem is I can't control speed of my motor with analogWrite.motor speed between 0-119 motor will not working.It will working on 120-255 but not matter how much is it.It will usually run at the same speedmy code\\int STBY = 22; //standby//Motor Aint PWMA = 30; //Speed controlint AIN1 = 34; //Directionint AIN2 = 32; //Direction//Motor Bint PWMB = 42; //Speed controlint BIN1 = 40; //Directionint BIN2 = 44; //Directionvoid stop(){//enable standbydigitalWrite(STBY, LOW);}void move(int motor, int speed, int direction){//Move specific motor at speed and direction//motor: 0 for B 1 for A//speed: 0 is off, and 255 is full speed//direction: 0 clockwise, 1 counter-clockwisedigitalWrite(STBY, HIGH); //disable standbyboolean inPin1 = LOW;boolean inPin2 = HIGH;if(direction == 1){inPin1 = HIGH;inPin2 = LOW;}if(motor == 1){digitalWrite(AIN1, inPin1);digitalWrite(AIN2, inPin2);analogWrite(PWMA, speed);}else{digitalWrite(BIN1, inPin1);digitalWrite(BIN2, inPin2);analogWrite(PWMB, speed);}}void setup(){pinMode(STBY, OUTPUT);pinMode(PWMA, OUTPUT);pinMode(AIN1, OUTPUT);pinMode(AIN2, OUTPUT);pinMode(PWMB, OUTPUT);pinMode(BIN1, OUTPUT);pinMode(BIN2, OUTPUT);stop();delay(5000);}void loop(){move(1, 255, 1); //motor 1, full speed, leftmove(2, 255, 1); //motor 2, full speed, leftdelay(1000); //go for 1 secondstop(); //stopdelay(250); //hold for 250ms until move againmove(1, 100, 0); //motor 1, half speed, rightmove(2, 100, 0); //motor 2, half speed, rightdelay(1000);stop();delay(250);}

author: JS
author_rank: Frequent Contributor
timestamp: August 20, 2018, 04:07:42 pm
content: What kind of motor are you using?It looks like you should stop the PWM generators in the stop function or the motors will start running at the speed they were, even the motor that is not supposed to turn.The PWM freq might be too slow, if you can try setting up (with registers) the PWM to run faster with less bits, or use a pwm genrrator from another source to test it.JS
cant find data sheet for this part Help! - Page 1
Forum section: electronics / projects

author: dbartlett41
author_rank: Newbie
timestamp: December 17, 2013, 12:49:09 pm
content: i ahve attached a picture of a sot-23 chip i am trying to get a replacement for it has markings N5 something DC can anyone help me decipher this code and what an equivalent would be. its in my garmin Montana 550 it gets super hot so i think its shorted.Thanks in advance for your help.

author: amyk
author_rank: Super Contributor
timestamp: December 17, 2013, 01:05:29 pm
content: I'm guessing it's an LDO of some kind, what voltages do you measure on either side of it?

author: SArepairman
author_rank: Frequent Contributor
timestamp: December 17, 2013, 01:09:51 pm
content: try to see what its connected to, maybe its connected to a 3.3v chip so you could just replace it with whatever makes the right voltage
Can't find datasheet for ICN2025BP by Chipone [this post may be removed] - Page 1
Forum section: electronics / projects

author: htm
author_rank: Regular Contributor
timestamp: October 08, 2024, 09:37:19 pm
content: Hi,i've got LED panel(type mentionedherein another post), having 2 rows of 6P10RGB-panels(16x32pixels).and i'm hoping to find a way to control them by software.But it has this ICN2025BP chip for which i can't find the datasheet.Ps. i searched mouser, used google and yandex, but didn't find anything useful.On youtube i did find someone who reverse-engineering a RGB panel which used another Chipone chip ICN2053 and had at least a datasheet.part 1part 2But i found nothing for the ICN2025BP :/I'm hoping one of you can find it.

author: htm
author_rank: Regular Contributor
timestamp: October 09, 2024, 07:39:17 pm
content: I tried to remove this post, because i feel this post is better suited for the 'Repair' page.But i can't seem to remove this post.. i get an error when trying
can't find where this wire goes inside VEF 206 radio - Page 1
Forum section: electronics / projects

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: December 24, 2019, 02:38:47 am
content: so I can't figure out where "51" goes, there isn't even a 50 it seems.you can probably find a better shematic searching it.[ Attachment Invalid Or Does Not Exist ]

author: floobydust
author_rank: Super Contributor
timestamp: December 24, 2019, 02:54:11 am
content: It goes to R54 by VT11 detector output. Main signal is 30.
Can't get Audio Codec to work - 2 boards in - Page 1
Forum section: electronics / projects

author: Scoop
author_rank: Newbie
timestamp: July 19, 2023, 06:00:01 pm
content: Hello,I'm working on a wireless mic setup over BLE.EFR32 + TSCS25 audio codec that I can't get the handshake with over I2C.I'm on my second board design and still can't get it to work. 4 Layer board SGGS, I did not split the ground.I used TS reference designhttps://temposemi.com/wp-content/uploads/2016/09/tscs25x_ref_sch_091616.pdfdatasheethttps://temposemi.com/wp-content/uploads/2022/06/TSCS454xx_DS_v1.5.pdfMy schematic is attached below along with analyzer read.System is powered with 2 LDO 1.8V, 3.3V and 1 Switching reg 1.8V. All pins got power, clean signal this is driving me crazyDoes this have to do with clock pin on audio codec left unconnected? That's only for master mode right?Any suggestion is appreciated!

author: MarkS
author_rank: Unknown
timestamp: July 19, 2023, 10:13:22 pm
content: Stupid question, but do you have the required pull ups on the I2C lines?

author: Scoop
author_rank: Newbie
timestamp: July 20, 2023, 12:47:58 am
content: Quote from: MarkS on July 19, 2023, 10:13:22 pmYes I started with 2.2k, then tried 1k,4.7k, 10k

author: moffy
author_rank: Super Contributor
timestamp: July 20, 2023, 01:02:58 am
content: Try slowing down the I2C clock rate and see if that works.
Can't get SDO data out of a LTC2402 - Page 1
Forum section: electronics / projects

author: RawCode
author_rank: Regular Contributor
timestamp: June 30, 2020, 10:00:20 am
content: Hello guys.I'm quite demoralized.I'm trying to build something like a source-meter for my thesis work. Everything seems to work, except for the LTC2402. Seriously, it's driving me crazy.I tied the LTC2402 to a Nucleo-F767ZI according to these schematics:i.e. CS to PE6, SCK to PG11 and SDO to PA6. I also setted the SPI configuration as follows:So, according to the LTC2402's datasheet, when CS goes low, SDO goes low too if the conversion is finished, otherwise it stays high. When CS goes high, SDO goes to Hi-Z.But, anything i do, i can't pull data from the LTC2402. SDO seems to stay in an unknown Hi-Z state, even if CS is low.I tried to pull-down SDO and SCK to DGND, but nothing changed.Here the signals at the oscilloscope. CH1 and CH2 represents SDO and SCK. I inverted CH1 and CH2 in a picture. Sometimes i get a "smaller" replica of SCK signal on SDO, sometimes something that seems a GND on SDO, sometimes a very noisy replica of SCK signal on SDO. I handsoldered it to a pcb, so maybe the solder job is not the best, but there is continuity in all signals, even touching the package leads.Please, can you help me?

author: exe
author_rank: Unknown
timestamp: June 30, 2020, 10:34:17 am
content: I'd clean flux, just in case. Also, may be the part is damaged...

author: Giaime
author_rank: Regular Contributor
timestamp: July 02, 2020, 10:30:45 am
content: After a quick look, I'd suggest you pull-up SDO instead of pulling it down. Try 10k resistor and let us know.

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 02, 2020, 03:45:56 pm
content: Couple thoughts:- You need to pull SDO to something, because it's in Hi-Z when /CS is high. Leaving it floating is not a good idea. The datasheet suggests pulling it low. You said you tried and it didn't make a difference. I can't believe it didn't. At least when /CS is high, instead of seeing a signal in a typical "hi-z" state, you should see a straight low level. If not, something else is clearly wrong. Maybe your soldering.- How do you control /CS? Did you take a look at it? Would be interesting to look at it with the scope. Maybe it's actually not controlled properly. This point might be due to an improper software configuration.

author: RawCode
author_rank: Regular Contributor
timestamp: July 03, 2020, 05:31:27 pm
content: Hello guys, thanks for all your replies.After trying everything, i changed the ic and now it works.My father checked the board in the microscope before changing the ic and he says it was well soldered. So I presume it was kinda faulty.Luckly enough i had a spare of this ADC.
Can´t read information from EEPROM(M95640-W) please help! - Page 1
Forum section: electronics / projects

author: diegoterc3
author_rank: Regular Contributor
timestamp: February 19, 2015, 06:00:34 pm
content: Hello, I am trying to use an EEPROM with my circuit. I just finished programming and can't even read the status register which btw shoul read 0b00000000, I get this weird signal from it. I am sure the read status register command is right, but the answer from the memory is nuts!The code goes something like this for the read status register:Code:#define RDSR 0b00000101unsigned char read_status(void){unsigned char a=0;CS_MEMORIA=0;putcSPI(RDSR);a=getcSPI();CS_MEMORIA=1;__delay_us(1);return(a);}void main(void){unsigned char data=0;TRISA=0;PORTA=0x00;TRISB=0b00000001;PORTB=0b00111100;TRISC=0;PORTC=0;CONTROL=0;CS_SENSOR=1;CS_MEMORIA=1;HOLD_MEMORIA=1;WP_MEMORIA=1;OpenSPI(SPI_FOSC_16, MODE_01, SMPEND);__delay_us(1);while(1){read_status();__delay_us(1);}}I have attached the schematics, oscilloscope responses and some parts of the datasheet.Please does anybody have a suggestion?.Regards

author: diegoterc3
author_rank: Regular Contributor
timestamp: February 24, 2015, 06:39:32 pm
content: Ok, something really weird is happening. I plugged my oscilloscope to my computer to get better readings and images of the problem and somehow it is working. Now I have two channels so when I probe only the output data from the eeprom nothing is shown but when I probe both the clock signal and the output data it works!. I have tryied probing bothe the output data and other signal and the oscillocope only shows the other signal and not the output.Could this be a grounding issue?Please let me know what you think.Thank you in advance
Can't simulate simulink model - Page 1
Forum section: electronics / projects

author: Achu
author_rank: Contributor
timestamp: April 20, 2020, 01:06:30 pm
content: I'm trying to simulate the following chopper controlled dc motor in MATLAB Simulink using a PI controller. Now without the freewheeling/flyback diode across the motor terminals I can simulate the model to get the desired speed output. But with the diode the motor seems to run at full speed and is uncontrollabe. Is it a glitch in the software? or is there anything I can do about it in the software?
Cap advice - Page 1
Forum section: electronics / projects

author: IvoS
author_rank: Frequent Contributor
timestamp: January 08, 2012, 06:10:19 pm
content: I am building a small amplifier with first stage like this:and have a question about the input cap. Is it important to have an input cap for this high pass filter with low leakage current? I want to use a cap 220-330uF with 100ohm resistor in series. The input voltage will be between 5-35VDC. The amp will measure DC noise.Thanks.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: January 08, 2012, 09:30:54 pm
content: The leakage will be amplified by the circuit, but if the gain isn't too high you should be ok. I'd be more worried about the polarity of the cap matching the polarity of what's being measured. As long as you only measure positive or negative supplies, and have the cap installed accordingly it's ok, but one mistake...Inverting circuits are also typically quite low impedance (100 ohms in your case) and will load whatever you're measuring. If the thing you're measuring isn't affected by an ac coupled 100 ohm load, great. I wouldn't take that as a given. People usually build a high impedance amplifier with a smaller cap value. That way you don't load the device under test, the cap can be a very high quality film cap, and leakage isn't an issue. In either case, you should also have protection on the input so excess voltage, transients and such don't damage the input stage of opamp.
Cap blows cooling fan transistor in power-supply unit.  - Page 1
Forum section: electronics / projects

author: paul8f
author_rank: Regular Contributor
timestamp: July 25, 2020, 09:00:53 am
content: Came across an interesting fail recently. In a power-supply cooling circuit, a small surface-mount 10uF electrolytic (C95) went short-circuit and burned out the main power transistor (Q51) that drives a parallel pair of DC cooling fans.The cap looked fine until I got out my magnifier and spotted a hairline crack across it. The component literally fell apart as soon as I brought my iron next to it. With the cap now out of circuit, and the blown transistor replaced, the fans started spinning again.At first glance at the schematic, I thought that C95 was there for some sort of soft-start/inrush function, but now I think it's there for electrical noise suppression of the motors. It's strange that C95 seems to float in the circuit (i.e. its positive side is permanently connected to 12 volts, but its negative side only ever gets connected to GND when the micrcontroller sends the 5V signal to Q50). The power-supply unit wasn't used that much, and when it was it was for light use in a cool environment, so the fans could have easily gone a year without getting a signal to turn on. Could the electrolyte have dried out?The+12andFAN+12rails are derived from different transformers, but share a common GND. The fans use identical motors (see photos), and the SMD electrolytic that cracked actually looked like a regular 1206 ceramic or MLCC cap.I found a separate issue with the power-supply, whereby the NTC thermistor spec had drifted with age, possibly causing the fans to continually cycle on and off repeatedly. I'm just curious as to what may have caused C95 to fail like that. Any suggestions?
Cap Drop Supply Strange Issue with Half Wave Rectifier - Page 1
Forum section: electronics / projects

author: paul_g_787
author_rank: Frequent Contributor
timestamp: February 15, 2022, 07:52:52 pm
content: I have been experimenting with capacitive drop supplies again and have been trying to use a half wave rectifier to cut the part count down, however I have encountered a strange issue I can't explain.I have just made the two circuits shown in the attachment to demonstrate the issue.The first has a half wave rectifier and the second has a full bridge rectifier.The circuit with the half wave rectifier only supplies 0.3mA of current to the LED but the other one with the full bridge rectifier supplies 4.8mA. How can this be?Am I missing something silly?I have tested all the components and these are the real world values.R1 is 99ΩR2 is 998KC1 is 71nFC2 is 216µFLED1 forward voltage drop is 1.9V

author: Benta
author_rank: Super Contributor
timestamp: February 15, 2022, 08:03:28 pm
content: Well, think about how C1 is charged by the AC input. And especially: not discharged.Pretty obvious what's going on.I think I said this in an earlier thread: you're in over your head here and designing something potentially very dangerous.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 15, 2022, 08:03:53 pm
content: The diode charges C1 too! The only current you will see in the load is due to the leakage current through the resistors. You need to have a path to discharge C1 on the aternative half of the cycle.

author: andy3055
author_rank: Super Contributor
timestamp: February 15, 2022, 08:06:51 pm
content: Check the actual voltage across the filter cap. You might find that they are very different in that, the full bridge configuration will have a much higher DC voltage. That should push more current through the LED.

author: paul_g_787
author_rank: Frequent Contributor
timestamp: February 15, 2022, 08:12:27 pm
content: Quote from: Andy Watson on February 15, 2022, 08:03:53 pmAha of course! Well spotted there, so silly now it has been pointed out! Thank you.
Cap extreme leak - Page 1
Forum section: electronics / projects

author: Bud
author_rank: Super Contributor
timestamp: May 28, 2014, 03:43:28 am
content: Bought a Tek differential probe on eBay, looked fairly new and unused but did not work properly. Opened the casing and found a axial electrolytic capacitor apparently leaked, rusting the capacitor body and literally turned to dust one of the leads. I cleaned the mess, replaced the cap, now the probe works fine.

author: amyk
author_rank: Super Contributor
timestamp: May 28, 2014, 12:38:29 pm
content: Looks more like a wet tantalum than regular electrolytic; they use a highly acidic electrolyte.

author: TimNJ
author_rank: Super Contributor
timestamp: May 30, 2014, 02:59:44 am
content: Wow! Hopefully you can get that working again assuming the leaked electrolyte hasn't damaged anything else.
Cap lead broken, Zobel network resistor overheated. Are they linked? - Page 1
Forum section: electronics / projects

author: Chris Wilson
author_rank: Super Contributor
timestamp: October 17, 2015, 11:27:31 am
content: Strange scope patterns from the output of my 136kHz Class D 1kW amp, both pre and post LPF. Took it apart and found one of the 2kV 4n7 caps on the primary of output transformer T1 had a broken lead. The 22 Ohm, 25 Watt panel mount metal cased resistor in the Zobel network (shown as "Z" in the schematic, a 22R wire wound and a 4n7 poly cap in series), had also got mad hot and exuded an end cap, explaining the hot smell! Resistor was still intact and still sat at 22 Ohms. Hadn't got a spare wire wound so refitted it, with a new 2kV DC poly cap. Trace now good. 50W wire wound on order. Would the effectively missing cap circled in red in the schematic attached cause the Zobel network wire wound to overheat, or do I have other issues? Thanks.

author: Phoenix
author_rank: Frequent Contributor
timestamp: October 17, 2015, 12:55:32 pm
content: The snubber circuit (zobel as you and the circuit designer call it) may not be well designed, a poorly designed snubber will dissipate a lot of heat - it's a balance between loss and snubbing really. I also don't really like the placement of those 4n7 caps (like the one you circled), they might do more harm than good.The purpose of that RC is to damp out very high frequency ringing caused by rapid dv/dt or di/dt exciting a resonance. If the RC break point is too low the circuit will dissipate more energy than it needs to damp the ring. If the resistor is too small it will also dissipate more energy. You really need to stick a scope on the drain-source and look for ring (without the snubber and 4n7) and compare to with them in place.https://www.maximintegrated.com/en/app-notes/index.mvp/id/3835might have a better idea on snubbing this topology.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 17, 2015, 01:10:21 pm
content: BTW, what's the transformer look like?
Cap working voltage? - Page 1
Forum section: electronics / projects

author: iXod
author_rank: Frequent Contributor
timestamp: October 16, 2021, 10:11:56 pm
content: Ordered this cap for a fan and after receiving it I notice that it has no marking of the voltage.I searched “CBB61” and see them in various voltages.Would you trust this one to be 250v, as the eBay listing says, or return it and find one with V marking?Thanks.EDIT:https://www.ebay.com/itm/185097694219

author: james_s
author_rank: Super Contributor
timestamp: October 16, 2021, 10:23:59 pm
content: Where did you order it from? What kind of capacitor is it? What is the purpose in the fan? Is it a run capacitor for a PSC motor, a start capacitor for a capacitor start motor or a noise suppression capacitor?

author: Psi
author_rank: Super Contributor
timestamp: October 16, 2021, 10:31:33 pm
content: google image search suggest it's some sort of 450V motor cap

author: iXod
author_rank: Frequent Contributor
timestamp: October 16, 2021, 11:06:15 pm
content: Quote from: Psi on October 16, 2021, 10:31:33 pmThis is to my point exactly. It’s advertised (in the title of the ePay page) as a 250v cap. No voltage markings on the cap.https://www.ebay.com/itm/185097694219What would you do with this cap?

author: TimFox
author_rank: Super Contributor
timestamp: October 16, 2021, 11:08:37 pm
content: The image in the eBay listing definitely shows 250 V on the capacitors, but they probably took the image from a datasheet rather than photographing the object (without voltage markings) that they sent you.You should have a case for a refund, should you want to pursue it.

author: iXod
author_rank: Frequent Contributor
timestamp: October 16, 2021, 11:42:49 pm
content: Quote from: TimFox on October 16, 2021, 11:08:37 pmWhat would you do? Return or use it?

author: james_s
author_rank: Super Contributor
timestamp: October 17, 2021, 04:11:04 am
content: I'd just use it, if it fails then buy a better one next time. The listing says 250V, it looks about the right size to be a 250V cap, I would assume that's what it is.
Capacitor downstream or upstream of step-down module - Page 1
Forum section: electronics / projects

author: ioncube
author_rank: Newbie
timestamp: October 07, 2025, 12:53:50 pm
content: I am using12V UPS moduleas following to power my SBC. I am also attaching component level details of hardware involvedThe problem I am facing is a jerk (blink of an eye) when main power is cutoff & my SBC resets. A surveillance camera images are neurally processed in it so this behaviour poses a security risk.Troubleshooting:My internet modem (mostly running at 10W) separately is also powered by a similar UPS module & its transition is smooth. I believe the buck boosterHW-688 modulehas to do something with it & is to be blamed. I replaced this module with another popular oneHW-140but to no availQuestion:I am looking for your ideas how can I sort this thing out. I am thinking of attaching capacitor but cannot find basis of where to attach it: Upstream of module (12V) or downstream (5V)

author: Siwastaja
author_rank: Super Contributor
timestamp: October 07, 2025, 03:38:30 pm
content: Conceptually this is quite simple:If your computer is browning out because the 12-to-5 V power supply cannot provide the maximum (short-term) peak current of the computer (which can be a lot more than average rating advertised!), then you need either to change to a higher-current power supply, or capacitorsat the outputof the supply.And then again, if the power supply can provide those peaks, but whatever is powering that power supply (battery; maybe long wires with resistance, maybe another power supply with limited capability) cannot, then add capacitance on theinput sideof that power supply. Advantage is that on the input side, same amount of capacitance gives more bang for buck. Energy storage in capacitors is dependent on voltage (C*U^2). Therefore, if your 5V output is only allowed to sag to, say, 4.5V, only (0.5V)^2 * capacitance is storing the energy. On the input side, maybe 12V can drop to 7V and the supply is still happily making 5V from it; then you would have 5V difference storing the energy. So much less µF needed for same amount of energy storage.And it might be that you want capacitors on both sides.

author: ioncube
author_rank: Newbie
timestamp: October 07, 2025, 08:15:39 pm
content: Extremely thanks. I understand now
Capacitance divider of Colpitts Oscillator - Page 1
Forum section: electronics / projects

author: promach
author_rank: Frequent Contributor
timestamp: July 18, 2019, 06:58:51 am
content: For the following Colpitts Oscillator, Why does employing the capacitance divider up-converts the source impedance of transistor by a factor of(1+C2/C1)2

author: TimFox
author_rank: Super Contributor
timestamp: July 18, 2019, 01:54:35 pm
content: It's the combination of the two capacitors and the inductor that effects the impedance transformation.Such resonant transformer networks are common in narrow-band RF applications. The text book you show probably covers that.

author: ferdieCX
author_rank: Regular Contributor
timestamp: July 18, 2019, 02:40:05 pm
content: Hi, the thing is called "capacitive transformer".Although the text in the picture is in Spanish, you can see the equations that demonstrates it.When both X1 an X2 are of the same sign, in our case capacitive, one of the two simplifying conditions automatically implies the other,and you can go from eq. (19) to (20)

author: promach
author_rank: Frequent Contributor
timestamp: July 19, 2019, 02:29:41 am
content: Wait, I am asking about sourceimpedance(not just resistance) of transistor (in the case colpitts oscillator) which is equivalent to the common, bottom node for X2 and RLWhat is RL' ?Edit:I foundhttp://www.zen22142.zen.co.uk/Analysis/analysis.pdfwhich is more explanatory in English text version.

author: ferdieCX
author_rank: Regular Contributor
timestamp: July 20, 2019, 05:35:44 pm
content: Quote from: promach on July 19, 2019, 02:29:41 amThe input capacitance Cin of the transistor is part of the tuned circuit, so it is canceled by the inductance L1 at the oscillation frequency and you only have to care about the input resistance.To make the oscillation frequency independent of Cin, the external capacitors are usually many times bigger than CinThe "capacitive transformer" admitance Yi looks like the parallel of RL' (the transformed resistance) an a capacitor of value C = C1 // C2The explanation in English that you have found is very complete.
capacitance leakage tester - Page 1
Forum section: electronics / projects

author: Deathwish
author_rank: Unknown
timestamp: May 29, 2015, 09:19:17 am
content: Thinking of building the little box on page 51. old but who knows. what do you think ?.https://ia601703.us.archive.org/5/items/radio_electronics_1986-05/Radio_Electronics_May_1986.pdf

author: tron9000
author_rank: Frequent Contributor
timestamp: May 29, 2015, 09:43:52 am
content: "Meat and spuds" electronics! go for it!

author: Unknown
author_rank: Unknown
timestamp: May 29, 2015, 06:38:14 pm
content: That looks a nice project may build one myself.

author: matseng
author_rank: Frequent Contributor
timestamp: May 30, 2015, 05:42:13 am
content: A blast from the past. I conveniently forgot that like 95% of the pages if those magazines was just ads - and we were paying good money for it. But today the ads for surplus stuff brings good memories to me...

author: kripton2035
author_rank: Super Contributor
timestamp: May 30, 2015, 06:50:57 am
content: a more modern approach (but with less voltage capabilities)http://kripton2035.free.fr/digital%20esr/esr-sprut-de.html

author: Unknown
author_rank: Unknown
timestamp: May 30, 2015, 02:20:26 pm
content: Quote from: kripton2035 on May 30, 2015, 06:50:57 amOh yes, this is a must and with the Hex, I'll get to use one of my pic chips taking up space

author: tron9000
author_rank: Frequent Contributor
timestamp: June 01, 2015, 08:05:06 am
content: Quote from: kripton2035 on May 30, 2015, 06:50:57 amahh now I like that!

author: LukeW
author_rank: Frequent Contributor
timestamp: June 02, 2015, 04:59:38 pm
content: May be of interest.http://archive.siliconchip.com.au/cms/A_111776/article.htmlhttp://archive.siliconchip.com.au/static/images/articles/i1117/111776_8mg.jpg

author: kripton2035
author_rank: Super Contributor
timestamp: June 02, 2015, 06:45:39 pm
content: ah yes there is also this one : (going to 630v)http://archive.siliconchip.com.au/cms/A_112073/article.htmland of coursehttp://archive.siliconchip.com.au/static/images/articles/i1120/112073_8mg.jpg
Capacitance Meter kit  - EA   Instructions - Page 1
Forum section: electronics / projects

author: JoeyG
author_rank: Regular Contributor
timestamp: August 20, 2022, 06:27:51 am
content: I'm looking for the instruction manual for this great kit . It has 4 pots for calibration and look on how to do this.Is there any repository for this kit (measures I think 99uF to 1pF)

author: moffy
author_rank: Super Contributor
timestamp: August 20, 2022, 07:19:48 am
content: Pretty sure this is what you are looking for, it's in Nuts and Volts but they shared a number of articles with EA. It also has 4 pots and a maximum of 999uF.https://www.nutsvolts.com/magazine/article/a_digital_capacitance_meter

author: ozcar
author_rank: Frequent Contributor
timestamp: August 20, 2022, 07:22:00 am
content: I guess Silicon Chip would want to sell it to you, and I thought that they had been successful in getting scans taken down, but I found what looks like what you are looking for here:https://ia600600.us.archive.org/26/items/EA1979/EA%201979-01%20January.pdfIf that is not it, (and not the Nuts & Volts one) then SC's index has four or five other capacitance meter projects, but I did not try to find any of the others.

author: JoeyG
author_rank: Regular Contributor
timestamp: August 20, 2022, 07:55:07 am
content: thank - not that one

author: JoeyG
author_rank: Regular Contributor
timestamp: August 20, 2022, 08:01:56 am
content: newer than this one

author: JoeyG
author_rank: Regular Contributor
timestamp: August 20, 2022, 08:15:30 am
content: OK... thanks for the hints I found the article
Capacitance Multiplier circuit - Page 1
Forum section: electronics / projects

author: mboich
author_rank: Contributor
timestamp: May 15, 2017, 10:35:16 pm
content: I’m building a CRT-based clock, much like the ones athttp://oscilloclock.com. The 9V wall wart powers both the high voltage board as well as the controller board that generates the waveforms for display. Because the high voltage board generates a fair bit of noise at around 180KHz, I’m using a capacitance multiplier circuit upstream of my 5V linear regulator on the controller board to filter most of the noise. Here's the circuit:The idea is to choose the value of R1 to create a voltage drop of around 1V, so that there is headroom for the transistor to regulate the output voltage. I breadboarded the circuit, and it works well. I implemented it on my PC board and learned empirically that to get the same 1V voltage drop, I need to reduce the value of R1 from 1K to 470R. I’m driving the same load in each case, and using the same 9V supply as the input in each case.Although the circuit works acceptably, I’m trying to understand the reason for the difference. I’m using exactly the same components, except that they’re through-hole packages on the breadboard, and surface mount on the PCB. I’ve built up two instances of the PCB, and they behave identically. The breadboard version matches up to the SPICE simulation.If I look at the 1V drop across the 1K resistor on the breadboard version, it implies a beta of around 100 for the transistor, whereas the 1v drop across 470 ohms on the PCB version implies a beta of about 50. Looking at the data sheet (https://www.fairchildsemi.com/datasheets/MM/MMBT3904.pdf) for the MMBT3904, I guess both values could be considered in spec with a collector current of around 100mA.Any ideas?thxMike

author: Someone
author_rank: Super Contributor
timestamp: May 16, 2017, 01:28:42 am
content: Quote from: mboich on May 15, 2017, 10:35:16 pmYou got it in one! The parts aren'tthe samethey're just the same specification which leaves a wide range of operating points. This is the technical side of engineering where you need to account for all possible ranges of all the specifications of all the parts and be sure that it still works.

author: mboich
author_rank: Contributor
timestamp: May 16, 2017, 03:36:23 am
content: Quote from: Someone on May 16, 2017, 01:28:42 amThanks. I've read that beta is not a value that should be relied upon, and this seems to illustrate that.-Mike

author: danadak
author_rank: Super Contributor
timestamp: May 16, 2017, 10:05:13 am
content: Not unusual to find in old test equipment transistors with a colordot or top on them. This was a beta/hfe classification used longago to screen parts for their gain. That in turn produced knowncircuit design results. Also feedback was, and is used, extensivelyto minimize effects of parameter device to device variation. Forexample look at today's Aol in OpAmps, 100's of % variation deviceto device, but closing the loop results in very accurate G circuits.- fdbk is everything, the original paper by Black -https://paengdesign.wordpress.com/category/theory/Regards, Dana.