hybridfree/eevblog-posts huggingface dataset:
Reading ADC - Page 1
Forum section: electronics / beginners

author: Sai Shoby
author_rank: Newbie
timestamp: October 21, 2020, 03:59:46 am
content: HI all,I am trying to adc value and print in LCD. when i check the adc pin it shows 1.27 V but in lcd it varying. I attached my code. help me to find the mistake.thank youunsigned int ADCResult=0;float voltage;char voltageTxt;void main(){ANCON0 = 0x01;TRISA.F0 = 1 settind RA0 as analog input pinI2C1_Init(100000);Lcd_begin(0x74); // Initialize LCDLcd_Cmd_(0x01); // Clear LCDADC_Init();Lcd_goto(8,1);Lcd_print("ADC");}while(1){ADCResult = ADC_Read(0);voltage = (ADCResult*5.0)/ 4096.0;floattostr(voltage,voltageTxt);voltageTxt = 0;LCD_goto(2,2);LCD_Print(voltageTxt);delay_ms(300);}Using 18f25k80 12bit adc.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: October 21, 2020, 04:53:37 am
content: ADC works with an error and never outputs two identical values.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: October 21, 2020, 05:26:11 am
content: Quote from: S. Petrukhin on October 21, 2020, 04:53:37 amDepends on your noise management. I have made boards that have zero noise with a 10 bit ADC. The chip is sitting on top of a ground plane and all loops are kept to a minimumHowever ADCs are very prone to picking noise. You can put a small cap between the ADC pins. Twist the wires of the sensor together. If you're using an ADC that is part of a MCU, it will probably pick up noise from the chip.Make sure your chip that is doing the ADC is properly decoupled 100nf cap on the power pin. Try to minimize the ground loop on the power supply.

author: Sai Shoby
author_rank: Newbie
timestamp: October 21, 2020, 07:04:55 am
content: So program correct??

author: JustMeHere
author_rank: Frequent Contributor
timestamp: October 23, 2020, 02:22:14 am
content: Yes. It looks right.You might want to write a software filter for the noise you're seeing. For example: Take the 10 samples, throw out the highest and lowest. Then average the rest.

author: brucehoult
author_rank: Super Contributor
timestamp: October 23, 2020, 03:18:30 am
content: Quote from: JustMeHere on October 23, 2020, 02:22:14 amJust to make that more concrete without it looking as if you have to sort everything or something:Code:unsigned int tot = 0, max = 0, min = 0xffff;for (int i=0; i<10; ++i){unsigned int ADCval = ADC_Read(0)tot += ADCval;if (min > ADCval) min = ADCval;if (max < ADCval) max = ADCval;}voltage = (tot-min-max) * (5.0/(4096.0*8));Check: can the sum of 10 values in 0..4095 overflow? 40950 < 65535, so no.
Reading amp schematics to find suspicious transistors - Page 1
Forum section: electronics / beginners

author: cincin
author_rank: Regular Contributor
timestamp: May 10, 2022, 05:43:42 pm
content: Greetings!I'm pretty new to reading schematics, and I'm a little confused about this one in particular:https://www.manualslib.com/manual/1441478/Nad-C-326bee.htmlI need to check the transistors that are after the volume control, on the left channel. Looking at the block diagram, the volume control board is between the pre-amp in and pre-amp out modules, so I figured I need to look at the pre-amp out module, and everything downstream from there.Following the schematics (page 16) from the inputs, the signal first goes to the pre-amp in module via pins LIN+I and RIN+I, labeled as a group as "IN MODULE", then to the volume control board, then to the "OUT MODULE". But looking at the right of the page 16, where the pre-amp in and out modules are drawn, I don't see a LIN+I or RIN+I pin on the "IN MODULE", those pins are in fact on the "OUT MODULE" above. So I'm confused as to which module comes after the volume control.I think I may be misunderstanding a schematics convention? Or is it badly labeled??Thanks!

author: LaryPant
author_rank: Contributor
timestamp: May 11, 2022, 11:13:26 am
content: Hi,I had a look at it and I am pretty sure that the "I"(in) and "O"(out) suffixes are supposed to be in respect to where they are drawn in the schematic or that is how it was supposed to be. So the LIN-O wire in the main schematic would be an output from the main schematic and an input to the OUT Module and therefore labelled as LIN-I in that module. Although I understand your confusion because with that logic the "LOUT-I" signal on the OUT-Module should actually be labelled "LOUT-O" as it is clearly an output. And I think that is were that the designer made an error.In short, the labeling is very confusing and could have been much clearer, but the OUT Module connects to theconnectorlabelled OUT Module in the main schematic and the same for the IN Module. If you have the physical product then I would take a multimeter and quickly check what's connected to what.I hope this helps and doesn't confuse further,LaryPS: The "I" and "O" suffices my also refer to how the PCBAs physically are connected together with male and female headers, but that would also be a bad naming scheme IMHO.
reading current of Power Supply  - Page 1
Forum section: electronics / beginners

author: AmirTheGreat
author_rank: Unknown
timestamp: March 16, 2013, 11:51:36 pm
content: Hey everyone,I'm making a simple power supply with an LM317. I want to be able to read the output voltage and current with an arduino and display it on an lcd or something.I made a voltage divider so I can do an analog read of 0-5v and calculate the Vout. But Im not sure how to measure the voltage drop of the shunt resistor since i would have to connect the other end to the arduino's ground which would short the whole circuit and what-not.how would I be able to measure the current?(wasn't sure whether to post in Microcontrollers/ FPGAs or Projects/Designs so I apologize for spamming the Beginners Forum.)

author: Monkeh
author_rank: Super Contributor
timestamp: March 17, 2013, 12:22:54 am
content: Use a low-side shunt.

author: AmirTheGreat
author_rank: Unknown
timestamp: March 17, 2013, 12:49:36 am
content: Thanks for your advice.is there any improvements I could make?I will add capacitors by the way

author: Rerouter
author_rank: Super Contributor
timestamp: March 17, 2013, 01:07:46 am
content: one big one, move the lm317's feedback network to the other side of the current shunt, this ensures its voltage drop does not matter
Reading current when voltage is at or near Zero - Page 1
Forum section: electronics / beginners

author: RileyKA
author_rank: Newbie
timestamp: November 22, 2021, 02:08:24 am
content: I have a cc/cv bench power supply, Tenma 72-7245 for those wondering. For this particular power supply to set the voltage and current you have to have the outputs on. You can set the voltage easily enough but to set the current limit you must short the outputs at which point it will enter CC mode and the voltage drops to 0 and you can then adjust your current limit. If the voltage has dropped to 0 how does it measure the current?I'm not looking for anything specific to this power supply but more of a general explanation.TLDR: how does a CC power supply measure output current in a short circuit situation when the voltage drops to 0.

author: IanB
author_rank: Super Contributor
timestamp: November 22, 2021, 02:15:18 am
content: It measures the current upstream of the output terminals. In other words there can be a current sense resistor behind the terminals, and even if the voltage across the output terminals is zero, the voltage behind the sense resistor can be greater than zero.
Reading datasheet package dimensions - Page 1
Forum section: electronics / beginners

author: michaelnjensen
author_rank: Newbie
timestamp: August 11, 2012, 02:47:36 pm
content: Hi,I'm just starting out to design my own board, and I have to use a part that isn't in Diptrace, I read/watched numerous tutorials, and it seems really simple, but they all show how to make parts from datasheets that just has one measurement, i'm trying to create this device TLE2426CD (SOIC-8)http://www.ti.com/lit/ds/slos098d/slos098d.pdfwhere they on all measurements have multiple lines, like the width of the IC is both 5.00mm and 4.80mm, what does those multiple widths/lines actually represent?Could just reuse the footprint of SOIC-8/150mil from the Diptrace library, but would like to understand how to read the datasheets properly

author: Rufus
author_rank: Super Contributor
timestamp: August 11, 2012, 02:54:16 pm
content: Quote from: michaelnjensen on August 11, 2012, 02:47:36 pmUsually the minimum and maximum values.

author: michaelnjensen
author_rank: Newbie
timestamp: August 11, 2012, 06:33:43 pm
content: Thanks
Reading datasheets (transistors, specifically) - Page 1
Forum section: electronics / beginners

author: brendan-petrol
author_rank: Contributor
timestamp: May 29, 2012, 10:10:37 am
content: Hello,I am trying to make a high gain - run a 1-2A load off a 74HC595 - multi-channel driver board with 5v logic and 12v supply for the load. I have a heap of 2N2222 transistors, and a few 2n3055s floating around from other projects - kits mainly, but I still have trouble reading datasheets.Would someone be able to point me in the direction of a good resource to help me learn how to read the datasheets so I don't try to overload the transistors?Thanks,Brendan

author: deephaven
author_rank: Frequent Contributor
timestamp: May 29, 2012, 11:46:22 am
content: This is quite a good document for explaining it all:http://webtools.delmarlearning.com/sample_chapters/04.pdf

author: brendan-petrol
author_rank: Contributor
timestamp: May 29, 2012, 12:26:58 pm
content: Ahh, that's fantastic!That PDF is going straight on my Kindle. Does anyone have any other tips for good books to use to learn electronics (I think mostly my tinkering has been luck... I don't know how much of it has actually worked due to real "skill"!

author: T4P
author_rank: Super Contributor
timestamp: May 29, 2012, 12:38:49 pm
content: It was a lot of blood(No kidding!) and sweat and smoke but i eventually knew how to properly "decode" a datasheet.Yes it was effort paid off and another gate opened.

author: TerminalJack505
author_rank: Super Contributor
timestamp: May 29, 2012, 01:57:23 pm
content: An oldie but a goodie...GE - Transistor Manual 1964

author: brendan-petrol
author_rank: Contributor
timestamp: May 30, 2012, 01:22:28 am
content: I wonder if there would ever be a blog post on decoding datasheets!

author: brendan-petrol
author_rank: Contributor
timestamp: May 30, 2012, 04:30:28 am
content: OK, Now that I've learnt a heap about reading datasheets (thanks for that you guys!) it's made me understand a whole lot of the detail about the 2n2222, enough to know that I will have to use the 2n2222 to drive a higher power transistor. Would the 2n3055 be suitable? I want to run PWM through them - 2A max.I have read about Darlington transistors (that is what this would be, right?) and it says that they switch much slower. Is there a number associated to "much"? I also read that a base-emitter resistor on the second transistor can speed up the switching speed. Would a Darlington transistor made up of a 2n2222 and a 2n3055 with a base-emitter resistor on the 2n3055 be suitable to PWM through?If so, how would I pick the base-emitter resistor?I am going to feel like a complete idiot if that is in that first PDF linked to, I am about halfway through it.
reading eschematic - Page 1
Forum section: electronics / beginners

author: dikkombe
author_rank: Newbie
timestamp: October 30, 2011, 09:02:14 pm
content: hello my name is dikkombe and study electronics and have difficulty reading schemes diagrams

author: Simon
author_rank: Unknown
timestamp: October 30, 2011, 09:02:58 pm
content: and what do you want us to do about it ?

author: deephaven
author_rank: Frequent Contributor
timestamp: October 30, 2011, 09:31:20 pm
content: Quote from: dikkombe on October 30, 2011, 09:02:14 pmHi dikkombe and welcome to the forum! Could you post a picture of the schematic you're having trouble with and point out the parts that need explanation.

author: Simon
author_rank: Unknown
timestamp: October 30, 2011, 09:37:25 pm
content: if it is a large schematic you need to firstly break a schematic into blocks, depending on how much you know about electronics you may or may not know of many basic blocks that are used that have a function in themselves and do something for the overall circuit, so effectively you break the schematic into a block diagram. Hopefully you then know what each block is doing so you can understand the circuit at a block level and component level as well as functional

author: Chet T16
author_rank: Frequent Contributor
timestamp: October 30, 2011, 10:34:27 pm
content: Related to this, on schematics i've seen some connections to ICs have a small circle on them.From my experience with logic circuits i would say this inverts the signal but not sure what it means in a circuit scematic

author: Simon
author_rank: Unknown
timestamp: October 31, 2011, 06:43:55 am
content: what sort of symbol does the IC have, if it is a bow with however many pins the IC has no idea if it is a functional symbol like a flip flop then yes it means active low ie there is an inverter on the input (I think)

author: vtl
author_rank: Regular Contributor
timestamp: October 31, 2011, 06:55:28 am
content: Quote from: Chet T16 on October 30, 2011, 10:34:27 pmIts called a bubble and it means its inverted, ie active lowhttp://en.wikipedia.org/wiki/Logic_gate#symbols

author: Chet T16
author_rank: Frequent Contributor
timestamp: October 31, 2011, 07:30:55 am
content: Right, so it only tells you how the circuit works.Simple example:http://www.sparkfun.com/datasheets/DevTools/Arduino/FTDI%20Basic.pdfLooking at that now it would make sense, the reset pin is active low and the led pins sink current.
Reading halleffect output on bldc motor - Page 1
Forum section: electronics / beginners

author: wrinklehead
author_rank: Contributor
timestamp: November 03, 2017, 02:17:04 pm
content: I am trying to control a 3 phase brushless dc motor with integrated hall-effect sensors. I understand how to do this with your typical open-collector hall effects, however according to the manufacturer these are "line-driver" hall effect sensors. I do not understand how to read them.Instead of just having 1 output for each halleffect this motor appears to have 2. I have hooked 12v to Vcc and Ground to ground and measured the output of both the + and - output of the halleffects. There seems to be 3 possible outputs at each output ~6.86, ~5.8, ~ 5. I have to missing something right??I have attached the very limited information the manufacturer has given me

author: jm_araujo
author_rank: Regular Contributor
timestamp: November 03, 2017, 02:41:22 pm
content: Linear sensor with differential outputs? The A+/A- style outputs suggests so.Edit: something like this:http://www.hallsensors.de/CYSH12AF.pdf

author: wrinklehead
author_rank: Contributor
timestamp: November 03, 2017, 03:13:03 pm
content: I took the motor apart to get a look at the hall effect sensors, and I believe you are correct it looks exactly like the part you posted the pdf for. So to simulate a digital signal (to fire an interrupt on microcontroller ). I should probably feed the + and - into an opamp correct?

author: Benta
author_rank: Super Contributor
timestamp: November 03, 2017, 03:24:59 pm
content: Comparator is better.

author: wrinklehead
author_rank: Contributor
timestamp: November 03, 2017, 04:07:20 pm
content: Quote from: Benta on November 03, 2017, 03:24:59 pmAssuming I'm reading the attached section of the datasheet correctly... whats a comparator going to do if there is 7mv of difference between outputs?

author: perieanuo
author_rank: Frequent Contributor
timestamp: November 03, 2017, 04:40:55 pm
content: Quote from: wrinklehead on November 03, 2017, 04:07:20 pmThe 7 mV is the offset... The output is Vh it's 'analog' so you have to translate it with an adc or setup a trigger/comparator to detect the position. Not easy stuff...Envoyé de mon HUAWEI NXT-L29 en utilisant Tapatalk
Reading "mains" frequency from 12v -120v inverter with Dso213. - Page 1
Forum section: electronics / beginners

author: ThatDane
author_rank: Newbie
timestamp: May 17, 2019, 01:39:27 pm
content: I've got a Dso213 on the way and a new "pure sine" inverter. My old inverter has bitten the proverbial dust after 10 good years of service, it was "modified sine". I'm curious to see if this new inverter is truly a smooth sine wave.The pocket dso I ordered has 1x and 10x probes . so I understand that I'd be using the 10x probe if I just slam it into the plug. But I'm willing to use a xformer. I have a few laying around, some 10:1 and a couple that im not sure of but can test. I understand how to properly wire up a plug, what is hot/neutral/ground and how to hook that to the primary of the xformer.What is the best method? I don't want to nuke the scope, electrocute myself etc... Being that the thing isn't actually "mains connected" but making mains for me in my truck , how should I ground what should I do?

author: radiolistener
author_rank: Super Contributor
timestamp: May 17, 2019, 02:47:30 pm
content: disconnect your inverter from mains and disconnect from ground. Then connect it to accumulator and measure output

author: exe
author_rank: Unknown
timestamp: May 17, 2019, 05:19:39 pm
content: OMG, this question really pops up every... week. Short answer: use isolation downconverting transformer and measure the secondary because it's the safest way, provided you don't mess up with wiring. Long answer -- search forum.

author: Ian.M
author_rank: Super Contributor
timestamp: May 17, 2019, 06:59:26 pm
content: This question doesn't pop up every week - probing an inverter output is *NOT* the same as probing your utility company mains supply.Direct connection is inadvisable unless you have name brand appropriately rated probes for a number of less obvious reasons, many of which don't apply to probing a utility company mains supply. e.g:* With inverters its unwise to assume that the output has a near ground Neutral - its quite possible it has two anti-phase Line terminals , as driving them in a full bridge configuration halves the HT DC bus voltage required for a particular RMS AC voltage. Therefore it would be extremely unwise to clip a scope probe ground to what you *THINK* is output neutral unless you have verified direct continuity to chassis, ground terminal or the negative side (0V) of the DC input.* Scope probes need to be derated with frequency e.g. a x10 probe that's rated for +/- 400V at DC, may only be good for 200V at 100KHz. With a switching waveform, its the edge slew rate that's important, so even if the inverter only uses a 10KHz PWM, if they've skimped on output filtering. there could be significant energy in the edges at an order of magnitude higher frequency, so you could well be pushing the limits of what a generic x10 probe can safely handle. I certainly wouldn't care to risk it with a no-name switchable x1/x10 probe.OTOH a transformer will cause some waveform distortion. However if you don't want to splash the cash for a Cat II or better rated differential probe you may not have any other good safe alternative.
Reading  Measurements over GPIB - Page 1
Forum section: electronics / beginners

author: Zh4ng
author_rank: Unknown
timestamp: December 08, 2013, 09:06:19 pm
content: Hi @all,A Little newbie question: How can i read measurments from my HP 34401A over GPIB? I have a PCI Card , a cable and the DMM but no Software. Are there any free software? or just LabviewThx....Zh4ng

author: Unknown
author_rank: Unknown
timestamp: December 08, 2013, 09:20:09 pm
content: Try Agilent IntuiLink for DMMs. If you want more flexibility, EZ-GPIB is a Pascal-like scripting environment with GPIB support.

author: Andy Watson
author_rank: Super Contributor
timestamp: December 08, 2013, 09:28:12 pm
content: National Instruments provide drivers that cover most GPIB cards and, for Linux at least, they are free. I can confirm that the drivers work under Linux with the C language.

author: free_electron
author_rank: Super Contributor
timestamp: December 09, 2013, 12:24:37 am
content: install the gpib driver.then download the free software from agilent website.
Reading NAND flash in place? - Page 1
Forum section: electronics / beginners

author: pcee
author_rank: Regular Contributor
timestamp: October 04, 2021, 01:28:07 am
content: I want to read the contents of a NAND flash via SPI, and I’d rather avoid desoldering it if I can help it.Can I simply clip onto it and power the in-situ flash from a bench power supply, or will that fry the voltage regulator on the PCB?The voltage regulation circuitry takes 12VDC and provides 3.3V to the various components. I don’t know how it would react to having an energized 3.3V output with nothing at the input.

author: amyk
author_rank: Super Contributor
timestamp: October 04, 2021, 02:18:36 am
content: Backfeeding voltage regulators is usually a bad idea. You can try to find the datasheet of the particular regulator in use to confirm this.

author: pcee
author_rank: Regular Contributor
timestamp: October 04, 2021, 02:47:14 pm
content: Thanks, I figured that might be the case.I think I can power the entire PCB and hold the microcontroller’s reset line low, and then tap the SPI bus without active contention.Do I need to do anything special with pull-up or down resistors when tapping a powered SPI bus? Is there any trick to matching logic levels when issuing commands?
Reading PWM spec - "garunteed off duty cycle" - Page 1
Forum section: electronics / beginners

author: justinjja
author_rank: Regular Contributor
timestamp: March 21, 2019, 12:00:00 am
content: I have the following spec for a pwm signal:- 15-23 VDC at 67-93Hz or 127 to 199Hz- 10% Guaranteed On and 5% Guaranteed Off Duty CycleWhat does that second part mean?I'm guessing it menas the signal needs to be between 10% and 95% duty cycle?

author: exe
author_rank: Unknown
timestamp: March 21, 2019, 07:40:01 am
content: I don't know, but for me it seems that from 0-5% the device will be "off", 5-9% it will be in some non-guaranteed state, 10-100% is when it's gonna be "on"

author: mikerj
author_rank: Super Contributor
timestamp: March 21, 2019, 08:41:51 am
content: A little more context is need for the device this specification applies to to. It sounds very much like the device is controlled by PWM, and whatever it controls is guaranteed to off with an applied PWM of 5% duty cycle and below, and guaranteed to be on with an applied duty cycle of 10% or higher.What happens in the 5-10% range is anyone's guess, probably the on/off switching threshold is simply somewhere in that range, but the device may have hysteresis built in causing a deadband.
Reading register using Modbus master/arduino uno - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 13, 2016, 09:49:10 am
content: 1. I ma using this modbus library to read (EM)6433, meter from scheider.Lib:https://github.com/4-20ma/ModbusMasterdoc:http://4-20ma.io/ModbusMaster/2. (EM)6433 documentation is here:http://tinyurl.com/z7696ys3. Page 3 of above doc says that protocol is Modbus RTU, data:8 bits, baud: 9600(default) , parity:even, device address:1, stop bit:1In uno code, default seting is 9600 & parity zero. Is below setting ok in code:ModbusMaster node;Serial.begin(9600, SERIAL_8E1);node.begin(1, Serial);4. (EM)6433 doc on page 7 shows, read register "Average current", with address "3913" & reurn type is float 4 bytes in little endian.However this library has function "readHoldingRegisters" to read holding register. But this function reads only 16 bit registers.So should I use the function as:result = node.readHoldingRegisters(3913, 2);if (result == node.ku8MBSuccess){for (j = 0; j < 2; j++){data = node.getResponseBuffer(j);}}parameter 2, shows that 2 16 bit values are read.How to convert it back to float?

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: October 05, 2016, 06:22:43 am
content: 1. I have interfaced EM-6433 using arduino over Rs485. Rs485 IC used is SN75HVD08.2. EM-6433 settings are slave id:1 & baud:19200, even parity & 1 stopConfirmed it aftr turing on meter & go to its settings table.3. Case 1: If I permanently pull down N_RE pin & pull up DE pin of SN75HVD08, then when I used the attached code I always receive 0xE2 in return from device ie ku8MBResponseTimedOut. In code ignore the code which ouput high & low the RE & DE pin. This is used in case 2. In this case, this is commented out.4. Case2: Since this SN75HVD08 is half duplex so I connected RE & DE pins to arduino as in attached circuit. Also I have modified ModbusMaster.cpp file in line 728 & 729, where I added code to disable Tx & enable rx from IC. When I use this code I receive error 0x02 in result, which is ku8MBIllegalDataAddress.What am I doing wrong here. I also interchanged A & B pins to slave device EM-6433 + & -. But no correct result obtained.5.All ckt diagram and code is here:https://drive.google.com/open?id=0B-jbeBk3wfkWaWo1ek5ISUxoTzA
Reading RPM of motorcycle's engine - Page 1
Forum section: electronics / beginners

author: huu_tri0101
author_rank: Contributor
timestamp: July 29, 2013, 05:05:33 pm
content: I want to measure rpm of motorcycle's engine. The engine is 4 stroke, one cylinder. So in one cycle, the crankshaft rolls 2 revolutions, the spark plug sparks 1 time. So I need to count time the spark plug sparks in one second to measure rpm.To count time the spark plug sparks, I use the hall sensor place near motorcycle spark plug wire, then use an op-am to compare the Voltage that hall sensor gives back with the V ref. Then read the result form the op-am by the MCU.Is that a good idea? Any suggest ?Thank you guys. Sorry for my English.

author: Kremmen
author_rank: Super Contributor
timestamp: July 29, 2013, 05:42:49 pm
content: A hall sensor is sensitive to a magnetic field so not the best possible one to sense the electric field around the HV spark cable. A better solution would be to make a pickup coil from a few turns of wire around the spark cable.Google will tell you more. Some infor e.g. here:http://www.eng-tips.com/viewthread.cfm?qid=320604

author: KJDS
author_rank: Super Contributor
timestamp: July 29, 2013, 06:44:15 pm
content: Pick up coil feeding a schmidt trigger is the way to go.

author: A Hellene
author_rank: Frequent Contributor
timestamp: July 29, 2013, 07:15:17 pm
content: If you do not know EXACTLY what you are doing,DO NOT touch the pick-up coil. There are better ways of reading the engine speed.Additionally, almost all of the single-cylinder motorcycle engines ignition controllers utilise the so-called "wasted spark" ignition system, since they are sensing the crankshaft rotational position and speed (where there is one spark for every crankshaft cycle); except, of course, if they have their sensors on the camshaft.The answer you might be looking for is at the first link, above, by reading the charging system output frequency.-George

author: AndyC_772
author_rank: Super Contributor
timestamp: July 29, 2013, 08:07:09 pm
content: If your bike has electronic ignition, then there may already be a perfectly good signal you can tap into at the back of the clocks, feeding the rev counter. My bike has a nice, clean 12V square wave available which I've used successfully, and there's a similar signal for the speedometer on a nearby pin.If you place a pick-up coil near to one of the ignition leads, then you should be able to pick up a strong signal quite easily - but it's worth checking it with a scope to see what it looks like before designing any kind of interface. Expect the ignition pulses to be surprisingly high in amplitude and very brief in duration.
reading thermistor datasheets - Page 1
Forum section: electronics / beginners

author: Simon
author_rank: Unknown
timestamp: June 30, 2014, 08:57:27 am
content: Attached is the datasheet in question, there are tables on page 2 that give values and some formula's to calculate temperature at any given temperature but I'm a bit lost for understanding them. How do i use the figures given to work out the resistance for a given temperature.I think I'm being asked to divide the difference between my new temperature and 25 by the new temperature (delta B/B) and then to i add the coefficient given in the table ?

author: Kremmen
author_rank: Super Contributor
timestamp: June 30, 2014, 12:07:03 pm
content: Not exactly. Thermistors behave in an exponential manner so the curve is nonlinear all the way. The coefficients give a close approximation to the curve and they are used as follows:- firstly, you have the nominal resistance at 25C (=298.15 K). This is given in the table. Lets call that Rn- you have the beta multiplier (B) used in the formula, also given in the table. Lets call that b.Using this info, you can calculate R at any temperature using the formula:-First take the reciprocal, in Kelvin, of the nominal and the target temperatures, 1/T1 and 1/T2*-then put all the numbers in this formula:R = Rn/ e(b * (1/T1 - 1/T2)), i.e divide the nominal resistance by the exponential of beta times the difference of reciprocal temps.and R is your uncle.* In case you forget, you get Kelvin from Celsius just by adding 273,15. This makes the temps absolute which is usually required in physics calculations.P.S. there is also the alpha coefficient given. That one indicates the percentage change of resistance per degree (Kelvin) of temperature. NOTE: The alpha is nonlinear; the magnitude changes over the temp range. That's why it is given at a specific temp. So be careful that your calculations make sense if you use the alpha coefficient.
Real power rating of Chinese LED power supplies? - Page 1
Forum section: electronics / beginners

author: LinuxHata
author_rank: Frequent Contributor
timestamp: September 03, 2023, 06:17:08 am
content: Hello.When searching forfanlesspower source for my RK6006 module, I came across these LED power supplies.They are cheap in China (around $10 for "400W" model), but I guess that these power ratings are way too optimistic.Even if it has efficiency of 90% (while it definitely has not, since uses classic forward converter with TL494), still, at 400W power, at least 40W should be dissipated, and for a fanless supply of this size, this is not possible I believe.So if anyone tested such power supplies, what is their actual, longtime run output power?
really bad output on 2 EL84 amp (whistling, barelly any sound) - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: February 08, 2020, 10:18:08 pm
content: so I built a copy of the "Matchless DC30" amp but I used only 2 6P14P tubes (Russian EL84's) and used the output transformer form a Rigonda 102 and connected the taps for screen grids to the screen grids of the pentodes (I connected it like an ultra-linear output)it also used 6N2P preamp tubes (Russian 12ax7's) I don't have the 2nd channel since the only 6J32P (also Russian, EF86) seems to be dead, while the heater measures 8Ohms it doesn't light up whatever I try.anyway,all the parts I used are pretty much scrap parts since I'm so cheapbut I used mostly ceramic or tubular caps and the only (I think) oil cap I have is the coupling cap to the PI cause I didn't have any other that was that value, but I never seen those Russian oil (I think) caps fail catastrophically i.e I only have seen a few of them be leaky in a sense that the next stage is over biased.the only way I've seen them fail "catastrophically" is when they go pretty much open.so that might be the case.I'll try finding a good cap that value and change it if I find any.I measure 293v on the output transformer for the output and 148v for the preamp tubes (but I have more dropping resistors dropping the voltage after that)so it may be too low voltage on the preamp tubes, I'll connect it to a sooner point on the PSU.I'll link a sound sample I recorded.I used a small 16Ohm resistor to load the output and they used a 47nF cap (in case there's any dc) straight to my sound card.and I have the amp cranked AND I have super-hot pickups and I am smacking the strings as hard as I can.also at the start, I just touched the tip of the input jack thus inducing some 50Hz hum into it.I have a 1Meg volume pot just before the PI.[ Attachment Invalid Or Does Not Exist ]EDIT: actually it's 148v for the output transformer and 293v for the preamp tubes. so I'll fix that.

author: bob91343
author_rank: Super Contributor
timestamp: February 08, 2020, 10:50:09 pm
content: Sounds like a bias problem, likely due to a leaky coupling capacitor to the output stage.

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: February 09, 2020, 09:46:25 am
content: without the schematics a shot in the dark: did you check for correct phase of the feedback winding (if any)?

author: bob91343
author_rank: Super Contributor
timestamp: February 10, 2020, 05:57:17 am
content: It could also be a ground loop.
Really bad smell on Preheating station - Page 1
Forum section: electronics / beginners

author: azigta
author_rank: Regular Contributor
timestamp: August 07, 2014, 01:35:46 am
content: Hi, I have a preheating station, it´s a Puhui T8280, When I put a pc board in it, I set the temperature to 250, and it starts to smell like ... god, too toxic to continue!Is it normal? It´s because the motherboard tin melting? Man, I haven´t smell the melted tin like that before... And it isn´t the plastic from the connectors, because the motherboard is fineThanks

author: IanB
author_rank: Super Contributor
timestamp: August 07, 2014, 01:38:34 am
content: Quote from: azigta on August 07, 2014, 01:35:46 amWell, in English, Puhui sounds like a really bad smell...Phewee!

author: mariush
author_rank: Super Contributor
timestamp: August 07, 2014, 02:07:15 am
content: Some heating elements release some smell for the first hour or so of operation. Same with plastics and whatever else is used in them.Normally, it should subside with time.

author: azigta
author_rank: Regular Contributor
timestamp: August 07, 2014, 02:28:06 am
content: Quote from: mariush on August 07, 2014, 02:07:15 amI think I´m going to build an air extractor with a filter and so, because the smell is too bad. Thanks

author: amyk
author_rank: Super Contributor
timestamp: August 07, 2014, 02:57:32 am
content: Run it outside for a while, the smell will go away. It's usually a protective oil-like coating on the heater to prevent corrosion before the first use.

author: pickle9000
author_rank: Super Contributor
timestamp: August 07, 2014, 03:02:28 am
content: It's pretty common, run it outside for a while (as suggested).

author: Psi
author_rank: Super Contributor
timestamp: August 07, 2014, 10:00:37 am
content: yep, quite normal.It just needs to burn off the protective coating/oil.
Really good videos on Spectrum Analyzer  - Page 1
Forum section: electronics / beginners

author: GameProgrammer79
author_rank: Contributor
timestamp: March 15, 2016, 06:33:08 pm
content: Hi All,I just wanted to share some really good videos on Spectrum Analyzers I recently found on Youtube. Hope these are useful.Spectrum Analyzer - Part 1https://youtu.be/9PumAvTzTUsSpectrum Analyzer - Part 2https://youtu.be/UYQ3EL_mpkUSpectrum Analyzer - Part 3https://youtu.be/bkFdQgmDbos

author: Audioguru
author_rank: Super Contributor
timestamp: March 16, 2016, 12:16:27 am
content: Shucks.When I saw the title of your thread I wanted to hear you tell how you connected your Spectrum Analyzer to show dirty movies on its screen.https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif

author: Alex Trofimov
author_rank: Contributor
timestamp: March 16, 2016, 09:43:49 am
content: Thanks!A would like to actually add an Agilent paper on Network Analyzers. It has great, neat and explicit epxplanations.It actually explains a huge part of basic RF Voodoo. For example it has full basic explanation of Smith's chart on one page.Agilent Network Analyzer Basics:http://cp.literature.agilent.com/litweb/pdf/5965-7917E.pdf
Really stupid question about led wiring - Page 1
Forum section: electronics / beginners

author: LinkZ
author_rank: Contributor
timestamp: April 24, 2015, 09:41:32 am
content: Hi guys, sorry for the stupid question, but I want to wire a couple of leds in the following mixed series-parallel scheme:Assuming each led is 3V 5mA, i will have 6V 15mA current in total, right? The "advantage" of this scheme SHOULD be that i need only a single resistor. However I don't know if there are disadvantages about this wiring scheme. Let me know and sorry for the ridiculous question.

author: jeroen79
author_rank: Frequent Contributor
timestamp: April 24, 2015, 09:52:50 am
content: There is no guarantee that the current will divide evenly over the parallel LEDs.With three series of LED-LED-resistor it will.

author: DmitryL
author_rank: Regular Contributor
timestamp: April 24, 2015, 10:42:12 am
content: Quote from: LinkZ on April 24, 2015, 09:41:32 amIf LEDs that you connect in parallel come from the same wafer, then you can assume that they have identical parameters and can be paralleled without much harm. You can see this approach in "LED clusters" that are usually sold as "20 Wt LED" etc.If you pick several LEDs from a box, you can't guarantee that their parameters (like voltage drop vs current and voltage drop vs temperature) are identical and current won't be distributed equially between them. In your case (currents are very small) this would just menan that you may have different brightness for LEDs in parallel.

author: TimFox
author_rank: Super Contributor
timestamp: April 24, 2015, 12:36:20 pm
content: In general, for all types of diodes, "equalizing" resistors in series with each diode in a parallel connection are required to ensure at least rough equality of current between the individual diodes.

author: SL4P
author_rank: Super Contributor
timestamp: April 24, 2015, 10:14:28 pm
content: I understand what the other replies are saying, but I don't get the circuit...Is the 7V supply AC - using the half wave characteristic of the diodes?Perhaps you could redraw the diagram to 'self explain' the intended operation...?

author: bills
author_rank: Frequent Contributor
timestamp: April 25, 2015, 07:28:36 pm
content: check here, will help with LED circuits.http://led.linear1.org/led.wiz

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 25, 2015, 07:58:28 pm
content: Repeating, hard-wiring LEDs in parallel is NOT RECOMMENDED.Use one of the online LED calculators like the one @bills suggested.
Reasonable price for 10-year-old ERSA i-Con 1? - Page 1
Forum section: electronics / beginners

author: CryptoPhoenix
author_rank: Newbie
timestamp: April 30, 2020, 10:33:29 pm
content: Hi everyone!I'm quite new to "proper" soldering and now I decided that I want to get a proper soldering iron, like Weller or similar as I see it as a long-time investment.So, I found out that someone is selling their 10-year-old ERSA i-Con 1 soldering iron for 92€ with a new tip. Seller said that he hasn't used the soldering iron daily or not necessarily even every week. So quite a bit but not daily. I just wanted to ask you if you would know what is a reasonable price for this old soldering iron? It is in quite good condition and reputable brand and has gone for 400€ in the past. Of course it has way too many fancy features that I don't need but still.. What do you think? At what price would you buy it?

author: thm_w
author_rank: Super Contributor
timestamp: May 01, 2020, 12:09:35 am
content: If you can still buy tips for it (appears you can ~$12?), seems like quite a reasonable price.

author: CryptoPhoenix
author_rank: Newbie
timestamp: May 01, 2020, 12:59:41 am
content: The seller was selling also replacement tips (1.2mm conical and chisel) for only 5€ a piece. But yeah, it is an auction so I follow if no one buys it the price might drop by 10€ as it already once dropped of course have to be careful to not lose the good purchase.

author: tooki
author_rank: Super Contributor
timestamp: May 01, 2020, 07:49:38 am
content: Quote from: CryptoPhoenix on April 30, 2020, 10:33:29 pmThat seems like an excellent price to me. They still sell that model today, after all. The only thing that ever seems to go wrong with them is the triac failing, which is easily fixed.Quote from: thm_w on May 01, 2020, 12:09:35 amIt’s still a current model. There is no newer line of Ersa tips.(A 10 year old one would just be from fairly shortly after the I-con series was introduced.)

author: CryptoPhoenix
author_rank: Newbie
timestamp: May 04, 2020, 07:18:25 pm
content: Thanks for your comments! I got the ERSA with a new tip + 5 new tips for 120€ I think I made quite a great purchase

author: Theboel
author_rank: Frequent Contributor
timestamp: May 04, 2020, 07:38:42 pm
content: I have 2 i-con 1 doing nothing because I lost the I-tools and the cost for new I tools include shipment to Indonesia is not interesting at all (expensive) but maybe in EU its a good choice.
Reasonable ripple in a PSU - Page 1
Forum section: electronics / beginners

author: StarFishPrime
author_rank: Contributor
timestamp: March 07, 2014, 05:35:20 pm
content: HiI've recent purchased an old Coutant LQT100 dual 0-30V psu and have been testing it under different loads. The output PD seems stable when changing load and over time. At 5V & 10V I am seeing approx 120mV peak-peak ripple regardless of load. Does this seem reasonable to you for a psu for home use?CheersIan

author: Andy Watson
author_rank: Super Contributor
timestamp: March 07, 2014, 05:43:17 pm
content: Manual says ripple should be 0.5mV or less. Probably wants its caps replacing.

author: valentinc
author_rank: Regular Contributor
timestamp: March 07, 2014, 07:18:15 pm
content: Giving the fact that it's a linear power supply, it's ripple must be in the order of a few milivolts... 100 mVpp is a ripple for a crappy switchmode power supply...

author: StarFishPrime
author_rank: Contributor
timestamp: March 07, 2014, 07:21:10 pm
content: Thanks for the advice. The larger caps are large cans some 5cm x 2cm which I presume are film?.. Apart from the specs is there a particular type that people would recommend?Cheersian

author: Andy Watson
author_rank: Super Contributor
timestamp: March 07, 2014, 07:30:04 pm
content: It will be the larger, electrolytic caps that need replacing. I assume you've found this:http://elektrotanya.com/coutant_lqt100_lqt200.zip/download.html
Recapping old electronics - Page 1
Forum section: electronics / beginners

author: joelgraff
author_rank: Contributor
timestamp: February 08, 2019, 02:04:52 am
content: So I have an old Sega Genesis 2 with audio but no video. It could be the video chip, but I've no way to really test it, so I thought I'd give recapping it a try - makes for good practice, anyway.In any case, I was wondering if there's any good guidance on what to replace electrolytics with... I know electrical performance varies with various types, so replacing an electrolytic with another type of cap may not yield the best results. Still, it would be nice to replace them with something that isn't electrolytic. I've not really seen much guidance on this - what little I've found isn't particularly clear. Are there alternatives?

author: viperidae
author_rank: Frequent Contributor
timestamp: February 08, 2019, 02:07:30 am
content: Are you planning on not having to service it in the next 20 years?I suppose you could replace most electrolytics with polymer caps?If you buy reputable brand caps, I don't see why regular electros won't last.

author: james_s
author_rank: Super Contributor
timestamp: February 08, 2019, 04:37:15 am
content: If you're referring to surface mount electrolytics, I typically replace them with MMLC or tantalum depending on the application. MMLC loses significant capacitance when there is a DC bias across it so you have to be careful where you use those. For through hole stuff I replace them with modern electrolytics, good quality through hole caps seem to last much better than SMT electrolytic.

author: joelgraff
author_rank: Contributor
timestamp: February 08, 2019, 06:54:23 am
content: I suppose I'll just replace them in-kind, then. Thanks!
Receiving garbage over telnet connected to keenetic 1 - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: September 17, 2023, 03:06:11 pm
content: SOLVEDNever mind, it was boud rate and parity.So on router I have header, GROUND, TX, RX, 3.3V. Connected just ground, tx to rx on the dongle, and rx to tx on the dongle. Not sure if that's how it suppose to be done. But here it is, and I'm receiving gibberish. Was hopping for a boot sequence or some log messages, because this router is stuck in some sort of loop and is not booting.Dongle I have is this oneI mean, it could be anything. Could be wrong PyTTY settings, or I'm doing it wrong, or it should be like this. I'm not sure. I'm doing it for the first time ever.
Recent Research In Nanometric Interfaces Center - Page 1
Forum section: electronics / beginners

author: paulevans
author_rank: Newbie
timestamp: January 06, 2018, 05:10:07 pm
content: (NC & T) The recent investment made by the University of Leicester in the Center for Virtual Microscopy and the Nanometric Interfaces Center, has placed the university in a key position to take the lead in the measurement of Casimir force in novel geometries.The strength of Casimir is a mysterious interaction between the objects that comes directly from the quantum properties of the so-called "vacuum". Within classical physics, emptiness is the simple absence of all matter and energy, whereas quantum theory tells us that it is in fact a boiling mass of quantum particles that constantly appear and disappear from our observable universe. This gives the vacuum an unimaginably large energy density.The research will help to overcome a fundamental problem of all nanomachines (that is, machines whose individual components are the size of molecules), because in these tiny dimensions everything is "sticky", and when one component comes in contact with another, Adhere to each other. If a method can be found to transmit forces through small spaces, without the problems described, then it may be possible to build nanomachines that work freely, without sticking together.According to the theory of the quantum field, each particle is a wave of an underlying field in the vacuum, and it is only the energy of the wave itself that we can detect.A useful analogy is to consider our observable universe as a mass of waves on an ocean whose depth is immaterial. From that sea, our senses and all our instruments can only detect waves directly, so it seems that trying to detect anything below them, the "vacuum" in itself, is impossible to achieve. But it is not exactly like that. There are subtle effects of zero-point energy that lead to perceptible phenomena in the "normal" universe, which we can observe.An example is a force, predicted in 1948 by the Dutch physicist Hendrik Casimir, who comes from theenergy from the zero point. If two opposing mirrors are placed in the empty space, they produce a disturbance in the quantum fluctuations, with the result that a pressure is exerted that tends to join the mirrors.However, detecting Casimir's strength is not easy, since it only becomes significant if the mirrors approach less than one micrometer. Producing sufficiently parallel surfaces, with the required precision, has had to wait until the appearance of the tools of nanotechnology, with which it is feasible to make the exact measurements of that force.The new instrumentation from the University of Leicester will allow researchers to extend their measurements to even more complex forms, and, for the first time, to look for a way to reverse Casimir's strength.This would be a discovery that would open a new field of research, since the Casimir force is a fundamental property of the void, and inverting it is similar to reversing gravity. Technologically, this would only have relevance at very small distances, but it would revolutionize the design of micro and nanomachines.