hybridfree/eevblog-posts huggingface dataset:
3 push on/off circuit - Page 1
Forum section: electronics / beginners

author: Jasen
author_rank: Newbie
timestamp: March 09, 2014, 10:46:44 pm
content: Introduction:Howdy all, I'm a novice but can build most anything with some guidance. I'm a residential carpenter by trade for 25 years , woodworker, shade tree mechanic for 35 years and have dabbled in electronics from a few simple circuits, playing with LEDs and repairing burnt component's and broken solder connections.To the point:I recent quite smoking after 35 years and I'm using an e cigarette and it's working. I've decided to build my own box mod using some schematics I got from a e cig forum. This is variable Volt 2.4-4.2v running off two 18650 3.7V 2600mah li-ion or li-ma batteries.Some of the manufactured e cigs have a safety feature where you have to push the power button 3 times quickly to turn it on/off so as to not accidentally activate the unit in ones pocket, once said button energizes the button is then used to heat the coil to produce the vapor.I've googled to no end and have found nothing. I can just use an on/off push button but that's to easy, I'd like to build a circuit like this, any guidance would be greatly appreciated.Jasen

author: Rerouter
author_rank: Super Contributor
timestamp: March 10, 2014, 06:17:20 am
content: short of using a 6/8 pin micro i am failing to see any non cumbersomely sized circuit options, (possibly a charge pump, you have to press it a few times quickly to turn it on and then every few seconds to keep it on)edit: you could use the charge pump idea with 2 op amps acting as a window comparitor, press it 3 times to pass the lower threshold and latch the device awake, and enable power to a second pole on the switch, which you then use to turn on or off, and if you press it a few more times in quick succession it passes the upper threshold and turns itself off

author: Jasen
author_rank: Newbie
timestamp: March 11, 2014, 02:32:43 am
content: Rerouter,Thanx for the input.
3 state mechanical switch? - Page 1
Forum section: electronics / beginners

author: wtoddp
author_rank: Newbie
timestamp: March 20, 2024, 07:24:04 pm
content: I'm hoping to find a very specific type of switch, and don't know if they exist or what they would be called, so my Googling is not producing the results I'm seeking.The switch I'm hoping to find would be:Small, like ~1/4" or ~6mm push buttonWould work with 2 very simple circuits running on a 3volt battery with 2 LED lights in separate circuitsWould be like a momentary switch, but have/allow for three "States"State 1 - Everything is OFFPush once to enter State 2 and a Red LED lights upPush again to enter State 3 and the Red LED goes out and a Blue LED lights upPush a third time and both lights go out (back to State 1)RepeatI can visualize how a mechanical switch like that could work, as each press would cause an interior part to rotate and create a different circuit with each press. I can also imagine a number of reasons why those may not be manufactured now, if they ever were.Any advice would be appreciated!

author: langwadt
author_rank: Super Contributor
timestamp: March 20, 2024, 07:43:11 pm
content: close enough?https://www.adafruit.com/product/1684

author: wtoddp
author_rank: Newbie
timestamp: March 20, 2024, 08:05:05 pm
content: Aw, man! Perfect! THANK YOU!!!
3 terminal SMD part labeled 6kaTJ - Page 1
Forum section: electronics / beginners

author: georgedone
author_rank: Contributor
timestamp: July 02, 2017, 02:46:03 pm
content: Hi !I just received for free an old Packard Bell EasyNote TK laptop (i3 380M) which seems dead. I'm trying to repair and use it. It seems to have a fault close to the power input as there is absolutelly no sign of life when I connect a working power adapter. When I check the motherboard, close to the power connector there are 2 small smd components labeled 6kaTJ(TJ is engraved in larger characters than 6ka), 6kaTJ, one of which is obviously burned (there is a hole in the casing just above the junction). I assume they are some Mosfet transystors but I'm unable to find a datasheet or a replacement part. Anyone knows what could be ?

author: bingo600
author_rank: Super Contributor
timestamp: July 02, 2017, 07:36:27 pm
content: The only 6ka i can find in the Turuta 2011 book are attached , but none of those are 3-pin (housing is in yellow/greenish)

author: floobydust
author_rank: Super Contributor
timestamp: July 03, 2017, 04:59:19 am
content: This website is good for SMT marking codes, but it's slow sometimes and Russian language:http://chip.tomsk.ru/chip/chipdoc.nsf/vc1!readform&view=smd&cat=6&start=4001&count=500If you knew the package, you can look for the root marking code. The TJ maybe the date code/plant ID.
3 terminals on Li Ion Battery - Page 1
Forum section: electronics / beginners

author: Greorge
author_rank: Regular Contributor
timestamp: December 06, 2014, 06:24:55 am
content: What is significance of 3 terminals on Li-Ion battery?It is Nokia BL-4 3.7V batteryIt doesn't last long enough in phone, so I repaced it, but I want to use it for LED or something.Is it OK just to find + and - and chage and not worry about the third one?

author: Psi
author_rank: Super Contributor
timestamp: December 06, 2014, 06:48:00 am
content: The 3 connections are +, - and BSI (Battery Size Indicator, or sometimes Battery Sensor Indicator)It's a resistor which the phone can use to detect the battery size.eg, 5k might indicate 1Ah and 10k might indicate 1.5Ah for example.So yes, you can just ignore the BSI pin.

author: Greorge
author_rank: Regular Contributor
timestamp: December 06, 2014, 07:21:31 am
content: Thank you very much for help.
3 wire USB adapter for connecting RC charger to PC for logging - Page 1
Forum section: electronics / beginners

author: vjekobalas
author_rank: Regular Contributor
timestamp: September 16, 2021, 05:12:56 pm
content: I wanted to make sure I'm about to do the right thing and not destroythe RC charger UART. I would like to connect a "3 wire" UART signal from a RC charger to USB/PC (further details below).Would it work to connect this RS232/USB cable (which I already own):https://ftdichip.com/products/us232r-100-bulk/with handshake looping as per this example:https://www.airborn.com.au/serial/rs232.htmlOR do I need another type of RS232/USB adapter eg. the Hitec HRC44168 mentioned belowor something cheaper like this which I presume is the same thing: ?https://www.ebay.de/itm/202055184678?hash=item2f0b6d7126:g:55cAAOSwoRBZr25SHere are all the details I have collected:RC charger is Ev-peak CQ3. According to advert on Ev-peak website(which seller is denyingand Ev-peak are not answering) for several chargers including CQ3, communication with pcis supposed to be possible and the pc monitor software + firmware update softwareis on their web page.According to the schematic I found on the web (attached), two pins from the temperaturesensor connector are supposed to be the TX/RX pins.This is the RC charger processor showing onboard UART:https://www.nuvoton.com/products/microcontrollers/arm-cortex-m0-mcus/m051-base-series/m0516ldn/?__locale=enIn the following thread post #46:https://www.rcgroups.com/forums/showthread.php?2589760-Does-anyone-have-experience-with-Ev-Peak-CQ3-charger/page4it is indicated that the USB adapter that could work would be the Hitec HRC44168 - here's a photo showing 3 wires:https://www.rcmodelscout.com/Batteries-and-Chargers/Hitec-USB-Adapter-Cable-X4-X4-X1-HRC44168/329765According to post #1 :https://www.rcgroups.com/forums/showthread.php?1616244-X4-charger-USB-adapter-install-troublethe hitec HRC44168 uses the "cp2102 usb to uart bridge controller"
30 Amp Automated Variable On Off Pulse - Page 1
Forum section: electronics / beginners

author: itsme1414
author_rank: Newbie
timestamp: May 19, 2019, 10:21:32 pm
content: I was able to determine the 30 amp DC power amp I would need to use for my solenoid project.Now I need to find out if there is anything made you can purchase that has adjustable on off timesExample would be a high power adjustable strobe controller.Need to come out of the amp into something that can be an infinite loop timer that could have variable on and off times for each pulse but could handle 30 amps.Does anyone make this or can anyone make this?Thank you

author: pwlps
author_rank: Frequent Contributor
timestamp: May 21, 2019, 03:53:36 pm
content: A LED lighting strobe controller ? Not sure they can handle such currents, but could be used to drive a 30 amp SSR.
3003XIII power supply question - Page 1
Forum section: electronics / beginners

author: robotic
author_rank: Contributor
timestamp: July 10, 2017, 01:04:38 am
content: Hi I am interested in buying the CSI 3003XIII power supply.I'm wondering if I am able to connect 2 of the outputs to combine their current. For example, if I happen to have to use 5A for an LED project.Or should I not buy the 3003XIII and go for a 10A one from ebay. I'm seeing a used for about ~$60. The ebay ones are around the same price but only 1 output, but are at around 5A or $80 for 10A.Thanks.

author: alm
author_rank: Super Contributor
timestamp: July 10, 2017, 01:17:34 am
content: Based on the picturehere: yes, you should be able to parallel the two channels for 30 V / 6A. There is even a convenient 'parallel' button on the front panel, so you can do it without any extra wiring.There has been some discussion on this forum about the cheap eBay bench power supplies (search this forum). Do not expect them to deliver their full rated power continuously.

author: robotic
author_rank: Contributor
timestamp: July 10, 2017, 01:42:35 am
content: haha thanks. Didn't even notice it. =)That's perfect.

author: robotic
author_rank: Contributor
timestamp: July 10, 2017, 02:45:27 pm
content: Just got it and don't have anything to with a high current to test it with currently. Hopefully it works like that.Since it was used. It didn't come with any cables.Hope it doesn't need thistype of cableon the left. Or i'll have to make one to get the 6A.

author: alm
author_rank: Super Contributor
timestamp: July 10, 2017, 03:55:29 pm
content: I doubt that you would need to make any special cables. Even if the power supply does not connect the terminals together when you enable parallel mode, then you could just use banana leads to wire the two black and red jacks together. Just make sure to use decent leads at 6 A, for example not those cheap crimped alligator clip leads.
300V AC source needed for multimeter calibration - Page 1
Forum section: electronics / beginners

author: DrJoe
author_rank: Contributor
timestamp: August 09, 2014, 02:36:13 am
content: I'm in the process of restoring an ancient Triplet Multimeter (model 60). I need a 300V AC source for calibration (60 Hz).Any ideas for the most economical way to get there?I was thinking about the voltage multiplier that Dave explained in the Uni-T UT513 Insulation tester teardown (episode #468) but I have no idea what diodes and capacitors to use in the circuit or if special precautions are needed as far as voltage isolation cut-outs on the circuit board.A 120:300V transformer is about $50 and I was hoping to do it cheaper.The only ac source I have besides direct mains is a signal generator that only does 10V peak to peak.Thanks,DrJoe

author: BillWojo
author_rank: Regular Contributor
timestamp: August 09, 2014, 03:37:53 am
content: Does it really have to be 300VAC? Small 240 to 120VAC control transformers are cheap, look on ebay. Run it backwards with 120VAC in and you should get 240 out the other side.BillWojo

author: mij59
author_rank: Frequent Contributor
timestamp: August 09, 2014, 04:31:10 am
content: Quote from: DrJoe on August 09, 2014, 02:36:13 amAn isolation tester uses a dc voltage, so you'll have to convert it to a ac signal.
30v MOSFET fails at 24 volts - Page 1
Forum section: electronics / beginners

author: scott216
author_rank: Regular Contributor
timestamp: June 21, 2015, 11:45:20 pm
content: Edit: Fixed MOSFET P/N and link.I've got a n-ch MOSFET P/N IRLML6344TRPBFCT-ND (Digikey link) hooked up for reverse voltage protection (see attached).I partially populated my PCB and applied power to the board. I started low at 7 volts and worked my way up to 24 volts. 24 volts is the nominal operating voltage. At 20 volts things were fine and the circuit was drawing less then 20mA. But then I bumped the voltage to 24 volts and my MOSFET shorted out. I had my power supply limit the current to 200 mA, so there was no magic smoke. I want back to thedata sheetand saw the the VDSis 30 volts, but the VGS+/- 12 volts. So I guess it's the VGSthat got me. Lesson learned.

author: codeboy2k
author_rank: Super Contributor
timestamp: June 22, 2015, 12:00:45 am
content: Yep. Vgs did it.Quote from: scott216 on June 21, 2015, 11:45:20 pmI think you got confused. MC7812 is a 12V regulator. But later you linked to a IRML6344PBF mosfet, so I think you just got confused here.When the mosfet is fully turned on, as in your case, then the Drain and Source are almost at the same potential. So Vgs is equal to your power supply voltage, minus the voltage drop Vds, which is Vds = ( Rds(on) * Iload ). This will be small since Rds(on) is small. So Vgs is always running really close to your supply voltage here.The solution is to put a 10k resistor in the gate, then put a 12V zener diode across the Gate and Source pins. Vgs(max) is 12V on that device.

author: scott216
author_rank: Regular Contributor
timestamp: June 22, 2015, 12:33:49 am
content: Quote from: codeboy2k on June 22, 2015, 12:00:45 amI fixed the P/N and link in the original post. That voltage regulator is also in my project and I wasn't paying close enough attention to what I was cutting and pasting.Thanks for the resistor + zener diode solution.

author: rx8pilot
author_rank: Super Contributor
timestamp: June 22, 2015, 01:02:29 am
content: I would only add that going with a 10v zener would give you some safety margin. The gate should be fully saturated at 10v and you are a little bit further from blowing it up.

author: Simon
author_rank: Unknown
timestamp: June 22, 2015, 06:47:51 am
content: Very few mosfets go over 20V for the gate and that is an absolute maximum 12-15V is more than enough and the datasheet specs generally quote against 10V on the gate. Don't worry easy mistake to make, I saw a post grad engineer do this on a peice of kit that was meant to keep people alive, needless to say we changed subcontractor.

author: scott216
author_rank: Regular Contributor
timestamp: June 22, 2015, 12:43:35 pm
content: I like my method of limiting the current on my power supply for new circuits I just built. It keeps things from blowing too quickly.
32.768KHz Crystal Not working - Page 1
Forum section: electronics / beginners

author: vishal
author_rank: Regular Contributor
timestamp: January 20, 2018, 04:56:52 am
content: HiI am trying to enable crystal (32.768KHz) connected in TOC1 and TOC2 pins of avr-atmega256rfr2 MCU. The Code that I used to initiate the timer2 in asynchronous mode is as followsCode:#include <avr/io.h>#include <avr/interrupt.h>#include <util/delay.h>//Prepare LED pinvoid PortInit(void){//Initlally LED OFFPIND=(1<<PD6);//PD0 as outputDDRD|=(1<<PD6);}//Timer2 init acording datasheetvoid RTCInit(void){TIMSK2=0;ASSR=(1<<AS2);TCNT2=0;TCCR2B|=(1<<CS22)|(1<<CS00);while(ASSR&((1<<TCN2UB)|(1<<TCR2BUB)));TIFR2=(1<<TOV2);TIMSK2=(1<<TOIE2);}//Overflow ISRISR(TIMER2_OVF_vect){//Toggle pin PD0 every secondPORTD&=~(1<<PD6);//asm volatile("nop"::);_delay_ms(100);}int main (void){SMCR|=(1<<SM1)|(1<<SM0);//Initialize portPortInit();//Initialise the timer2RTCInit();//Enable global interruptssei();while(1){SMCR|=(1<<SE);//asm volatile("sleep"::);SMCR&=~(1<<SE);//Do nothing}}But the crystal is not working .Controller is working with internal RC oscillator (8Mhz).what are the reasons for it ?

author: phil from seattle
author_rank: Super Contributor
timestamp: January 20, 2018, 06:45:37 am
content: Haven't looked at the data sheet but the first thing that springs to mind is have you set the fuses correctly?
330ohm resistors on headphone jack? - Page 1
Forum section: electronics / beginners

author: dentaku
author_rank: Frequent Contributor
timestamp: May 04, 2016, 01:32:00 am
content: I salvaged some parts from an old Akai audio/video receiver and the headphone jack has 330 ohm resistors on the left and right channel pins.I don't think I've seen this before. What purpose do they serve?

author: Audioguru
author_rank: Super Contributor
timestamp: May 04, 2016, 01:36:20 am
content: They reduce the levels so the headphones are not so loud that your ears and head blow off!

author: dentaku
author_rank: Frequent Contributor
timestamp: May 04, 2016, 01:40:15 am
content: Quote from: Audioguru on May 04, 2016, 01:36:20 amWell yes, but I usually haven't seen resistors attached directly like this to the headphone output.The device has a volume control so adding a fixed 330 that way looked weird.

author: basinstreetdesign
author_rank: Frequent Contributor
timestamp: May 04, 2016, 02:05:02 am
content: They reduce the power delivered to the headphones so they sound just as loud as the speakers at the same volume control setting. Most people like a certain volume control setting and want the same volume either way.

author: Zero999
author_rank: Super Contributor
timestamp: May 04, 2016, 08:02:49 am
content: The disadvantage with adding a resistor in series with the headphones is it results in a poor damping factor.Another option is to use a potential divider with a lower output impedance than the headphones.

author: wraper
author_rank: Unknown
timestamp: May 04, 2016, 08:14:59 am
content: That receiver does not have dedicated headphone amp, therefore they use resistors to reduce the power from the main amp. If connected directly, even if volume could be decently controlled (it cannot, it will be like minimum level and a bit higher headphones already get overloaded and damaged), in the absence of sound at zero volume background noise would be just huge.

author: Gyro
author_rank: Super Contributor
timestamp: May 04, 2016, 08:51:35 am
content: Regarding the positioning of the resistors right on the Headphone jack PCB, I would think that they might have done it to minimise the possibility of high level signals accidentally being applied to the headphone outputs, particularly if there's a lot of hard-wiring in the receiver. I had a JVC receiver that had them in the same place.

author: mzacharias
author_rank: Frequent Contributor
timestamp: May 04, 2016, 01:38:44 pm
content: Virtually every home stereo amp or receiver has these. Prevents damage to the amplifier channel with a mis-wired or damaged headphone plug or wire as well as level matching. I still see these resistors burned from time to time.
34063 switching regulator 9-14VDC in, 12VDC out - Page 1
Forum section: electronics / beginners

author: chrisnisbet
author_rank: Newbie
timestamp: February 27, 2014, 04:14:14 am
content: HiI was thinking of using a 34063 switching regulator to provide regulated 12VDC to a circuit. However, the input voltage is in the range 9-14VDC. Do I connect the chip in the boost or buck configuration? Will either configuration work? I'm just wondering what needs doing when the input voltage may be lower or higher than the output voltage. Do I need to do something else altogether?Thanks.

author: mariush
author_rank: Super Contributor
timestamp: February 27, 2014, 04:30:44 am
content: You need a chip that can run in SEPIC mode (both boost and buck) , 34063 will work in either boost or buck, not both (*).See ICs likeLM2621http://www.digikey.com/product-detail/en/LM2621MM%2FNOPB/LM2621MM%2FNOPBCT-ND/363740CS5171http://www.digikey.com/product-detail/en/CS5171GDR8G/CS5171GDR8GOSDKR-ND/1831789MIC2145http://www.digikey.com/product-detail/en/MIC2145YMM%20TR/576-1540-1-ND/1121876Alternatively, if you don't care about efficiency, boost everything to 16v with one 34063, then take it down to 12v with a second 34063.(*) later edit, ok, technically you could make a 34063 work in sepic mode (see here for an example:http://radiohlam.ru/pitanie/preobr_sepic_34063.htm) but you need an extra mosfet, more parts so it all adds up. you might as well pay 50 cents to a dollar more for a proper IC like lm2621 or cs5171.

author: chrisnisbet
author_rank: Newbie
timestamp: February 27, 2014, 04:40:23 am
content: That's great thanks.Yes, I figured it would be possible to step up and step back down, but that seemed a bit bodgy.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 27, 2014, 07:09:55 am
content: Besides it not really being a very suitable chip for the purpose, I would dismiss it out of hand because it's such an awful controller!Something like a UC3843 with external switch would do a fine job, or take your pick among newer integrated-switch types.Tim
34401a - Remove front panel. - Page 1
Forum section: electronics / beginners

author: Rafael
author_rank: Regular Contributor
timestamp: June 09, 2021, 12:13:37 am
content: Hi there,Please, is there a video or a top to remove the front panel os 34401a?Is there only one screw and move the metal locking mechanisms to release the front panel.I don’t have space to move the metal locking, the power switch extension don’t allow to move the metal and in another side is hard to move the metal frame. I am worried by damage the front panel.Thanks.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 09, 2021, 11:30:04 am
content: I have done this many times and it is easy, if you know how to do it.Here are my steps (from memory)1. Take the one screw out of the side of the front panel2. Remove the ON/OFF switch plastic extension bar3. Remove the PCB holding screw at the front at the front of the PCB, so the metal frame can move freely4. Press the metal frame on the side of the main switch slightly inwards and remove the panel on this side only5. Now remove the panel from the other side of the metal frame.

author: Rafael
author_rank: Regular Contributor
timestamp: June 09, 2021, 03:22:14 pm
content: Quote from: HighVoltage on June 09, 2021, 11:30:04 amThank you!I am stuck on step 2.I can easily disconnect the switch plastic extension bar from the switch, on rear, but I cannot remove this bar from the front panel as it appears to have a lock on the front panel fitting into the rail of this bar. I will try again later.Thanks.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 10, 2021, 05:15:37 pm
content: you forgot to tell : 1A remove the special clips on the input output connectors, theses have a special way to clip4: but should be 2:You have one side who will be easier to push in the enclosure, just to sligthly pry the front panel over the metal nut inserts it should open / unclip at an angle, and after you can dismatle the switch levers, do the oposite to put them back and close the front panel over the casing ...

author: HighVoltage
author_rank: Super Contributor
timestamp: June 11, 2021, 09:51:13 am
content: Quote from: coromonadalix on June 10, 2021, 05:15:37 pmOOPS, of course, that is a very important step I forgot.
3478a,  NI pci gpib,  LabVIEW home?  - Page 1
Forum section: electronics / beginners

author: Kennylxix
author_rank: Regular Contributor
timestamp: February 13, 2017, 09:24:55 am
content: Ok so I want to play with gpib starting with my 3478a. LabVIEW home seems to be the easy choice software wise. I'm looking at the NI pci gpib interface card or possibly an Mccdaq one. I know already that setup can be a chore but am I missing anything obvious? Is the Mccdaq solution OK or do I need to stick to ni? I'm going to try this on Windows 10 but can use a different version if necessary. Any noob advice is greatly appreciated!

author: Kennylxix
author_rank: Regular Contributor
timestamp: February 15, 2017, 07:09:29 pm
content: Did I maybe post this in the wrong section?
36V Golf Cart Charger to Ruideng Supply - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: November 03, 2022, 08:02:11 pm
content: How would you approach this?The charger is exactly like this:https://www.petesgolfcarts.com/chargers-batteries/chargers/36-volt/dpi-36-volt-golf-cart-battery-charger-crowsfoot-connectorIt has a battery sensing circuit that switches a relay on the AC mains side, so it does not energize the huge transformer until the voltage is right. I thought about bypassing that relay but it is nice to be able to shut it off when not in use. I guess I could wire a mechanical switch.Then I suspect it will not output the full beans because it's a smart charger, so I could tap the wires coming off the rectifiers, but I suspect there is some regulation that would be advantageous to use. Maybe not as the main circuit looks pretty basic. I think it should put out at least 42V.A drawback is that the main circuit sits next to the analog current meter. It would be nice to use the analog meter and have the Ruideng display next to it, but that circuit and sheet metal would need to be moved.________

author: SmallCog
author_rank: Frequent Contributor
timestamp: November 04, 2022, 12:26:27 am
content: I'd put 3x lead acid batteries across it, use it as intended, then power the Ruideng from the battery bankI'd likely use SLA/VRLA/Gel Cell batteries rather than car style batteriesBut I'm both lazy and dodgy
3842 problem - Page 1
Forum section: electronics / beginners

author: 5282
author_rank: Regular Contributor
timestamp: February 22, 2016, 06:46:05 pm
content: i have problem with 3842 ici use 150k resistor for r1 the voltage on c3 is only=2.8vi don't connect the mosfet to 3842

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 22, 2016, 07:15:04 pm
content: ...Yes?Do you understand the datasheet? Have you read the datasheet?This circuit has problems. I have never seen R3 used before. There is usually a capacitor from pin 3 to ground, pin 8 to ground, and an R+C across the '431. As shown, it will oscillate horribly (once the MOSFET is connected and all, that is).Tim

author: Andy Watson
author_rank: Super Contributor
timestamp: February 22, 2016, 07:18:09 pm
content: What have you done with pin 5 on the 3842 ?

author: prawncrackers
author_rank: Contributor
timestamp: February 23, 2016, 08:39:37 am
content: i burn 3842 ICs when i dont connect them to the mosfet AND the current sense resistor(R6 in your schematic) so definitely check that out.you can try a series incandescent bulb(around 100w mains voltage) to limit the current to your circuit if youre afraid something might pop.you also forgot your pin 5 in the schematic; this goes to ground right?also you might want to try and omit R3. experiment only when your very basic circuit functions then work your way up for the modifications.

author: 5282
author_rank: Regular Contributor
timestamp: February 23, 2016, 02:24:41 pm
content: thank alli not use R3 in my boardyes i already connect pin 5 to GNDthere is low votlage in 3842 vcc=2.8v with 150kohmnow the mosfet is useless because 3842 not work with 2.8v

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 23, 2016, 08:12:51 pm
content: ...I guess that's a no, then...The startup circuitry will keep turning itself on and off, holding VCC at a low average voltage. It's still peaking high enough to turn on the MOSFET. If you do not have an oscilloscope, you will not be able to see this.Without a MOSFET connected, there is no power from the AUX winding, and the controller will never remain on.I don't recommend building SMPS without an oscilloscope, anyway, because you will never have a way to tell whether it's working well or not.Tim

author: Seekonk
author_rank: Super Contributor
timestamp: February 23, 2016, 10:54:07 pm
content: Two things to try: Greatly increase the value of C3. Reverse terminals 3&4.

author: prawncrackers
author_rank: Contributor
timestamp: February 24, 2016, 12:57:53 am
content: also did you check the orientation of transformer windings? im thinking this is a flyback converter.in any case you might want to try using an auxiliary power supply to power the 3842. i sometimes use one when making converters, just a 12-15v wallwart/charger to pin7.

author: Seekonk
author_rank: Super Contributor
timestamp: February 24, 2016, 02:35:44 pm
content: A LED indicator on the output may give an indication if the oscillator ever starts working when you don't have a scope. As said before, powering the chip independently is the best step
3D Printed storage for resistors, caps, diodes, small parts, etc. - Page 1
Forum section: electronics / beginners

author: Urshurak776
author_rank: Contributor
timestamp: April 13, 2020, 06:52:55 pm
content: Came across these today. If you have a 3D printer, worth checking out:https://cults3d.com/en/3d-model/tool/stackable-resistor-storage-box-customizable

author: Urshurak776
author_rank: Contributor
timestamp: April 13, 2020, 09:07:57 pm
content: Here it is on thingiverse with lots of mods and user additions. Really amazing.https://www.thingiverse.com/thing:3125601

author: HobGoblyn
author_rank: Unknown
timestamp: April 13, 2020, 09:34:59 pm
content: I know nothing about 3D printers. Might treat myself one day.I wonder how much this stackable storage box would cost in materials to print?

author: aeberbach
author_rank: Regular Contributor
timestamp: April 13, 2020, 10:46:22 pm
content: Looks like about $3 worth (if you're using premium PETG). Very economical but it would take a couple of days!

author: thm_w
author_rank: Super Contributor
timestamp: April 13, 2020, 11:53:08 pm
content: As aeberbach says, material cost is not too high, about 30c per drawer, $1.20 per box, so close to $3 for each "set". You can download Cura and it will calculate for you.The bigger issue is having a machine with enough build area and speed. These are not too big, so most can do that, but speed wise my machine estimates ~16hr print time. Could cut it to 8hrs with thicker layers.

author: Urshurak776
author_rank: Contributor
timestamp: April 14, 2020, 03:11:06 pm
content: I also recommend using a slightly larger nozzle. Most stock printers come with a .4 nozzle. Using a .6 - 1.0 will cut time down significantly as you can print a larger layer. Tweak your settings a bit and the final product does not lose any quality. As mentioned above, it is very economical to print, just takes a bit of time.My Ender 3 costs $179 (they go on sale all the time.) Love it. My son and I are having a blast. I made cases for my breadboards, Arduino's, etc. Lots of uses, plus learning a lot.

author: jimjam
author_rank: Regular Contributor
timestamp: June 09, 2020, 12:54:03 pm
content: Quote from: thm_w on April 13, 2020, 11:53:08 pmIs that 16hr per drawer set?

author: thm_w
author_rank: Super Contributor
timestamp: June 09, 2020, 09:27:20 pm
content: Quote from: jimjam on June 09, 2020, 12:54:03 pmyesI think that was ~30mm/s, some printers can go faster.
3D printer (My first 3D printer) - Page 1
Forum section: electronics / beginners

author: yashrk
author_rank: Frequent Contributor
timestamp: February 20, 2014, 07:38:04 pm
content: Hey friends,I am thinking of building a 3D printer, I did my research and concluded that RepRap 3D printer will be the cheapest and easy to build (if not plz suggest any other). As of now in India there no kit available I have to order it from USA (ebay), I searched and came across this plastic parts which will make its frame Link-eBay auction: #http://www.ebay.com/itm/3D-printer-Reprap-Kit-RAMPS1-4-for-Arduino-Mega-2560-PCB-heatbed-MK2a-A4988-/231162477519Then this electronics parts Link -eBay auction: #http://www.ebay.com/itm/RepRap-KIT-RAMPS1-4-Arduino-compatible-Mega2560-StepStick-stepper-driver-A4988-/271405781106?pt=LH_DefaultDomain_0&hash=item3f310b9072Will this covers the hole RepRap or I have missed anything please tell me, I know that I have missed out the rods and stepper motors but I will try and get them in my locality, except that please tell me if I have missed out any thing else, any more advice from your side will be helpful.Thanx.

author: yashrk
author_rank: Frequent Contributor
timestamp: February 20, 2014, 07:57:17 pm
content: Link 1:http://www.ebay.com/itm/Reprap-Prusa-Mendel-i3-Rework-Plastic-Parts-KIT-ORANGE-3D-Printer-/331094464101?pt=LH_DefaultDomain_0&hash=item4d16c49665Link 2:http://www.ebay.com/itm/RepRap-KIT-RAMPS1-4-Arduino-compatible-Mega2560-StepStick-stepper-driver-A4988-/271405781106?pt=LH_DefaultDomain_0&hash=item3f310b9072

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 20, 2014, 08:10:39 pm
content: Looks like you are also missing the nozzle and printbed?

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 21, 2014, 05:30:56 am
content: 1st link. The plastic parts are made from PLA not ABS. PLA low melting temperature. Bad for frame parts. very bad for extruderAlong with the hot end (nozzle) and heated bed mentioned. You also need prusa 3 frame, 8mm linear bearings, roller bearings, beltsstepper motors, pulleys, power supply smooth rods,many fasteners and I'm sure some other things.

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 21, 2014, 05:39:43 am
content: On a side note. This you might save some shipping.http://www.3dprintronics.com/3d-store/prusa-kits#!/~/product/category=6664678&id=28256064I don't know anything about this company so due diligence.If you want to order from USA then I can and do recommend MakerFarm. Colin at maker farm is very helpful and know the product.Excellent kit. Built the v2 prusa and then the v3 prusa 6" bed.http://www.makerfarm.com/index.php/3d-printer-kits/prusa-8-i3-kit.html

author: yashrk
author_rank: Frequent Contributor
timestamp: February 21, 2014, 01:19:41 pm
content: Thanks for reply.. looking for ward to it
3d printer project  - Page 1
Forum section: electronics / beginners

author: lancewhite
author_rank: Newbie
timestamp: April 01, 2015, 06:03:06 am
content: Hello Techies,Our team planning to do project in 3d printer. Especially in auto leveling build plate and calibration.We found Migbot prusa i3 is cheap and best 3d printer with auto leveling feature.https://www.3dprintersonlinestore.com/migbot-prusa-i3-kitStill any recommended 3d printer out there?Thanks in advance.
3P Car Hoist Contactor Identification/replacement - Page 1
Forum section: electronics / beginners

author: nick.trim
author_rank: Newbie
timestamp: March 02, 2016, 05:29:11 am
content: My old man is restoring an old car hoist (German) shipped over from Europe years ago and the switchgear looks like it could use some attention. The hoist is a 2 post screw type 3 phase hoist. Have got a few photos of the contractors. There are 4 of them (guessing 1EA for up and down on each side), unfortunately the labels are faded and there was a sticker over the rating section which is now unreadable doh (sorry about the quality). Did not get a photo of the motor nameplate but they are relatively small maybe 2.2kW from memory, cant check easily as he lives 2hrs away.Does anyone recognize the logo on the contactor so I can try to dig up some specs? They are probably 30 years old and haven’t been able to find anything under DL06a. Looking to source replacement contactors and get a sparky mate to replace them. Hoping someone can recommend some reasonable price/quality contactors to use.
3pdt switch pspice model - Page 1
Forum section: electronics / beginners

author: Narside
author_rank: Newbie
timestamp: April 29, 2023, 05:25:06 pm
content: Hello. Please help to model a 3pdt switch in pspice. I tried time-control switch x3 in one model but had no success. Is there any approach to model it? Thank you in advance

author: Zero999
author_rank: Super Contributor
timestamp: April 29, 2023, 09:03:34 pm
content: Please post what you've already tried.There are several ways to do this. One is to use a current or controlled switch model.

author: Narside
author_rank: Newbie
timestamp: April 30, 2023, 08:38:39 am
content: So here is my model and circuit:* For DC and AC analyses, the switch will be Open..SUBCKT Sw_tClose 1 2 3 4 5 6 7 8 9 PARAMS:+ tClose=0 ; time at which switch begins to close+ ttran=1u ; time required to switch states (must be realistic, not 0)+ Rclosed=0.01 ; Closed state resistance+ Ropen=1Meg ; Open state resistance (Ropen/Rclosed < 1E10)V1 6 0 pulse(0 1 {tClose} {ttran} 1 10k 11k)S1 2 1 6 0 SmodV2 6 0 pulse(0 1 {tClose} {ttran} 1 10k 11k)S2 5 4 6 0 SmodV3 6 0 pulse(0 1 {tClose} {ttran} 1 10k 11k)S3 8 7 6 0 SmodR100 3 9 1e-5.model Smod Vswitch(Ron={Rclosed} Roff={Ropen}).ends

author: Narside
author_rank: Newbie
timestamp: April 30, 2023, 12:05:32 pm
content: Quote from: Zero999 on April 29, 2023, 09:03:34 pmI've tried spice model of 3pdt from Altium as well but no success

author: Narside
author_rank: Newbie
timestamp: May 01, 2023, 08:57:28 am
content: Any ideas?
3phase full wave rectifier question - Page 1
Forum section: electronics / beginners

author: Jimbz
author_rank: Contributor
timestamp: December 08, 2013, 02:23:50 am
content: Hello, doing schoolwork, nearly done, but I dont know what to make of one thing.We were doing works on diode rectifier, we reached 3phase full wave rectifiers with having a source voltage of 24 VA on a single phase. We had hooked up a multimeter to read the DC readings across a load and it gave us ~32 V. According to the formula (3*SQRT(3)*Vpeak)/PI() it should read roughly 56 V. However there is a massive difference, why ? I do not know if the phases were 120 degress apart or not and im fairly certain it was fullwave not half wave rectified. Could anybody enlighten me on what is going on in here ? Also could anyone enlighten me why the average voltage of 56 V is above the amplitude of 34 V ?

author: IanB
author_rank: Super Contributor
timestamp: December 08, 2013, 05:52:56 am
content: You need to consider various details of the system to be able to answer your question. Some details to consider might be:Was the source voltage the line voltage or the phase voltage?Was the source voltage the RMS average voltage or the peak voltage?How was the three phase rectifier wired in relation to the three phase supply?Were you using a true RMS multimeter to measure the voltage, or a simple sine averaging meter?About the voltage magnitudes, consider the following:If the supply was 24 V AC RMS measured phase to neutral, then you would have 42 V RMS phase to phase. If you considered the peak voltage of this 42 V sine wave, you would have about 59 V. So the available voltage in the system is certainly higher than the 56 V that you measured.Note: you may want to sketch out the system you were examining, and then sketch the wave forms you expect at various parts of the system with magnitude and phase angle.

author: Zero999
author_rank: Super Contributor
timestamp: December 09, 2013, 04:53:56 pm
content: If you connect 24V phase to phase across the rectifier input, you should expect 32V on the output.

author: IanB
author_rank: Super Contributor
timestamp: December 09, 2013, 06:03:01 pm
content: Quote from: Hero999 on December 09, 2013, 04:53:56 pmIf you have 24 V between phases (i.e. the line voltage is 24 V) this is true. But if you have 24 V phase to neutral, you will have a line voltage of 41.5 V phase to phase. And if you connect this to the bridge rectifier you will have 56 V DC on the output.When working with three phase supplies it is important to know what is your phase voltage and what is your line voltage.
3rd pin in a small li-ion battery? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: March 10, 2018, 10:17:39 pm
content: I have a small capacity li-ion battery - 3.7V, 770 mAh - which has 3 terminals. The red and black wires seem to be the + and - terminals. I wonder what the yellow wire is used for.These appear to be the datasheets for the battery:-https://www.beck-elektronik.de/fileadmin/templates/beck_folder/batterie-akku/akkupacks/BST-38.pdf-http://www.whaleyfoodservice.com/EquipmentManualsIntegration/Manuals/SAY0069.pdfThe 1st datasheet describes the middle pin as "PIN2: TH (LNSR16H333JP-33K?/±5%)"

author: glarsson
author_rank: Frequent Contributor
timestamp: March 10, 2018, 11:43:15 pm
content: Thermistor, 33 kohm at room temperature, used for temperature sensing of the battery (over temperature protection).
3rd unused hole on PCB for THT caps: solder filled for a reason? - Page 1
Forum section: electronics / beginners

author: lpc32
author_rank: Frequent Contributor
timestamp: March 25, 2014, 02:56:29 pm
content: Some boards that use thruhole caps are designed to support alternative cap sizes, like 3.5mm and 5mm lead spacing, and so have holes for both options (one hole is common). It seems usually the unused hole is filled with solder.Is there a real reason for it being filled, or is it just a side effect of wave soldering?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 25, 2014, 03:13:45 pm
content: Hi,It is the effect of wave soldering.Jay_Diddy_B

author: lpc32
author_rank: Frequent Contributor
timestamp: March 27, 2014, 01:02:11 pm
content: Thanks. Speaking of which, why are some test points drilled and some not?

author: kayvee
author_rank: Regular Contributor
timestamp: March 27, 2014, 01:51:34 pm
content: Generally they are drilled when the same signal needs to go through to the other side of the board, so it just doubles as a via and a test point. Of course if the signal has no need to be on the other side of the PCB there is no reason to drill it.Having just said that sometimes they are drilled to allow self centering of test pins onto pads.If they are drilled and undrilled test points on the same PCB most likely the former reason.

author: lpc32
author_rank: Frequent Contributor
timestamp: March 27, 2014, 03:44:54 pm
content: I mean versus ones that similarly go all the way through, just solder filled. If to help with pin alignment/contact, why not do it all like that?

author: gxti
author_rank: Frequent Contributor
timestamp: March 27, 2014, 04:58:53 pm
content: An undrilled pad takes up room on the top layer. A drilled pad takes up room on every layer.

author: miguelvp
author_rank: Super Contributor
timestamp: March 28, 2014, 01:57:52 am
content: My Cyclone V GX Starter Kit has some via test points for things that are not connected to the FPGA pins in case you want to use them you can add a header on the test points and connect them to GPIO pins if you want that functionality.One set in particular are the pins that drive the audio part of the HDMI transmitter, so if you want sound via HDMI you have to connect them yourself.It also comes with an Arduino header and it has 2 extra analog inputs as vias, so you can put a 2 pin header and use them if you wanted to.

author: lpc32
author_rank: Frequent Contributor
timestamp: March 28, 2014, 02:27:06 pm
content: gxti, all the pads I'm talking about are drilled. But some are solder filled and some aren't. (Drill + wave soldering + selective drill + plating?)
3th IR-211x driver for cross deadtiming both A & B banks in a H-bridge  - Page 1
Forum section: electronics / beginners

author: Hr_Satch
author_rank: Contributor
timestamp: June 25, 2025, 07:21:31 pm
content: Dear Forum,as I am in the process of developing a full H-bridge Low frequency transformer based inverter:with a massive inductive Load as a Toroidal power transformer is:As to allow for the Transformer to discharge its flux before inversing polarity:I am thinking: why not using a 3th IR-211x driver, as twin low-side driveralternating the PWM-control signals for both Banks of the full H-bridge.So both Banks have a standard Low and H-side driver,and the additional 3th one serves to dead-timing the switching between both Banks.A-bank Lo + B-bank Ho deadtimes with A-bank Ho & B-bank Lo , . . .Here both drivers serve as Low-side drivers.Has there ever been someone running with this same idea ?Appreciate some pozitive reactions on this ;-?
3v pic outputting 4v, or not..... - Page 1
Forum section: electronics / beginners

author: cloudscapes
author_rank: Regular Contributor
timestamp: July 23, 2015, 11:18:01 pm
content: Hey all,I feel a little stupid. I bet this is one of those 'trap for young players' that I just can't figure out. I'm not an EE mind you, just hobbyist. I'm missing a lot of theory that might no doubt explain this.I have a PIC32 powered by a pickit3 (3.2v). Probes say it is indeed properly powered at around 3v, and I can run code on it no problem. If I hold a pin high, 3v, as expected. Both my cheap scope and multimeter probe 3v. However, if I toggle said pin, or generate any kind of clock via SPI or PWM, a little over 4v peak to peak. Huh?That's with bandwidth limited to 20MHz. Turning off bandwidth limit and it's nearly 5v. Now, probing the clock, my multimeter reports around 1.45v, which suggests a 3v clock with 50% duty. That's what it SHOULD be, but my scope says 4v or more.Is it my cheap scope/probes? The hantek MSO isn't the best scope, for sure, but it's not owon cheap at least, or those pocket scopes. I wouldn't expect hantek to make that huge a mistake. DC or AC coupled, same thing. There's no extra hardware. This is straight from the pin.Is it the scope? Is it some normal electrical behavior seen in clock signals that I'm not aware of? Some kind of weird ground trick? Will I damage 3v parts hooked up to this clock?I'm sure the answers obvious.

author: Andy Watson
author_rank: Super Contributor
timestamp: July 23, 2015, 11:30:13 pm
content: Have you trimmed your probe compensation to match the scope?Edit: Good video/description here:https://www.eevblog.com/forum/beginners/often-requested-video-the-importance-of-10x-scope-probe-compensation/msg708498/#msg708498

author: Ian.M
author_rank: Super Contributor
timestamp: July 23, 2015, 11:30:51 pm
content: +1The most likely cause is the probes have the input compensation capacitor misadjusted. The give-away is that the top and bottom of the squarewave sag after the leading edge.

author: cloudscapes
author_rank: Regular Contributor
timestamp: July 23, 2015, 11:38:09 pm
content: Quote from: Ian.M on July 23, 2015, 11:30:51 pmQuote from: Andy Watson on July 23, 2015, 11:30:13 pmI've never touched those, and pretty much forgot about that. Again, lacking a lot of knowledge.Did the trick, thanks! I figured it was something obvious.