hybridfree/eevblog-posts huggingface dataset:
boosting cap voltage and or uf rating - Page 1
Forum section: electronics / beginners

author: Jesset1996.5
author_rank: Regular Contributor
timestamp: October 14, 2015, 03:40:27 am
content: im currently working on an old tube radio and some of the caps are of a voltage that i simply can not buy anymore.is there a way i can combine capacators to boost voltage or uf? im new to substatuting caps. usually i dont need to do this. please ignore my bad spelling and grammer, its a buissy day in my small electronics lab

author: JoeB83
author_rank: Regular Contributor
timestamp: October 14, 2015, 03:50:09 am
content: Safest policy is to go for a higher voltage rating. Example, 100u/25V, go for 100u/35V or 100u/50V. What values do you need to replace? I know tubes can run pretty high voltages-my only project I've done with tubes ran on 48V, I used all 63V caps.

author: Jesset1996.5
author_rank: Regular Contributor
timestamp: October 14, 2015, 05:05:18 am
content: Quote from: JoeB83 on October 14, 2015, 03:50:09 am600v 300v and 400v

author: JoeB83
author_rank: Regular Contributor
timestamp: October 14, 2015, 05:28:00 am
content: Capacitance values? (usually in uF.....in old stuff, sometimes marked as mfd.)

author: Jesset1996.5
author_rank: Regular Contributor
timestamp: October 14, 2015, 05:38:00 am
content: Quote from: JoeB83 on October 14, 2015, 05:28:00 amx4 .10 mfd 400v , x4 .05mfd 600v ,.005mfd 600v, .1mfd 600v , x3 .003 mfd 600v, .02mfd 600v .02mfd 300vihave already found the 20mfd , 30mfd and 50 mfd 150v caps. it goes to a rca 46x23 from 1939

author: Zero999
author_rank: Super Contributor
timestamp: October 14, 2015, 07:49:42 am
content: Quote from: Jesset1996.5 on October 14, 2015, 05:38:00 amIt is possible to connect capacitors in series to increase the voltage rating, but it's generally not recommended and high value resistors in parallel are often required to help them share the voltage.Those values should be widely available and if they're not, what's there should be close enough.They'll be marked differently, so for 0.10mfd, look for 100nF or 0.1uF. For the others you might not be able to get the exact value so go for the nearest E6 value (10, 15, 22, 33, 47, 68 multiplied by a power of 10), so for 0.05mf go for 47nF which should be near enough.

author: JoeB83
author_rank: Regular Contributor
timestamp: October 14, 2015, 07:51:15 am
content: Quote from: Hero999 on October 14, 2015, 07:49:42 amWhat he said.
boosting FM transmitter signal for cell adapter in a car - Page 1
Forum section: electronics / beginners

author: dennisyuki
author_rank: Contributor
timestamp: May 30, 2013, 04:13:27 pm
content: I have an older van that does not have an aux port for the radio. I could connect a aux port to the radio myself but the majority of the dash would have to be removed to get to the radio. So to get my music from my cell to the car radio I am stuck with an FM transmitter. (I do not have a tape deck). I have bought an fm transmitter to hook to the headphones port in my cell, but I do not get a clean signal from the FM transmitter to the radio. also it has only 5 preset radio stations to tune into but I live in a metropolitan area of Atlanta, GA where those stations get over powered by commercial radio stations. Is there a way to modify the transmitter to boost the signal? Or modify the transmitter so I can change the FM frequency manually, ie fine tune the frequency, to a different station on the FM band.Or is there another simpler solution that I am not thinking of.Thanks.

author: SeanB
author_rank: Super Contributor
timestamp: May 30, 2013, 04:35:48 pm
content: Pop the transmitter into the dash next to the rear of the radio, so it will be close to the antenna lead. You might have to extend the power and audio input leads to it and tape it up to keep it from rattling, but there it will be pretty strong signal wise.

author: KJDS
author_rank: Super Contributor
timestamp: May 30, 2013, 04:47:50 pm
content: If there's an external aerial on the vehicle then removing this will reduce the level of the stations you don't want to listen to.

author: dennisyuki
author_rank: Contributor
timestamp: May 30, 2013, 08:41:28 pm
content: Good idea. I will try to move the transmitter closer.I would remove the aerial but i sometimes listen to talk radio for my news.Thanks guys!

author: DavidDLC
author_rank: Frequent Contributor
timestamp: May 30, 2013, 08:49:49 pm
content: Then do not remove the antenna, just put a switch to connect/disconnet it, so when you want to listen to the radio switch the antenna onDavid.
Boosting my boost module  - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: January 20, 2021, 07:20:32 pm
content: HiI'm using one of these for a Nixie clock project -https://www.ebay.co.uk/itm/264785680757Without a load, I can tune the output to get 180v. However, when I apply the load (the tubes), the voltage drops down to about 150v.The tubes still work ok but maybe a little dimmer than I'd like.This may be because I'm running everything at 5v with the boost module officially needing a little more (9-12v) to go beyond the 150v.If I use a longer USB cable for the power, the voltage drop below is clearly measurable and the boosted voltage is even less. The tubes don't get enough to work at this point.Is there a cheap / simple way with a few discretes to get an extra volt or two from the 5v to keep the boost module happy ? Having to add a separate proper 12v supply would just make the whole project unwieldy. Or even would one of these be enough ?https://www.ebay.co.uk/itm/DC-DC-MICRO-USB-MT3608-Voltage-Step-Up-Adjustable-Boost-Converter-Module-UK/193540866970?hash=item2d0fef439a:g:lEwAAOSw8Sde2hCfThanks

author: EEauroro
author_rank: Contributor
timestamp: January 21, 2021, 05:27:05 am
content: Can you use USB-C (with a USB-C charger/source) ? If yes, you can use the power delivery feature in USB-C to give you the voltage that you need. You will need a dedicated IC to handle the power delivery request. If you cannot do it on your own, you can buy off the shelf modules that will do this for you:https://www.tindie.com/products/clarahobbs/pd-buddy-sink/PD Buddy Sink is a smart power jack for USB Power Delivery. Configure it with the voltage and current your project needs, then plug it into any USB PD power supply with a high enough power capability. It negotiates with the power supply and turns on its output, giving your project up to 3 A at 5, 9, or 15 V, and up to 5 A at 20 V

author: ledtester
author_rank: Super Contributor
timestamp: January 21, 2021, 08:32:56 am
content: The MT3806 module might work.The ebay listing of the high-voltage module has this chart:In order to get 220V output it says you need to supply it 0.5A at 9V.Assume that the MT3806 module is 80% efficient. If you feed it 5V at its input, it needs0.5*9/5/0.8 = 1.125 Aof current to output 0.5A at 9V.Can you get that much current from your 5V power supply?With a lot of these ebay power modules, the only way to find out if something is going to work is to just try it.

author: VEGETA
author_rank: Super Contributor
timestamp: January 21, 2021, 12:03:16 pm
content: I think you can add a pass transistor to your module to increase current output since drop voltage is caused by limited current supply.another solution is to use 2 boost modules in parallel but using the same feedback setting potentiometer. this is not so recommended but still can deliver results.
Boosting voltage for microcontroller - Page 1
Forum section: electronics / beginners

author: rexxar
author_rank: Frequent Contributor
timestamp: March 13, 2014, 04:33:34 am
content: I'm working on an LED driver project, and I was planning on running the whole thing from a single lithium cell. I thought the mosfets I bought would saturate around 3 volts, but they seem to... not. To get this prototype working, I took the microcontroller off the battery supply, and stuck an L7805 on a 9V battery. This seems to drive the mosfets into saturation, and everything's fine.Obviously a 9V battery hot-glued to the board isn't a real solution, so what would you do? I'm thinking of using a MAX1683 voltage doubler, then a 5V regulator to keep the fets and uC happy. I don't know if this is the 'correct' thing to do, though.

author: Psi
author_rank: Super Contributor
timestamp: March 13, 2014, 04:42:22 am
content: You could make a simple voltage doubler with two MCU outputs generating psudo AC into a diode/cap. Check out Dave's video on exactly thisThe current wouldn't be that high 5mA or so, it would depend how many mosfets you need to switch and how fast.I'm not sure exactly what the mosfet in your circuit is doing but it should work fine to drive a simple mosfet switch.Probably not enough current to drive a led array though, if that's what your doing.A lower Vgs mosfet maybe in order. or a small dc/dc boost module.

author: magetoo
author_rank: Frequent Contributor
timestamp: March 13, 2014, 06:19:11 am
content: For the lazy:EEVBlog #473 – Microcontroller Voltage Doubler
boot problem with Voltcraft MSO-5062B - Page 1
Forum section: electronics / beginners

author: erulogoss
author_rank: Newbie
timestamp: October 01, 2017, 03:55:41 pm
content: At first I would like to say hello and apologize for my poor english.I got from my father Voltcraft MSO-5062B osciloscope which does not want to boot (shows only blue screen for a while and reboot). Is there any chance to bring it back to the living ??

author: flash2b
author_rank: Regular Contributor
timestamp: October 02, 2017, 04:12:05 pm
content: Maybe this guide will help you to reset the device:https://marcowuen.wordpress.com/2013/09/01/dso-hacking-quick-guide-voltcraft-dso3062c-hantek-dso5062b-tekway-dst1062b/

author: cssack
author_rank: Newbie
timestamp: January 21, 2018, 12:45:48 pm
content: Hello, i am sorry for my english too.I managed to find a solution for the problem. But let me begin with how the problem actually started.I tried to patch my firmware of the device with the firmware I downloaded from here:http://voltcraftdownload.info/Default.aspx?modelno=MSO-5062BAfter that the device wasn't able to boot anymore.So I opened the device and connected with my raspberry pi to the UART inside the device.I found the pins for the uart near the "usb" port at the backside of the device.I measured the voltage of the four pins and found VCC (3.3V), GND(0V), TX(2.5 -3.3) and RX(~0.7V) during boot time.Be careful with the high voltage.Then I looked into the serial data (8N1 115200 baud rate) and saw something like this:mkdir <SOMEDIRECTORY> failed directory already existsSegmentation faultThen I deleted the <SOMEDIRECTORY> and after that, the device booted properly.Hopefully this helps some one in a similar position.Don't hesitate to ask further questions
Bootloader and startup program of DSOX-2014A - Page 1
Forum section: electronics / beginners

author: Thuyvv
author_rank: Newbie
timestamp: December 04, 2020, 03:51:06 pm
content: Hi everyone,I have a problem and need your help,I have a error device DSOX-2014A of Agilent, it can not power on because the bootloader or solftware in NAND FLASH is error (ic as image attached) so i need the program is stored in NAND FLASH IC, please help me !
Bootstrap capacitor capacitance selection - Page 1
Forum section: electronics / beginners

author: steve13579
author_rank: Newbie
timestamp: June 19, 2015, 06:15:40 am
content: Hey all I'm working on a buck converter for 300mA to 1A constant current operation and I am having a hard time fully understanding the process on choosing a bootstrap capacitor value for the high side driver portion. Specifically the quiescent current of the bootstrap current. Looking at the FAN7382 mosfet gate driver with bootstrap circuit it lists IQBSor quiescent VBSsupply current to have a maximum value of 120uA. Is that the maximum average current per duty cycle that can be sourced from the bootstrap capacitor to operate the high side gate of an N channel mosfet? Here is a calculator I found online and it uses IDDO which I believe is the 120uA rating I saw in the datasheet:https://www.silabs.com/support/Pages/bootstrap-calculator.aspxAlso if I can throw this in here too; I am working on my EE degree and wanted to know an example of a project with a complexity level that would put me ahead of other graduates, I fear I am behind at the moment, but I still have over a year left.Thanks to everyone who reads this

author: Simon
author_rank: Unknown
timestamp: June 19, 2015, 06:52:46 am
content: It could be the average current once the gate capacitance has been charged you shouldn't actually need any current but it does limit the size of mosfet and frequency. The higher the rating of the mosfet the larger the gate capacitance usually.

author: steve13579
author_rank: Newbie
timestamp: June 19, 2015, 07:03:42 am
content: I was looking at NTR4503N; it has a total gate charge of 3.6nC typically and 7.0nC max. This is probably the largest demand as leakage current I believe would be small, should I consider these occurring from the diode leakage, gate leakage, etc? Edit: Your first sentence helped significantly, should of thought of that knowing the definition of quiescent.
Bootstrap capacitor for gate drivers such as IR2104 and IR2302 - Page 1
Forum section: electronics / beginners

author: karakis
author_rank: Newbie
timestamp: April 23, 2025, 08:03:12 am
content: I need to use IR2302 or IR2104 gate driver for my synchro buck application, but I could not find a good explanation about the capacitor between pins VB and VS, I guess it is called bootstrap capacitor but I could not understand what is the purpose and what should be the value or even a type for this capacitor. Is a regular film capacitor will work or I need an electrolytic capacitor or Should the capacitor be a polarized or not? I couldnt find any information about this in the datasheets of both.

author: Benta
author_rank: Super Contributor
timestamp: April 23, 2025, 10:27:22 am
content: Uncritical, film or ceramic is fine. IIRC, 100 nF is normally the value.

author: karakis
author_rank: Newbie
timestamp: April 23, 2025, 08:59:50 pm
content: Also, is this 100 nF capacitor independent of the circuit's power rating? I'm working on a synchronous buck converter rated at about 50V and 10A.

author: Benta
author_rank: Super Contributor
timestamp: April 23, 2025, 09:39:13 pm
content: Fully independent.I have the feeling you should start with a simpler circuit.

author: BadeBhaiya
author_rank: Regular Contributor
timestamp: April 24, 2025, 07:41:34 am
content: For a synchronous buck coverter, you would be using 2 N-channel mosfets to switch th current through an inductor. Now if you recall, N channel MOSFETs work when their gate-source voltage is higher than 5V. At the initial state, where both mosfets are off, everything is fine. If you apply 5V to the high side mosfets gate, it will turn on (since the source is at 0V, and hence Vgs is 5V). But the moment it turns on, the source voltage will be the same as drain voltage, which will likely be higher than gate voltage. So long story short, you will need a higher voltage on the gate than the drain voltage that you are actually trying to switch to actually turn on the high side MOSFETIts probably difficult to understand like this, just google "high side n channel mosfets" and read up on itIf you don't want to mess around with gate driver chips, you can use P-channel MOSFET on the high side. They're pretty good these days, i personally wouldn't bother with a bootstrapped gate driver if it's just for a personal project.The reason N channel mosfets stree preferred is because they have a low on resistance, compared to P channel mosfets. At least it used to be that way, but these days you can find comparable P channel ones.

author: BadeBhaiya
author_rank: Regular Contributor
timestamp: April 24, 2025, 07:43:55 am
content: Sorry forgot to addThis bootstrap capacitor is used to generate that higher voltage to turn on the high side mosfet. Its usually between 10nF to 100nF. The exact value doesn't matter but it's usually about 10x larger than the gate capacitance of the FET that you're trying to switchPolarized, or not it doesn't matter.
Bootstrap circuit and exceeding VGS(max) of high-side n-chan FET?  - Page 1
Forum section: electronics / beginners

author: julian1
author_rank: Frequent Contributor
timestamp: April 15, 2017, 04:58:56 am
content: A bootstrap circuit (capacitor and diode) look like they work as a voltage doubler.Does this impose an indirect limit on the input voltage that can be switched by a high-side n-channel FET in source-follower configuration - since otherwise the bootstrap circuit will drive the Gate over VGS(max).Eg. With a 20V input (on Drain), the FET is turned on, and the bootsrap will provide 40V to the mosfet driver for the Gate, which is 20 VGS. That's at the limit of a FET such as the IRF540.Is there a way around this - perhaps with a Zener shunt?

author: Rerouter
author_rank: Super Contributor
timestamp: April 15, 2017, 06:56:11 am
content: I believe a zener shunt is the norm, but before the driver switched side, so you have your bootstrap supply that creates a not horrible 10V or more referenced to the source, that then gets switched between by the driver, meaning the mosfet never sees the higher gate voltage,

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2017, 09:22:09 am
content: Quote from: julian1 on April 15, 2017, 04:58:56 amSchematic?What's the voltage on the source, when the MOSFET is turned on?I hope you're aware it's the voltage between the gate and source which counts, rather than the absolute gate voltage.
Bootstrap Operation Charging Path to drive Mosfet - Page 1
Forum section: electronics / beginners

author: renni1080
author_rank: Newbie
timestamp: October 15, 2020, 01:42:44 pm
content: Hello everyone, When I look at basic operation of bootstrap circuit from ti document(https://www.ti.com/lit/an/slua887/slua887.pdf?ts=1602767577940&ref_url=https%253A%252F%252Fwww.google.com%252F), in bootstrap charging path look like VDD DC voltage pass through Cboot capacitor. But capacitors block DC voltage. I dont understand how that operation works. What point do I miss about that circuit ? can you help me to understand that ? I attached figures.

author: Cerebus
author_rank: Super Contributor
timestamp: October 15, 2020, 05:05:12 pm
content: Yes, capacitors block DC voltage, but they alsocharge. If a capacitor has charged to a voltage V1when it has one end connected to ground, and you then move that end from ground and connect it to V2, then the other end of the capacitor will now be at (V1+ V2) volts above ground.

author: renni1080
author_rank: Newbie
timestamp: October 18, 2020, 07:22:38 am
content: So in the first figure, the path to ground shows actually charging, as understand. There is no current flow to ground from Cboost while charging. Am I right?

author: Cerebus
author_rank: Super Contributor
timestamp: October 18, 2020, 02:32:16 pm
content: Yup. it's even labelled "bootstrap charging path". Looked at simplistically there's no significant current flowthroughthe capacitor, there is obviously a temporary charging current flowintothe the capacitor (which obviously stops once the capacitor charges to the same voltage as the current source, roughly VBias- 0.7V). AC components of the charging pulsewillpass through the bootstrap capacitor during the transition to a steady state (i.e. on the edges of the applied waveform).Saying that "capacitors block DC" is a simplification of their true behaviour, which is to follow the characteristic equation:$$I(t) = C{{dV(t)}\over{dt}}$$Which means that whenever the voltage is changing, there will be a current flow. One way of looking at it would be to say that with one end of the capacitor clamped at a fixed voltage there can't be an outward flow of current because that plate on that side can't move in charge terms because it can't change voltage , so the other plate charges instead of passing the current though.Edit: Left the C out of the equation. Embarrassing!
Bootstrap options - what it is for? - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: June 17, 2015, 08:41:08 pm
content: Some SoC have bootstrap options. As far as I understand it controls how a device( using that SoC) starts.E.g. SoC BCM7440 ,made by Broadcom and that is used in a blue ray devices , has several bootstrap options and one isstrap_test_debug_en_, which probably enables debugging. Butwhat kindof debugging? JTAG, UART or different? Can anyone explains? Thank you
Bottlefuse (DIAZED) operational class marking gL/gG. - Page 1
Forum section: electronics / beginners

author: Vtile
author_rank: Super Contributor
timestamp: April 22, 2017, 11:54:37 pm
content: Does anyone of you older pros remember which decade the gL were deprecated by the now in use gG (general) as operational class marking. Not so electronics related, but might be good to know for everyone in the parts of the world that is using the system. I just today did unmount an old gL fuse that did come end of its life span at home. The question is which is the decade the gL were solely used as a marking.(edit. damn standards can not find anything worth from free sources or my current papers/books and proper IEC standard costs about 125€ .. I need a sponsor to with atleast 10k to spend standards)
Bottom entry receptacle but wider connectors - Page 1
Forum section: electronics / beginners

author: VEGETA
author_rank: Super Contributor
timestamp: May 19, 2024, 12:24:40 pm
content: Hello,Please check this:https://www.digikey.com/en/products/detail/molex/0009483054/863356I need the same type of bottom entry receptacle but instead of the hole being single pin i need it to be wide.the reason is that i design a replacement psu for a device but it has 2 versions, each version with different connector pins placement (very close though)... so I thought instead of putting 2 connectors i could check to see if there is a solution of using one connector which should be cheap as well.i don't want to make any daughter board or so, one board only.regards,
Bottom preheat 220V 50Hz on 60Hz American power line? - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: September 12, 2019, 11:59:13 am
content: How you doing guys. There is this great bottom preheat made by Russian defense industry corporation,Termopro NP 10-6 Pro, when it comes to iPhone pcb repair it's the caddilac of preheaters, precise, ergonomic, super advanced, bar none the best out there. However, it is designed to work with 220 - 230 volts an 50 Hz. I'm not sure if it has switching mode PSU or linear, I asked tech support, waiting for reply, but let's assume both cases.I know that in the US you can get 240 volts 60 Hz (btw, voltage in my outlets in Russia is 239 volts). Question is will this preheater work at 60 Hz voltage frequency?Another related question, I bought me Aoyeu 2703+ (yea I know, but it does it's job), this station is for 220 volts and 50 Hz and it has linear PSU inside it. Can I use it in the U.S. at 60 Hz? I just don't want to sell it for a lot less money if I move, although I might out of convenience.

author: Zero999
author_rank: Super Contributor
timestamp: September 12, 2019, 12:37:38 pm
content: The heater itself will just be a resistor and won't care whether it's AC or DC, but the controller will.Running linear or switched mode power supplies at 60Hz, rather than 50Hz is not an issue. There will be very slightly higher hysteresis losses in the transformer but the ripple on the DC side of the rectifier will be lower. It's running 60Hz equipment at 50Hz which is more troublesome.The only issue I can think of is it might use the mains frequency as a timebase, which would result in it running a bit fast, on 60Hz vs 50Hz.It's also possible to use an inverter to generate 50Hz from 60Hz.

author: u666sa
author_rank: Frequent Contributor
timestamp: September 12, 2019, 02:55:35 pm
content: I doubt they would use mains freqfor reference, this is nuclear weapon and space company we talking about, that’s why I want that preheat so badanyway. Though I will ask techs about this. Thanks you.Quote from: Zero999 on September 12, 2019, 12:37:38 pm

author: wraper
author_rank: Unknown
timestamp: September 12, 2019, 03:12:28 pm
content: Quote from: u666sa on September 12, 2019, 11:59:13 amLOL. Where did you get this nonsense? BTW it's rated for 220-230V, 50-60Hz. No issue there.

author: u666sa
author_rank: Frequent Contributor
timestamp: September 12, 2019, 03:18:36 pm
content: Where did you get 50-60 hz??I read twice everything.As far as what was said, because it is what used by different bearous. In repair industry it is confirmed to be king here, dudes who went jbc dropped it and went this way. There is a reason, precision, speed, and enorgonomics. I wont argue, I seen it, I want it. i want nothing else.It goes to me nimizing return rates. I’m a simple man.

author: wraper
author_rank: Unknown
timestamp: September 12, 2019, 03:25:53 pm
content: Quote from: u666sa on September 12, 2019, 03:18:36 pmOn Russian version of their website.
Bought a brand new Smart Cable SC821 Plus for $5. Is it worth keeping - Page 1
Forum section: electronics / beginners

author: ExodusEffects
author_rank: Contributor
timestamp: August 18, 2018, 09:54:53 pm
content: Found a smart cable SC821 Plus at value village brand new still in the wrap, what can I use it for. Is it worth keeping as a beginner or should I sell it and buy an old 80’s 4.5 digit bench meter like a 175 or 179a [ also which of those two models is better? )Thank you so much for all of the help I greatly appreciate itJesse Bélanger

author: rstofer
author_rank: Super Contributor
timestamp: August 19, 2018, 12:57:22 am
content: The SC821 is used to debug serial communication between, say, a uC and a PC. I don't know if it only works with RS232 voltage levels or whether it also works with TTL levels. In most cases, when I use RS232, it is at the RS232 voltage levels because I use a USB->RS232 Serial converter cable. I also have USB->TTL Serial converter cables for 3.3 and 5V.It's a fairly expensive tool, I would hang on to it. Forty years ago it would have been in very high demand! Time moves on...

author: Brumby
author_rank: Unknown
timestamp: August 19, 2018, 02:45:06 am
content: For $5, I'd hang on to it - at least for the time being. You're not going to get much bench meter for that sort of money.Down the road you may ask yourself the question again ... and you won't need our thoughts to make your decision.
Bought an old oscilloscope for cheap, but how do I use it ?! - Page 1
Forum section: electronics / beginners

author: TripleW
author_rank: Newbie
timestamp: February 05, 2015, 06:59:03 pm
content: Hi everyone.This might seem like a pretty stupid question... but I bought this old French oscilloscope a while ago for 15 euros (~20 dollars) and I'm not sure how to connect/configure it without potentially destroying it.It's a CRC OCT 568 (similar model with pictures here:http://www.radiomuseum.org/r/crc_oscillographe_transistor.html)You can find more pictures here:https://www.dropbox.com/sh/a7ipvpzushei3mk/AAB2kgqskPMseio2pns_Rbtha?dl=0It seems to have a lot of options to power it up:- AC 110/127V- AC 220V ---> the one I want to use- "Batterie"It has 3 fuses in the back, I measured them all and they're still OK.This looks like a beautiful piece of "vintage" hardware and I would love to see it working!Anyone got any ideas on how to connect&configure this for AC 220V?- TripleW

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2015, 07:09:09 pm
content: Welcome to the forum.Did you get in the same country you are from? Put your country flag in your profile.Ask the seller what voltage it was set for.With old equipment it's always best to get a Service manual if you ever need to fix it which is highly likely.Post pics of the voltage selector options,

author: TripleW
author_rank: Newbie
timestamp: February 05, 2015, 07:18:28 pm
content: Quote from: tautech on February 05, 2015, 07:09:09 pmThanks.Actually my grandpa got it for me, in my own country. It should've been set for the correct voltage...The previous owner didn't know very much about it, he didn't even know if it worked.I can't really seem to find much about this oscilloscope.. do you happen to know where to search for service manuals?I have added a picture of the voltage selector to the dropbox album. I think it's set to 220V, but when I plug it in and crank up the intensity, I can't see anything on the display. Are there any voltages that I can/should measure?

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2015, 07:32:14 pm
content: There are many links for manuals in the sticky thread in the Repair board.Google searches are normally the quickest, but results are very dependant on your keywords.

author: TripleW
author_rank: Newbie
timestamp: February 05, 2015, 07:54:28 pm
content: Quote from: tautech on February 05, 2015, 07:32:14 pmThanks for the help. I searched all the links in the sticky thread for my oscilloscope but haven't found anything.Can't find manuals on Google or even eBay.I guess this is one exotic piece of equipmentI'll mess around with it a bit more and see if I can get it to work.

author: tautech
author_rank: Super Contributor
timestamp: February 05, 2015, 08:10:47 pm
content: Be aware old equipment should be powered up "gently" over some time to let E-caps reform.Variac or light bulb in series is normally used.Take at least an hour or two.
Bought Broken Radio To Learn - Page 1
Forum section: electronics / beginners

author: GradeAweirdo
author_rank: Newbie
timestamp: April 19, 2019, 10:41:22 pm
content: Hello electronics have always interested me, i picked up a cheap broken pyle gps radio for real cheap, i want to try to fix it, no big deal if i dont im just interested in learning, something to tinker with, the radio doesnt power on but i think i found the problem but i dont know what the parts are or what they do or what caused them to go bad, any help is greatly appreciated. Thanks! I dont know what the part is that says IN on it. I can solder and i have a multimeter and such, just trying to learn a new hobby.Sent from my SM-G955U using Tapatalk

author: ataradov
author_rank: Super Contributor
timestamp: April 19, 2019, 10:58:11 pm
content: The blown part is a diode. It is likely there for reverse polarity protection. But its death may be an indication of something else dead past that. It is impossible to tell without actually looking at the rest of the unit.

author: bob91343
author_rank: Super Contributor
timestamp: April 19, 2019, 11:09:38 pm
content: It's not IN. It's 1N and there are more numbers to finish the part number. I am guessing it's a 1N4002 or close to that. Very common and cheap part.
Bought Framework PCB stencil instead of just stencil... - Page 1
Forum section: electronics / beginners

author: Jackster
author_rank: Frequent Contributor
timestamp: November 11, 2017, 03:45:55 pm
content: Hi allI accidently bought a framework stencil instead of just a plain one from PCBway.What does one use this with?I know there are those auto machines and ones that hold stencils, is that what this is for?ThanksJack,
Boundary conduction mode LED driver problem - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: November 20, 2018, 06:23:24 am
content: Hi,Why do virtually all offline LED driver IC’s involve the Boundary Conduction Mode (BCM) principle? (AKA critical conduction mode) It certainly has advantages, but the one huge disadvantage is that you can’t dim them down to low light levels without the switching frequency getting ridiculously high. It’s possible to avoid this by making them with a minimum off time, but virtually none of these BCM led dirver chips have this facility.So why is this?LED driver datasheet (NCL30002)https://www.onsemi.com/pub/Collateral/NCL30002-D.PDF

author: Giaime
author_rank: Regular Contributor
timestamp: November 20, 2018, 08:28:23 am
content: Quote from: treez on November 20, 2018, 06:23:24 amBecause it's zero voltage switching in theory, thus reducing losses. Very few in the industry are concerned about dimming to less than 10% or so.If you need better dimming, it's best to go to a two-stage principle, maybe with a pulse-skipping PFC front-end to avoid going too high with switching frequency.
Box Enclosure Case - recommendation - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: December 31, 2015, 08:25:56 pm
content: Can anyone suggest a material for a Box Enclosure Case for my DIY project?The project will use 220V.I was thinking about a plastic box but when searching for a such box I came across a seller that says plastic boxnot being safe for those 220V.Can anyone explain please?Do you use plastic or aluminium or different material for your projects

author: Macbeth
author_rank: Super Contributor
timestamp: December 31, 2015, 10:36:59 pm
content: Of course plastic is safe. With a metal enclosure you have to make sure you have a good earth connection to the case with shake proof washers and the like. If this is going into production then there are standards to follow I have to admit I don't know, but there is no reason you can't have a plastic case for mains equipment. I would say the opposite in fact!How do they get away with cheap "wall-warts"?

author: retrolefty
author_rank: Super Contributor
timestamp: December 31, 2015, 10:57:00 pm
content: Plastic enclosure are available for such service, however be aware that if multiple conduit penetrations are made that the conduits must be connected together with wire jumpers inside the box to maintain electrical grounding of the external conduits.
Box of goodies free to good home - Page 1
Forum section: electronics / beginners

author: Sengcid
author_rank: Regular Contributor
timestamp: March 22, 2024, 12:28:18 am
content: Lots of basic components plus some interesting items for the newbie experimenter, if you are willing to pay for the postage. GB mainland only.Opamps (lots of LM741 plus a few higher spec types, power opamps and ready built modules).Audio power amp chips and ready built modules.Selection of transistors and SSI/MSI logic chips.Passive components.See pic of shoe box.PCB module from which linear and switch-mode regulators (plus external components) can be scavanged (see pic of PSU PCB).Prototyping materials including stripboard and protoboard (see protoboard pic).Coax cables, 4mm sockets, project boxes, selection of heatsinks etc.Hurry – I will not be around much longer.Pls PM me if interested.

author: p.larner
author_rank: Frequent Contributor
timestamp: March 23, 2024, 10:41:41 am
content: are these still up for grabs?.
Boxcar FFT ripple - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: May 10, 2017, 09:58:11 am
content: If you use oscilloscope FFT while in enhanced resolution mode that is using boxcar/rectangular window function,will you get distorted reading? Boxcar funcion have perfect time domain behavior,no ringing but it have freqency domain ripple,ERES/Gaussian window have tiny bit of ringing but its freqency response is smooth curve,no ripple.I wonder,does it matter what type of window funcion is the scope using to get more bits as tradeoff for less samplerate? Is it possible that the ERES/Gaussian is better for FFT than HiRes/Boxcar/Rectangle due to freqency ripple?

author: dmills
author_rank: Super Contributor
timestamp: May 10, 2017, 10:23:08 am
content: Depends on what you are doing.Boxcar incidentally does NOT have perfect time domain behaviour, it is in fact shockingly poor if the input has any harmonic components above the output rate Shannon limit.To enhance resolution at lower rates properly means low pass filtering followed by decimation which is not the same as a boxcar average (That has very poor attenuation out of the new passband so will be prone to aliasing causing weird spurious responses when you take the FFT), which impulse to chose for that LPF is again something dependent on what you are trying to do.Iff the scope gets this right then you get to do the FFT on the reduced rate signal, and at this point the question of FFT window comes up, window choice depends on what you are trying to measure (Which is why there are so many of the damn things).There is a reason RF folks laugh at scope FFT mode ('spectrum analysers').Regards, Dan.
Boy, I know even less than I thought about diodes - Page 1
Forum section: electronics / beginners

author: rp58
author_rank: Newbie
timestamp: February 27, 2022, 08:08:56 pm
content: Can someone please explain how this simple circuit:can generate this waveform?That's an almost dead 12v SLA, a 50v 3A diode, and the scope is dc coupled. When I flip the diode it conducts and displays normally. The frequency looked suspicious, but it does not equal my mains frequency which is 59.56

author: xrunner
author_rank: Super Contributor
timestamp: February 27, 2022, 08:14:55 pm
content: Just picking up 60 Hz noise from the surrounding lines. The battery/diode has nothing to do with it per se, except acting as a slightly better antenna.

author: ataradov
author_rank: Super Contributor
timestamp: February 27, 2022, 08:16:28 pm
content: And you can't rely on the frequency value as measured by the scope. It is on the ballpark of the 60 Hz, it is mains.

author: rp58
author_rank: Newbie
timestamp: February 27, 2022, 08:43:47 pm
content: Ok, got it.As a follow-up, what I was preparing to do was protect my benchtop power supply while I reverse charged this battery. But then I realized there is no way to do that, is there? You can use a diode to forward charge a battery, but how do you protect the power supply for reverse charging? (This is an experiment in desulfation)

author: ataradov
author_rank: Super Contributor
timestamp: February 27, 2022, 10:04:25 pm
content: No, your power supply need to be able to sink current. Many supplies can do this, but usually for a limited amount of time.
bps26 battery reset after change fuse and cell - Page 1
Forum section: electronics / beginners

author: tahirmaqsood
author_rank: Newbie
timestamp: May 21, 2024, 10:57:36 am
content: I have sony laptop battery bps26 i have changed its fuse and reset it with be2works. By this method.Its pin no 7 is getting only 1.2 volts. Tried to activate pin no 7 by giving 12 volts for a while but still the battery does not activate.Can anyone help me how to activate the battery. Thanks

author: m k
author_rank: Super Contributor
timestamp: May 31, 2024, 12:10:37 pm
content: One possibility is that you didn't reset it.Maybe it is not supported.

author: tahirmaqsood
author_rank: Newbie
timestamp: June 01, 2024, 04:01:23 am
content: I have reset it again but the battery still won't start

author: m k
author_rank: Super Contributor
timestamp: June 01, 2024, 11:13:42 am
content: Are there still markings on the memory chip?Maybe it's a ROM of some unusual type.

author: tahirmaqsood
author_rank: Newbie
timestamp: June 01, 2024, 02:44:25 pm
content: I have exactly the same battery.And I have done all the work in exactly the same way.

author: m k
author_rank: Super Contributor
timestamp: June 01, 2024, 03:32:51 pm
content: If full charge capacity has changed then there must be some other problems.

author: tahirmaqsood
author_rank: Newbie
timestamp: June 02, 2024, 03:12:46 am
content: Yes I have changed the full charging capacity.According to the capacity of the new cells that have been inserted into the battery.What is the solution now?

author: m k
author_rank: Super Contributor
timestamp: June 02, 2024, 09:53:10 am
content: If new max is more than old max there can be a capacity fault check for too high value.Try changing the full capacity to what it originally was.
BQ2002C and NCP3065 battery charging questions - Page 1
Forum section: electronics / beginners

author: fishy12
author_rank: Newbie
timestamp: March 18, 2017, 05:00:02 am
content: Hey folks - first - thanks for your help.I'm trying to charge a NiMH battery (2Ah) from a USB supply (mains, not a low powered computer one)I'm thinking to charge it using the BQ2002C, configured at 1/2C charge rate. I'm a bit puzzled by the 'open drain output' of the chip though, and how I can use this to trigger a current source. I realise that when the gate output is high, it's tied to ground, but I'm confused how to get this to control a current source.That brings me to my second question. I'm aware a linear regulator would just ditch a fair bit of heat which is less than ideal as my board is inside a narrow tube, and thus won't get much airflow. Thus, I was wondering if the NCP3065 might be appropriate - and if so, the best way to control it/turn it on and off with the BQ2002C (which pulses the current source to allow trickle charging once the battery is full)? I've used the manufacturer's design spreadsheet for the chip, which suggests that it is possible to configure it to limit current to 1A max at 2V, with a 5V supply, with only 1.6W lost to the chip/resistors etc. Does this seem like a reasonable way forward/what might be better/simpler/easier/cheaper?Thanks very muchClaire
BQ24650 MPPT charger for "normal" lithium-ion battery pack charging - Page 1
Forum section: electronics / beginners

author: derGoldstein
author_rank: Regular Contributor
timestamp: August 26, 2016, 07:24:15 am
content: I was looking over battery charging ICs and the BQ24650 gets mentioned very often, even though its data sheet's title is "Battery Charge Controller for Solar PowerWith Maximum Power Point Tracking".Can I use that if I want to charge a battery pack from a stable voltage (no solar panel involved)? Would the MPPT functionality prevent it from being use that way?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: August 26, 2016, 09:16:45 am
content: 1. Not the right chip for the job2. If you really want to use it it would probably be ok, but to be sure you could put a power resistor in series with the stable voltage so that your "stable voltage" had an mpp that wasn't at full current.

author: derGoldstein
author_rank: Regular Contributor
timestamp: August 26, 2016, 06:26:35 pm
content: Ok. Now I'll alter/expand the scenario: I have a power source that's stable *most* of the time, but not all. There's a solar panel that's potentially charging a bunch of different batteries. Most of the time, there's a large lead-acid battery that acts as a pool, but it's *possible* that it's not there and I have to charge directly from the panel. So most of the time I have a power source that won't benefit from an MPPT, but there are exceptions where MPPT is useful.So now the question becomes -- can I use the BQ24650 for both scenarios, or will I have to create 2 different pathways with 2 different ICs to charge the battery pack?From your answer I assume that the BQ24650 can be used for both scenarios, but it would behave sub-optimally when the power source is stable?BTW, I was just reading the following thread:https://www.eevblog.com/forum/beginners/another-must-read-for-beginners/-- and I realize the irony, but I really needed to know the answer to question Y in order to know if my potential solution to question X was viable... Even if I can't use/understand the answer to question X, I can still make use of the answer I received to question Y.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: August 27, 2016, 09:03:35 am
content: Considering that you will need a solar charger some of the time, you should build the MPPT charger.I am almost certain it will be fine from a low impedance voltage source as well so you can test it when you get it built. When the MPPT tracks it is looking for a single global power maxima, which is the nature of PV panels. If you use a voltage source it will still have a single global power maxima but it will be at a current greater than the batteries you are charging probably need. If this is the case the charger intelligence should limit the current and therefore the power to something appropriate.When testing/creating even small power electronics, fuses, polarised power connectors and current limiting supplies are your friend.
BQ25606 battery management IC: Auto detect USB via USB-C - Page 1
Forum section: electronics / beginners

author: Holup
author_rank: Newbie
timestamp: February 10, 2025, 11:50:36 am
content: Hi,I want to use Texas Instruments BQ25606 battery management IC for charging a lithium-ion cell.Datasheet:https://www.ti.com/lit/ds/symlink/bq25606.pdfMy goal is to charge the cell at 2.5A if powered from unknown source such as wall adapter, and auto-limit the input current when connected to USB port of a computer to protect it from damage."The device sets the default input current limit based on the built-in USB interface."PIN 3 (D+): Positive line of the USB data line pair. D+/D– based USB host/charging port detection.PIN 4 (D-): Negative line of the USB data line pair. D+/D– based USB host/charging port detection.I want to use the USB detection feature with a USB-C connector, such as this G-Switch GT-USB-7004N:https://www.lcsc.com/product-detail/USB-Connectors_G-Switch-GT-USB-7004N_C2848971.htmlMy question is if this will work when I connect D1+ and D1- from USB-C connector to BQ25606's D+ and D-, and left the D2+ and D2- from the USB connector floating (as well as all other pins except power - as on attached schematic).Note: I don't care about negotiating higher voltage than 5V from the USB.

author: squadchannel
author_rank: Frequent Contributor
timestamp: February 10, 2025, 12:07:02 pm
content: You must first understand the specification of Type-C.This means that only "one" of the two sides of the connector works.also, important for Type-C is the "CC" pin. without cc pin, no voltage is supplied at all. (some do).

author: Holup
author_rank: Newbie
timestamp: February 10, 2025, 01:14:46 pm
content: Thanks, I thought that the other D pins are second data pair used for higher transfer speeds.So if only one side is connected, can I just short the D+ and D- pins of the connector together like in the updated schematic? I also added 5k1 pull-down resistors to CC pins.
bq25700 Usb-C Li-Ion chaging circuit - Page 1
Forum section: electronics / beginners

author: ruumoo
author_rank: Contributor
timestamp: December 04, 2018, 07:14:42 am
content: I hope this isn't too advanced for the beginners thread, but here goes:I need help designing a circuit around the TI bq25700 chip. I want to charge a 2s Li-Ion pack via USB-C PD, but the datasheet is 84 pages long and I don't understand it compleatly, as it is, in typical TI fashion, not understandable for mortal humans. I did about 3 days of research on this whole topic, but I never found anything helpful on using this chip.If anyone would be willing to help me, that would be greatGesendet von meinem LG-H930 mit Tapatalk

author: ruumoo
author_rank: Contributor
timestamp: December 04, 2018, 09:45:13 am
content: Never mind, the programmer costs 200+ €. I will find another solutionGesendet von meinem LG-H930 mit Tapatalk