hybridfree/eevblog-posts huggingface dataset:
Car relay and continuity - Page 1
Forum section: electronics / beginners

author: allanw
author_rank: Frequent Contributor
timestamp: July 02, 2010, 01:05:21 am
content: I don't understand why terminals 1-3 are connected. From the schematic, I'd think only 2-4 was connected initially. Then when voltage is applied across 3-5, then 1-2 is connected. Am I missing something here?

author: MrPlacid
author_rank: Frequent Contributor
timestamp: July 02, 2010, 01:19:00 am
content: Quote from: allanw on July 02, 2010, 01:05:21 amI am quite sure you're right. Maybe it's bad datasheet you got there. If you have the same relay, pull it out and check it. If your right, it'll make you feel very good.

author: allanw
author_rank: Frequent Contributor
timestamp: July 02, 2010, 01:21:39 am
content: Yep, testing my relay, putting 12V across 3-5 makes a click, and switches continuity from 2-4 to 2-1.The trouble is, I'm trying to figure out what's wrong with my car and having this service manual have wrong instructions like this isn't helping...

author: MrPlacid
author_rank: Frequent Contributor
timestamp: July 02, 2010, 11:45:47 am
content: shafri, I think this is what happen. #3 and #5 form a complete circuit when it is switched on, but it never connect to #1, #2, or #4 inside the relay.PS: I think allan's relay is working fine and isn't the culprit.

author: allanw
author_rank: Frequent Contributor
timestamp: July 02, 2010, 01:38:10 pm
content: Yeah the documentation is wrong. The relay appears to be fine, so something else is broken (ac/fan stopped working on my car)

author: allanw
author_rank: Frequent Contributor
timestamp: July 02, 2010, 02:08:48 pm
content: Luckily I do have a full service manual. It says to check this heater relay for fan failure, so I tried that. I believe something must be wrong with the whole a/c power system, because the a/c light won't even turn on. I'll check the fuse next.
Car Xenon light drivers, DC/AC? - Page 1
Forum section: electronics / beginners

author: firewalker
author_rank: Super Contributor
timestamp: September 01, 2016, 06:54:55 pm
content: The high voltage output of car Xenon lights is usually "DC" or AC?Alexander.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 01, 2016, 07:09:12 pm
content: Discharge lamps are typically dc, with a high voltage impulse to strike them

author: firewalker
author_rank: Super Contributor
timestamp: September 01, 2016, 07:20:37 pm
content: Can someone use it as a high voltage supply (like people use neon lamp drivers)? Or the continuous high voltage output (arching) will destroy it?Alexander.

author: bktemp
author_rank: Super Contributor
timestamp: September 01, 2016, 07:58:14 pm
content: The burning voltage of those discharge lamps is somewhere between 30-100V. I wouldn't call this high voltage. The only high voltage is the striking voltage (>10kV for striking a hot lamp), but this lasts only a couple of microseconds.The lamp driver will probably shut down if it does not see the correct load, because those lamps are often driven using constant power regulation.

author: firewalker
author_rank: Super Contributor
timestamp: September 01, 2016, 08:03:11 pm
content: I have half a dozen of those. I will test one tomorrow. I will leave arching away in air. From the sound of the output, the pulse should be in the range of hundreds of hertz.Alexander.

author: bktemp
author_rank: Super Contributor
timestamp: September 01, 2016, 08:12:23 pm
content: The sound you can hear is the repetition rate of the ignition pulse, but each pulse is very short and has not much power. The actual power delivered to the lamp is the low voltage DC output, after the arc has ignited.
Caravan mppt controller - Page 1
Forum section: electronics / beginners

author: JZac75#
author_rank: Newbie
timestamp: February 13, 2022, 07:07:48 am
content: Hello forum members,I have just joined your forum as it was recommend to me to question I asked a friend ( I have liked 240 or 12 volt knowledge).Before we escaped lock down in June 2021 in Victoria ( only returned to VIC. 2 weeks ago ), on recommendation, I had a mppt controller and lithium battery installed in the caravan with 2 Anderson plugs installed on the caravan and one on the tow vehicle. 1 Ando on the van is for the solar panels.My question is: can I have the caravan continually connected to the vehicle while travelling and therefore charging the house battery, we may not have used the house battery in van for awhile because we where connected to 240v in a c/park for days. Will the mppt controller stop the battery from overcharging the van house battery while travelling for 4/6 hours. Hope that made sense?I ask this I was recently told it would damage the battery as I hadn’t drawn down the stored charge in the house battery before hand! Thank you John

author: cods4
author_rank: Contributor
timestamp: February 13, 2022, 07:40:53 am
content: I'm guessing the anderson connection to the van is connected directly to the battery or alternator so it will be providing 13.7v or whatever to the lithium battery in the caravan?Without seeing a drawing of the full system and knowing the exact battery and charge controller. I'd suggest it is definitely possible that the charging voltage from the vehicle could be too high for the battery and might overcharge it resulting in quicker wear of the battery.I'd recommend you try to rely primarily on the solar panel to charge the battery and only connect to the towing vehicle when you really need to, I.e if the battery is low and there's no sun to charge it.The charge controller should be configured to charge your battery using the correct voltages etc. Whereas the vehicle alternator is not designed to charge a lithium battery

author: JZac75#
author_rank: Newbie
timestamp: February 13, 2022, 07:52:35 am
content: Thanks for the reply cods4,I’ll keep advise in mind when towing, only connect to tow vehicle after been free camping for some days and relied on the house battery.We have a 20amp Atem Power dc to dc battery charger and 120 lithium battery.Just found the box and it states it has over charge protection, but will work on your advise.Thanks John

author: JZac75#
author_rank: Newbie
timestamp: February 13, 2022, 07:55:58 am
content: Forgot to add it’s a: 20Amp Atom Power dc to dc MPPT charger.Thanks John

author: Renate
author_rank: Super Contributor
timestamp: February 14, 2022, 06:35:31 pm
content: Usually I have the house and the truck systems separate.I do have a tie relay that I can activate if need be.I might turn it on for a while if I've been up late draining the house battery and I have to drive somewhere before sunrise.Still, I usually have a good idea of how my systems are going.
Carbon brush for cordless driver - Page 1
Forum section: electronics / beginners

author: najrao
author_rank: Regular Contributor
timestamp: December 16, 2024, 01:12:47 pm
content: They want circa $40 for my Hilti sfc22a brushes.These are 8 × 3 mm in section and 13 long. Must have pigtail shunt exiting from top, and must be offset to one side in the 8mm dimension.I can make the size starting with a bigger brush, and can drill a precise hole for the shunt. I can steal pigtails from scrap brushes.How do I attach the pigtail into the hole well enough to carry bursts of 20A? 'Tamping' you say, but how at home?Thanks for suggestions.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 16, 2024, 04:36:33 pm
content: How much is your Hilti worth.If you mess up the DIY brushmaking are you happy to right it off?

author: Gyro
author_rank: Super Contributor
timestamp: December 16, 2024, 06:42:55 pm
content: I don't know how precious you are about your Hilti, but aftermarket brushes, including the complete holder assembly seem readily and cheaply available...https://www.ebay.com/sch/i.html?_nkw=motor+brushes+hilti+sfc22a&_sacat=0
carbon jumper - Page 1
Forum section: electronics / beginners

author: Lucky-Luka
author_rank: Unknown
timestamp: June 30, 2019, 10:16:15 pm
content: Hi allI was watching an EEVBLOG2 video.carbon jumpers were mentioned.Since I've never heard of them, what are they, what are their function and can an hobbyst use them?Cheers

author: rs20
author_rank: Super Contributor
timestamp: June 30, 2019, 10:48:43 pm
content: They're just like normal jumper wires, and serve the same purpose. It's just that they can save a few cents by splodging carbon on the board rather than using real wire, especially if some other part of the board has carbon on it (e.g. for touch button contacts).The carbon jumpers have a much higher resistance than real wire, which is either known by the designers to be harmless, or may even be desireable (adding a pull-up resistor between two distant nets on the board without even buying a resistor = saving half a cent).No, this has no relevance to hobbyist electronics, because it's all about saving fractions of a cent. The carbon is doing nothing other than being a very imprecise resistor.
Carlo Gavazzi 10 A rms Solid State Relay - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: November 20, 2016, 07:55:27 pm
content: HiIs it fair to say that the below SSR would be ok for use in the UK, to be driven by a TTL level microcontroller output ?http://uk.rs-online.com/web/p/products/4790634/The plan would be to put the outputs in series with a socket and the mains supply via fused plug.I'd then plug in a lamp or whatever as required.Thanks

author: Ammar
author_rank: Regular Contributor
timestamp: November 20, 2016, 08:07:17 pm
content: Yep, looks fine for your purpose.

author: Gyro
author_rank: Super Contributor
timestamp: November 20, 2016, 08:10:51 pm
content: Yes, it should be fine from the mains perspective - as long as you mount it in a suitably earthed metal enclosure and ensure earth continuity from input to output. If it's a lamp load then I'd put a 3A fuse in the plug. Don't fit a 13A fuse as it will exceed the max rating of the SSR. Also ensure that the logic circuit feeding it is earthed as an added precaution.I note that the minimum control voltage is 4.5V, which is cutting it fine. A TTL level wouldn't be sufficient but a 5V CMOS (74HC etc) might. To be on the safe side I'd feed the logic into an open collector transistor and feed it from a higher voltage (the unregulated input to your 5V regulator for instance).

author: newbrain
author_rank: Super Contributor
timestamp: November 20, 2016, 08:57:16 pm
content: Quote from: Gyro on November 20, 2016, 08:10:51 pmIn the datasheet it's actually specified as 3V, for the RS1A23D10 model, so not much to worry on that front.On the other hand, consider that an heatsink is more or less mandatory according to the tables in DS page 3 (the "Apply silicon paste" in the picture is quite a hint...), maybe it's possible to do away with it for much less than 1A, but not recommended (40 K/W Rth j-a).The minimum operational current of 150mA (~35W) might be a problem with light loads.
car/motorbike second battery - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: April 23, 2014, 05:12:25 pm
content: Had this thread earlier about 12V car voltage stabiliser. This is complementary to it.I found out the magic number 6 for my second battery. I think 6 is ideal to combine 3.7 V Li-ion batteries in series.-> I understand that these batteries are alive at 3V. 6*3 = 18, this is a good voltage for a step down converter to 12V-> for charging I need 4.2, 6*4,2 = 25,2 which is a good voltage for step up from the alternators voltage.please tell me your opinion. Anybody has any experience in building such batteries?was thinking about such cells, (of course they are not 5000mah, but max 2000mah)http://www.ebay.com/itm/10-X-For-UltraFire-18650-5000mAh-3-7V-Rechargeable-Li-ion-Battery-for-Flashlight-/111323267883?pt=US_Rechargeable_Batteries&hash=item19eb62432b
Carry lookahead adder confusion - Page 1
Forum section: electronics / beginners

author: anvoice
author_rank: Frequent Contributor
timestamp: June 15, 2025, 07:26:05 am
content: In a text on digital design and computer architecture (included picture), there is an explanation of the operation of the carry look-ahead adder (CLA).It is worth noting that the actual gate-level implementation includes gates for the propagate and generate signals and was omitted from the figure for brevity. If I understand correctly, the CLA for an N-bit number is implemented as N/k k-bit blocks consisting of ripple-carry adders with special look-ahead logic to calculate the generate and propagate bits. The most significant k-bit block, however, is a regular ripple-carry block with no look-ahead logic because it's unnecessary for that block. Thus I understand why the delay through the CLA adder has a (N/k -1) * tAND_OR (assuming that's the critical path of the entire block that calculates propagation and generation) and the k*tFA terms. When a number comes in (on all inputs), the adder quickly (relative to the delay through the ripple-carry portion) calculates the carry out for the least significant four bits, then it does the same for the next four bits using the previous result as carry-in, and so on until it reaches the last adder and computes the result. Meanwhile, since computing of the k-bit result for each block can start as soon as carry-in bit is computed, all the other four-bit results are naturally already complete. However, I am trying to figure out where tpg and tpg_block comes from. The book describes it as such: "tpg is the delay of the column propagate and generate gates (a single AND or OR gate) to generate Pi and Gi , tpg_block is the delay to find the block propagate and generate signals Pi:j and Gi:j for a k-bit block, and tAND_OR is the delay from Cin to Cout through the final AND/OR logic of the k-bit CLA block." From the figure, I assumed that tAND_OR is the delay through Cin to Cout for each of the look-ahead chunks of the blocks, and thus should account for everything once you add the delay through the final adder. Clearly I'm missing something, but what exactly? Where do the standalone delays come from?
Cascading counters, something I do not get - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: January 06, 2021, 03:00:32 pm
content: Hello,I was trying to experiment with some spare parts that were gifted to me and I stumbled into counters. Specifically, I have a load of74AC163(4 bit synchronous.I was trying to cascade a bunch of them and count at different speeds (up to 10 or 20 MHz). Then I am puzzled.The RCO pin, if I underrstand correctly is to be fed forward to the CLK of the next-in-line counter, in order to cascade them, BUT that pin transitions from low to high when the count is 0x0F, not when it is reset after a 0x0F (ie count of 0x10). So doesn't this produce the count 0x1F before the count 0x10?I hope I made myself clear, I know I'm in the wrong, but I don't know how. Thanks

author: Andy Watson
author_rank: Super Contributor
timestamp: January 06, 2021, 03:41:32 pm
content: Quote from: Moriambar on January 06, 2021, 03:00:32 pmNo. The RCO should connect to the ENT of the next counter. This willenablethe clock of the next counter - whenever that clock occurs. Note, all counters should share the same clock.

author: Moriambar
author_rank: Unknown
timestamp: January 06, 2021, 04:34:16 pm
content: Quote from: Andy Watson on January 06, 2021, 03:41:32 pmah! That's it, thanks

author: Benta
author_rank: Super Contributor
timestamp: January 06, 2021, 05:55:36 pm
content: This could help:https://www.eevblog.com/forum/oshw/how-to-programmable-divide-by-n-counters-using-standard-logic/The only difference between 74AC161 and 74AC163 is the RESET signal, which is unimportant here.
Cascading DC-DC switching regulators. - Page 1
Forum section: electronics / beginners

author: varunkoganti
author_rank: Contributor
timestamp: September 12, 2021, 12:19:01 pm
content: Cascade DC-DC switching regulators?My project is to design a power supply for a drone.Here are the specifications.Input Range = 6.5V - 30V Imax@3A.Vcc - 5V conversion must be done using SMPS.Vcc/5V to 3.3v can be a regulator must output at least 1A.Input reverse polarity protection.Power monitoring is a must.I have selected TPS5430DDAR to step down VCC to 5V.My question is can I use another DC-Dc converter connected to the TPS5430DDAR?5V from TPS5430DDAR will be fed into another regulator like XCL219/220 or ST1S12GR.Is this a good practice or a terrible one?

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 12, 2021, 04:11:06 pm
content: It is ok. Some may interfere with each other, but in general, it is ok.

author: David Hess
author_rank: Super Contributor
timestamp: September 12, 2021, 06:13:28 pm
content: Quote from: varunkoganti on September 12, 2021, 12:19:01 pmAbsolutely and it is likely the preferred solution. See below.QuoteThere is nothing wrong with it, and it has an advantage in that only the first regulator has to be designed to handle the wide input voltage range instead of both regulators. 6.5 to 30 volts is a little more than a 1 to 4 input voltage range which will complicated the design of the first regulator.
Cascading multiple counters - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: April 29, 2021, 02:32:05 pm
content: Hello, I'm trying to experiment with'163counters.I just want to cascade three of them. Or perhaps more but I'd like to understand how to cascade more than two basically.I already have two perfectly cascaded:they share the CLK lineENP of counter 2 is connected to RCO of counter 1The problem is how to cascade the third one: if I share clock and make its ENP connect to RCO of counter 2, that makes it count exactly like counter 1 when counter 2 is in HHHH state.I really would like to understand what is the "correct" way to cascade more than two counters. I thought about ANDing the two RCO outputs and make those the ENP of counter 3 but it seems like a waste, having to use an extra logic gate/IC (and also: I have to mind about the delay? That won't matter when I count at 1Hz but I plan to take the counters up to 10MHz).Is there a general way to proceed? IE: what if I want to cascade 10 or 20 counters?Cheers

author: langwadt
author_rank: Super Contributor
timestamp: April 29, 2021, 02:42:52 pm
content: https://www.ti.com/lit/ds/symlink/sn54163.pdfpage 21

author: Moriambar
author_rank: Unknown
timestamp: April 29, 2021, 03:33:12 pm
content: Quote from: langwadt on April 29, 2021, 02:42:52 pmyes! I mixed up enp and ent.I would've never found that document though, not without a direct link or suggestion. Thanks again
Cascode amplifier with Back Emf usage Simulation in LTSpice - Page 1
Forum section: electronics / beginners

author: doodlejump53
author_rank: Newbie
timestamp: February 13, 2023, 08:24:56 am
content: Greetings everybody.So my problem is the following:I wanna simulate a switch with a inductive load where I actually use the back EMF and dont destroy it with something like flyback diodes.There are also some extra components to avoid destroying the power supply and other components.The voltage can get really high and thats why a circuit with just one switch (mosfet) just isn't enough so I wanna use multiple mosfets in series as a cascode.The simulation program is LTSpice.The load is a coil with ~300uH, 300pF, 1 Ohm, theres a capacitor with 1nF connected to the upper side of it and ground to get rid of unwanted oscillations to make the diodes block the reverse current properly.There are 4x blocking diodes [VS-E5TX0812] in my circuit that block 1200V each which should be enough.The mosfets being used are STW11NM80 with 800V max, so ~ 3200V max for all.Switching frequency is 30Khz.Everything is biased right.I tried simulating the cascode switch with voltage divider biasing, zener diodes at the gates, gate resistors and capacitors with 1nF each behind the mosfets also but the back emf always travels back through the capacitor chain at the mosfet gates and makes everything not work again.I tried changing the capacitor values, resistor values, frequency and pretty much everything else but the results stay the same.Is there a way to make it work or do I have to use isolated gate drivers for this circuit?A screenshot of the circuit is attached to this post. If you need anything else in order to help me out then please let me know.Any Help is of course greatly appreciated, thank you very much guys.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 13, 2023, 10:53:17 am
content: I think the problem is from the direction of the back EMF. It makes the current flow on the same direction as befor. So the diodes and 1 nV capacitor will not have much effect, as least not initially ( It could be after ringing).I don't think isolated gate drivers will help - there is more the problem of making them switch at the same time.The capacitve divider for the gate voltages is from the wrong side of the inductor - as show it only prevents the mosfets to share the voltage.The problem with the cascade is that it needs quite some power to let the gated in between follow.
Cascode voltage drop - Page 1
Forum section: electronics / beginners

author: TheBaconWizard
author_rank: Regular Contributor
timestamp: September 07, 2018, 09:28:07 pm
content: Can I assume that a pair of mosfets as a cascode amplifier can each have a smaller voltage drop than the top rail is at? (ie half what one would use in a single fet)Also, I guess the top fet has to be able to take the entire current flow?

author: coppercone2
author_rank: Super Contributor
timestamp: September 07, 2018, 09:55:10 pm
content: your name makes me happy

author: Cerebus
author_rank: Super Contributor
timestamp: September 08, 2018, 01:55:28 am
content: Quote from: TheBaconWizard on September 07, 2018, 09:28:07 pmYes and no. Yes, kind of obviously, the drop across the individual transistors has to add up to the drop across both of them (plus any passives). They don't however share the voltage drop equally. The whole point of a cascode is to fix the voltage at the drain (collector) of the input transistor to remove (as far as possible) the effects of capacitance and other variances due to changing VDSor VCE. So the cascoding, output transistor has to do all the work of varying voltage drop to leave a fixed drop across the input transistor.QuoteYes, it has to pass as much current as the bottom transistor wants to. Obviously in doing this the changing Isof the cascoding transistor will slightly change the Vgsof the cascoding transistor and so slightly change VDfor the input transistor, thereby removing a small fraction of the cascoding effect.

author: TheBaconWizard
author_rank: Regular Contributor
timestamp: September 08, 2018, 03:54:59 am
content: Thanks, probably saved me some blue smoke!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 08, 2018, 04:36:35 am
content: The voltage can be whatever you want, but understand that less voltage means less transconductance or more capacitance, give or take exact specifics of the transistors in question. On the other hand, lower voltage means higher current for the same power limit, if operation is limited by power dissipation. That can be helpful.Transconductance is usually ~flat until saturation, and the bottom transistor sees little change in voltage thanks to being constrained by the top one; so it can have low headroom, and fairly high capacitance, without significant impact on operation. This in turn leaves more voltage swing for the top transistor, and it will have lower  capacitance over that range.A dramatic example of this was from some CRT monitors I once salvaged: bottom transistor PN2369, a fairly large (200mA), low voltage (15V), reasonably fast type; followed by a BFQ225 (100V 100mA TO-202 5W 1GHz) to deliver the required swing (>30Vpk at >50MHz).Tim
Casio CTK 3500 (electronic keyboard) doesn't turn on - Page 1
Forum section: electronics / beginners

author: gigglyrip
author_rank: Newbie
timestamp: June 09, 2023, 07:44:02 am
content: I've Casio CTK 3500, which I purchased in 2019. It was working fine till last week but suddenly it stopped turning on. I'm not sure what happened as nothing has changed. I'm using the same old adapter that used to work, using the same generic pedal that I've always used.The bars on LCD blink while pressing the power button but as soon as I release the power button, it goes off.I also checked my adapter using a multimeter (no idea what I'm doing here, just followed some youtube video), and the output was 9.5V - 9.6V, so I think the adapter is okay. Is there any hard reset key that I'm unaware of?I also cleaned everything inside with a brush along with alcohol. The power button looks fine to me, no circuit break or anything suspicious (Although, I don't know much so don't take my word for it, please check the images).How can I fix it?Please help me fix it.Motherboard:Image of the motherboardCurrent behavior:

author: barshatriplee
author_rank: Regular Contributor
timestamp: June 10, 2023, 06:37:20 am
content: If no sound is coming out, perhaps there is something wrong with the speaker. I think it's better to contact the seller for an after-sales service.

author: gigglyrip
author_rank: Newbie
timestamp: June 10, 2023, 06:43:13 am
content: It doesn't turn on, not really about no sound.

author: Nusa
author_rank: Super Contributor
timestamp: June 10, 2023, 07:05:43 am
content: You can eliminate the power adapter as a problem by trying the unit on batteries. If the problem remains, it's not the power adapter. If the problem goes away, it IS the power adapter.

author: gigglyrip
author_rank: Newbie
timestamp: June 10, 2023, 05:04:27 pm
content: Nope, I checked with batteries. That didn't fix it. It's basically the same, just blinks at the click of power button.

author: LinuxHata
author_rank: Frequent Contributor
timestamp: June 11, 2023, 06:00:49 am
content: Well if there's blink, that means that at least power button watchdog is ok, but when circuit starts, something is wrong at power line, so protection kicks in and turns off the voltage regulator. A thermal camera would help a lot in finding which component is misbehaving.

author: gigglyrip
author_rank: Newbie
timestamp: June 11, 2023, 05:20:32 pm
content: I'll take it for repair. Don't think it can be fixed by me with zero electronics knowledge. Thanks for your suggestion though.
Casio FX type calculator interfacing with Arduino or similar for data collection - Page 1
Forum section: electronics / beginners

author: geggi1
author_rank: Frequent Contributor
timestamp: August 30, 2025, 08:51:57 am
content: Hi.I have started to play with my old FX9750GII calculator and logging in to a way to interface it with a Arduino or similar MCU board.Looking on the internet i can not find enything relevant.I know the 3-pin port is a ttl level serial port but that is just about what i can find.My idea is to use the Arduino as a IO for data collection.

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: September 01, 2025, 01:26:35 pm
content: Seeing this discussionhttps://forum.arduino.cc/t/casio-calculator-and-arduino-joining-circuits-of-different-voltage/157962it looks like this is not feasible. What's your purpose? Do you want to use the keypad only?

author: ledtester
author_rank: Super Contributor
timestamp: September 01, 2025, 03:00:48 pm
content: Searching for "fx9750 data logging" Brave's AI returned a summary which included this link from nexusresearchgroup.com:http://www.nexusresearchgroup.com/technical-data/casio-picaxe.htmThe original page is not there but it is available from the Wayback machine - web.archive.org.The page from January 2011 is archived here:https://web.archive.org/web/20110122013508/http://www.nexusresearchgroup.com/technical-data/casio-picaxe.htmand it contains a link to a PDF file "Casio_Pixaxe_manual.doc". That document contains examples of how to talk over the serial connection as well as schematics of this serial port adaptor to aPIXAXE microcontrollerRS232 interface:It also contains wiring diagrams for a direct connection between a PIXAXE microcontroller and the Casio -- see page 13 of the PDF.I've also attached the Casio-Pixaxe Manual below.
cassette motor - Page 1
Forum section: electronics / beginners

author: skerdzius
author_rank: Contributor
timestamp: April 01, 2013, 08:17:47 pm
content: Hello, i ripped of a motor from old radio.http://allegro.pl/silnik-do-magnetofonu-9v-m34w-6c-9ld-i3053896796.htmlbut i don't know for sure what kind of motor is it and how to control it. It has + - A B pins. i connected + - to 9 V DC and it spins at unknown speed, however i want to control it completely

author: David_AVD
author_rank: Super Contributor
timestamp: April 01, 2013, 09:00:11 pm
content: The A & B may or may not not be internally connected. You can usually adjust the speed by a certain amount using the internal trim pot accessed via the small hole. Make sure you insulate the screwdriver shaft though so you don't touch the pot to the motor case.
Castellation soldermask contamination - Page 1
Forum section: electronics / beginners

author: JWoodrell
author_rank: Contributor
timestamp: June 30, 2016, 01:22:14 pm
content: Hey guys i had my first boards made with castellations, and the red soldermask has gone down into the holes and is an issue. The holes were set to 30 mil which i have had 30 mill holes all day long without this soldermask issue (it completely covers some of them). The board house came back and said they should be 1.2mm minimum to allow the soldermask to wash out.Has anyone had this kind of issue before.Sent from my iPhone using Tapatalk

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 30, 2016, 11:05:56 pm
content: You didn't leave exposed pads on the top and bottom??How did you expect to solder the poor things in the first place?Tim

author: JWoodrell
author_rank: Contributor
timestamp: July 01, 2016, 01:33:53 am
content: Quote from: T3sl4co1l on June 30, 2016, 11:05:56 pmI did leave the pads. That is what is strange, it is only in the barrel of the castellation.Sent from my iPhone using Tapatalk

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 01, 2016, 01:55:48 am
content: Wow, that's bizarre. I wonder if they goofed something in the cut-off area?Tim

author: DasBasti
author_rank: Newbie
timestamp: July 01, 2016, 08:32:08 am
content: Is there even ENIG underneath the catellated edges? I once had the problem that they did goof up the electrolytic process for building up copper in the vias and therefore the solder mask did not rinse of properly. Maybe have a scratch and check for copper in the holes

author: IconicPCB
author_rank: Super Contributor
timestamp: July 01, 2016, 01:22:23 pm
content: Looks like soldermask phototool may be the culprit
Cat5 vs Cat5e vs Cat6 - Page 1
Forum section: electronics / beginners

author: Legion
author_rank: Frequent Contributor
timestamp: April 12, 2014, 12:57:32 am
content: What is the difference in construction between these? Since the cables all have to fit into the same jacks and still have 8 conductors it doesn't seem like you could change too much. Do they just heavier gauge wires for Cat6?

author: David_AVD
author_rank: Super Contributor
timestamp: April 12, 2014, 01:02:11 am
content: There must be hundreds of Google search results about this.

author: Legion
author_rank: Frequent Contributor
timestamp: April 12, 2014, 01:09:44 am
content: Quote from: David_AVD on April 12, 2014, 01:02:11 amYou're right, my search terms were bad. Too late now. For future reference:Quote
Cat6a Shielded Patch Panel - grounding - Page 1
Forum section: electronics / beginners

author: PowerNet
author_rank: Regular Contributor
timestamp: May 31, 2017, 02:09:56 am
content: Hello,Have anyone used the keystone jacks which are for the shielded Cat6a cables with a the ground wire ? If so with the patch panels, do you just connect the earth wire to the frame of the Comms cabinet ? if so I assume the cabinet is earth via the power cord right which in term its earthed.any ideas ?

author: Monkeh
author_rank: Super Contributor
timestamp: May 31, 2017, 03:13:26 am
content: Silly question: Why are you installing shielded cables?

author: PowerNet
author_rank: Regular Contributor
timestamp: May 31, 2017, 03:31:06 am
content: trying to minimise noise in the cables as I will be terminating them with HDMI ports and just overall trying to create higher bandwidth.I bought these:

author: Wirehead
author_rank: Regular Contributor
timestamp: May 31, 2017, 02:54:15 pm
content: Do remember that you need to groundbothsides with that set-up. Otherwise: you've got a nice noise source

author: PowerNet
author_rank: Regular Contributor
timestamp: May 31, 2017, 09:09:57 pm
content: One side ground only. Otherwise your create a ground lopp

author: Kjelt
author_rank: Super Contributor
timestamp: May 31, 2017, 09:22:36 pm
content: Quote from: PowerNet on May 31, 2017, 09:09:57 pmYou already have a ground loop by connecting the cable, because the equipment needs to be grounded.Best way is to assure all equipment with these jacks have a very low impedance to the same ground reference. One reason I dont use them, for my 10Gb/s connections I use optical cabling.
cathode follower outputs 200vdc - Page 1
Forum section: electronics / beginners

author: Deactivated-1
author_rank: Frequent Contributor
timestamp: February 02, 2020, 07:47:05 am
content: I have a basic triode gain stage going into a cathode follower without a coupling cap and the cathode follower is outputting 200volts? shouldn't it not output dc?I didn't have the gain stage before and it didn't output dc so

author: gbaddeley
author_rank: Regular Contributor
timestamp: February 02, 2020, 12:00:49 pm
content: Under DC static conditions and normal biased operation, the cathode voltage will be more positive than the control grid, by a few volts. Check the theory of operation of your circuit.

author: IvoS
author_rank: Frequent Contributor
timestamp: February 02, 2020, 03:00:03 pm
content: Post a schematic.

author: gbaddeley
author_rank: Regular Contributor
timestamp: February 03, 2020, 08:07:47 am
content: First stage has no bias arrangement shown. How are you doing it?What is the load impedance after the 68nF cap? This will determine the low frequency response.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 05, 2020, 02:34:23 pm
content: "I dunno, I just threw it together cause I wanted more gain"A cathode follower is an impedance converter to prevent loading the previous gain stage and it will have a gain less than one. This is basically how it is used as a pass element in a power supply where the output voltage on the cathode of the pass stage 'follows' the grid voltage and is almost the same value.
caution to take; AC input for SMPS/Charger through generator - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 17, 2017, 08:29:01 am
content: 1. We need to install a SMPS based lithium battery chargers 29.2V/15A in a system.2. System is always powered by generator, which runs around 6 hours a day. Seems a bit old type of generator, we measured its output, it fluctuates between 180-250vac at different loads.Freq variation is 45-55hz this is not measured but told by user.Depending upon what kind of load in nearby system, voltage spikes may be high.3. We opened up earlier system which got damaged, it had two circuits before their SMPS, a voltage correction & a frequency correction system as written on them. they were potted so cannot check what inside it.4. Now we have to replace system. I think the freq correction is not required, as it is SMPS based & we have to convert ac to dc here.5. For voltage correction, is there aby ready to use circuit/board which we can use. As we were able to check only for few load types the generator outout, it may fluctaute more.6. Can we add a freq corection ckt also here?7. What are the other precuations to take before SMPS?

author: fourtytwo42
author_rank: Super Contributor
timestamp: September 17, 2017, 09:27:17 am
content: Depending upon the type of SMPS frequency is not an issue, certainly one without power factor correction and a straight rectifier input. Most SMPS operate over a wide input voltage range it's simply a case of matching the SMPS specification to your application, you have already stated the input conditions here.There is a possibility of voltage surges when generator loads are switched off and you may need some additional voltage surge suppressors such ashttp://uk.rs-online.com/web/p/surge-suppressor-units/2266448/to protect the SMPS input.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 24, 2017, 02:56:14 am
content: Since the output is coming from generator, we have decided to use a Constant voltage transformer or servo stabilizers to protect our system.

author: Brumby
author_rank: Unknown
timestamp: September 24, 2017, 04:25:09 am
content: Quote from: fourtytwo42 on September 17, 2017, 09:27:17 amI agree. A SMPS should be able to operate over your frequency and voltage ranges without any difficulty - it will be just a matter of ensuring a robust design and covering any transient issues.Going with an intermediate transformer step seems unnecessary - unless it is required for other systems on the generator fed supply.That is, of course, unless you are limited to off-the-shelf solutions.

author: oldway
author_rank: Super Contributor
timestamp: September 24, 2017, 07:18:58 am
content: Be aware that output voltage of a Constant voltage transformer is frequency depending.....Check if it will not exceed the max input voltage of the SMPS charger.
CC and CV mode implementation - Page 1
Forum section: electronics / beginners

author: Ravenghost
author_rank: Contributor
timestamp: March 17, 2016, 04:03:08 pm
content: I'm working on a project where i need to charge multiple li-ion cells. I'm thinking of buck converter circuit powered by ac-dc 24V 1A wall adapter and controlled by Atmega328P MC PWM. I've covered theory behind li-ion battery charging, buck converters, PWM. I believe constant voltage mode implementation is quite straight forward. A simple voltage divider to get feedback voltage to ADC and Rsense resistor with current sense amp to ADC adjusting PWM duty cycle to keep stable voltage while checking current drop to 10% to cut off power(correct me if i'm wrong about this). But i'm unsure how to approach constant current mode.

author: Audioguru
author_rank: Super Contributor
timestamp: March 17, 2016, 06:39:15 pm
content: Multiple lithium battery cells? In series or parallel makes a charger very complicated. You must not charge a cell that has been discharged too low so your charger must detect a low voltage then refuse to charge.A constant 4.20V charger will explode a lithium battery cell because its current is not limited. The cell will have a recommended charging current and a maximum do not exceed charging current, your charger must limit the current.www.batteryuniversity.comrecommends sensing a charging current drop to 3% to 5% of its mAh rating for a full charge then the charger must turn off.

author: ion
author_rank: Regular Contributor
timestamp: March 17, 2016, 11:31:39 pm
content: Multiple lithium cells in parallel will appear as one larger cell to the charger, so no more complicated to charge than a single cell. That said, make sure they are within a few mV of each other before connecting them for the first time, and ideally they should be the same type of cell.Cells in series is where it gets complicated because you reallyshoulduse balance charging if you want the pack to be reliable and safe.The constant current mode basically involves limiting the charging current to the cells until the voltage rises to 4.2V (or a bit less to reduce wear on the cells if you don't need every last bit of the capacity). The current limit would mostly depend on the capacity of the cells you are using.Then you just keep supplying that voltage until the current drops to some value below 10% of the limit (determined by how full you want the cell vs. how long you want to wait for the charging to end), then you cut off the power - trickle charging is bad for lithium cells.As for the actual implementation - I would personally look for a li-ion charging chip that meets your requirements first. It would make the charger design simpler and possibly safer. As Audioguru mentioned, cells that have been discharged too low can be dangerous, and at least some of these chips are built to handle these situations.
CC control before CV control? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: April 24, 2018, 08:57:51 pm
content: When using two LM317s to create a CC/CV power supply I've always seen the current controlling LM317 placed before the one used for voltage control - (e.g. EEVblog #221).Is there a good reason for this or would it work equally as well the other way around?

author: Ian.M
author_rank: Super Contributor
timestamp: April 24, 2018, 09:16:19 pm
content: Use a bit of critical thinking and consider the voltage drop of the CC LM317 when passing less than the CC limit current.Is it stable? Is it easily predictable? Where do you put it so it does not affect the CV mode output voltage?

author: ledtester
author_rank: Super Contributor
timestamp: April 25, 2018, 12:47:56 am
content: Oh right there will always be a voltage drop across the CC LM317 which will depend on the current setting.

author: Ian.M
author_rank: Super Contributor
timestamp: April 25, 2018, 01:56:22 am
content: Not just on the current setting. The voltage drop will also depend on the actual current through it, the temperature, and vary from one device to another.Lets take a look at the datasheet. The OnSemi version has the classic 'laboratory' PSU circuit (fig. 22), and also the graph we need - Dropout voltage (fig 10)https://www.onsemi.com/pub/Collateral/LM317-D.PDFThere will be up to 1.25V (assuming Vref is at its nominal value, and the current limit is set to max) across Rsc, and the dropout voltage of the regulator can be up to 2.5V. That means there is up to 3.75V drop across the CC LM317. At very light loads, the voltage across Rsc is negligible, but the voltage drop across the LM317 typically varies between 1.75V and 1V with temperature. Therefore the fig.22 arrangement is the only way to use two LM317 or similar regulators to implement a CC/CV PSU.However it makes a fairly crappy PSU if you need much current, as the CV LM317 will also need up to 2.5V across it to regulate at max current, so you need 6.25V headroom from the trough of the ripple on the unregulated supply. As the absolute maximum input-output differential is 40V, the peak unregulated input voltage for the fig 22 circuit must *NEVER* exceed 41V (assuming a minimum 1V drop in the second regulator) or it will die if the output is shorted. After allowing for line voltage variation, this makes it effectively impossible to build a 0-30V PSU capable of any significant current using that circuit without a preregulator.If you can tolerate a less precise current limit, take a look at the LM723 - With external pass transistors, its a far better choice to build a low cost bench PSU around.
CC3000 Package Help - Page 1
Forum section: electronics / beginners

author: rahandford
author_rank: Regular Contributor
timestamp: April 26, 2014, 03:52:12 pm
content: Hi all at EEVBlog,Can anyone please help clarify the difference between the CC3000 as produced by TI (http://www.ti.com/product/cc3000) and the module available from Element14 in the UK (http://uk.farnell.com/ls-research/450-0067/module-tiwi-sl-cc3000-wlan-2-4ghz/dp/2324809) that states it's manufactured by LS Research.I just want to add some wi-fi connectivity to a project and want to make sure that I obtain the correct module to be able to use the CC3000 libraries that are available.Many thanks to all in advance.
CCFL cold cathode lamp power supply voltage? - Page 1
Forum section: electronics / beginners

author: wilfred
author_rank: Super Contributor
timestamp: August 13, 2013, 02:00:13 pm
content: /.

author: Zero999
author_rank: Super Contributor
timestamp: August 13, 2013, 04:11:58 pm
content: It's normally a self-oscillating circuit made with a couple of transistors and a transformer. The open circuit voltage will around 1kV but once the tube lights, it will drop to about 200V. You'll find the frequency also reduces when the lamp lights.http://en.wikipedia.org/wiki/CCFL_inverter

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 14, 2013, 11:24:33 am
content: They use a series resonant circuit (secondary inductance plus external series cap) to provide 1-2kv to strike the tube. Once struck, the series cap has little effect, and running voltage is low hundreds of volts.

author: Zero999
author_rank: Super Contributor
timestamp: August 14, 2013, 12:58:07 pm
content: Quote from: wilfred on August 14, 2013, 12:04:48 pmThere's no output voltage control, it just gives 1kV unloaded and 200V when the intended load is connected.You could clamp the output voltage to the desired level but the clamp must be able to dissipate the same amount of power as the CCFL.Another option is to simply turn the converter on when a certain voltage is reached and turn it off again when it falls below a certain threshold, using a comparator but you have the inverter start up time and ripple to deal with.
CCFL inverter board - Page 1
Forum section: electronics / beginners

author: Daxxin
author_rank: Regular Contributor
timestamp: February 13, 2017, 04:42:11 am
content: How to test easily if the high voltage is present at output?

author: tautech
author_rank: Super Contributor
timestamp: February 13, 2017, 04:54:25 am
content: Wave a scope probe near it, ahla near field like.Normally the controller IC shuts the output down if there's a problem. Get the IC datasheet and have a study.
CCFL Lamps - Page 1
Forum section: electronics / beginners

author: anker_by
author_rank: Contributor
timestamp: October 01, 2017, 12:13:47 pm
content: hello everyone, I need to buy some CCFL for a laptop and the screen, but the problem is where i can find some supplier/store where i can buy in european union, if anyone give me feedback, thanksBest Regards,- Anker_by

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 21, 2017, 10:04:51 am
content: I do a retrofit to LED strips and the proper driver. They are more available than CCFL's. Do a Google search and you will find many sources.

author: Zero999
author_rank: Super Contributor
timestamp: November 21, 2017, 12:01:30 pm
content: Quote from: Quarlo Klobrigney on November 21, 2017, 10:04:51 amThat will work but it's likely the colour rendering will be poorer with LEDs, than a CCFL, especially if the display was designed for CCFLs.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 21, 2017, 01:11:24 pm
content: Or just get the right color temp LEDs or adjust the colour temp in the settings. Certainly better than a black screen..

author: Zero999
author_rank: Super Contributor
timestamp: November 21, 2017, 01:35:52 pm
content: Quote from: Quarlo Klobrigney on November 21, 2017, 01:11:24 pmThat still won't give as good colour rendering as the original CCFL.The screen's filters will be designed to match the spectral output of a CCFL and if it's changed to LEDs, the colour rendering will suffer. LEDs is they have a different spectrum than CCFLs, even if the colour is exactly the same. One of the common problems is they lack the red end of the spectrum. Decent LED backlit screens have LEDs with special phosphors or a combination of blue/violet dies with a phosphor and red dies to produce the missing red end of the spectrum.The bottom line is, replacing the CCFL with an LED will work, but don't be surprised if it gives disappointing colour performance.