hybridfree/eevblog-posts huggingface dataset:
old philips PM3215 50mhz oscilloscope - ground not present - Page 1
Forum section: electronics / beginners

author: Aisalord
author_rank: Newbie
timestamp: September 30, 2020, 12:55:24 pm
content: Hi all!I bought the oscilloscope in the subject some days ago on ebay, with a complete set of manuals (user and service) and a pair of probes. The machine has a two pole alimentation plug, so there is no ground like the modern ones (It was the 1981 baby...). When I take a measure in the DC part of a circuit that is fed by a switching power unit (or generally, that has a connection to ground) I must pay attention as stated in the Youtube episone #279 (how not to blow up your oscilloscope) or I can measure everything everywhere I want because my oscilloscope is not grounded (obviously not measuring the live wire from the AC with the negative crocodile of the pole, off course!)Thanks a lot

author: Benta
author_rank: Super Contributor
timestamp: September 30, 2020, 05:29:43 pm
content: The PM32xx series of oscilloscopes has a double-isolated power supply with no earth connection. I had a PM3212 myself once (20 MHz).The floating nature of the scope can be useful in certain situations, but can also lead to very dangerous situations.Think very carefully about what you do.
Old Q, what money for ESR/LCR/Discharge Capacitor current tester ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: October 07, 2017, 03:09:24 am
content: What kind of prices are separate ESR, LCR, and the type that also measures discharge current at selectable voltages???And VS. whatever all in 1 meterThat does all the above ? I don't even know what they are yet. I bet they aren't cheap.What are the 1/2 respectable ESR meters to start with, and the discharge current ones? I have an at328 microcontroller esr meter/tester/etc, so that's a start nd works great at what it does, but now onto the dedicated ESR/LCR/Discharge current type testers

author: lordvader88
author_rank: Frequent Contributor
timestamp: January 12, 2018, 08:38:13 pm
content: Anyone ? maybe 1 of those $100 ones ?I hAVE A Mega328 based multitester already, but thats not a "real" ESR tester, and not accurate enough
Old school 2N2222A - TO-92 - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: July 22, 2015, 04:57:02 pm
content: Hi all,I have some 90's vintage 2n2222A's. I think when I bought them these were rated as 250 mW 40V. What is the likely maximum frequency (fT)of these transistors?TIA

author: Zero999
author_rank: Super Contributor
timestamp: July 22, 2015, 05:03:39 pm
content: The 2N2222A is in a TO-18 metal can package.The TO-92 version is called PN2222A.fTis on the datasheet which can be found using your favourite search engine.

author: commie
author_rank: Frequent Contributor
timestamp: July 22, 2015, 05:10:27 pm
content: Quote from: kc3ase on July 22, 2015, 04:57:02 pmDon't think they are vintage yet, they are still a viable transistor to use.Are your's to-18 or to-92?, Ive just bought 250 P2N2222A to92 from RS just the other day. The approximate compliment is 2N2907A.These transistors peak at around 10 to 150mA and ft roll's in at around 250MHz, if you need a more beefy transistor then look no further the 2N2222A is it, very good viable switching transistor too.

author: Unknown
author_rank: Unknown
timestamp: July 22, 2015, 05:17:25 pm
content: Quote from: commie on July 22, 2015, 05:10:27 pm

author: SeanB
author_rank: Super Contributor
timestamp: July 22, 2015, 05:56:16 pm
content: They pretty much will be useless over 50MHz as anything other than a grounded base amplifier with low gain. While the original claimed a Ft of 250MHz you would be hard pressed to get anything useful out of them at that, I found they stop amplifying in emitter follower at around 30MHz.

author: commie
author_rank: Frequent Contributor
timestamp: July 22, 2015, 08:18:49 pm
content: Quote from: SeanB on July 22, 2015, 05:56:16 pmFt is the transition frequency, this figure is when the current gain becomes unity, this doesn't mean it will amplify up to 250MHz. I'm not sure how your circuit was arranged but 30MHz for a 2N2222A is not bad at all. In your common collector configuration(buffer), try it with an active load and watch the speed increase.CheersCommie

author: Zero999
author_rank: Super Contributor
timestamp: July 23, 2015, 08:53:46 am
content: The old 2N2222A will work perfectly well at VHF if it's properly tuned. It's easy to build an FM transmitter working around 100MHz with the PN/2N2222A.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 23, 2015, 11:15:28 am
content: Beware that the datasheet gives minimums only, so the fT could be considerably higher than expected. This is the biggest hazard when using old, poorly specified devices like the '2222.Tim

author: SeanB
author_rank: Super Contributor
timestamp: July 23, 2015, 05:42:29 pm
content: Correct, the genuine Motorola devices I tried would not run at 100MHZ as an amplifier, but a modern device made with a different process would probably work, as it is not the same device, just meets the minimum JEDEC spec for a 2N2222, and could exceed them wildly in some areas.I have seen nominally 20V parts running fine on 60V with absolutely no problems, while conversely different batches would pop at 22V.
old technics amp sux77 - Page 1
Forum section: electronics / beginners

author: trigstig
author_rank: Newbie
timestamp: September 18, 2013, 11:35:39 am
content: can anyone help, im trying to recreate a circuit i thought real interesting, it was used in technics su-x77 amp i had once,maybe in other makes as well back in 1986.the volume control was a potentiometer,but, clocked a micro when you turn in either direction. all i remember was it had 2 flip flop and something like 100mh inductors, plus some other bits. does any one remember this circuit or how it might work. when you turn one way one flip flop would pulse turn the other way the other flipflop would pulse, i think they were d type flip flops.can anyone shed some light on this for me
Old Thread Warning, Ok to Restart discussion or where to start a new one? - Page 1
Forum section: electronics / beginners

author: DarkMode
author_rank: Contributor
timestamp: July 03, 2023, 12:18:23 pm
content: Is it ok to reopen an old thread?EEVBlog 1439 - Analysing Veritasium's electricity videoI'm only asking here because I'm not sure what Category these discussions should be listed under?Imhop this is correct electronics understanding (no Water models here)

author: xrunner
author_rank: Super Contributor
timestamp: July 03, 2023, 12:51:33 pm
content: IMHO it's OK. The warning just let's you know the interest has dropped off for a long time, because the topic has no interest or has been debated to death. But if you have new information then you can post in it. Just my opinion.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 03, 2023, 01:03:26 pm
content: In theory it's a good idea to reuse old thread, but in practice if you do that, then the old thread bumps on the top and every idiot (myself included) starts replying to the OP again without reading the thread, causing a lot of unnecessary messages, and then meta discussion starts about bumping old posts. Based on this observation, IMHO, I'd say bump the old thread only if your message is very specifically related to some of the messages. A good metric would be, can you open a new thread without referring to the old one? If you can, do that. If you would need to quote the old post, then reply to that thread instead.
Old unused UPS: good or doorstop? - Page 1
Forum section: electronics / beginners

author: Axtman
author_rank: Regular Contributor
timestamp: December 05, 2014, 08:43:19 pm
content: Today while cleaning up, I dug up an old (2005) uninterrupted power supply (APS Back-UPS 350). I got it as a Christmas present but never used it. It has never been opened or plugged in. Do you supposed that it is still good? Do batteries last long unused?Thanks!David

author: denelec
author_rank: Regular Contributor
timestamp: December 05, 2014, 09:22:47 pm
content: The battery is probably dead.But you should try it anyway.If the battery is dead, a new one cost $15.99 on Amazon.com.http://www.amazon.com/Replacement-Battery-APC-Back-UPS/dp/B006X98A7CA new 350VA UPS cost about $45. So don't spend too much for the battery.I bought a Back-UPS 350 in 2006 for my PVR. On a 30W load, the battery lasted about 30 minutes.This UPS is probably too small for a desktop computer. But it would be great for a router, a modem or a PVR.

author: Seekonk
author_rank: Super Contributor
timestamp: December 05, 2014, 10:15:44 pm
content: I get a lot of old UPS from our town dump recycling. Don't know how emotionally attached you are to this one. They are a good source of 60V 50+ A FETs. I've built my whole solsr home system out of them.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 06, 2014, 12:59:52 am
content: There's a local electrical shop here that sells various size batteries for a really good price, like under 20 bucks. I would check local electrical distributors or maybe even alarm companies.If not, UPSes have lot of fun parts inside. I actually use the transformers as door stops, they look cool and are heavy.May find some nice beefy capacitors in there too.

author: divelectservices
author_rank: Contributor
timestamp: December 06, 2014, 01:44:25 am
content: Try shaking the battery...if you hear any rattling...it is junk.We have about 100 UPS units where I work and I have some that the batteries are over 3 years old and work fine and others that seem to fail every few months.I take apart all the old/defective units and salvage everything I can.Lots of nice FET's. relays. connectors, heavy-duty power cord, switches, etc inside.The transformer is not very useful unless you want to rewind it or salvage the copper wire from it.
Old Weller 140W soldering iron NO WORK - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 23, 2017, 12:44:20 am
content: I could get 1 free and it doesn't work with the only 2 tips it has. They are probably brunt up.But how common/likely is it that the winding burn out on these ?

author: Gregg
author_rank: Super Contributor
timestamp: September 23, 2017, 02:09:32 am
content: I have three or four old (like 40 years or more) large wattage soldering irons and never have had the heating element burn up. The usual failure is the conductors in the power cord break and separate beneath the insulation near the handle from too much bending. The other somewhat common failure is the connection from the power cord to the element nichrome wire which often can be repaired with a tiny screw, nut, washer combination. The tips are solid copper and often can be filed to the desired profile and simply tinned with solder (the old school way).

author: jeroen79
author_rank: Frequent Contributor
timestamp: September 23, 2017, 10:03:19 am
content: Is it a magnastat iron?Then the switch could be stuck in the open position.

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 23, 2017, 05:06:47 pm
content: IDk or what model it is, I'll get it soon, and if the tip is gone I'll use some real heavy bare copper wire

author: floobydust
author_rank: Super Contributor
timestamp: September 24, 2017, 12:51:07 am
content: I'd give the Weller some love and repair it with real parts. Because I hate Mickey Mousing tools and they don't work so good. Just my opinion.These larger soldering irons are popular for making stained-glass windows. If you have local shops, they will have the large tips and elements etc. for possible parts.

author: Spaghetti_142
author_rank: Newbie
timestamp: September 24, 2017, 02:05:43 am
content: rectifier I would think. Are you drawing current?

author: gibbled
author_rank: Regular Contributor
timestamp: September 25, 2017, 07:03:44 pm
content: If its the 8200 model they sometimes don't heat well until the tip holding nuts are loosened and tightened again improving conductivity to the formed wire tip.

author: innkeeper
author_rank: Unknown
timestamp: September 27, 2017, 12:48:36 am
content: Quote from: lordvader88 on September 23, 2017, 12:44:20 amnot much can go bad, as long as the primary winding is ok, then its likely easy to fix.quick ohm check across the primary winding can determine that.heck get it and take it apart. worst case you throw it outrepair video:
Older "Bulky" box type voltmeter vs pocket sized multimeter/voltmeter? - Page 1
Forum section: electronics / beginners

author: mike3177
author_rank: Contributor
timestamp: July 13, 2016, 02:26:42 pm
content: Hello guys, I do some hobbying with electronics but am in no means a pro (hence why im posting in the beginners section).Now, I understand the difference between a voltmeter and a multimeter so that is not what I'm asking. My question is more along the lines of "is there a reason that one of the bigger desktop type voltmeters (like this one:https://www.eevblog.com/forum/testgear/hp-3403c-digital-true-rms-voltmeter-annunciator-leds/) would be better than, say, a Fluke 117 True RMS multimeter which is much much smaller?"The reason I ask is because I came across an old impedance analyzer (HP 4192A) and I would like to calibrate it. The service manual calls for the HP 3403C voltmeter and I'm wondering if I should stick to what the manual says or if I should buy a newer true RMS multimeter like the Fluke 117.I can find a lot of discussions about multimeters vs voltmeters but I couldn't really find anything explaining whether a big bulky unit has any advantage over a small handheld size unit.

author: helius
author_rank: Super Contributor
timestamp: July 13, 2016, 02:39:19 pm
content: Horses for courses. Each instrument has its own particular parameters and utility for an intended application. In the case of the 3403C it is an extremely wide RMS sensitivity range (DC to 100 MHz!) That is well beyond the performance of any handheld meter for that specific purpose.In general, benchtop DMMs feature greater precision (more digits), and most have 4 wire resistance measurement (Kelvin connections). There are a few handheld meters that do have these, but not many. Benchtop instruments are also designed more with sophisticated test setups between several devices and controllers, such as GPIB and LXI, whereas handheld DMMs are only available with simple, optically isolated communications to a single computer.

author: dmills
author_rank: Super Contributor
timestamp: July 13, 2016, 02:45:03 pm
content: Quote from: mike3177 on July 13, 2016, 02:26:42 pmThe 4192A (Which by the way is gods own impedance analyser, brilliant bit of kit, nothing modern comes close for certain applications) covers up to 13MHz IIRC, so they may be pushing you to use something that is still accurate a long way from DC.I would be so lucky as to just come across one....Regards, Dan.
Older green resisters. - Page 1
Forum section: electronics / beginners

author: Hammer_651
author_rank: Newbie
timestamp: September 29, 2024, 06:31:52 am
content: Hi all. Can anyone tell me what type of resistors are in this PCB from a 1980 Multi-meter please. They have size but not sure of wattage.Thanks.H.

author: madires
author_rank: Super Contributor
timestamp: September 29, 2024, 11:37:59 am
content: The greenish grey ones should be film resistors. No idea if carbon or metal film. I'd guess, the smaller ones are 0.25W and the larger 0.5 or 1W.

author: Gyro
author_rank: Super Contributor
timestamp: September 29, 2024, 11:46:49 am
content: My guess would be that, with very specific values like 140.6k, they are metal film. Unless broken, leave them as they are.

author: Paul T
author_rank: Regular Contributor
timestamp: September 29, 2024, 09:02:39 pm
content: Looks like older German-manufacture resistors marked with the older DIN standard for ohms as "D".Perhaps the PCB and solder joints need more attention than the resistors?

author: TimFox
author_rank: Super Contributor
timestamp: September 29, 2024, 09:05:24 pm
content: I think that the "D" indicates tolerance, not ohms.Probably 0.5%.

author: Paul T
author_rank: Regular Contributor
timestamp: September 29, 2024, 10:28:29 pm
content: You’re right.

author: Poroit
author_rank: Frequent Contributor
timestamp: September 30, 2024, 07:39:12 am
content: G'day Hammer,What switch ranges are these resistors associated with in your Multimeter?
Older Linear Power Supply Advice - Page 1
Forum section: electronics / beginners

author: glee
author_rank: Contributor
timestamp: September 10, 2012, 11:53:27 pm
content: Hi All,I notice that there are some 1980's model TTi Precision Linear power supplies for sale via eBay which suit my budget. I'm looking for reasons why not to buy these (at about half the price of a Jaycar branded Chinese power supply, for example). Do power supplies have a use by date?Thanks.

author: Simon
author_rank: Unknown
timestamp: September 11, 2012, 06:08:45 am
content: there will be no clear answer to that

author: jackbob
author_rank: Regular Contributor
timestamp: September 11, 2012, 06:16:05 am
content: Linear power supplies don't go bad, however you will get the usual component wear such as caps starting to give in. As long as they were not abused you should be absolutely fine.

author: Chris Wilson
author_rank: Super Contributor
timestamp: September 11, 2012, 10:01:34 am
content: I am currently (excuse the pun...) running a rest home for elderly linear power supplies. I have this knack of finding huge, originally very expensive, high output current supplies that are dead or operating incorrectly. One has a PCB board missing altogether. The good thing about them is most have schematics available, either from the original maker, or somewhere on the web, or from a kindly fellow owner. They are essentially of fairly simple circuitry and construction, so even dead ones can be brought back to life if the transformer is still OK. Buying a working one of good make and keeping it working should be fairly trivial. Expect to find dead electrolytics, or ones that might, for peace of mind, benefit from being replaced. Failed rectifiers and SCR's often take some of the rest of the circuitry out with them, so again, given their low price, it may be prudent to just change them. If it's just a cheap supply you might just want to consider it a throw away item if it goes wrong, but my beasts are all high end, high current ones that are worthy of restoration or component change to ensure long term reliability. If you are into RF, like amateur radio you may already appreciate how "noisy", RF wise, some switched mode power supplies are, which makes linear one more desirable to have around

author: ptricks
author_rank: Frequent Contributor
timestamp: September 12, 2012, 12:58:48 pm
content: Before you purchase see if you can locate a service manual or schematic for the supply. With those in hand you can decide if it is something you want to repair should it need to be done before you spend any money.
Oldschool soviet cooking mixer speed changer - Page 1
Forum section: electronics / beginners

author: skerdzius
author_rank: Contributor
timestamp: November 07, 2013, 09:08:47 am
content: Hello,I have an old soviet union cooking mixer, it's working great, but it has 0, 1, 2 speed modes. I want it to have it's speed regulated via simple potentiometer from 0 to max gradualy. Can I do that, how to connect it and what resistance it should have?0, 1, 2 speed changer it has that V - KD 202 K Diode as noted in schematicschematic given in manual, but I barely can read russian

author: abyrvalg
author_rank: Frequent Contributor
timestamp: November 07, 2013, 10:56:04 am
content: I can:Code:Electric circuit elements:C1,C2,C3,C4 - capacitors of type KT3-11 (ceramic pipe), no value givenL1,L2 - inductors 30uH 1.2AR -metal film thermostable resistors 0.5W, no value givenV - diode KD202K 280V 5AM - motorS - switchX - power cordMost of the parts are for EMI suppression, the speed limiter is diode (cuts one half of AC sine wave).

author: DmitryL
author_rank: Regular Contributor
timestamp: November 07, 2013, 10:57:50 am
content: You can use a simple triac-based dimmer to control speed of this motor. Throw away everything apart from motor and C1 (which is very likely to be mounted directly on it).Such dimmers are used in filament lamps dimming and in mains-powered drillsGoogle "triac dimmer".Some implications:- it might be tricky to fit a dimmer into the existing case (of cause, you can put a dimmer outside the mixer, but it will be weird- don't fiddle with mains if you don't have enough experience. It can be very dangerous.I do appreciate the love to some old ex-Soviet appliances, but can't understand this :-/ (the quality is usually very poor)Why not to buy a normal mixer with proper speed control ?

author: skerdzius
author_rank: Contributor
timestamp: November 07, 2013, 11:14:15 am
content: Quote from: DmitryL on November 07, 2013, 10:57:50 amthank you. I guess this is the answer. I saw triac dimmer implementation on youtube and that's exactly what I want

author: skerdzius
author_rank: Contributor
timestamp: November 07, 2013, 11:16:27 am
content: Quote from: abyrvalg on November 07, 2013, 10:56:04 amthanks for info! It will be useful

author: wraper
author_rank: Unknown
timestamp: November 07, 2013, 08:03:18 pm
content: Quote from: DmitryL on November 07, 2013, 10:57:50 amWhy he would need to throw away all parts including EMI suppression? I would throw away only diode and switch and put there dimmer instead.

author: SeanB
author_rank: Super Contributor
timestamp: November 08, 2013, 04:48:17 am
content: Dead variable speed drill will have a speed controller optimised for an universal motor in it is a small compact package that likely will fit in the space of the old switch assembly. Remove the reversing switch ( it clips off the top easily) leaves you with a 2 wire speed controller that simply replaces the switch. They generally have a variable push along with a small control to give you some preset max speeds. Free with an old drill in the recycling centre.
Oled 128x64 dislay - Page 1
Forum section: electronics / beginners

author: chinoPR
author_rank: Newbie
timestamp: March 21, 2021, 02:25:16 am
content: Hi, I want to control an oled 128x64 but without i2c. I have all the pins, I can't found information or examples , only found arduino and i2c/spi example.. can someone provide me information about how i should design a library, thanks

author: ataradov
author_rank: Super Contributor
timestamp: March 21, 2021, 03:10:55 am
content: What display do you have? They all are different and some only support I2C, so there is no way around it.

author: solhuebner
author_rank: Newbie
timestamp: March 21, 2021, 03:44:42 am
content: Quote from: chinoPR on March 21, 2021, 02:25:16 amThe most common controllers for 128x64 OLEDs (depending on the size) are SSD1306 and SH1106 (sometimes also the SSD1306 "compatible" SPD0301 - not 100%).And if you want to use it via SPI you usually need one that has 7 pins instead of 4 but here is a breakout for the most common controller:https://vivonomicon.com/2018/04/20/diy-oled-display-boards-ssd1306-and-ssd1331/
OLED module +5V noise and PSU undervoltage issues - Page 1
Forum section: electronics / beginners

author: kimballa
author_rank: Contributor
timestamp: January 30, 2024, 04:49:55 pm
content: Hi folks,I have a couple of issues that have confounded my last couple of days at the bench I hope you can help me with.I am working on a circuit that will use the ADC on an Arduino (Adafruit Feather M4 Express) to measure a small signal, so I want a minimum of noise. Testing the Arduino on a breadboard with a DC test analog signal, and configuring it in oversampling mode to get 15 bit resolution, I see drift over a range of 6 counts in 32767 (0.18%) in a one second monitoring period, which is acceptable for the application.When I also wire up a Newhaven 2x16 char OLED module, the ADC drift increases 10x, to 60-70 counts - not OK.The Arduino pulls about 15mA. The oled module adds 25mA load on the 5V bus. When I probe the 5V bus I see a 100mVpp noise signal at 22kHz with the oled plugged in, silence otherwise.A 4R7 in series with the oled power wire (it's connected via a set of 12" 28awg wires to the pin header; in the final application it will be panel mounted so this is a realistic test) does knock the spikes down a bunch, though it's also dimmer due to the 100mV drop. A 100uF electrolytic helps even more - but this would occupy board space that's in short supply near where I'll connect the oled wiring harness to the board so I'd prefer to avoid it if I can. (An LRC filter makes it whisper quiet but uses up even more space and voltage headroom I don't have.)The *weird* part however is that the oled module drags down the voltage beyond what I can account for. If not plugged in, I measure 4.95V on the breadboard rail. With the Vcc wire for the module plugged into the rail it drops to 4.75V! The PSU is a Siglent linear supply. It is not in current limit, it's sourcing only 50mA and the cutoff is configured to 10x higher. With the oled power passing thru the resistor the 5v bus is somewhere in between these voltage extremes, but wanders around unstable.This leaves me confused and also doubting the utility of the filter tests. Is the issue just that breadboards suck? 28AWG jumpers too thin? (I don't have any thicker dupont header jumpers on hand to test with.)In the application I plan to use a 4 layer board with a 5V power plane, and a wiring harness with 24AWG leads for the display. Should I just ignore all this as bench test jankiness and trust it'll work out on the board? Or do I need a filter - or something even more drastic to combat this inexplicable supply undervoltage?I plan to set a 0R jumper on the board near the pin for the Vcc lead that I can replace with 4R7 if needed, I've got space for that at least. The analog and digital domains on the board are also well separated with a solid inner ground plane.

author: jobitjoseph1
author_rank: Contributor
timestamp: January 31, 2024, 12:02:29 pm
content: Most OLED displays will have there own charge pump circuit. If the nice only appears when the display connected, then you can be certain it is from the OLEDs charge pump.
OLED SSD1306 128x32px I2C display power supply - Page 1
Forum section: electronics / beginners

author: bipolunipol
author_rank: Contributor
timestamp: August 09, 2021, 08:48:46 am
content: Hello,I create a system powered by a LiPo battery. It will have an OLED SSD1306 128x32px I2C display and a microcontroller. And I wonder how this display could be powered. According to the documentation:- Pin VDD (Power supply pin for core logic operation) should have a voltage of 1.65V to 3.3V. So I decided to use a 3V LDO stabilizer, which will lower the battery voltage (I assume the range of volatility: 3.2V-4.2V), which varies in a fairly wide range.- The VBAT pin (Power Suppply for DD / DC converter) can have a voltage in the range of 3.5-4.2V. So I decided to power this voltage conventer directly from the battery. I know the battery voltage can go below 3.5V, but I checked it and the voltage conventer works fine for 2.8V, so it shouldn't be a problem here. (The internal converter generates a voltage of VCC = 7V to 15V).So I designed a diagram like this bellow.I added a Q1 transistor to connect the internal DC / DC converter to +3.6V (battery +). According to the documentation, the power should be connected first to Vdd, then to Vbat / Vcc (power to the OLED panel).Now I wonder if this approach is right and is the circuit diagram correct?

author: perieanuo
author_rank: Frequent Contributor
timestamp: August 10, 2021, 09:21:03 am
content: C1+C13 i think are overkill

author: bipolunipol
author_rank: Contributor
timestamp: August 13, 2021, 03:30:54 am
content: Quote from: perieanuo on August 10, 2021, 09:21:03 amI wanted to reduce the impedance of the resultant capacitor this way, but I will see without.And is the power supply from 2 different voltages - voltage regulator (display logic) plus directly from the battery (converter in the display) is ok?
Olympus Fe-230 remote? - Page 1
Forum section: electronics / beginners

author: makerimages
author_rank: Regular Contributor
timestamp: November 13, 2015, 11:16:55 am
content: I have an idea for a build. It involves an arduino-trigerred camera. I have an olympus fe-230 to test with. Has anyone got information regarding remote triggering options for this camera? Something trough the USB would be pretty good. Can go trough a PC aswell if needed.
Omnivision OV5640 camera sensor interfaced to an Arduino - Page 1
Forum section: electronics / beginners

author: pefford
author_rank: Newbie
timestamp: July 14, 2016, 01:50:31 pm
content: Hallo everyone!I want to interface an Omnivision OV5640 camera sensor directly to an Arduino without using a commercial shield, and I wanted to ask if there is someone who had already had some experience in this matter.The Arduino platte will not be relevant at this stage, so that it means I could choose any suitable one.I would do appreciate very much your help and suggestions!Thanking you all very much in advance,Paul
omp-amp circuit - Page 1
Forum section: electronics / beginners

author: belialakos
author_rank: Newbie
timestamp: December 06, 2014, 07:13:20 pm
content: Hello everyone,as i am new with electronics i would to ask a questionif am using the attached circuit how can i find out the output current..?thanks in advance

author: Zero999
author_rank: Super Contributor
timestamp: December 06, 2014, 07:19:26 pm
content: What do you mean by the output current?

author: belialakos
author_rank: Newbie
timestamp: December 06, 2014, 07:24:58 pm
content: if i use the arduino PWM output at 5V to power the omp-amp circuit, how can i get the value of the current at the output of the omp amp?

author: Zero999
author_rank: Super Contributor
timestamp: December 06, 2014, 07:46:34 pm
content: It's still not clear what you're asking for.The PWM output is not powering the op-amp, it's one of the inputs.The current flowing out of the op-amp's output depends on the load connected to it and the voltage. As drawn, with nothing else connected to the op-amp, its output current can be calculated using Ohm's law:IOUT= VOUT/(R1+R2)

author: IanB
author_rank: Super Contributor
timestamp: December 06, 2014, 08:10:16 pm
content: Let me see if I can clarify.The op-amp is being used as an output buffer. The question would be, what is the capability of the op-amp output to drive external loads? How much current can it source (or sink)?

author: belialakos
author_rank: Newbie
timestamp: December 06, 2014, 08:18:38 pm
content: thank you a lot for your repliesthe omp amp is used as a voltage multiplier .in this case it doubles the arduino PWM voltage.you understood the right thing ,my question is how much current can it source.With this circuit i want to control an 1-10v dimming ballast and at its datasheet it is written that the nominal current at the 1-10v terminals is 0.8mA max.here is also the datasheet:http://www.hepgmbh.de/uploads/datenblaetter/Dimmable_ECG_for_2_Lamps_1398845992.pdf

author: IanB
author_rank: Super Contributor
timestamp: December 06, 2014, 08:48:21 pm
content: Yes, the op-amp should be able to supply that much current. You can look at the op-amp data sheet for more detailed information about it.

author: belialakos
author_rank: Newbie
timestamp: December 06, 2014, 09:03:10 pm
content: i am not worried if the omp amp can supplied it , i am worried if the current is too much and burn the ballast.I checked the datasheet of the Lm 358. The only thing mentioned is that typical output current is 20mA.

author: Zero999
author_rank: Super Contributor
timestamp: December 06, 2014, 09:12:14 pm
content: Quote from: belialakos on December 06, 2014, 09:03:10 pmNo that won't happen because the current is determined by Ohm's law - the ballast will take as much current as it needs.20mA is just the maximum current which can be drawn from the op-amp before the current limiter kicks in and reduces the voltage.
Omron clone Yumo E6B2-CWZ3E-1024 - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: October 04, 2023, 07:20:23 am
content: Hi,I have the E6B2-CWZ3E-1024 (voltage output) but the project I want to use it for (Clough42 ELS) specifies the E6B2-CWZ6C-1024 (NPN open collector output), is substituting with the 3E as easy as adding an NPN transistor to the circuit?Reading a bit about it, I think the open collector versions have 5v output independent of the input voltage and my one just outputs pulses at the same voltage as the output voltage, so if I make the input voltage 5v then i should be alright?I found adatasheetbut I don't really understand the circuit diagrams.Thanks.Richard

author: eblc1388
author_rank: Frequent Contributor
timestamp: October 05, 2023, 03:41:26 am
content: Quote from: rthorntn on October 04, 2023, 07:20:23 amNo. You don't have to add anything, simply connects the E6B2-CWZ3E to the Launchpad board and it will work. If you look carefully at the following image, the difference between the two types is a single 2K resistor on the output side, which serves as a pull up. This pull up resistor is probably installed on the Launchpad already so you will now have two pull up resistors working in parallel in your case, but this is still alright because of the small current involve, as long as you are using +5V as power supply for the encoder. The Launchpad J12 header can accept 5V signal without problem.
OMRON NX1P2 PLC Issue - Page 1
Forum section: electronics / beginners

author: Z. Khalid
author_rank: Contributor
timestamp: August 21, 2025, 05:30:05 pm
content: Hi all,Is it possible to transfer the user programme from a bad NX1P2 Omron PLC (SoC chip is defective) to another PLC by installing the defective PLC's NAND flash/SD card board in the new PLC?Thank you!

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 21, 2025, 06:23:02 pm
content: I assume that you can no longer communicate with the bad PLC using the Sysmac Studio software and you don't have a copy of the program and you can't contact the machine builder to get a copy of the program. In that case you can try, it may work. I have never done such a thing but I think it may work,

author: Z. Khalid
author_rank: Contributor
timestamp: August 21, 2025, 07:03:07 pm
content: That is the exactly the case and what is worse is that I couldn't read the programme from another PLC of the same machine because it is locked.

author: BeBuLamar
author_rank: Super Contributor
timestamp: August 21, 2025, 07:43:48 pm
content: Yes I hate that because the machine builder doesn't want you to copy his program. He was afraid that you buy exactly the same components and put together the same machine for less. Well I am sure this is a business thing and not personal. I think the best way is to contact the people who built your machine and ask them to supply with a preprogrammed CPU unit. It's more expensive but I don't think you should waste too much time on looking for solution.At one time I was contracted to write an entirely new program based on what the machine supposed to do because the machine builder refused to give the program.
OMRON P2RF-08-E relay socket mounting question - Page 1
Forum section: electronics / beginners

author: ckambiselis
author_rank: Regular Contributor
timestamp: August 04, 2018, 07:44:59 pm
content: I ordered a few of these relay sockets for a machine I'm building and haven't seen the M3 mounting holes, these have in the middle, on other DIN stuff I have used before, can someone elaborate on how the mounting hole is used, nothing really comes in mind on how it would work on a DIN rail that is mounted in place and couldn't find anything on a quick search. Unless the idea is to use a bolt and nut while the rail is not in place?
On a PCB, what are "tracks" made of? - Page 1
Forum section: electronics / beginners

author: Solares
author_rank: Contributor
timestamp: July 20, 2020, 12:16:00 pm
content: On a PCB, what are tracks made of to make them conductive?

author: jpanhalt
author_rank: Super Contributor
timestamp: July 20, 2020, 12:24:51 pm
content: Usually the same copper used for the PCB. Sometimes,you will see them coated with a layer of solder for increased current carrying capacity.

author: SmokedComponent
author_rank: Regular Contributor
timestamp: July 20, 2020, 12:34:19 pm
content: They are made of gold...GOLD!(Well, not really. Exposed copper is sometimes plated with gold (instead of cheapies like tin, silver, etc...) for corrosion resistance and better contact.)

author: fordem
author_rank: Regular Contributor
timestamp: July 24, 2020, 10:30:11 pm
content: I believe the only place you'll find gold plating on a PCB track is when the track is used as part of an edge connector, and the intent there is better contact - if corrosion resistance is a requirement, conformal coatings are available and less expensive.

author: langwadt
author_rank: Super Contributor
timestamp: July 24, 2020, 11:00:00 pm
content: Quote from: fordem on July 24, 2020, 10:30:11 pmto add, the gold on edge connectors are hard and thick, there is no gold on traces gold is added after the solder mask so it only on the pads and it is very thin, not only for cost but also because too much gold mixed into the solder makes it brittle
On Arduino, digitalWrite LOW = connection to ground? High = short to Vcc? - Page 1
Forum section: electronics / beginners

author: analogo
author_rank: Regular Contributor
timestamp: May 23, 2017, 08:00:40 am
content: What happens electrically when I run execute adigitalWrite(PIN1, LOW)on an output pin on an Arduino? Can I think of the pin as being physically shorted to ground?And what about HIGH? Can I replace the pin in my calculations with a short to Vcc (5v or 3v depending on the model)? Or is there some non-negligible resistor between the pin and the Vcc?

author: Rerouter
author_rank: Super Contributor
timestamp: May 23, 2017, 08:28:58 am
content: When you write the pin to output a 0 or a 1, you are switching a mosfet for that pin, this mosfet has a resistance, and it does vary with temperature and voltage.If you look on the datasheet it will tell you the maximum current per pin, and maximum per device, sometimes they even tell you the driver resistance, still, never exceed those maximum's, and you should be in the right ballpark for what the pins can safely source or sink.

author: danadak
author_rank: Super Contributor
timestamp: May 23, 2017, 10:00:57 am
content: Generally speaking the transistor drive to ground can handle morecurrent than to Vcc with a lower V drop, due to source bulk effecton threshold for the switch to Vcc.http://www.egr.msu.edu/classes/ece410/mason/files/Ch7.pdfhttp://nptel.ac.in/courses/117101058/downloads/Lec-15.pdfAlso, some controllers have an additional limit, the sum of all currentsinto pins on a specific port power domain. Eg. some UPs handle poweron a per port basis.Regards, Dana.

author: analogo
author_rank: Regular Contributor
timestamp: May 23, 2017, 10:16:04 am
content: Quote from: danadak on May 23, 2017, 10:00:57 amThank you Dana, the circuit in the first slide was exactly what I was looking for.BTW, comic sans in the slides of an EE university course?

author: VEGETA
author_rank: Super Contributor
timestamp: May 23, 2017, 11:05:19 am
content: low -> ground voltagehigh -> Vcc voltageBut might not be exactly perfect due to switch drop voltage and heating...etc.

author: Seekonk
author_rank: Super Contributor
timestamp: May 23, 2017, 11:40:02 am
content: Since we are talking at the beginner level, do not forget to declare the pin as an output. Failing to do so will prevent the pin from latching in the state. The pin will go into a floating state at the next instruction. The compiler will not warn you when this is done. It does have a useful purpose.
On delay timer using NE555 timer IC - Page 1
Forum section: electronics / beginners

author: robsims
author_rank: Frequent Contributor
timestamp: December 17, 2022, 06:10:21 pm
content: Hi,I'm trying to make an on delay timer with a NE555 timer IC. I attached the schematic. I can't seem to get it to work. The output stays low 0.000 volts when input 7.00 volts is turned on. Is the schematic good? Many thanks in advance

author: Zero999
author_rank: Super Contributor
timestamp: December 17, 2022, 07:06:29 pm
content: It should work. The output will be low on power on and go high after a delay. A diode in reverse parallel with the resistor will speed up the discharging of the capacitor, when the power is removed.

author: robsims
author_rank: Frequent Contributor
timestamp: December 17, 2022, 07:11:27 pm
content: Quote from: Zero999 on December 17, 2022, 07:06:29 pmMany thanks zero999. I'll try again

author: robsims
author_rank: Frequent Contributor
timestamp: December 17, 2022, 07:34:26 pm
content: Yes it works. The pins of the new NE555 timer had a bit of an oxidized layer on them i think. Scraped them with a knife and now everything works perfect. Many thanks again zero999
On-line UPS - how to check it is faulty or not without batteries - Page 1
Forum section: electronics / beginners

author: dvas
author_rank: Contributor
timestamp: February 02, 2014, 12:37:58 pm
content: Hi,I got a True on-line UPS that looks like being in superb condition, but it is without batteries. I managed to locate the attached document (I removed some non-relevant pages due to doc size) and I found out it runs from 8x 12VDC batteries. Now, I don't have those batteries laying around just for test and I don't know how to test this beast without them.If the UPS is OK, I will be gladly purchase them, but not just for test.Any help is appreciated to help me do the basic troubleshooting if it is working or not.Systel ON-LINE PM1500 UPSNeedless to say, when connected to mains, it looks dead.thanks,Sasha

author: SeanB
author_rank: Super Contributor
timestamp: February 02, 2014, 12:48:49 pm
content: No obvious blown parts, just plug it in and see if it complains about battery fault. If so then it is likely to be working, and you can get 8 7Ah SLA batteries and test it.

author: dvas
author_rank: Contributor
timestamp: February 02, 2014, 12:52:16 pm
content: thanks Sean for quick reply, but when plugged in, nothing is happening... dead.... no LEDs, no beeps,.....

author: SeanB
author_rank: Super Contributor
timestamp: February 02, 2014, 01:36:15 pm
content: So it needs the battery to bootstrap then. You need a power supply that can deliver the required 90VDC it needs then it should start up and complain with no mains connected. If not then it is spare parts.

author: dvas
author_rank: Contributor
timestamp: February 02, 2014, 01:40:56 pm
content: that is my problem. how to get 96VDC supply.another option was that I scrap from different UPSs around some batteries and to ask friends for some more.

author: dr.diesel
author_rank: Super Contributor
timestamp: February 02, 2014, 01:44:23 pm
content: Variac, rectifier and a few caps?

author: SeanB
author_rank: Super Contributor
timestamp: February 02, 2014, 01:52:05 pm
content: And hot gloves.......

author: dvas
author_rank: Contributor
timestamp: February 02, 2014, 01:52:14 pm
content: possible. I will see what can i easily get....

author: dr.diesel
author_rank: Super Contributor
timestamp: February 02, 2014, 01:55:48 pm
content: Quote from: dvas on February 02, 2014, 01:52:14 pmDo be careful, DC is much more dangerous, especially if you got across both the positive and negative leads.
On motor starter voltage drop - Page 1
Forum section: electronics / beginners

author: mindentropy
author_rank: Contributor
timestamp: August 07, 2013, 12:26:23 pm
content: Hi,I am thinking of doing motor control using a MSP430 microcontroller. As I was going through different resources I came across thishttp://lars.roland.bz/controlling-motors-with-an-msp430/In the "voltages and batteries" section there is a line sayingQuoteWhere do I get a voltage drop? Is it on the internal resistance of the battery?Thanks.

author: Kremmen
author_rank: Super Contributor
timestamp: August 07, 2013, 12:56:20 pm
content: Yes. Every real source has an internal resistance. Small batteries or cells have considerable amounts.Two easy ways to work around this issue:1: use a diferent battery to supply the motor and electronics. That way a dip in the motor battery voltage won't affect the voltage the MCU sees.2: take the motor voltage directly from the batery but the MCU supply via a diode, followed by a largish bypass cap, say 100 uF off the cuff. The cap will supply the MCU during the dip, and the diode will preven the motor from sucking the cap dry. Of course the diode will cause a ~.7 V drop so make sure you have margin to the minimum MCU supply voltage.
On PC PSU Im reding PSON 3,86V - Page 1
Forum section: electronics / beginners

author: Vido05
author_rank: Newbie
timestamp: January 07, 2024, 09:27:31 pm
content: Hi guys,I have GR8331 IC and and on input pin 5 Im getting 3,86V as well as on output on PSON, but on purple wire im reading 5vOn left side of R45,R21,R47 Im getting 3,86v but on right side of them Im reading 5v

author: Vido05
author_rank: Newbie
timestamp: January 07, 2024, 10:41:40 pm
content: Oh I just find out that I have two orpc 817c optocoupler in middle of board where red line goesSo I want to test them I voltage should I measure on "hot" side of tows two ?
On sd card connector datasheet picture - Page 1
Forum section: electronics / beginners

author: mindentropy
author_rank: Contributor
timestamp: December 25, 2013, 08:33:33 am
content: Hi,I have ordered a multicomp 412D02F-09PC003SV SD card receptacle connector from element14 (http://in.element14.com/multicomp/412d02f-09pc003sv/receptacle-sd-card-smt/dp/2226409?Ntt=412D02F-09PC003SV). The weird thing is the picture in it makes no sense even inside the data sheet. I have taken some pictures of itThe SD card connector pins looks like it is in reverse. Also the side PCB mounts does not make sense.Can I trust the CAD drawings in the data sheet as I am trying to do my first SD card mounted PCB?

author: codeboy2k
author_rank: Super Contributor
timestamp: December 25, 2013, 09:23:56 am
content: These are available in bottom mount and top mount , so the pins would be flipped, yes.Make sure you get the right one, so the SD card label is facing the direction you want it (up or down) when in your device.The one in your picture on imgur is top mount, it mounts on the top side of a board, and the label faces up when inserted.The one in the picture on farnell is bottom mount, it mounts on the bottom side of a PC board, and the label is still facing up.

author: mindentropy
author_rank: Contributor
timestamp: December 25, 2013, 05:02:08 pm
content: The picture on Imgur is what I ordered and that is the datasheet. Would the bottom mount and the top mount have the same spec?

author: gxti
author_rank: Frequent Contributor
timestamp: December 25, 2013, 09:23:34 pm
content: No, the pinouts will be reversed. Either you got shipped the wrong part, or you are mistaken about which part you ordered.

author: mindentropy
author_rank: Contributor
timestamp: December 26, 2013, 07:05:22 am
content: I ordered the right part as the code printed on the receipts is the same including the order code. They have shipped the wrong part and the funny thing is there is no data sheet for it and to add to it the manufacturer is hiding behind MultiComp (Multiple Companies).

author: ConKbot
author_rank: Super Contributor
timestamp: December 26, 2013, 02:07:41 pm
content: Thats an RP-SD card, mandated by the FCC to be used in equipment that also has RP-SMA/RP-TNC connectors. Something to do with keeping unlicensed consumers from putting uncertified accessories on equipment. Though microSD to RP-SD adapters are easy to get now so its kind of pointless.

author: tszaboo
author_rank: Super Contributor
timestamp: December 26, 2013, 04:51:08 pm
content: Quote from: mindentropy on December 26, 2013, 07:05:22 amMulticomp means "farnell could get cheap from china". I would not trust them with anything more important than 1K 0603 resistor. Use a brand one, even if it costs the double. It is still better than doing a new revision 3 months from now, because farnell stopped having them on stock.