hybridfree/eevblog-posts huggingface dataset:
Can number of joints matter - Page 1
Forum section: electronics / beginners

author: Charkel
author_rank: Contributor
timestamp: May 19, 2018, 11:07:44 am
content: While working with cables that has the be joined together I often wanna add some extra wiring just to make it a bit longer or just to easier make changes to it later by just cutting of a bit of the extra wire.But that would add 1 or 2 extra solder-joint cables. Would that have any risk of disturbing the signal if it's not just the current going through?Of course everything is current but let's say the data wires of the USB cable as an exampleEDIT:Just wanna add that my solder joints on cables are not perfected and often working with thin cables like 7-10 stranded I have a hard time wrapping them together so it's often a strange joint

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: May 19, 2018, 03:56:58 pm
content: Outside of RF applications its probably not going to present any issues.From a mechanical perspective, every joint is going to be a potential point of failure. Its good practice from a reliability standpoint to have single continuous runs of wire wherever they are required, with a single termination at each end (whether it soldered, or a connector). Outside of mission-critical applications this isn't really an issue provided your soldering technique is sound and you can be confident in the reliability of the joints you're creating. Anywhere you're joining wires together with solder will become a rigid joint in otherwise flexible wire, so planning to accommodate adequate strain relief for the joint can go a long way in avoiding issues with joint failure.

author: rstofer
author_rank: Super Contributor
timestamp: May 19, 2018, 05:59:05 pm
content: At higher frequencies, the discontinuity will cause reflections. Just something to watch out for.The entire business of using a time domain reflectometer is based on locating these discontinuities:https://en.wikipedia.org/wiki/Signal_reflection

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 21, 2018, 12:46:19 am
content: Signal speed over USB cables varies ... extremely widely.From 1.5Mbps (any cable will do) to somewhere int the Gbps ( Every small thing becomes critical).Also:For reliable connections, you do not want cables to be able to bend at the end of a solder joint.They break very easily there over time.A trick often used is to feed them through a hole in the PCB and then solder it a cm or so further on.(Or add real pull / bend / stress relief).
Can programming pins on AtTiny84a be connnected to LEDS while being programmed? - Page 1
Forum section: electronics / beginners

author: buck converter
author_rank: Regular Contributor
timestamp: April 27, 2017, 09:20:01 pm
content: So I want to use a Attiny84a-ssu to drive some leds. Can LEDS be connected to the programming pins (sck, mosi, miso) while being programmed?I only need 5 leds, but i am etching single layer boards at home and it is for a REALLY tiny project. It would make the board layout much smaller if the programming pins were driving the LEDs.I would be programming it with my UNO and the Arduino IDE.

author: ataradov
author_rank: Super Contributor
timestamp: April 27, 2017, 09:59:52 pm
content: Yes, they can. I do it herehttps://github.com/ataradov/logic/blob/master/hardware/logic_probe_v2.pdf, for example.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 28, 2017, 01:58:17 am
content: yes you can as long as you have high impedance to the led or anything for that matter. (the high value resistor, such as R4 R5 R6 in Alex's diagram)
Can some one check if my Arduino Nano V3 circuit will work as intended? - Page 1
Forum section: electronics / beginners

author: whileloop
author_rank: Newbie
timestamp: November 25, 2014, 02:27:21 am
content: I'm working on a robot project. I will program these pins on the Arduino IDE:IR Distance Sensor -> A0bottom servo -> 10top servo -> 9left servo -> 11top photoresistor -> A1bottom photoresistor -> A2The servos are rated for 5-7 volts, and the IR sensor is also rated safe at 5volts. The photoresistors are within the rated voltage range as well.What I'm most confused about is the power supply. I will have the 5 volt (+) connected to the VIN, and the GND to (-). Is this the proper setup?Will my configuration work as intended?Thank you for your timeCircuit Photo:http://epicness.us/img/circuitDiagram.pngArduino Nano V3 photo (without circuit):http://epicness.us/img/nano.png
Can somebody explain this circuit? - Page 1
Forum section: electronics / beginners

author: Zillolo
author_rank: Contributor
timestamp: February 24, 2014, 06:42:35 pm
content: Hello friends,I was wondering if anybody could help me understanding this circuit. I dont understand how the part with the Tristate-Logic works.Also what is the stuff in the lower right about?Thanks, if anybody can help meSN74AC245N :http://pdf.datasheetcatalog.com/datasheet2/2/04s23w7ofajcr2cwwiz11icct2wy.pdf

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 24, 2014, 08:06:13 pm
content: What is there to understand? The Tristate output never comes into play because pin 19 on both chips is hardwired to ground. That pin needs to see a high to put the outputs into the floating state, and it can never get there. The way things are set up on IC1, whatever goes in on an "B" input comes out on the corresponding "A" output. IC2 is set up via jumper P1 to be just the opposite, Data in on A lines, out on B lines.The thing in the lower right is a "title block". It gives information on who made the drawing, when it was drawn, what it is used on, etc. That one is pretty basic. On mechanical drawings, they also include stuff like scale, surface finish, material specs, etc.

author: Zillolo
author_rank: Contributor
timestamp: February 24, 2014, 08:13:31 pm
content: Quote from: N2IXK on February 24, 2014, 08:06:13 pmSorry, my brain was malfunctioning again. I obviously meant the lower left corner.Do you know of any reason anybody would hardwire pin 19 to ground?

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 24, 2014, 08:16:46 pm
content: Because their application doesn't need the tristate capability?The stuff in the lower left shows the distribution of the 5V power supply rail. It has a power indicator LED, a reverse protection diode, and 3 bypass capacitors. 5V power goes to each of the '245 chips via pins 20 and 10.

author: kc9qvl
author_rank: Regular Contributor
timestamp: February 26, 2014, 01:00:53 am
content: Building a cnc something? If you are going to build a design similiar to this Think I would just use one as output and one as input. and forget about theopto couplers, pwm, etc. Might be better to have more switches for things like end stops.
Can somebody review my PCB?  (re: first PCB;  simple I2C EEPROM to HDMI adapter) - Page 1
Forum section: electronics / beginners

author: sofakng
author_rank: Regular Contributor
timestamp: September 29, 2023, 05:58:33 pm
content: I've tried to design a simple I2C EEPROM to HDMI adapter:https://oshwlab.com/jklimek/hdmi-dummyIt uses anonsemi CAT24C208I2C EEPROM to connect to the DDC pins of the HDMI connector. This is usually called a "dummy" or "ghost" adapter that pretends a monitor is plugged into a video card. This project is different because it uses a more advance EEPROM that supports E-EDID and 512 Kb using segment pointers.The CAT24C208 datasheet shows the following requirements:47.5k resistor on SCL10k resistor on SDAI'veassumedthe following is correct:Unused pins are grounded (DSP SDA, DSP SCL, and EDID SEL)I've added the following 'features':HPD (hot-plug detect) is pulled-up with 1k resistor [correct value?]0.1uf decoupling capacitor on 5V line (is this ok?)Exposed 5V, GND, SCL, and SDA on pin headersThanks so much to anybody who can take a few minutes to see if I did anything wrong or for any advice.Thanks!!- John
Can someone explain how a crt adjustable width coil adjusts the picture size? - Page 1
Forum section: electronics / beginners

author: DC Jack
author_rank: Contributor
timestamp: August 14, 2025, 01:50:35 am
content: I've been working on an arcade monitor chassis for a while now and I can't quite understand how adjusting the inductance on the "width coil" in turn adjusts the picture size.I'm hoping someone can explain, or point me to the theory behind it.

author: gcewing
author_rank: Regular Contributor
timestamp: August 14, 2025, 02:06:04 am
content: Can't say for sure, but here's what I think is probably happening: The horizontal drive circuit essentially applies a square wave to the deflection coil, and its inductance results in a steadily rising current that produces a linear sweep. The maximum value of the current depends on the inductance, so putting a variable inductor in series with the deflection coil (or equivalently, in series with the primary of the output transformer) allows the width of the scan to be adjusted.

author: amyk
author_rank: Super Contributor
timestamp: August 14, 2025, 04:28:13 am
content: Quote from: gcewing on August 14, 2025, 02:06:04 amThat's exactly it. More details here:https://cdn.badcaps-static.com/pdfs/4e22ec499ec8fa7bc9e10796564c4d75.pdf

author: DC Jack
author_rank: Contributor
timestamp: August 14, 2025, 04:59:57 am
content: Thank you, both. This is amazing info.
Can someone explain this circuit? - Page 1
Forum section: electronics / beginners

author: ElectricPower
author_rank: Frequent Contributor
timestamp: November 02, 2023, 01:16:51 am
content: I know what the circuit under do. It is an known circuit made for protecting a commodore 64 against over voltage. I know that the TL431 works as an adjustable zener that turns off when voltage goes over 5.4V.I also see an P-channel and a small N-channel mosfet.But can someone explain how the circuit actually works and how the electricity flows?I just want to understand what actually happens in the circuit

author: Ian.M
author_rank: Super Contributor
timestamp: November 02, 2023, 02:24:33 am
content: What you think you know isn't so!A TL431 is *NOT* an adjustable 'Zener', and although it can indeed be wired to operate as a shunt regulator, in your circuit, it isn't wired that way. You can think of it as a single-ended OPAMP (i.e. it can only drive low and needs an external pullup to function) powered from its 'Cathode' pin with an internal 2.5V reference wired to its inaccessible +in, and its -in brought out to the Adj pin.In your circuit, its acting as a comparator, comparing Adj to its internal reference, pulling its output low if the Adj pin is higher than the reference voltage.With that misconception corrected, you should be able to analyse the rest of the circuit, determine its trip threshold, and how low the 5V rail must drop to reset it.N.B. it may not be a particularly good circuit as its slower to turn off than it could be, as the N-MOSFET gate charge has to discharge through a total of 7.2K of resistance. A push-pull gate drive circuit could speed that up considerably, reducing the risk of it letting through a high voltage spike.

author: pqass
author_rank: Super Contributor
timestamp: November 02, 2023, 02:57:01 am
content: Here is asimulationof your circuit.Use the "Voltage Input" slider on the right margin to see what happens.Also, see below for screenshots of before and after the trip point.

author: Plinsboorg
author_rank: Newbie
timestamp: November 02, 2023, 09:23:39 am
content: This app note explains a similar circuit to the one you're asking about.https://www.ti.com/lit/an/slva987a/slva987a.pdf?ts=1698852310909&ref_url=https%253A%252F%252Fwww.google.com%252F
can someone explain this mosfet configuration in video #173 #931 - Page 1
Forum section: electronics / beginners

author: apoorv3in
author_rank: Contributor
timestamp: August 30, 2019, 10:19:22 am
content: Hican someone explain these mosfet configuration,as i cannot understand this switch how it is working with body diode in anti parallel configuration.https://youtu.be/xSEYPP5Xsi0?t=1869https://youtu.be/gUpPJ8HLEEA?t=353

author: mikerj
author_rank: Super Contributor
timestamp: August 30, 2019, 01:37:08 pm
content: The diodes won't conduct until the voltage across them approaches the diodes Vf (~0.5v for a typical MOSFET at room temperature). In the screenshot of Daves video he has shown what the burden voltage of each of those resistors is at full scale, and they are all well below the Vf of a body diode. The diodes will conduct in the event of an overload which will help protect the sense resistors.
Can someone explain what this gizmo is? - Page 1
Forum section: electronics / beginners

author: EasyGoing1
author_rank: Regular Contributor
timestamp: November 21, 2024, 01:44:12 pm
content: Can someone tell me what this gizmo is on this ceramic heating element, and what it does?(see attached image)

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 21, 2024, 01:56:07 pm
content: Temperature switch, opens when a certain temperature is reached, it should be written on it.

author: themadhippy
author_rank: Super Contributor
timestamp: November 21, 2024, 01:56:46 pm
content: looks like thermal switch,things get a bit warm it opens,when they cool down it closes

author: EasyGoing1
author_rank: Regular Contributor
timestamp: November 21, 2024, 02:23:19 pm
content: Quote from: themadhippy on November 21, 2024, 01:56:46 pmAnd is that temperature selected because if the heating element got hotter than that, it could be damaged?

author: Zero999
author_rank: Super Contributor
timestamp: November 21, 2024, 02:37:25 pm
content: Quote from: EasyGoing1 on November 21, 2024, 02:23:19 pmIt depends. There are three different types: auto-reset, manual-reset and non-resettable.If it's auto-reset, then it might be used as a thermostat, in which case, if there's a risk of fire due to it overheating, there should also be a manual or non-resettable thermal fuse, which might be a different type.It might be there in addition to a thermostat, in which case, it could any of the three types.

author: Siwastaja
author_rank: Super Contributor
timestamp: November 21, 2024, 02:49:51 pm
content: Quote from: EasyGoing1 on November 21, 2024, 02:23:19 pmOr start a fire... Think about someone covering the heater with a cloth, or fan stopping due to failure (e.g. seized bearing).This being said, it's a PTC heating element which already self-regulates to produce less heat when overheated, but this is an extra layer of safety (and possibly still pretty important, maybe the PTC still runs too hot when covered).This is very likely a self-resetting one. But those have sometimes very large hysteresis so it might need to cool down a lot before it allows current to flow again.

author: valcher
author_rank: Contributor
timestamp: November 21, 2024, 03:30:18 pm
content: This is a thermostat, one of many -https://honeyvell.energy/wa-data/public/site/electronics/Honeywell%202455R--00980748.pdf

author: BeBuLamar
author_rank: Super Contributor
timestamp: November 23, 2024, 08:29:05 pm
content: Actually the heating element generally won't get damage but what houses the heating element may get damaged and causes fire.
can someone figure this out and build it? - Page 1
Forum section: electronics / beginners

author: damzam12
author_rank: Newbie
timestamp: January 01, 2025, 04:04:59 pm
content: Admin Edit: Video Removed, user is just spamming the video to drive up viewsreferring to this video id like 1k or 5k of these circuit's made and combined to power a usbc pd board with all or the protection features and a battery connected. how much would this be?and how much energy can we expect to get from this configuration.?

author: janoc
author_rank: Super Contributor
timestamp: January 01, 2025, 05:53:11 pm
content: And how many more times are you going to spam this crap?Are you trying to drive up traffic for that junk Youtube channel?

author: ataradov
author_rank: Super Contributor
timestamp: January 01, 2025, 06:00:57 pm
content: Do you realize that it "harvests" energy that is in your house, so past the electricity meter? There is no free stuff, this circuit creates load. Normally it is minuscule and does not matter, but if you plan on building something that produces substantial output, it will draw substantial input as well.Just plug in the wireless charger and you will get a way more efficient version of that and you won't need 5000 of them.

author: Aninjaflamingo81
author_rank: Newbie
timestamp: January 01, 2025, 07:35:51 pm
content: Napkin math from the other thread said 25uW of power.... you would need 40k for 1 watt... or 600k for 15w phone charger. (I may be wrong, it's new years day) even at wholesale pricing of components, that's expensive power.
Can someone help identify this chip? - Page 1
Forum section: electronics / beginners

author: nanjo
author_rank: Newbie
timestamp: October 23, 2023, 01:52:05 am
content: Hi,I was wondering if anyone would be able to help me identify this chip. It's used on a small 3 port ethernet switch. I googled the numbers and I couldn't find anything at all about it. Has anyone heard of this HJ company?Thanks.

author: RayRay
author_rank: Frequent Contributor
timestamp: October 23, 2023, 08:08:24 am
content: Never heard of HJ, and couldn't find anything either!I guess it's a custom made chip that isn't publicly available.Anyway, a new 5 port gigabit switch would cost you $10-15, so this isn't really repair worthy

author: coromonadalix
author_rank: Super Contributor
timestamp: October 23, 2023, 10:25:15 am
content: sound like an home made rebrand with a lazer

author: Zenith
author_rank: Frequent Contributor
timestamp: October 23, 2023, 11:01:19 am
content: Chinese manufacturers are well known for removing the ID of chips, or removing it and replacing it with something made up.It's probably a standard chip used in many three port switches, which for some reason they've decided to give a new ID.I assume you want to fix this thing. As RayRay said, you can buy a new 5 port gigabit switch, from a respectable seller, for about $15. That said, it seems like an awful lot of work to identify it, source a replacement, remove the old one, solder in the new one, and with no guarantee of success.

author: SeanB
author_rank: Super Contributor
timestamp: October 23, 2023, 02:20:08 pm
content: From the number of unused pins likely a common 8 port controller with built in SRAM, and with 5 ports unused.
Can someone help me ID this diode? - Page 1
Forum section: electronics / beginners

author: TT_Vert
author_rank: Regular Contributor
timestamp: November 18, 2023, 04:33:08 pm
content: I don't know if it's 26 or maybe Y2, U2 or G2. It's a SOD-882 or similar package. I googled all of these #s to try to figure it out but didn't find much.Thanks much,Dave

author: Kim Christensen
author_rank: Super Contributor
timestamp: November 18, 2023, 04:54:21 pm
content: Have you looked through adatabase like this one?
Can someone help me Identify these components? - Page 1
Forum section: electronics / beginners

author: THATguy
author_rank: Regular Contributor
timestamp: May 07, 2017, 05:38:41 am
content: https://flic.kr/p/Unc5ViFrom left.White/light grey, Pink/violet, Cream/tan, Greenish, Yellow, Brown, Black/navyThe top two white sizes, I'm not totally sure if they are Capacitors.Same for the Pink & Cream top ones that have 8 contacts, these were marked as CN on the PCB.Here is another picture of the 8 contact ones on the Pentium motherboard.https://flic.kr/p/UhAEKYAny idea what E is in this picture?https://flic.kr/p/UkcpB8

author: ataradov
author_rank: Super Contributor
timestamp: May 07, 2017, 05:44:01 am
content: CN is a capacitor network, basically 4 capacitors in the same package. The rest of them look like caps too.

author: THATguy
author_rank: Regular Contributor
timestamp: May 07, 2017, 06:25:45 am
content: Thanks. Any chance the 8 contact ones could be ESD suppressor Array?Oh and I have a feeling the White MLCC's could infact beEMI Noise Suppression Filter, ESD protection device made of silicon.The Mystery item could also beCeramic Resonator, or Balun, or RF passive Coupler.(I just came across images of these components while searching for other things).

author: ataradov
author_rank: Super Contributor
timestamp: May 07, 2017, 06:31:17 am
content: Quote from: THATguy on May 07, 2017, 06:25:45 amNope. Here is what they arehttps://www.digikey.com/product-detail/en/samsung-electro-mechanics-america-inc/CL31B104KACNBNC/1276-2741-2-ND/3888399Quote from: THATguy on May 07, 2017, 06:25:45 amMLCC is a MultiLayer Ceramic Capacitor. They are made out of ceramics and metals, and they are just capacitors.

author: THATguy
author_rank: Regular Contributor
timestamp: May 07, 2017, 06:37:39 am
content: Yes but I believe I've miss identified them as MLCC'sI think the Black/navy are actuallyThe special SMD chip anti-EMI bead ferrites.

author: ataradov
author_rank: Super Contributor
timestamp: May 07, 2017, 06:40:02 am
content: Quote from: THATguy on May 07, 2017, 06:37:39 amSo here is is what you do with components like this - carefully collect them, and put them into a trash bin.They cost fractions of a cent. What's the point of trying to identify them?

author: THATguy
author_rank: Regular Contributor
timestamp: May 07, 2017, 06:50:37 am
content: So I can reuse them.But also so I don't collect the wrong ones.

author: ataradov
author_rank: Super Contributor
timestamp: May 07, 2017, 07:00:18 am
content: Quote from: THATguy on May 07, 2017, 06:50:37 amThat is a really bad idea. The chance of misidentifying is high, and results can be bad. Those things are stupid cheap.
Can someone help me identify this connector please? - Page 1
Forum section: electronics / beginners

author: equalizor
author_rank: Newbie
timestamp: August 19, 2023, 02:57:37 pm
content: This connector is from a BambuLab P1S 3D Printer. Title says it all, I'd just like to identify it.Any help would be appreciated.CheersRob

author: tooki
author_rank: Super Contributor
timestamp: August 19, 2023, 07:57:47 pm
content: To successfully identify a connector, you need to provide multiple clear images from multiple angles, as well as carefully measured dimensions, especially pin pitch (=distance from center to center of adjacent pins).
Can someone help me translate what these readings are on a transistor? - Page 1
Forum section: electronics / beginners

author: requim
author_rank: Regular Contributor
timestamp: January 20, 2012, 06:19:32 am
content: I have a transistor that I think is bad and I have the datasheet for it (or I think it's the right one). The results I get are 0L for everything but red on pin 3 and black on pin 2 which gives me a voltage drop of about 0.5 V. I used a Fluke 87V on the diode setting.I've attached a pdf of the datasheet. What should I be expecting from a good transistor? And what do my readings mean?Thanks!

author: IanB
author_rank: Super Contributor
timestamp: January 20, 2012, 06:40:08 am
content: It's a MOSFET and unless you turn it on it conducts only from source to drain? In other words, it seems to be behaving as the datasheet implies it should behave?Now I'm no expert, so doubtless an EE will be along shortly to put me right.

author: amspire
author_rank: Super Contributor
timestamp: January 20, 2012, 06:55:47 am
content: Quote from: requim on January 20, 2012, 06:19:32 amThose results are exactly what you would expect. It is almost certainly fine.

author: requim
author_rank: Regular Contributor
timestamp: January 20, 2012, 04:35:19 pm
content: Bummer. Looks like I'll have to keep searching to figure out what died on me. It appears something shorted out since I'm getting 0L on a number of circuits on the power supply.For clarification I took readings while it was powered on and the readings I had were:pins 1 & 2 - 168Vpins 2 & 3 - 168Vpins 1 & 3 - 0.2VDoes that seem reasonable?

author: IanB
author_rank: Super Contributor
timestamp: January 20, 2012, 04:43:34 pm
content: Pin 1 is the gate. A voltage on this pin switches on the transistor and allows current to flow between pins 2 & 3.In a power supply the transistor is probably being used to chop up DC into pulses, so you would expect the gate voltage to be changing at some moderately high frequency. You would really need to probe the waveform at the gate to see if this looks right, but that's not easy as the circuit is on the high side of the power supply and is mains live.

author: requim
author_rank: Regular Contributor
timestamp: January 21, 2012, 01:03:12 am
content: I'll re-solder it back into place and pull out the iso transformer and oscilloscope and try probing it. With any luck I won't kill myself or my equipment.What should I look for in the waveform, or should I just post it on youtube and put a link to it here?edit: nevermind.. I think I know what to look for based on your statement of high frequency change..

author: IanB
author_rank: Super Contributor
timestamp: January 21, 2012, 01:23:16 am
content: I think you would be looking for a PWM waveform. The control circuitry will vary the PWM signal on that transistor to regulate the output voltage on the secondary side.
Can someone help to find best alternate for these mosfets - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 05, 2021, 09:55:06 pm
content: Can someone help me to find best suitable alternate MOSFETRUM001L02T2CL‎ (N Channel) datasheet attached‎RZM001P02T2L‎ (P Channel) datasheet attachedThese ones are only available in very small package SOT-723 but i need SOT-23simple requirements are 3.3v 200mA lowest Q currentI tried finding on digikey but it does not show alternate for this item.

author: Simon
author_rank: Unknown
timestamp: February 06, 2021, 10:17:34 am
content: What are they being used for? Depending on use putting the salient characteristics into a distributors parametric search will find you alternatives. Gone are the days of reference books with equivalents and with so many out there something must be a fit.

author: RES
author_rank: Regular Contributor
timestamp: February 06, 2021, 01:12:24 pm
content: For RUM001L02T2CL ; took Vdss 20V / 30V and Id up to 500mA, all SOT-23 packages): (long link!)https://www.digikey.nl/products/en/discrete-semiconductor-products/transistors-fets-mosfets-single/278?FV=570|377049,606|378999,608|147781,608|160341,608|182286,608|192962,608|236753,612|120765,612|136151,612|426106,612|55475,612|55480,612|59403,1291|405399,1291|405400,1291|405409,1291|405410,1291|405431,1291|405436,1291|405446,1989|0,mu20V|2068,mu22V|2068,mu24V|2068,mu25V|2068,mu28V|2068,mu30V|2068&k=mosfet%20N&ColumnSort=1000011&pkeyword=mosfet%20N&cur=EUR&lang=en#

author: sairfan1
author_rank: Frequent Contributor
timestamp: February 06, 2021, 09:35:14 pm
content: Quotethat's good approach, if i know the parameters i can find best suitable myself, and it will help me in future as well.I want to use it for logic level signals, it will be running on battery and i have to take care of lowest currently consumptiononly one MOSFET of them i want to use for powering on ESP8266 (it takes 200mA on avg. and peek current spikes @ 500mA)What else are the parameters I should take care to keep current consumption lowest even while idle. (for both MOSFETs logic level, and powering ESP)

author: rhodges
author_rank: Frequent Contributor
timestamp: February 06, 2021, 10:00:02 pm
content: Just guessing out loud... Would AO3400 and AO3401 work for you? They are rated 30v, 2.5v gate, and well over 1A.
Can someone identify this component for me? - Page 1
Forum section: electronics / beginners

author: OrangeJacketGuy
author_rank: Contributor
timestamp: March 25, 2017, 08:07:02 pm
content: Can someone identify this component for me? Apparently I've got dozens of them.

author: gamalot
author_rank: Super Contributor
timestamp: March 25, 2017, 08:31:53 pm
content: Looks like a 0.33uF/250V capacitor.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: March 26, 2017, 11:27:26 am
content: Yes.

author: Audioguru
author_rank: Super Contributor
timestamp: March 26, 2017, 02:01:57 pm
content: The "K" is 10% tolerance, "J" would be 5%. It is a plastic film capacitor that has no polarity. 250V capacitors were used a long time ago with vacuum toobs.

author: wraper
author_rank: Unknown
timestamp: March 26, 2017, 02:26:36 pm
content: Quote from: Audioguru on March 26, 2017, 02:01:57 pmBut they did not look like anything like this, and usually had paper dielectric. 250V rating has not anything to do with tubes and is still used for a hell a lot of things.
(SOLVED) Can someone PLEASE explain how I'm wiring the LM317 wrong????? - Page 1
Forum section: electronics / beginners

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: April 02, 2021, 10:08:58 pm
content: Seriously, I want to pull my hair out. With (https://ibb.co/80n1knK) wiring of my LM317, feeding in 12V, I get ~10V at the output tab! With (https://www.st.com/en/power-management/lm317.html) calculator, I should be getting ~5V!I'm so frustrated trying to get this to work. Please help.Edit: I've also used 2 different LM317's (both branded ST), so I don't think it's a faulty part. I think I'm just being stupid and wiring it wrong, and it's so frustrating.

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 02, 2021, 10:24:20 pm
content: Something is wrong. If you have 10V instead of 5V, then there is a broken wire or broken contact.First picture is unclear. Is resistor 240 R - a potentiometer?700/240 R resistors must give 4.9VDC at the output, if everythyng is ok.

author: wraper
author_rank: Unknown
timestamp: April 02, 2021, 10:29:14 pm
content: How it comes that a wire to 700 Ohm resistor is going from the middle of 240 Ohm resistor?

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: April 02, 2021, 10:30:18 pm
content: Here's another image of it [dead-bug style](https://ibb.co/sjX9hKZ)Hopefully this slightly clears up what I'm talking about.I'm glad I'm somehow doing the circuit wrong!Edit: 12V Pos + Neg is being fed into both legs of the capacitor

author: wraper
author_rank: Unknown
timestamp: April 02, 2021, 10:33:23 pm
content: You connected 680 Ohm resistor from output pin to GND, why do you expect it to work?

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 02, 2021, 10:37:46 pm
content: First leg must has both two resistors connected, but not one.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: April 02, 2021, 10:47:20 pm
content: I'm a bit confused. Sp

author: Andy Watson
author_rank: Super Contributor
timestamp: April 02, 2021, 10:51:14 pm
content: Attach the 680 between adjust and output. Attach the 220 between adjust and ground.

author: LooseJunkHater
author_rank: Frequent Contributor
timestamp: April 02, 2021, 10:52:33 pm
content: WOOPS. Wow that was a silly mistake. Now it works and produces ~5.1V on both resistors.Thanks for the help! Solved!

author: Vovk_Z
author_rank: Super Contributor
timestamp: April 02, 2021, 11:18:19 pm
content: Quote from: Andy Watson on April 02, 2021, 10:51:14 pmVice versa?

author: Andy Watson
author_rank: Super Contributor
timestamp: April 02, 2021, 11:32:49 pm
content: Quote from: Vovk_Z on April 02, 2021, 11:18:19 pmPossiblyGood catch.

author: Terry Bites
author_rank: Super Contributor
timestamp: April 03, 2021, 04:32:58 pm
content: What's the deal here? It's a standard jellyfish part!
Can someone recommend a synchronous dc boost/buck converter? - Page 1
Forum section: electronics / beginners

author: vgamesx2
author_rank: Regular Contributor
timestamp: February 01, 2016, 04:12:14 am
content: The title is mostly self exploratory, does anyone know of a boost/buck converter I can buy? or help me build one?I want something similar to the LTC3780s from china, with about a 1V to 30V range for input and output but something higher spec such as the LT8705 would be nice too and I need it to be very efficient as I plan on using this for charging/discharging batteries, but I also need current control as I plan on using it as a portable bench power supply.Why do I need this and not any of the hundreds of dc converters on ebay? well I have a small solar system with a couple lead acid batteries and I'll often want a lot of different voltages, as high as 19.5V to charge my laptop or as low as 5V to charge power banks, phones, etc.. for example thus I need something that can both boost and buck but of course since I'm dealing with batteries I also need that high efficiency so I don't throw away over 10% of my power through heat alone.Any suggestions? Thanks.
Can someone say what is this detail? - Page 1
Forum section: electronics / beginners

author: tpd
author_rank: Contributor
timestamp: November 11, 2022, 06:50:26 pm
content: As I can see on it is written 152K 8175. If tested with ohmmeter is shows 0,5 Ohm in both directions (almost a short circuit).Best regards and thanks

author: tunk
author_rank: Super Contributor
timestamp: November 11, 2022, 06:58:03 pm
content: Please post a photo.

author: Jon_S
author_rank: Contributor
timestamp: November 11, 2022, 07:16:13 pm
content: That sounds like an inductor.The first numeric part would be the value: 152 becomes 15 * 10^2, but there are a couple of choices for what the 'base' units for that are (nH or uH, usually). If it was uH then you would have a 1.5mH inductor. If it was nH then you have a 1.5uH inductor.If you don't have an LCR bridge then I would go by the physical size to guide me, a 1.5mH inductor with a low-DCR is going to be physically bigger than a 1.5uH inductor with a similar DCR.The 'K' means the tolerance is 10%.The 8175 is possibly a batch/date code.

author: bidrohini
author_rank: Regular Contributor
timestamp: November 15, 2022, 04:33:00 am
content: I think, posting a picture will be better.
Can someone tell me what this component is? - Page 1
Forum section: electronics / beginners

author: Andrew LB
author_rank: Contributor
timestamp: January 09, 2021, 08:53:44 pm
content: So ive got this medical device thats basically a beverage cooler that sends either heated or chilled water through a pump a pad that wraps around your knee and while i had no problem identifying most parts of the system (bridge rec, thermal fuse, cartridge heater, etc)... one part is confusing the hell out of me. It appears to have written on it "V7 AM" and in very faint letters "016A5" and "H 32". below is a photo. I bet its something stupidly obvious but i'm not an EE and my knowledge of such stuff is pretty basic.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 09, 2021, 09:09:28 pm
content: It looks like a heater with a spiral of wire inside.

author: Andrew LB
author_rank: Contributor
timestamp: January 09, 2021, 09:48:45 pm
content: Here's the back of it. It's small. And i just now noticed it says "VICTOR" on the rolled metal edge. The cartridge heater that was in the unit was about 4 inches long and 1 inch wide.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 09, 2021, 09:53:15 pm
content: Maybe it's a shunt or a damping resistor. Or two electrodes. Have you tried exploring?

author: Andrew LB
author_rank: Contributor
timestamp: January 09, 2021, 09:53:35 pm
content: And that VICTOR just got me the answer. It is a Snap Action Thermostat/Current Protector V7AM.https://www.victor-tw.com/productshow.php?cid=14&id=22
Can someone tell me what this is? - Page 1
Forum section: electronics / beginners

author: darrenb
author_rank: Contributor
timestamp: July 28, 2020, 02:14:33 am
content: I'm trying to figure out a circuit but have no idea what this weird looking little glass thing is. Any clues?

author: jmelson
author_rank: Super Contributor
timestamp: July 28, 2020, 02:28:57 am
content: It is a diode, and guessing by the marking "Z2" it is likely a Zener diode. That is a "MELF" package, an old way to make standard through-hole diodes into surface mountable format. They are mostly obsolete now.Jon

author: darrenb
author_rank: Contributor
timestamp: July 28, 2020, 02:36:38 am
content: Thanks Jon. Awesome reply.Now I have to figure out what it is doing in the position it's in. I'll ask in another post.
can spectrum analyser measure signals below its phase noise? - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: May 12, 2017, 08:52:36 pm
content: Or is phase noise the ultimate limit of how low analyser can go,so if specs say -90db at 10khz offset there is no possible way to see 10khz signals below -90db?

author: w2aew
author_rank: Super Contributor
timestamp: May 12, 2017, 09:09:10 pm
content: Quote from: fonograph on May 12, 2017, 08:52:36 pmThat's not the way Phase Noise is applied. When you see a Phase Noise spec - something like -90dBc/Hz @ 10kHz offset at 1GHz - this means that at a frequency of 1GHz, the "skirts" appearing on either side of the 1GHz signal will be 90dB down from the 1GHz signal when measured at 10kHz on either side of the 1GHz signal (thus, at 1.00001GHz and at 0.99999GHz). Phase noise will limit the ability to see very small signals adjacent to large signals.A better measure of how small a signal can be measured is by looking at the DANL, or Displayed Average Noise Level. This is a measure of the noise floor of the analyzer, and is usually spec'd as something like -150dBm/Hz, which means that at a 1Hz RBW, the noise floor will be at -150dBm. For each order of magnitude that the RBW is increased, the noise floor increases by the same amount. Thus, at a 1kHz RBW, this same analyzer would show a noise floor of -120dBm.
can teensy 3.0 or above run fingerprint scanner fps gt-511c1r? - Page 1
Forum section: electronics / beginners

author: akashmittal
author_rank: Newbie
timestamp: July 30, 2016, 09:19:24 am
content: I have an fps gt-511c1r fingerprint scanner module. I want to know whether i can run it using teensy 3.0 or above?I have already tried it successfully using arduino uno.

author: rstofer
author_rank: Super Contributor
timestamp: July 30, 2016, 02:48:48 pm
content: No reason why not, all it takes is TTL serial.

author: akashmittal
author_rank: Newbie
timestamp: August 03, 2016, 12:23:53 pm
content: The led blink sketch for the fingerprint scanner uploads successfully on the teensy 3.2 board, but there is no response from the fingerprint scanner:( I also tried powering it with 3.3v arduino uno and it worked. So why is it not working with the teensy board? Even when the sketch uploads successfully?

author: rstofer
author_rank: Super Contributor
timestamp: August 03, 2016, 02:07:57 pm
content: Well, it would seem that there is something wrong with the teensy code. Or, maybe there are multiple USARTs brought out and you're not connected to the right one. I think I would start looking at that first. I can see a scenario where they would use a secondary port for the scanner and leave a primary port for the console connection.You're probably going to have to tear into the teensy code and see what it is actually doing.You have an advantage: You know the scanner works with the Arduino so the issue isn't with the scanner. Half the battle is over!

author: ianriley0
author_rank: Newbie
timestamp: August 03, 2016, 03:02:11 pm
content: Fromthe datasheet, it looks like looks like the scanner only works down to 3.3V; are you sure that the voltage supplied to the sensor by the teensy isn't drooping under load?

author: akashmittal
author_rank: Newbie
timestamp: August 03, 2016, 08:02:29 pm
content: maybe problem lies in the library of the fingerprint scanner. The .cpp file uses software serial. But teensy already has a bunch of hardware serial uart pins.
Can the "slip" of a fixed frequency induction motor be used to estimate power?  - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: May 18, 2016, 01:19:40 pm
content: I have a single phase induction motor and centrifugal pump that pumps water through a filter that gets clogged over time.As the flow decreases, does the motor speed increase and get closer to the line frequency? In other words does the rotor slip decrease because it is moving less water and therefore doing less work?In theory it sounds like it should but I don't know in practice and I don't have an easy way of clogging the filter to do the experiment.If this is correct it would be an easy way of measuring the flow rate without installing flow meters.Mike

author: amiq
author_rank: Regular Contributor
timestamp: May 18, 2016, 01:24:41 pm
content: Hello Mike, yes the slip can be used to estimate the output power. But you'd have to test your pump to see how it behaves when blockages are introduced.

author: Zero999
author_rank: Super Contributor
timestamp: May 18, 2016, 03:33:27 pm
content: What sort of pump is it?

author: TimFox
author_rank: Super Contributor
timestamp: May 18, 2016, 03:41:49 pm
content: In an induction motor, there is a curve for rpm vs. torque, where the slip (rpm less than synchronous frequency) goes to zero at zero torque (although there is always some torque required for the bearing). You could use the manufacturer's data curve to estimate the torque for a measured rotational frequency.

author: Delta
author_rank: Super Contributor
timestamp: May 18, 2016, 04:00:39 pm
content: If it's a positive displacement pump, the mechanical load on the motor, and therefore the slip, willincreaseas the filter clogs, due to the increase in backpressure.If it's a centrifugal pump, the load (and slip) will decrease as the increased backpressure results in a reduction in flow. (I think...)

author: Seekonk
author_rank: Super Contributor
timestamp: May 18, 2016, 08:37:09 pm
content: I think I would look a phase angle between voltage and current.

author: G7PSK
author_rank: Super Contributor
timestamp: May 18, 2016, 08:43:16 pm
content: If the filter is on the output side of the pump the load on the motor increases as the pressure rises, dose not matter whether that is due to the head height or restriction on flow. If the filter is on the input side less fluid in the pump will reduce the load but either way with an induction motor the speed will not vary very much. It would be better to put a pressure sensor in the filter.
can the hantek dso5072p measure 220v mains ? - Page 1
Forum section: electronics / beginners

author: raff96
author_rank: Newbie
timestamp: May 04, 2017, 08:17:34 pm
content: I have the hantek dso5072p , and i've read that it can handle a max input voltage of 300VRMS with the 10x probe , does that means that it can handle 220v non rms (i don't own a true rms meter )?In the channel menu i can also select the probe (1x,10x,100x,1000x) , if i set the 100x probe there , does that mean that the scope is doing 100:1 rateo or it's just there to let the scope know that i have a 100x probe ?

author: electr_peter
author_rank: Unknown
timestamp: May 04, 2017, 10:11:56 pm
content: Hi,Short answer - do not measure mains with your oscilloscope. It is dangerous(to you and oscilloscope) because oscilloscope and probes that come with it are not rated for such voltages.Scope cannot handle 300V RMS safely. 1x/10x probes that come with it also are not rated for 300V RMS. And you can inadvertently turn on 1x mode...Question is why you need to measure such high voltages with scope at all. It is not suited to that purpose and you seem to lack experience in this area. So do not do it just because you want it. It is serious.To measure high voltages safely, you would need isolated high voltage probe. EEVblog has one for sale, other manufacturers make them as well.Quote from: raff96 on May 04, 2017, 08:17:34 pmWrong unless special probe is used. Typical probes are not suitable for such high voltages.QuoteNot enough information to tell. RMS has meaning for all waveforms, so 220Vnon RMSis meaningless. What kind of waveform do you want to measure?QuoteSetting on scope only changes scale units on screen. With 1V input, 1x setting will show 1V on LCD display. 10x will show 10V, 1000x will show 1000Vfor the same 1V input.SW settingdoes not changeanything in hardware, so you cannot apply 10/100 or 1000 higher voltage. High voltage will blow scope inputs.

author: raff96
author_rank: Newbie
timestamp: May 05, 2017, 06:00:04 pm
content: Thanks for the answer ,i don't want to measure the mains , but i wanted to know if i was able to do it.What's the max voltage that the standard probe can handle (safely) ? right now i only use it with less than 50v because i know it's safe to touch .
Can the IRF1405 realy switch 169 Amps at 10v ?! - Page 1
Forum section: electronics / beginners

author: whatsthegeek
author_rank: Contributor
timestamp: November 03, 2017, 09:20:11 pm
content: Hi, I bought a couple of IRF1405 after reading in the datasheet that they can switch up to 169 Amps. Is it real or do I not undertsand the datasheet ?If so, can I paralelle them to get even higher power ?Datasheet:https://www.infineon.com/dgdl/irf1405pbf.pdf?fileId=5546d462533600a4015355db084a18bb"Continuous Drain Current, VGS @ 10V: 169A"Sorry, probably a n00b questionThanks !

author: stmdude
author_rank: Frequent Contributor
timestamp: November 03, 2017, 09:36:14 pm
content: So, the (6) note on the line you copied into the post says:"Package limitation current is 75A."You'll also need to calculate the thermals for it to see if you can dissipate the heat well enough for the junction temperature to not exceed 175C.It's a TO-220 package. Don't expect miracles from it. Like being able to pass almost 1.7KW of power.

author: whatsthegeek
author_rank: Contributor
timestamp: November 03, 2017, 09:47:34 pm
content: Oh ok, thanks a lotSo, how can I calculate the maximum amps I can pass though it know the voltage and the power dissipation ?Thanks !

author: danadak
author_rank: Super Contributor
timestamp: November 03, 2017, 10:33:51 pm
content: You can back into it from max Tj you want to limit to, using thermal Rof heatsink that will tell you for worst case ambient T how much poweryou can dissipate. Then you can compute the current voltage conditionsfrom the max Pdiss at your max Tambient and Tjunction.Google this - "computer heat sink requirements calculator java"Regards, Dana.
Can the low cost thermal cams (Seek, FLIR ONE) be used without a cellphone? - Page 1
Forum section: electronics / beginners

author: alsetn
author_rank: Newbie
timestamp: May 11, 2015, 04:28:20 am
content: I'm interested in taking the imaging from these modules and transmitting it via wifi or radio. Does anyone know how to interface the signals to Bluetooth or?TIA
Can the NCP5359 be used with an external charge pump? - Page 1
Forum section: electronics / beginners

author: ConnorGames
author_rank: Regular Contributor
timestamp: September 02, 2012, 05:59:17 pm
content: I am trying to make an H-Bridge with n-channel switches for high and low side (as much for the challenge as for the performance boost), and am trying to drive them with the NCP5359, but so far I've been met with limited success. I do not want limited duty-cycle, so I am trying to use it with an external charge pump for the upper FET. Should I just use a BJT+resistor to drive the high side FET? Or can I use the NCP5359? So far, it seems it is meant for bootstrapped operation only, and is kind of fragile(only tolerates -1v on the switch node pin), and fails by causing shoot-through! Yuck!.Thanks -- Connor