hybridfree/eevblog-posts huggingface dataset:
Help with calculating - Page 1
Forum section: electronics / beginners

author: DMagus
author_rank: Newbie
timestamp: March 07, 2020, 09:59:11 pm
content: How can I calculate the voltage, current and power for each of the resistors in this circuit?

author: Zero999
author_rank: Super Contributor
timestamp: March 07, 2020, 10:26:12 pm
content: When does the homework have to be done by?

author: ataradov
author_rank: Super Contributor
timestamp: March 07, 2020, 10:26:59 pm
content: You want us to do your homework for you?What are your thoughts on this?

author: DMagus
author_rank: Newbie
timestamp: March 07, 2020, 10:32:22 pm
content: In two days. I'm starting to learn electronics so I was trying to figure out how to calculte what I say, but I have no clue where to begin.We were learning that when a circuit is in series the current is the same for all the resistors and the current splits between them and when the circuit is in parallel is the opposite.What confused me is that all of the resistors aren't only in series or parallel, so maybe I have to calculate a equivalent resistor to find the other values?I dont want the full resolution, just some insight in how to begin to calculate.

author: ataradov
author_rank: Super Contributor
timestamp: March 07, 2020, 10:34:11 pm
content: Yes, start with calculating a total resistance. This will let you calculate current out of the voltage source.

author: Zero999
author_rank: Super Contributor
timestamp: March 07, 2020, 10:52:30 pm
content: Start with R2 and R3, which are in series, so that's 1290 Ohms. Now you can work out the resistance of 1290 Ohms in parallel with 680 Ohms.Once you've got the total resistance, you can calculate the current. The voltage across R1 is easy to calculate V = IR. The voltage across R4 will be equal to V1- V(R1).You can check your working with a simulator such as LTSpice or falstad.https://www.falstad.com/circuit/
Help with charge amplifier circuit for piezo disk - Page 1
Forum section: electronics / beginners

author: teslinius
author_rank: Regular Contributor
timestamp: August 02, 2021, 10:55:39 pm
content: I have a project where i will use a piezo disk, after some online search i found that charge amplifier circuit is most suitable, i found it on this websitehttps://www.allaboutcircuits.com/technical-articles/how-to-design-charge-amplifiers-piezoelectric-sensors/but it doesn't mention what component value should be used except for Rin, what value should Cp(100pF?), Cf(10nF) and Rf(100k) be?Best regards.

author: TimFox
author_rank: Super Contributor
timestamp: August 02, 2021, 11:07:08 pm
content: Cfdetermines the gain of the amplifier in Volts/Coulomb (V/Q= 1/C).Rfdetermines the low-frequency response of the amplifier and the decay time of the output from a pulsed charge. Without it, the circuit would integrate its DC offset until the output hits one or the other limit of the amplifier.I thinkCpin your circuit is the actual capacitance of the piezo disc.To get real component values, you need to specify these performance requirements on your circuit.

author: Terry Bites
author_rank: Super Contributor
timestamp: August 03, 2021, 08:13:08 am
content: Here's thorough guide. High Impedance Charge Output SensorsSensor Signal Conditioning (part 3).pdf(484.85 kB - downloaded 1371 times.)

author: teslinius
author_rank: Regular Contributor
timestamp: August 03, 2021, 10:10:17 pm
content: I want the piezo disk to detect when a object is moved, circuit will be supplied by a liion battery (3-4.2V), piezo capacitance is around 5 nF, i don't know if it's correct but i got Cf value around 8nF, what value should Rf have IS 100K ok?
Help with choosing a Waveform Generator, now looking at the Siglent SDG2042 - Page 1
Forum section: electronics / beginners

author: LPS
author_rank: Contributor
timestamp: December 08, 2016, 01:42:08 am
content: Hi All,I want to get my final purchase which is a Waveform Generator for a pre Christmas delivery. I’m looking to get back into hobby electronics, projects, learning. Budget US$350 to US$500.Either a Rigol DG1022Z or SDG1032X, or if I go for the upper end of my budget a Rigol DG1032Z or SDG2042X. Been watching the videos and reading up.Actually the top of my list is the Siglent SDG2042X, it features the highest bandwidth, 40Mhz, of the group I am looking at, touch screen and the only one with 16 bit resolution. I don’t see any down side but because a seemingly lesser spec 30Mhz 14 bit Rigol DG1032Z is about the same price, I feel maybe I am missing some information as to why the Rigol is set at about the same price.I would appreciate any comments and suggestions as to my first choice of the Siglent SDG2042X. Also any comments on the current state of unlocking extra features (bandwidth) would be welcome.thanksLen

author: alank2
author_rank: Super Contributor
timestamp: December 08, 2016, 03:08:20 am
content: I love my SDG2082X - I don't think you can go wrong with the SDG2042X. It is one of my favorite tools to use.

author: tautech
author_rank: Super Contributor
timestamp: December 08, 2016, 03:48:21 am
content: SDG2042X is currently the forum favourite and has its own thread that probably has the most up to date on these units on the web:https://www.eevblog.com/forum/testgear/the-siglent-sdg2042x-thread/(improvement info within)If you want to use a EEVblog member discount you can ask for the code here:https://www.eevblog.com/forum/testgear/equipment-discounts-from-saelig/

author: K2CK
author_rank: Newbie
timestamp: December 13, 2016, 05:55:23 pm
content: I've been using the SDG2042 for a couple of months. I have nothing bad to say about the sig gen. Take a look on-line for ways to improve it. Also take a look at the reviews and teardowns. I think you'll be impressed.Regards,Scott

author: julian1
author_rank: Frequent Contributor
timestamp: December 13, 2016, 08:21:53 pm
content: The Rigol DG1032Z has a 200 MSa/s generation sample rate. The 2042X has a 1.2G/s and 16 bit. Ignoring the fact that the prices are similar, they're basically different classes of instrument.
Help with choosing resistors  - Page 1
Forum section: electronics / beginners

author: Johadart
author_rank: Newbie
timestamp: November 27, 2022, 07:27:45 am
content: Hi, I don’t have a 240 ohm resistor, I’m building a power supply, didn’t come with the kit, any suggestions on what to use in place please?

author: connectTek
author_rank: Regular Contributor
timestamp: November 27, 2022, 09:48:37 am
content: A 240 ohm resistor of course, a couple of cents.

author: magic
author_rank: Super Contributor
timestamp: November 27, 2022, 10:23:25 am
content: Either that or a different resistor or a pair of resistorsWhat are the tolerance and power rating specs of the part you want to replace?For example, 220+22 is 242, which is less than 1% off. 220 alone is 10% off.In a pair, the 220 will carry most of the load, so its power spec should match the original part.

author: JohanH
author_rank: Frequent Contributor
timestamp: November 27, 2022, 11:26:55 am
content: The easiest is soldering two resistors in parallel. Use this calculator to calculate parallel and series resistances. You can set it to output values based on resistor series you have.https://www.qsl.net/in3otd/parallr.htmlFor 240 ohm in total, select for instance (based on which resistors you have) 270 in parallel with 2200, which makes it more or less exactly 240 ohm.

author: Johadart
author_rank: Newbie
timestamp: November 28, 2022, 12:44:41 am
content: Thanks everyone for your answers 🤙🏼

author: gbaddeley
author_rank: Regular Contributor
timestamp: November 28, 2022, 01:57:47 am
content: Or two 120 ohms in series. Perfect power sharing.

author: themadhippy
author_rank: Super Contributor
timestamp: November 28, 2022, 02:11:07 am
content: Quotesounds suspiciously like it could be based around something like a lm317? is so you can change the 240 ohm to something else and recalculate the other resistor

author: JohanH
author_rank: Frequent Contributor
timestamp: November 28, 2022, 08:35:00 am
content: Quote from: themadhippy on November 28, 2022, 02:11:07 amThere are online calculators for that, too!https://circuitdigest.com/calculators/lm317-resistor-voltage-calculator

author: Johadart
author_rank: Newbie
timestamp: December 16, 2022, 02:07:54 am
content: Thanks for all your help, got it done. Cheers 🤙🏼🇦🇺

author: Terry Bites
author_rank: Super Contributor
timestamp: December 16, 2022, 08:11:11 pm
content: I think themadhippy is right on the money here. If its for a regulator feedback divider just use 180 to 330 and recalculate.www.omnicalculator.com/other/lm317If it doesn't carry more than few mA any series or parallel combo will do. 2 470s in II will give you 235. Good enough?
Help with circuit involving old composite video. (Experienced needed) - Page 1
Forum section: electronics / beginners

author: rickey1990
author_rank: Regular Contributor
timestamp: May 28, 2015, 06:57:58 pm
content: Okay so my problem is iv come across a circuit that takes a video signal and maps that signal onto a LED array. I am wanting to use the circuit as a micro-controller-less eye for a robot. There's a description and simplified circuit diagram but i am not sure how they go together.Written information,BEAM circuits are very similar to the older analog type video technology, still used in simple B/W TVs and 20 years ago all televisions used analog beam like circuits for decoding video signal. So it's not surprising that it is fairly simple to use BEAM circuit blocks to convert video into digital or analog signal suitable for interfacing with other beam circuits. In the example suggested by Dennison below, The video signal is converted into a 2x2 matrix which corresponds to the average light level of a quadrant of a video frame. The attached block diagram shows the general concept of such BEAM video decoder.A composite video signal (ie a sugar cube camera output) is processed by a sync separator to produce Horizontal and Vertical sync pulses as well as a DC restored video signal. This circuit requires some 2N3904s and a few passive components. The H and V sync signals each trigger a Hsync Nv and Vsync Nv (74HC14) respectively which are adjusted to time out at a point corresponding to the horizontal and vertical midpoint of the screen. The signals are connected to one half of a 74HC139 (Z bridge) which generates 4 control signals corresponding to each screen quadrant. These 4 Q signals are used with four 4066 analog gates to route the video signal to one of 4 Nu (74HC14). The analog voltage on each Nu cap corresponds to the average video signal of that quadrant This can be used to "influence" a central pattern generator like a microcore. A digital signal can be generated with a one bit A/D converter also know as a comparator or Schmitt trigger. If the video level on the Nu cap is above the trigger level of the comparator, a LED turns on. A bright light moving from one quadrant to the next, will turn on the corresponding LEDs indicating the relative position of the light.This concept can be scaled up to a low resolution "gray scale" (or red scale) monitor (ie 8 by 8 LED matrix) which can also be easily made with a V and H chains of 8Nvs each buffered with HC240 LED drivers which can drive 64 LEDs in real time. The video signal is "sliced" by a comparator the output of which drives the HC240 tristate enable lines. No Nu stages are needed to measure the average video since your eyes will do a visual integration of the LED light level. Any old video signals can be used for experimenting with this concept including a camcorder or VCR video output.regardswilf
Help with circuit test - Page 1
Forum section: electronics / beginners

author: cmumford
author_rank: Contributor
timestamp: June 09, 2018, 11:31:07 pm
content: I'm fairly new to electronics and I'm currently assembling a software defined radio kit called theSoftRock Lite II Combined Receiver Kit. I love the kit and after each build stage the instructions have a set of tests to verify that the stage was properly constructed. The functional tests for theOp Amppass - sort of, and I'm not sure there is a problem or not. In short they pass, but if I leave the circuit energized for > 20 seconds the current draw steadily increases from 29 mA, up to 100 mA where my current limit is set. The voltages also drop. If I de-energize the circuit and immediately re-power it, it's right back up to 100 mA, but if I leave it disconnected for 24 hrs. or so then it's back down to 29 mA. So... a few questions:I know capacitors will hold a charge, but I don't see how this would result in increasing power draw. What could cause thisIs the increased current draw indicative of a problem, or could this be normal?The kit author is retired and no longer supporting it which is why I'm reaching out here. Here's theschematicif anybody is interested.Any advice is much appreciated.

author: bson
author_rank: Unknown
timestamp: June 09, 2018, 11:47:49 pm
content: My immediate suspicion would be you've reverse biased a polarized cap - most likely put it in backwards.

author: cmumford
author_rank: Contributor
timestamp: June 10, 2018, 02:33:38 am
content: Thx bson. I don't see one on theSchematic. All of the symbols are --||-- and none are --|(--

author: digsys
author_rank: Unknown
timestamp: June 10, 2018, 03:03:43 am
content: There's really nothing in that circuit that could draw that current, IF latched accidentally. Even the oscillator is only ~10mA.Your best bet is to check the 5V rail, see if it increases. Also look for warm / hot items. At that current, SOMETHING will be getting HOT !Most DMMs have a temperature sensor probe, or use your pinky finger. Itshouldbe obvious. Maybe a bad track?

author: DC1MC
author_rank: Super Contributor
timestamp: June 10, 2018, 05:10:56 am
content: As somebody else pointed out: capacitors, look at the 4.7uF ones, the fact that in the schematic are non-polarized ceramics doesn't mean that someone didn't put some polarized one (electrolytic or tantalums).Also have a look if the ICs are installed in the correct position (rotation) or place, I had a rather complex board behaving exactly like this because one IC was rotated during assembly. Especially with the new packages where the orientation notch is no so large, it's very easy to overlook, especially for self-assembled boards.Another place to look at is the voltage regulator if it's put correctly in place and produces 5V, I will decrease the input voltage to 8-9V for testing.My bet is either an IC output shorted to ground or Vcc, or a rotated/misplaced IC, usually the misplaced capacitors are much more "energetic" in showing up their displeasure.Best of luck,DC1MC
Help with circuit to manually switch between two in line capacitors - Page 1
Forum section: electronics / beginners

author: Mgmgtech
author_rank: Newbie
timestamp: May 03, 2019, 05:23:46 pm
content: Hello I was hoping somebody might be able to help me design a circuit that when I presson switch or slide switches the power starts running throufg a different inline calacitor.Maybe an idea of what I'm trying to build will help better explain itI build tattoo coil machines these rely on a capacitor usually one of two values for a liner type machine in two different values for a Shader type. These are simply run in line positive power and I might be able to incorporate both types of capacitors used for each machine type until 1 machine prototype I even have 2 capacitors selectable the Shader in two different ones selectable on a liner machineI hope this made sense and some helpful that'll come my way thanks

author: bob91343
author_rank: Super Contributor
timestamp: May 03, 2019, 06:21:49 pm
content: It would make more sense if you would be careful to use complete sentences and proper grammar. I have a lot of trouble understanding what you want to do and what you have.Having said that, why can't you just put in a switch to choose whichever capacitor you want to use?

author: Mgmgtech
author_rank: Newbie
timestamp: May 05, 2019, 08:19:49 am
content: Jeez..I didnt realize how intoxicated i was when i wrote that..Wow i thought i even previewed it before posting, i guess not because thats horrific...I wish i could say english wasnt my native language!Its embarassing and im sorry i even posted that.Thanks for replying bob, what you suggest is essentially what im asking about.Is it that easy to do? Just a simple toggle switch on the wire to swap between the caps.Maybe im over thinking it?Thanks

author: bob91343
author_rank: Super Contributor
timestamp: May 05, 2019, 04:58:42 pm
content: When you change capacitors with a toggle switch the important things are, is there any charge on the capacitors? and if so what current do you expect through the switch when you transfer it? The surge can damage switch contacts. Also, for high frequency work, you need to be concerned about stray impedances. And the voltage across open contacts must not exceed the switch rating. Arcing across open contacts can damage them.Other than these reasonably obvious precautions, the toggle switch ought to work.
help with Comparator design - Page 1
Forum section: electronics / beginners

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 20, 2017, 03:54:40 am
content: Hi All,Forgive me for this silly design and questions. I am just getting started with comparators i understand the basics of comparators but need some help understanding it when applying this in real life.In the schematic the voltage is sensed during the off state of the transformer via an optocoupler only sensed when the mains voltage is OFF via an arduino. The voltage is 1.05vac, this is sensed by a comparator and it is compared to a reference voltage of 1vdc. My normal voltage at the open circuit is 1.05vac and when the secondary are shorted it is 0.5vac, i wish to detect the voltage drop and trigger a MOT via an SCR controlled by an Arduino.The idea here is to detect when the secondary are shorted.Thank you in advance.

author: danadak
author_rank: Super Contributor
timestamp: December 20, 2017, 11:31:36 am
content: In an Arduino you could do this mostly in code, using A/D. Youwould have to offset the AC signal into Arduino, or just use 1/2the sine and use diode clamps to insure you do not exceed rails.Thats a -AC Source >> Resistor (1K) >> Diode to + rail & diode to - rail >> Arduino input.In Arduino just sample input and code for peak detect.Regards, Dana.

author: anishkgt
author_rank: Frequent Contributor
timestamp: December 20, 2017, 01:51:54 pm
content: Thank you dan !Could you please explain with a bit more clarity. Trying to make it as simple with least BOM and safety in mind (preferably an isolation like an opto-coupler)

author: danadak
author_rank: Super Contributor
timestamp: December 20, 2017, 02:05:01 pm
content: In this ap note is an interface circuit.http://www.cypress.com/file/157911/downloadHere are some approaches for power supplies but show general considerations for AC line interface,transformerless.http://ww1.microchip.com/downloads/en/AppNotes/00954A.pdfhttps://www.edn.com/design/power-management/4418393/AC-power-your-circuit-without-a-transformerhttp://www.farnell.com/datasheets/1930673.pdfRegards, Dana.
Help with complex wave equation - Page 1
Forum section: electronics / beginners

author: KSP
author_rank: Regular Contributor
timestamp: May 21, 2014, 01:26:08 pm
content: Hi allI need a hand with the attached problem. Yes, it is an assignment, so I know the whole moral issue of someone giving me the answer, but if you could just point me in the right direction I would be very grateful.I can probably do everything else once a) is done, but I can't remember how to work out the current from the complex voltageCheers

author: TMM
author_rank: Frequent Contributor
timestamp: May 21, 2014, 01:38:25 pm
content: divide the complex voltage by the complex impedance of the resistor and inductor in series ... don't forget that the impedance is different for each frequency

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 21, 2014, 11:27:55 pm
content: I* = V* / R(using * to indicate a phasor quantity)(Ed: well, to be fair... R --> Z* is a phasor too, and works just the same. Oh, I forget if there's a conjugate in there too.)Do this at each frequency (mumble mumble superposition something).Or if you're a masochist,V = (bunch of sin terms as a function of t)= I*R + L * dI/dtSolve for I.Tim

author: KJDS
author_rank: Super Contributor
timestamp: May 22, 2014, 08:29:35 am
content: I perked up seeing the title, fully expecting to see something relating to Schrodingers wave equations, but instead get something less complex and the route to solving it already explained.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 23, 2014, 02:51:03 am
content: You can still show us the solution for the hydrogen atom if you want toTim
Help with connector type - Page 1
Forum section: electronics / beginners

author: rarswk
author_rank: Newbie
timestamp: May 05, 2015, 02:40:27 pm
content: Please any help to identify these connectors (see attachement), I wish to extend the camera from main body by about 30 cm, don't know how to find it as I don't know the name to search.The device is a dash camera and I want to have the lenses under the rear view mirror and the screen /body on the roof's sunglass holder.
Help with crystal oscillator  - Page 1
Forum section: electronics / beginners

author: leham
author_rank: Regular Contributor
timestamp: September 14, 2019, 07:33:21 am
content: Hello!I’m trying to find a way to replicate a QXO-1100, I’m having a hard time finding a 4 pin equivalent.From my understanding I can use a 2 pin crystal and make a driver for it.Can someone point me in the direction on how to make this work haha

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 14, 2019, 08:54:02 am
content: You didn't set your flag so here are some random suggestions:https://www.reichelt.de/quarzoszillator-4-433619-mhz-oszi-4-433619-p13708.html?&trstct=pos_2https://www.ebay.com/itm/5pcs-4-433619MHz-4-433619-MHz-4-433619M-Crystal-Oscillator-Osc-DIP-14/163144026841https://www.wagneronline.com.au/4-433mhz-colour-christal/components-misc/electronic-components/qxo-1100-1931/140/pd/

author: ledtester
author_rank: Super Contributor
timestamp: September 14, 2019, 11:58:45 am
content: Just google "crystal driver circuit". The ones involving a CMOS inverter are commonly used, e.g.:For technical details have a look at Fairchild Application Note AN-340:https://www.changpuak.ch/electronics/datasheets/AN-340.pdf
Help with DAC Pinout  - Page 1
Forum section: electronics / beginners

author: vidarr
author_rank: Frequent Contributor
timestamp: January 25, 2025, 11:58:08 pm
content: My DAC has a 9 pin USB plug and a 6 pin ATX power cable plug.The power cable I know how to hookup, but I don't know how to connect the 9 pin USB. I see a lot of people only needed 4 of the pins like a standard USB pinout, but others required the 4 pins plus some of the others.Can I wire the standard, USB 4 pins and plug into my laptop and see if it works? If it doesn't work, how can I figure out what other pins need to be hooked up?edit: ASUS Extreme FX DACTHANKS!

author: Haenk
author_rank: Super Contributor
timestamp: January 26, 2025, 11:09:03 am
content: https://images.anandtech.com/doci/9788/Maximus%20VIII%20Extreme_SupremeFX%20Hi-Fi-7.jpgThat should be a standard mainboard USB-panel connector.

author: vidarr
author_rank: Frequent Contributor
timestamp: January 28, 2025, 12:06:55 am
content: Dude, THANK YOU!!! The picture you posted (https://images.anandtech.com/doci/9788/Maximus%20VIII%20Extreme_SupremeFX%20Hi-Fi-7.jpg) answered the question.I don't know how you found the pic, but Thank You!It wasn't the connector I needed to know, it was how many of the pins/wires of the connector were needed. Thanks.
Help with darlington output transistor - Page 1
Forum section: electronics / beginners

author: multime
author_rank: Regular Contributor
timestamp: September 16, 2024, 02:41:17 pm
content: I am building this power supply and will be using the option at the bottom right of the diagram as the output stage and want to use a tip122 as the darlington driver which will be driving 6 x Tip35c but i am a little unsure about the resistors. Are r25 / r26 integral in the darlington package or do they need to be added. Emiter resistors r28 to r30 are shown as 0.05r but r27 value is not shown, would this also be 0.05r

author: PGPG
author_rank: Frequent Contributor
timestamp: September 16, 2024, 03:49:45 pm
content: Quote from: multime on September 16, 2024, 02:41:17 pmYou have darlingtom marked with a rectangle drawn with a dashed line.R25 is insied, R26 is outside.If R26 would be integrated in Q17 darlington than package would have to have 4 pins.Quote from: multime on September 16, 2024, 02:41:17 pmCertainly not.Voltage drop at this resistor will be at least 0.7V higher than at those 0.05r. I suppose its value depends on exact transistors used (for example on h21e of Q19..Q21).It is in base of output transistors and not emitter.

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 16, 2024, 03:53:21 pm
content: The transistor's datasheet will show any internal resistors and their values.

author: multime
author_rank: Regular Contributor
timestamp: September 17, 2024, 02:39:04 pm
content: Thanks for the replies, that's solved a few things but without values for r26 -r27 i am going to be stuck.PGPGIs this a typo, h21e and should it be hfeI thought of contacting the original poster of the circuit but sadly he died in 2019

author: PGPG
author_rank: Frequent Contributor
timestamp: September 17, 2024, 04:29:04 pm
content: Quote from: multime on September 17, 2024, 02:39:04 pmSee top of page 3:http://www.gvpcew.ac.in/LN-CSE-IT-22-32/ECE/2-Year/ECA-All-Units.pdfQuote from: multime on September 17, 2024, 02:39:04 pmThese resistors are to not allow Icb0 to drive the following transistors. So you should check in datasheets (not typical values but the max values) and count these R to make voltage at R not enough to drive the next transistor when previous gives Icb0.

author: multime
author_rank: Regular Contributor
timestamp: September 17, 2024, 08:55:12 pm
content: Thanks PGPG, h21e is something i had not heard of. As for my original post i have taken another look at the schematic and i had assumed Q18 was simply the forth transistor of the output stage, but of course its not its part of the drive for Q19-Q21, silly me. That changes things as the Darlington tip122 should be able to drive the bases of the 6 x tip35c sufficiently as i would want each of them to supply a maximum of 3amp.

author: PGPG
author_rank: Frequent Contributor
timestamp: September 17, 2024, 10:59:59 pm
content: I noticed that I was writing Icb0 when thinking Ice0.
Help with diy tube Pre amp pcb Design  - Page 1
Forum section: electronics / beginners

author: Nestor227
author_rank: Newbie
timestamp: January 15, 2023, 01:00:13 am
content: Hi everyone , I'm trying to make a hi gain tube preamp for guitar , i've built a few turret board amps before but this time i decided to do a pcb based amp. I simplified the schematics so that it would be only one channel i'm also making the B+ supply on a different board instead of having all together on one board. The idea is to put everything in a 1u Rack.This is my first time making a board from scratch and i wanted to share it with you guys so that i could receive feedback from people with more experience than me in the subject. any help , tips or comments are greatly appreciated thanks.

author: jonpaul
author_rank: Super Contributor
timestamp: January 15, 2023, 03:25:11 am
content: schematic? where's the valves?jon
Help with eInk Driver circuit (SSD 1680) - Page 1
Forum section: electronics / beginners

author: OrlandoBlyat
author_rank: Newbie
timestamp: April 02, 2025, 07:57:59 pm
content: It’s been a couple of months since I started working on this project, so I’m creating a new post.Four months ago, I began prototyping with a 2.13-inch SSD1680 e-ink display, based on a design from WeAct Studio’s module (which uses the same display). The only differences in my prototype are:The inductor (I used a 47 µH one I had on hand, confirmed functional).[The PCB layout (since WeAct’s design isn’t publicly available)./li]The Problem:The display isn’t updating. After suggestions from this forum, I bought an oscilloscope (which took two months to arrive). Since then, I’ve:Ordered a new board with only the display circuit (to rule out interference from other components).Discovered that the display isn’t sending a GDR signal to the boost converter (I verified the boost converter works using a signal generator).This makes me suspect an SPI communication issue, but I’m not sure how to diagnose it further.What ive Tried:Replaced the MOSFET and inductor with ones from a working board (diodes are identical).Connected both the working module and my prototype to the same MCU and compared all relevant signals side-by-side—no differences found.I’m completely out of my depth, any help would be appreciated!All relevant links:Driver schematic from WeAct Studiohttps://github.com/WeActStudio/WeActStudio.EpaperModule/blob/master/Hardware/WeAct-EpaperModule%20SchDoc.pdfSSD1680 Docshttps://github.com/WeActStudio/WeActStudio.EpaperModule/blob/master/Doc/SSD1680.pdfMy schematicsMy layout

author: xvr
author_rank: Frequent Contributor
timestamp: April 04, 2025, 11:03:08 am
content: SSD1680 contains OTP rom with various setup for voltages and other. It could run with unprogrammed OTP ROM, but it required special programming from software side (as I can decide from DS). I suspect that WeAct Studio’s module has preprogrammed OTP ROM contents, but your SSD1680 have not.

author: OrlandoBlyat
author_rank: Newbie
timestamp: April 04, 2025, 04:18:32 pm
content: I'm testing with the display on WeAct's module, so the OTP ROM should be fine.
Help with EPROM Programming (27C400) - Page 1
Forum section: electronics / beginners

author: mbarszcz
author_rank: Contributor
timestamp: May 17, 2019, 09:58:29 pm
content: I'm trying to burn some 27C400 EPROMs on a TL866II with one of the gglabs adapters, and whenever I try to burn the EPROMs (AAAA in this example), this is what I get back, a repeating pattern of zeroes every few lines:I have tried various jumper/dip switch settings and double checked everything, and it all seems fine. I also ordered some new EPROMs from a different seller in case they were counterfeit, but the results did not change.The schematic for the design is here:https://gglabs.us/sites/gglabs.us/files/e2r16-b01_sch.pdfAll the address and data lines are just traces to adapt the 4096 pinouts to the 27C400, so I can't see how they wouldn't be working.The rest of the circuitry is just dealing with the VPP and select lines, so I can't see how that would cause a repeating pattern of zeros to be programmed.Any ideas?

author: amyk
author_rank: Super Contributor
timestamp: May 18, 2019, 01:05:38 am
content: I would first determine whether it's the actual programming that didn't work, or the readback, by manually wiring the chip with the appropriate bad addresses and probe the data lines to see what the values are.Either way, the pattern suggests what to look for on the address lines:80-9F = 00100xxxxx180-19F = 01100xxxxx280-29F = 10100xxxxx380-39F = 11100xxxxx...Using a logic analyser or scope, you can see if A5-A7 correctly take on the values 0,0,1 respectively.
Help with fan module controll - Page 1
Forum section: electronics / beginners

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: October 11, 2015, 05:45:18 pm
content: Hi everyone!I recently scored a nice "little" fan module on ebay for one single euro.It is an Comair Rotron JQ48B0X which was pulled from some unknown unit. I would love to know how to use the various controll wires those puppys have. As I searched throughwww.comairrotron.comI found a simmilar model named JQ48R7. Even though, the datsheed wasn't really helpfull at all, I could see that the wire colours that were used at my fan array seem to be fairly standard at that producer.I have the following wires:red - supply voltage + 24 - 56 VDCblack - groundyellow - "programming wire" -> take a look athttp://www.comairrotron.com/different-methods-control-fan-speedwhite - part of tachometer output?blue - part of tachometer output? ->http://www.comairrotron.com/methods-monitoring-fan-performanceI already tried to connect a 1k pot between yellow and black, but whatever resistance I give to that lead, it doesn't make any difference. I am scared giving a voltage directly onto that lead as described at the fan speed controll info page, as the pot-method should have the same effect but didn't work at all.the white/blue should, as far as I understood, be a single blue/white striped wire, not two seperate? However, I can't get anything out of there at all.Has anyone an Idea or information about that?Thanks!You can find some pictures of the fans attached. Please excuse the bad quality, I didn't find my better camera...

author: picandmix
author_rank: Frequent Contributor
timestamp: October 12, 2015, 08:33:09 am
content: Typically the fan control wire needs a PWM signal to control it.As you can see from the screenshot of some other fans from that company, you need a PWM with a frequency around 1k to 10k and with an adjustable duty cycle, with an output voltage around 10v dc.All you need is a 555 timer , plenty of examples on the web, here is just one, though you need to change the frequency components for 1khz , as the text describes.http://www.dprg.org/tutorials/2005-11a/

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: October 12, 2015, 05:26:10 pm
content: Hi picandmix and thank you for your reply!I should have mentioned that I would like to avoid PWM, but I tried it (using my toellner frequency generator), just to ensure the fan does respond to anything at all. Even though I can't controll the duty cycle using the frequency generator, regarding to the datasheet the fan speed should drop noticably feeding a pure square wave to the controll pin which would be 50% duty cycle. But it doesn't do anything.Am I missing something?
Help with fault pin on DRV8701 gate driver. - Page 1
Forum section: electronics / beginners

author: no1no2no3no4
author_rank: Newbie
timestamp: February 08, 2024, 06:22:43 pm
content: Hi, quick question about the fault pin on the DRV8701 gate driver. I'm looking at the data sheet(https://www.ti.com/lit/ds/symlink/drv8701.pdf) and it states for the nFAULT pin "Pulled logic low with fault condition; open-drain output requires an external pullup". I'm not exactly sure how to interpret this. What output voltages am I expecting on this pin? Would it be high when there is no fault and low when there is a fault? And I'm also assuming the voltage would be the same as the logic input, for example if I'm using 3.3V, the output on this pin would also be 3.3V.

author: pcprogrammer
author_rank: Super Contributor
timestamp: February 08, 2024, 07:48:38 pm
content: In this case it being open drain means that it is based on a n-channel FET where the drain is on the pin, the source is on ground and the gate is controlled from the internal logic. It needs an external pullup to the desired voltage level for your logic. Probably the 3.3V you mentioned.The datasheet might state a maximum voltage that can be used on the pullup.If it states that it is pulled low in case of a fault, then there is a fault condition when you see it as a low and not when you see it as a high.Edit: the datasheet states that the pullup on nFault needs to be >= 10K Ohm. See table "External Passive Components"It also states that the absolute max voltage on this pin is 5.75V and the current should not exceed 10mA.

author: Zero999
author_rank: Super Contributor
timestamp: February 08, 2024, 08:12:55 pm
content: The pin has a switch which connects it to the 0V pin, during a fault condition. It needs a 10k or higher resistor connected to VDD to enable it to output a logic high.A detailed schematic showing how this is done can be found on page 13 of the data sheet.This arrangement is very common, especially for comparator ICs, e.g. LM311, LM393, LM339.

author: no1no2no3no4
author_rank: Newbie
timestamp: February 08, 2024, 08:18:19 pm
content: That makes perfect sense. Thanks!
Help with finding correct transistor please - Page 1
Forum section: electronics / beginners

author: Jeff5
author_rank: Newbie
timestamp: August 31, 2022, 01:57:55 am
content: Hello everyone, I am new here. I'm working on repairing a Engine Control Module(ECM). This module is from a 2007 Acura TSX 2.4L. It is beleived that the Canister Vent Valve(EVAP system solenoid on a car) shorted causing damage to ECM. The transistor that controls this valve inside of the ECM is damaged. I can not for the life of me find the correct one. These MCUs can be really picky as they check on themselves to see if the circuit is working. This Canister Vent Valve is a solenoid that draws between .5 to .8 amps(mass produced OEM and aftermarket). I tested a known good transistor from the same module with my TC1 multi-function tester, I get a BJT symbol but I have a weird diode in between the collector and emitter. I have scoured SMD markings but no datasheets show the symbol. The transistor package is a SOT-89-4. This transistor drives a solenoid that would have a good inductive kick, I am assuming right now that that is what the diode is for. I hope the pics are good enough! Thank you in advance to all that help.I am assuming that the top of the transistor is the SMD marking of E0(Ezero) not EO. Bottom would be date code or batch, correct? I have tried SMD code book and S-manuals. I don't ecpect anyone to do my research for me, pointing me in the right direction will help greatly in the future. I fix a lot of automotive electronics and knowing how to find this stuff is key. I have also looked through WEIXY.. I have tested this transistor more that once with the TC1. I removed some other transistors from another ECM and tested. I got BJT as a result but no diode, I then tested the good one again and was same. I hope I have been descriptive enough, thank you!!

author: gamalot
author_rank: Super Contributor
timestamp: August 31, 2022, 04:42:56 am
content: DTDG14GPhttps://fscdn.rohm.com/en/products/databook/datasheet/discrete/transistor/digital/dtdg14gpt100-e.pdf

author: Jeff5
author_rank: Newbie
timestamp: September 01, 2022, 12:56:25 am
content: Thank you Gamalot. I don't understand what I'm looking at in the datasheet completely. Could you explain? What I see in the data sheet is that there is a connection between emitter and base that is a resistor. There is also the connection between the collector and base which is a diode. In a round about way there would be a diode between collector and emitter but its not the same as I see in on the TC-1. I know not to trust the TC-1 but it is the only device I have to identify whats what. I would assume this would work the same? Just treying to learn as much as possible. Thank you for your help!
Help with flowmeter output - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: February 10, 2013, 12:28:44 am
content: G'day,One of the most helpful sites on the planet, thanks everyone!I am adding a paddlewheel flowmeter (bluwhite f-2000) to my pool plumbing and would like to interface the flowmeter with an arduino, the meter has 2 options:Coil Sensor, no power required, coil generates AC voltage (from .06 volts to approximately 3 volts) depending on the flow rate, AC sine wave output.Hall Effect Sensor, requires 6-24V DC power, DC square wave output, TTL/CMOS compatible digital (current sinking) output signal.I would like the coil because it doesn't need a PSU but I am worried it will be tricky to integrate with the arduino, I am fairly sure none of the pins on the arduino will accept and measure AC, so I would need some kind of interface board, if so, is it something available off the shelf?The hall effect option outputs a digital signal and from what I read that probably can be read directly by the arduino?Advice, thoughts, recommendations?Thanks everyone!CheersRichard
Help with getting the right resistor - Page 1
Forum section: electronics / beginners

author: britsmp
author_rank: Newbie
timestamp: November 17, 2015, 05:29:20 am
content: HiI have a V6AC Charger that is giving me a Short Err I noticed a resistor that seems damaged. I just need some help in getting the right parts as I don't want to mess this up. The attachment with the blue pcb is my model the closest I could find was the model with the red pcb. To be honest im not good when it comes to colorsI would appreciate if someone could help me please.Thank you

author: JoeN
author_rank: Frequent Contributor
timestamp: November 17, 2015, 05:50:01 am
content: Green Black Silver Gold Black? If so, 0.5 ohm, 5%. This is a pretty common value for a current-sense resistor.You might want to break out the multimeter and see if either are still good and what the value actually is. The second picture indicates they are the same value, but your board is a little hard to tell.

author: britsmp
author_rank: Newbie
timestamp: November 17, 2015, 06:20:20 am
content: Thanks JoeNThe one on the right Green Black Silver Gold Black measures 4.2 ohmThe other one Black Gold Silver Green Black Gives me 1.998M ohm on the meterIf I look closely under the resistor on my board the colors do match now I just need to confirm value are they both 0.5 ohm ?

author: britsmp
author_rank: Newbie
timestamp: November 17, 2015, 10:58:11 am
content: could the Black Gold Silver Green Black Given be a 0.05 ohm ?
Help with high pass and low pass switches in guitar - Page 1
Forum section: electronics / beginners

author: Scornn
author_rank: Contributor
timestamp: July 06, 2023, 01:58:49 pm
content: Here is the current wiring of my jazzmaster style guitar, Just wondering when it comes to what would have been the rhythm circuit, what would I need to add to the two top DPDT switches to make them become low pass and high pass switches. Also if I was to activate both at the same time, how would they interact with each other?

author: liaifat85
author_rank: Regular Contributor
timestamp: July 06, 2023, 03:10:35 pm
content: I never worked with Rhythm circuits. You can get some ideas from here:https://www.offsetguitars.com/forums/viewtopic.php?t=108747

author: eugene
author_rank: Frequent Contributor
timestamp: July 06, 2023, 09:51:03 pm
content: I'm sorry to sound crass, but high pass and low pass filters are very basic AC electronics. Nobody could count the number of web sites that currently discuss them. More importantly, why would you ask a bunch of grey haired electrical engineers how to wire up a guitar? It's entirely a subjective thing. So go buy a bunch of capacitors in a range of values, get a handful of alligator clips, and start experimenting. That's the ONLY way to work with musical instruments.Either that, or go to one of the many websites that cater to owners of offset Fender guitars and see what they might recommend. Honestly, asking here is like asking a knitting club full of old ladies about the latest fashion in athletic footwear.
Help with IC identification - Page 1
Forum section: electronics / beginners

author: rkosegi
author_rank: Newbie
timestamp: October 14, 2025, 09:50:18 am
content: Hi community,can someone help with identifying this IC?It's bicycle blinking light, most likely this onehttps://kellysbike.com/lighting-sets/twins-set-orange_6132If I'm not mistaken, it reads "TS1625B-V6".Despite hard try, I was not able to find datasheet in any of SMD lookup sites.

author: Psi
author_rank: Super Contributor
timestamp: October 14, 2025, 10:05:44 am
content: I tried, but couldn't find anything.

author: pinkystu
author_rank: Newbie
timestamp: October 14, 2025, 02:50:04 pm
content: could it be a 555 timer?https://electronicsarea.com/flashing-led-bike-lights-circuit/

author: rkosegi
author_rank: Newbie
timestamp: October 14, 2025, 03:10:02 pm
content: Nope, it's most likely some ASIC.Switch cycles between different blinking modes and off state.Will add reverse-engineered schematic shortly

author: rkosegi
author_rank: Newbie
timestamp: October 14, 2025, 03:36:01 pm
content: Here is my attempt to reverse engineer that board in kicadPin 7 is NC.Battery is 2xCR2032
Help with ICs..... - Page 1
Forum section: electronics / beginners

author: Seaofdep
author_rank: Regular Contributor
timestamp: August 22, 2017, 07:17:56 am
content: Hey there , I have searched in the database topic and found nothing or different uses in database . Besides the LM I don't know anything of the others . Being that it came like this in a little antistatic zipbag I assume it is a set for a project or something . Can someone confirm or does anyone recognize them . If so can you point me to a link of some sort? Is there something I can throw together with them on the breadboard and using arduino ? Thank you in advance ( sorry forgot to add picture lol)Sent from my iPhone using Tapatalk

author: Seaofdep
author_rank: Regular Contributor
timestamp: August 22, 2017, 07:22:49 am
content: Sent from my iPhone using Tapatalk

author: Ian.M
author_rank: Super Contributor
timestamp: August 22, 2017, 07:38:05 am
content: All the 14 pin ones are 74LS series TTL logic. That's a newer, faster, but otherwise generally compatible version of the74xx seriesYou've got two741OPAMPs, which were second sourced by a *LOT* of manufacturers, and one555timer, a clone iof the classic NE555.I cant imagine any useful circuit that would use all those parts and no other ICs, and there is a wide range of brands and date codes so IMHO they are just a random assortment that someone tidied into the same bag.The logic chips *MAY* be useful in an Arduino project, but the 741 and 555 are unlikely to be - The 741 OPAMP is a rather old design and doesn't work well if at all powered by a low voltage single supply, and the Arduino can already do almost any timing function you could use a 555 for. OTOH, with an appropriate supply voltage both are still useful in standalone circuits.

author: Seaofdep
author_rank: Regular Contributor
timestamp: August 22, 2017, 07:58:55 am
content: Thank you so much for such a detailed reply . Now I know why I kept looking at the timer and repeating 555, I came across it while researching ransoms.... hmm I'll have to look up them up and look for something easy for a Beginner to use them for. Thank you again , I appreciate the help
Help with identifying capacitor specs - Page 1
Forum section: electronics / beginners

author: JHAnd
author_rank: Contributor
timestamp: October 24, 2023, 08:35:40 pm
content: HiI attached two photos of the cap in question.I'm unsure if this is a ceramic disc capacitor or a tantalum?Also I would like help with what the markings on it mean:1. X5F2. JL100 (100pF but what does JL mean?)

author: Benta
author_rank: Super Contributor
timestamp: October 24, 2023, 08:56:26 pm
content: Silvered Mica.100 pF, 1 kV.

author: TimFox
author_rank: Super Contributor
timestamp: October 24, 2023, 09:02:49 pm
content: No, it's an X5F dielectric ceramic capacitor, 100 pF, 1 kV, 20% tolerance.The "J" is a manufacturer's type designation.RMC was a manufacturer of disc ceramic capacitors (I believe it stood for "Radio Material Corp" or similar) later acquired by Mallory.With older disc ceramic capacitors, it is hard to parse "100": it could mean 10 or 100, but probably 100 pF

author: JHAnd
author_rank: Contributor
timestamp: October 25, 2023, 04:50:05 am
content: Thanks!I found a Vishay pdf, explaining what X5F means.https://www.vishay.com/docs/48299/_did-you-know-hotcap_vmn-ms7407.pdfX = minimum operating temp - 55C5= maximum operating temp +85CF = capacitance change allowed ± 7.5% (within above temperature range)

author: TimFox
author_rank: Super Contributor
timestamp: October 25, 2023, 01:38:12 pm
content: The choice of dielectric for a ceramic capacitor is very important: see many posts on this site about the differences.X5F is an example of a non-linear capacitor, where the capacitance depends noticeably on the voltage.