hybridfree/eevblog-posts huggingface dataset:
Domestic capiliary thermostat for DC current switching? - Page 1
Forum section: electronics / beginners

author: V_King
author_rank: Regular Contributor
timestamp: February 27, 2018, 07:18:08 am
content: Hello,I have a domestic capillary thermostat of a hot water cylinder. I want to switch DC currents with it, but can not find any current switching ratings for DC currents. It is rated at 10(6)A 250VAC. It is as I understand 10A for resistive and 6A for inductive loads. I tried goggling loads of domestic hot water cylinder thermostats specs and none provide DC switching current. I just want to control a couple of 12VDC relays so the current would be max 1A.Is there a safe assumption to make how much DC current I could switch with such a rated switch or is it a complete no?Thanks

author: Gyro
author_rank: Super Contributor
timestamp: February 27, 2018, 09:43:11 am
content: The reason that DC rating is different (lower) is that AC current crosses through zero every half-cycle, helping to extinguish the arc that occurs as the contacts open. This does not occur with DC, causing a much longer arc before extinction. Looking at relay contacts as an example, the de-rating for DC is normally around 90%, ie. around 24V DC for the same current rating.In practice using it to drive your 12V relays will be fine. Too low a voltage and current across high current Silver-Cadmium contacts can actually cause intermittent contact due to loss of self-cleaning action but I think you are probably safely above that threshold too.
Can anyone help with these parallel diodes in 555 circuit? - Page 1
Forum section: electronics / beginners

author: seb1982
author_rank: Regular Contributor
timestamp: May 14, 2013, 02:12:54 am
content: Hi all!I was looking at this simple 555 adjustable PWM circuit below today. I understand the reason for placing a diode between pins 6 and 7 when you want a duty cycle of <50%, but I can't get my head around why you'd have two diodes with opposite biasing like in the diagram below. No matter how hard I think about it, I keep coming back to thinking that they'll just cancel each other out, as it were.If any of you guys can shed some light on it for me, I'd be very grateful - I've been pondering it for hours now today!Thanks again.

author: c4757p
author_rank: Super Contributor
timestamp: May 14, 2013, 02:15:22 am
content: They're not in parallel! The charge current will go down one side of the pot and the discharge current will come back up the other.

author: digsys
author_rank: Unknown
timestamp: May 14, 2013, 02:35:09 am
content: If you Redraw it like this, it will make a lot more sense. R1+R2 make up the pot at one extreme position.C1 charges 100x faster than it discharges.

author: seb1982
author_rank: Regular Contributor
timestamp: May 14, 2013, 01:03:46 pm
content: Ah, of course!God, I feel mighty stupid right now! What an absolute brainfart!Thanks ever so much for the replies poking my brain in the right direction!

author: SeanB
author_rank: Super Contributor
timestamp: May 14, 2013, 04:10:15 pm
content: The quick and dirty way to change duty cycle while keeping something closish to a constant frequency at the output.

author: dentaku
author_rank: Frequent Contributor
timestamp: May 14, 2013, 11:58:10 pm
content: You might also be interested in seeing Dave build this circuit in one of his videos.http://www.eevblog.com/2012/11/29/eevblog-392-555-led-pwm-hack/

author: Unknown
author_rank: Unknown
timestamp: May 16, 2013, 09:07:18 am
content: A quick and dirty get you going... remove pin 7 discharge from the diodes with no connection, move R2 from +12 supply end, re-connect to pin 3 output; the duty to frequency timing cap might require adjustment ?... otherwise one can go that bit further, and remove the diodes altogether and the pre-set/pot too, just take R2 from pins 2 and 6 to pin 3, alter R2 value for required period, duty-cycle is near 50/50.
Donor Stepper From Printer - What Voltage Does It Need? RG5-0765 Solved=12V - Page 1
Forum section: electronics / beginners

author: t1d
author_rank: Super Contributor
timestamp: April 16, 2021, 02:28:38 pm
content: It came out of a HP 4L Laser Jet. Its model number is RG5-0765. I searched for it, but I didn't find the answer. Thanks for your help.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 16, 2021, 04:51:58 pm
content: For stepper motors the important parameter is usually the current, not so much the supply voltage. The normal way is to have the driver control the current. The supply voltage mainly sets the maximum speed. So at low speed some 3 V may be sufficient, while higher speed may need some 30 V.The resistance and motor size can give an approximate value for the current - compare to other motors of similar size and look for comparable ohmic loss. So I²R is about constant for a given motor size.Using slightly lower current is OK with reduced torque.

author: thm_w
author_rank: Super Contributor
timestamp: April 16, 2021, 11:27:18 pm
content: The part number is on the side of the motor "MSC..." if you google that you will find more information and some videos:https://www.google.com/search?client=firefox-b-d&q=mscm048a50

author: JustMeHere
author_rank: Frequent Contributor
timestamp: April 16, 2021, 11:45:56 pm
content: Do you have access to the printer? Measure the power supply.

author: ozcar
author_rank: Frequent Contributor
timestamp: April 17, 2021, 02:31:41 am
content: Quote from: JustMeHere on April 16, 2021, 11:45:56 pmI had a HP 4L for over 20 years (!). I still have the service manual for it (found it online somewhere, years ago, it must still be out there), and that indicates that the power for the "main motor" is 12V.

author: t1d
author_rank: Super Contributor
timestamp: April 18, 2021, 12:58:33 pm
content: Thank you, so much, one and all, for your efforts to help me. And, a special salute to Ozcar, for the exact answer!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 18, 2021, 01:53:26 pm
content: The first response from kleinstein is much better than the later response from Ozcar. Stepper motors usually have a driver IC to make the phase currents, and these work at the same time as a buck converter, and regulate the current through the motor coils.Even if your motors power supply was 12V to begin with, if you just put 12Vdc on a motor winding, the motor is likely to fail. With a proper driver circuit however, the motor will run happily on an 24V power supply or even higher voltages (Depending on the driver IC used. Such IC's have a maximum input voltage).
Don't throw out that used braided solder wick - Page 1
Forum section: electronics / beginners

author: bobbydazzler
author_rank: Regular Contributor
timestamp: April 19, 2021, 03:06:47 pm
content: It turns out to be really useful for tinning copper claded stripboard, I didn't need to add any solder to the wick to do this though I did add some extra flux. I'm sure it could be used to tin any type of solderable surface.

author: SilverSolder
author_rank: Super Contributor
timestamp: April 19, 2021, 03:11:19 pm
content: I like the idea - even using a fresh piece of braid to "swab" the traces is a good idea, if you don't have any used ones to hand...

author: bobbydazzler
author_rank: Regular Contributor
timestamp: April 19, 2021, 04:49:06 pm
content: Fresh braid is good too, I didn't have much "used" solder braid when I did it and thought for sure I'd have to add some fresh solder to do the whole board but no, a small amount of used braid was enough. I think I could do 2 more boards with the same braid.

author: AmnevaR
author_rank: Contributor
timestamp: April 19, 2021, 05:17:27 pm
content: Also you can reuse used braided solder wick as a low resistance grounding wireAfter some cleaning with IPA of course.
dont understand dave's micro current project.. Someone explain - Page 1
Forum section: electronics / beginners

author: krappleby
author_rank: Contributor
timestamp: January 11, 2017, 11:27:02 pm
content: ok.. i posted this cause im relatively new to electronics.i been watching daves videos quite a bit lately and im confused regarding dave's micro current project, as far as im aware the project is created to provide a better value for the measurements of resistors in a circuit..now.. if a resister on the circuit has a say 5% tolerance, then you measure it direct, you get a result with a 5% tolerance.. Daves system is also a 1% tolerance, adding that to an already made 5% tolerance, would produce 6% tolerance, so basically would be a worse result. how does this help, add that on to the tolerance of the cable and its even worse.keith

author: Delta
author_rank: Super Contributor
timestamp: January 12, 2017, 12:04:37 am
content: The tolerance of the resister current decreases by the 1% of the cable 5% so when u measure wire voltage the resister = 1 -5%THX

author: ataradov
author_rank: Super Contributor
timestamp: January 12, 2017, 12:13:38 am
content: What resistors are you talking about? MicroCurrent is made so you can measure small currents with a multimeter without worrying about burden voltage.

author: LA7SJA
author_rank: Regular Contributor
timestamp: January 12, 2017, 12:38:51 am
content: Quote from: krappleby on January 11, 2017, 11:27:02 pmNo this project is a mA/uA/nA to mV adapter for measuring smal currents.Specifications – µCurrent™ GOLD•3 Current ranges: •+/- 0-1250mA (20µV / mA burden voltage typical) * switch contact resistance plays a role here. 10uV due to the shunt resistor.•+/- 0-1250µA (10µV / uA burden voltage)•+/- 0-1250nA (10µV / nA burden voltage)•NOTE: Higher currents are available by increasing the battery voltage, to a maximum of 5.5V, which would give +/-2250mA/2250µA/2250nA maximum)•Output Voltage Units: •1mV/mA•1mV/µA•1mV/nA•NOTE: You simply read your mV multimeter range as if it were mA/µA/nAJohan-Fredrik

author: JiggyNinja
author_rank: Regular Contributor
timestamp: January 12, 2017, 04:40:11 pm
content: QuoteAn accurate prediction.QuoteEmphasis mine.Yes it absolutely does matter. How are you supposed to use Ohm's Law to calculate I from V without knowing R?

author: LA7SJA
author_rank: Regular Contributor
timestamp: January 12, 2017, 09:39:40 pm
content: In the uCurrent Gold the shunt resistors are ±0.05% on the uA and nA range, on the mA range it is 0.1% this gives the unit a good accuracy on the voltage in to the x100 amplifier. So even if the burden voltage can vary due to cable an switch resistens the current measured should be accurate.Johan-Fredrik
Don't understand how to read datasheet for OLED display, also current resisting? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: February 06, 2019, 11:35:54 am
content: Hi all, two questions.I just bought one of these displays to replace an old EL backlit LCD from a device with a dead inverter.https://www.mouser.com/datasheet/2/427/oled040n002alpp5n00000-1153452.pdf1. I can't tell from the datasheet what i need to do to switch it between 4 bit and 8 bit mode. I don't know which I actually need. I know these displays are a drop in solution but i don't know whether they are set to 4 bit or 8 bit by default.https://www.buydisplay.com/default/4002-40x2-character-lcd-display-module-hd44780-white-on-black2. Will i need a current limiting resistor on the OLED? If so where would i put it?

author: mariush
author_rank: Super Contributor
timestamp: February 06, 2019, 12:02:58 pm
content: The OLED display uses OLED-100 controllers which seem to use the same command set as those HD44780 modulesYou can find a datasheet of some sort here:https://docs-emea.rs-online.com/webdocs/1401/0900766b814011cc.pdfThe standard hd44780 or clones can work either in 4 bit mode or 8 bit mode - YOU select the mode during initialization.In 4 bit mode, you only need to use RS, RW, EN and 4 of the 8 data pins... actually only RS is needed out of the RS,RW and EN - you can hardwire EN to have the lcd always on, and you only need RW connected to a microcontroller if you need to read data from the lcd display back to the microcontroller. For just controller to lcd communication, the RW can be left unused.Here's a display which uses a clone of that hd44780 chip, with the same instructions :http://www.newhavendisplay.com/specs/NHD-0208AZ-FL-GBW.pdfYou can see the pinout and the way you'd connect in 4bit mode or 8bit mode, and how you use a potentiometer to adjust contrast.Also, you have in that datasheet the minimum of instructions you need and code that shows you how to initialize the display in either 4bit mode, or 8bit mode.The datasheet also links to the full documentation for that controller, which is here:http://www.newhavendisplay.com/app_notes/ST7066U.pdfOLED displays shouldn't need a backlight, so I don't see why you'd use a current limiting resistor.
Door controller - Page 1
Forum section: electronics / beginners

author: richardnhoffman
author_rank: Newbie
timestamp: July 25, 2017, 12:21:47 am
content: Hello everyone,I was just given a project from work to make a door controller using an arduino as the main microcontroller to operate a set of doors. It has been some time since I have worked on electronics and I am trying to find a simple way to operate the doors. All I need is an output to operate a relay and two feedback lines of when the door is open and closed. My biggest problem is operating the coil from 5V to 36V unregulated and getting feedback from the 36V unregulated back to the pins of the arduino at 5V without blowing it up.Output: Drive an unregulated 36V via 5V to a relay coil to ground. (opens door). The door is rigged to close when no voltage is applied to the relay.Input: 36V unregulated from open door switch to 5V input pin.Input: 36V unregulated from closed door switch to 5V input pin.What components do I use to achieve this task?Thank you for any feedback on this.

author: Nusa
author_rank: Super Contributor
timestamp: July 25, 2017, 12:30:58 am
content: Google "arduino relay circuit". The subject is well covered.For input, I'd suggest an optoisolator as the safe approach. Google "arduino optoisolator input" for some ideas.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: July 25, 2017, 12:26:51 pm
content: There are plenty of ways to do this and I don't want to cramp your style.... but here is how London Hackspace control access...https://wiki.london.hackspace.org.uk/view/Door_control_systemMight give you some ideas.It's got to be internet connected hasn't it.(ESP32, RPi, .... millions of possibilities)
Doorbell (AC current) sensor design for alarm system door/window sensors - Page 1
Forum section: electronics / beginners

author: sequoia
author_rank: Unknown
timestamp: September 30, 2015, 06:56:36 am
content: I've been playing with design to implement simple sensor that detects when doorbell button is pressed. Goal was to design sensor that could be plugged into (wireless) alarm system sensor as external door/window "switch". And also avoiding to having to modify doorbell wiring other than hooking up the detector between the door bell and the transformer. Also, I wanted to avoid using mechanical relay to mimic real (magnet) switch...Any feedback on the design would be very welcome (any obvious mistakes?, can it be simplified?, etc..)Detector works by detecting "significant" A/C current, by using simple current divider and when enough current is flowing through the smaller (ohm) power resistor it ends up triggering the optocoupler. My doorchime uses about 850mA and and the lighted button about 40mA, so with some trial and error I ended up choosing resitor pair 2.2ohm/200ohm, this seems to work for this purpose. But it would be nice if someone could explain how to calculate the "trigger" current needed to trigger the optocoupler (H11AA1 in this case)(It's been too long since I took my electronics course...)Since it might be good to choose the "trigger" current to be rather low, so that this would work if ever change from mechanical door chime to electronic one, that presumably would use significantly less current...After I added indicator LED to the circuit to show when door bell button is pressed I had trouble triggering the alarm sensor, so I ended up adding second optocoupler which seemed to work (but I suspect this could work withouth it?)I'm using this with Interlogix NX450 wireless window/door sensor that has connector for external switch. Unit works on 3V and after hooking it up to scope it was clear that the sensor sends tiny 3V pulse every 250ms (apparently to save battery) to test if "switch" is closed.[EDIT: wrong schematic was initially attached, now should be "correct"...]

author: Seekonk
author_rank: Super Contributor
timestamp: September 30, 2015, 04:38:42 pm
content: I always use a current transformer. Have a whole carton of very small 120/9V transformers that are wound on a split bobbin. Pretty easy to cut out the 120V side with razor knife then replace that with a couple turns of hookup wire. That gives a lower voltage burden than an opto. Speaker transformers would also work and used to be everywhere, they are now hard to find.
doorbell - Page 1
Forum section: electronics / beginners

author: ascot
author_rank: Contributor
timestamp: October 16, 2020, 08:10:40 am
content: attached is a photo of a doorbell receiver is it possible to attach wires to power it from power supply it's normally powered from the mains and if so wereand also could i be able to attach esp32 module to it

author: eblc1388
author_rank: Frequent Contributor
timestamp: October 16, 2020, 08:46:32 am
content: First you would need to measure the DC voltage across capacitor C11(markings 470,10V,VT) near resistor R4, with mains supply ON(so be careful !!!). The whole circuit board might be HOT(Live).I would guess it would be either around 3.3V or 5V. You can then removes the board from mains connection and connect the external dc supply with approximate same voltage across this capacitor to power up the rest of the circuit. Measure the idle current, and you may need to cut off some circuit tracks if the idle current is too high. Let's do it a step at a time.

author: ascot
author_rank: Contributor
timestamp: October 16, 2020, 09:12:17 am
content: i already cut the mains out dc i,m fine with, ac tend to err on caution ,the bell should ring once enough dc current is reached i,m assuming .just the tracks having trouble reading ie which one is + which is -

author: ascot
author_rank: Contributor
timestamp: October 16, 2020, 09:23:19 am
content: you were right works from 3 and 5 volts trial and error with probes thanks
DOSS SOUNDBOXPRO CHARGING ISSUE - Page 1
Forum section: electronics / beginners

author: Charlie6
author_rank: Newbie
timestamp: October 15, 2023, 12:44:59 pm
content: Yes, I have a Doss speaker that is indicating a flashing red LED upon connection to the USB charging port and I have since contacted the company for guidance after having changed the Lithium cell as it hasn't rectified the situation. The company has indicated that a capacitor needs to be added to rectify this. The engineer did not offer any explanation as to whether there's a bad capacitor, nor did he let me know the value of the said capacitor. There is one 1000mf regular capacitor and all the rest are SMD. Has anyone had any experience fixing these things and if so, I can use a little guidance. Thanks in advance.

author: alligatorblues
author_rank: Regular Contributor
timestamp: October 16, 2023, 02:05:00 am
content: If he said 'added', there should be some place on the PCB board to add one. It should be marked 'C' with a number after it. There should be 2 holes in a circle with one half shaded. To tell which hole is positive, turn the board over. the hole through a larger copper plane is negative. The short wire on the cap is negative. For smd resistors there's differrent methods to determine polarity:https://www.pcbonline.com/blog/smd-polarity-led-capacitor-diode-inductor-ic.html#tip3
Double Balanced Mixer - Page 1
Forum section: electronics / beginners

author: Kudesunik
author_rank: Newbie
timestamp: April 02, 2023, 02:18:59 pm
content: Hello!I want to make a diode ring balanced mixer operating at 100 MHz (VHF broadcasting range). On the FT37-6 ring (μ=8) at the transformer (not a mixer, but so far only one transformer) on the second winding, the phase of the applied signal begins to drift away from 180 degrees already at 70 MHz. Accordingly, at 100 MHz I no longer have either phase or normal amplitude. I suppose it makes no sense to use such a transformer in a mixer. What are the options to make a mixer at this frequency (without using Gilbert Cells or microcircuits)?Thank you!

author: edavid
author_rank: Super Contributor
timestamp: April 02, 2023, 04:05:45 pm
content: Where did you buy the cores? They may be mismarked or just the wrong material.Or maybe your winding technique or circuit building technique is not good enough for 100MHz. Can you post photos?What is your test circuit, and how did you perform the phase measurement?Can you obtain a packaged mixer like a Mini-Circuits SBL-1?

author: Kudesunik
author_rank: Newbie
timestamp: April 02, 2023, 08:20:08 pm
content: Thanks for the reply!Quote from: edavid on April 02, 2023, 04:05:45 pmKits and Parts shopQuote from: edavid on April 02, 2023, 04:05:45 pmMaybe. Sad if so. I can't be more careful. Here photos:https://imgur.com/a/PZC26nEQuote from: edavid on April 02, 2023, 04:05:45 pmHere oscilloscope measurement images. It is still not mixer, only single transformer check. First is comparement between input signal (1st winding) and 2nd winding:https://imgur.com/a/9fQ2wFSSecond is comparement between 2nd winding and 3rd winding:https://imgur.com/a/oYsRXFyI see that, in fact, maybe I’m panicking in vain, since it’s the phase difference between 2 and 3 windings that should interest me, but the 95 MHz offset annoys me a lot.Quote from: edavid on April 02, 2023, 04:05:45 pmWell, maybe yes, but I would like to do it myself. Otherwise, I will immediately use SA612.

author: edavid
author_rank: Super Contributor
timestamp: April 02, 2023, 08:53:29 pm
content: It looks like you have a T37-6 core, which should not be used above 40MHz.https://toroids.info/T37-6.php
Double function generator output voltage?  - Page 1
Forum section: electronics / beginners

author: MrRedHat
author_rank: Unknown
timestamp: March 14, 2014, 03:25:41 am
content: If I have a two channel function generator, can I add the output voltage of both channels to double my output voltage? For example, if my function generator’s channel 1 goes up to 20 Vpp, and channel 2 goes up to 20 Vpp, can I add the two channels to get 40 Vpp? If so, do I do something with the sync? If not, what is the sync used for?

author: ktemkin
author_rank: Contributor
timestamp: March 14, 2014, 03:43:08 am
content: Quote from: MrRedHat on March 14, 2014, 03:25:41 amNearly all function generators produce output referenced against the system's ground-- and thus the "black lead" on your function generator's output is connected to the system's ground. If you tried to put those two channels in series, you'd inadvertently be shorting one of the output channels to ground! (Contrast this to the many power supplies with "floating" outputs, whose current returns aren't tied together, or to ground.)If you'd like to produce an increased voltage output, you'll likely want to amplify the signals after they leave your function generator. If you'd like to add the two channels together for reasons beyond simply increasing your peak-to-peak output voltage, you might want to look into summing amplifiers.[Edit: It's also worth mentioning that most function generators can produce amplitudes that are "twice as large" when driving high-impedance loads, compared to 50-ohm loads. This is a result of the 50-ohm output impedance of these generators; for a 50-ohm load, the output and load impedances are matched, and thus half of the voltage is dropped over the output impedance. To provide an accurate display of voltage dropped over the load, most function generators halve their display when put in 50-ohm load "mode".]Quote from: MrRedHat on March 14, 2014, 03:25:41 amThe synchronization waveform is designed to produce a waveform which produces a transition each time the function generator begins a new cycle of output-- this allows you to easily "sync up" another piece of equipment, such as your oscilloscope-- which can be set to trigger on a rising or falling edge of the synchronization signal.
double sided adhesive for pcbs? - Page 1
Forum section: electronics / beginners

author: deltawars
author_rank: Contributor
timestamp: March 07, 2015, 12:52:59 pm
content: My brother broke the screen on his A7 camera so he bought a replacement, he said there was a pcb held to the back of the screen by some clear double sided adhesive tape and when he peeled it of it didn't leave any residue. Can someone please tell me what type of tape this is.

author: lapm
author_rank: Frequent Contributor
timestamp: March 07, 2015, 05:04:37 pm
content: Personally i have used double sided photograph tape.. where you can get that now days when paper photographs are going away... Camera shops still good bet..Holds good and comes of with little care...

author: Kjelt
author_rank: Super Contributor
timestamp: March 07, 2015, 05:08:50 pm
content: http://solutions.3m.com/wps/portal/3M/en_US/Adhesives/Tapes/Products/~/3M-Tapes-3M-Adhesives/Double-Sided-Bonding-Tapes/3M-VHB-Tape?N=6105&rt=r3

author: StylinLP38
author_rank: Newbie
timestamp: March 12, 2015, 06:01:30 pm
content: Question, what about hot glue? I am adding a circuit board (video mod kit) to my Atari 2600 heavy sixer and need to place it either in the bottom of the case or on top of the existing main board. Ive seen poeple attach it to the top of one of the big IC chips with double sided tape. What are the draw backs or a dab of hot glue?
Double sided board, ground pour on both sides or ground/vcc? - Page 1
Forum section: electronics / beginners

author: allanw
author_rank: Frequent Contributor
timestamp: November 06, 2010, 05:05:20 pm
content: What's better: using a ground pour on both sides of the board, and then routing Vcc intelligently or just pouring the top VCC and bottom GND?

author: tyblu
author_rank: Frequent Contributor
timestamp: November 15, 2010, 08:38:17 am
content: Ground on both sides, routing Vdd intelligently, paying attention to ground currents with respect to Vdd currents, and paying attention to separating noisy grounds/voltages from sensitive areas of the board.(In other words, we can't really answer this question.)

author: vimark
author_rank: Newbie
timestamp: November 24, 2010, 08:46:33 am
content: Hi,From my experience pour ground on both sides usually is the standard and route power (Vcc or Vdd) with larger width depending on the current demand. Keep digital and analog ground on a common spot on the board (star ground) if your on mixed signal designs, if possible don't route power traces near analog signals. Also don't route in-parallel traces with high speed tracks, cross it instead under/over the board if it is unavoidable.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 24, 2010, 09:59:39 am
content: There is no right answer - depends entirely on the requirements of your design.

author: vimark
author_rank: Newbie
timestamp: November 24, 2010, 10:08:40 am
content: Just my clues, thoughQuote from: mikeselectricstuff on November 24, 2010, 09:59:39 amAcknowledged.
double sided breadboard - Page 1
Forum section: electronics / beginners

author: Simon
author_rank: Unknown
timestamp: July 18, 2015, 05:45:24 pm
content: Anyone know where to get some of that double sided breadboard that dave showed in one of his videos, the one where you make the joints instead of break them and there are tracks on both sides going across each other ?

author: lapm
author_rank: Frequent Contributor
timestamp: July 18, 2015, 07:35:56 pm
content: Maybe from one that makes them:https://www.eevblog.com/forum/crowd-funded-projects/perf/
double sided prototype pcb veroboard - Page 1
Forum section: electronics / beginners

author: golash
author_rank: Contributor
timestamp: November 22, 2014, 08:02:31 pm
content: HiI`ve been searching but have not located a source for double sided prototype pcb in a veroboard configuration.Does this item exist. My searches come up with nothing.Thanks

author: Simon
author_rank: Unknown
timestamp: November 22, 2014, 08:56:42 pm
content: Never seen such a thing

author: Fraser
author_rank: Super Contributor
timestamp: November 23, 2014, 12:51:25 am
content: I have someIt has tracks on both sides but they are orientated at 90 degrees to eachother. Mine is also plated. No idea where to buy it as I have had the boards for at least 30 years !

author: Andy Watson
author_rank: Super Contributor
timestamp: November 23, 2014, 01:49:54 am
content: I built my first Z80 system on double sided vero complete with 128 bytes of RAM. I've not seen any double sided strip board for at least 20 years, probably longer.

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: November 23, 2014, 04:25:47 am
content: I used to hate the product ! I found it very confusing to use, and still have a sheet tucked away in my workshop which will probably go in the box with me when I'm carried out.

author: tautech
author_rank: Super Contributor
timestamp: November 23, 2014, 05:34:30 am
content: Quote from: golash on November 22, 2014, 08:02:31 pmBest you put your country flag in your profile for local recommendations.Google search for "double sided stripboard" finds plenty.

author: Flenser
author_rank: Regular Contributor
timestamp: November 23, 2014, 01:14:06 pm
content: QuoteI thought I'd try some of these x-y veroboards so I did the google.All the search hits go through to other types of double sided prototyping boards. There are eurocards, matrix boards, the type of prototyping boards for DIP chips with power rails down the middle, etc but I could not find anyone selling double-sided veroboard style stripboard with the traces on the two sides running at right angles.I did find a few references to it on element14 and Farnellhttp://au.element14.com/jsp/level5/module.jsp?moduleId=en/204671.xml&sku=147900,http://au.element14.com/images/en_AU/pdf/rohs_AU_part2.pdfandhttp://common.leocom.jp/pdfcat/catalogpage/2-281.pdfbut searching for these stripboards by part number or name comes up with no double sided products.

author: denelec
author_rank: Regular Contributor
timestamp: November 23, 2014, 02:02:23 pm
content: http://www.veroboard.com/index.php?main_page=advanced_search_result&search_in_description=1&keyword=double+side&x=0&y=0

author: LEDAero
author_rank: Regular Contributor
timestamp: November 23, 2014, 10:26:28 pm
content: http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20141123142500&SearchText=pcb+prototype+board+double20 assorted boards for $6
doubt abt SN65DSI86 bridge ic - Page 1
Forum section: electronics / beginners

author: electricenthusiast
author_rank: Contributor
timestamp: December 19, 2022, 09:45:01 am
content: I got this SN65DSI86 ic. Dont know how to program it. Texas provided me a tool to enter parameters of the source and the output (DSI tuner). When i entered the parameters, it gave me a text file with full of data to upload to ic via 12c lanes of the ic. But im figuring out how can i upload the program through it. there is no source on the web. I even tried in deep web. No results and i dont know what are the uses of these pins (marked inside the red box)See image below

author: electricenthusiast
author_rank: Contributor
timestamp: December 19, 2022, 10:08:36 am
content: a fast reply would be great

author: Terry Bites
author_rank: Super Contributor
timestamp: December 22, 2022, 06:35:58 pm
content: e2e.ti.com/search?q=SN65DSI86&category=forummaybe

author: Terry Bites
author_rank: Super Contributor
timestamp: December 22, 2022, 06:37:04 pm
content: e2e.ti.com/search?q=SN65DSI86&category=forummaybe
DOUBT: EMI input switching - Page 1
Forum section: electronics / beginners

author: chinoPR
author_rank: Newbie
timestamp: April 29, 2021, 05:39:58 pm
content: Hi community! I have a doubt with a common mode choke (EMI) for my switching source. I use ST1S14 chip, It work with 850 kHz and 3A output(MAX), but I´m working with 500mA.. my question is.. for select the EMI, I use a part with high impedance in this frecuency (850kHz)? what is the parameter to evaluate for the selection?Thanks, greetings from Argentina.
Doubt in Feedback Amplifier Reg - Page 1
Forum section: electronics / beginners

author: Gurumurthy
author_rank: Regular Contributor
timestamp: October 21, 2022, 05:52:29 pm
content: Hi to all,In the Circuit Io flows out of Collector, Why?the normal direction should be flowing in to the collector terminal, why there is change in current direction?Its is a current Series Feedback From Millman Book, Integrated Electronics.thank you all

author: TimFox
author_rank: Super Contributor
timestamp: October 21, 2022, 06:02:06 pm
content: In that drawing, the arrows for current merely define the positive/negative polarity for the current in each resistor, as used in the corresponding algebraic equations.Obviously, the DC current in the collector flows "down" from the positive Vcc.The author is probably more interested in the AC current, the variation from the quiescent current with small signal currents (compared with the quiescent value).

author: eugene
author_rank: Frequent Contributor
timestamp: October 21, 2022, 06:12:27 pm
content: When I think about transistors I tend to consider electron flow instead of conventional current. To me, the arrows pointing in to the base and out of the collector look correct. Perhaps the author suffers from the same affliction.

author: Gurumurthy
author_rank: Regular Contributor
timestamp: October 21, 2022, 06:17:43 pm
content: Current flow from higher potential to lower potential. The current direction says collector terminal is higher than VCC. Then transistor may reach saturation due to reduction in VCE.

author: andy3055
author_rank: Super Contributor
timestamp: October 21, 2022, 06:57:09 pm
content: As Tim has explained, the notation is Io. It is not Ic.. It is the output current with respect to the input current Ii.The text should explain it. I have used that book and it is not wrong. You have to change your mindset to what the author is referring to and you will get it.

author: TimFox
author_rank: Super Contributor
timestamp: October 21, 2022, 08:07:18 pm
content: I assume that the reason the "output current" arrow points up is that this is a small-signal analysis, where the "wiggle" in the output current is small compared with the DC quiescent current.To get the "output voltage" (again, small signal), you need to multiply the output currentIOtimes the load resistanceRL.For AC analysis, the top end of that resistor is considered to be at AC ground, since the voltage there does not change with the AC current.Therefore, the arrow for output current (through that resistor) is in phase with the output voltage (with respect to ground).

author: andy3055
author_rank: Super Contributor
timestamp: October 22, 2022, 01:09:38 am
content: Also, output current flows out from the device in to the load. OP must recognize that the DC analysis is different to the AC signal analysis.
Doubt of BOOST/BUCK circuit operation - Page 1
Forum section: electronics / beginners

author: Leo86
author_rank: Contributor
timestamp: February 27, 2019, 04:24:26 am
content: Hi everone!I am studying circuits of power converters, and researching found the GreatScott channel! on youtube and it explains how to develop a BOOST / BUCK converter with a microcontroller.I was in doubt trying to understand his circuit.I did not understand why he used an MCP602 in the circuit. Could someone explain?Another question, is this circuit a SEPIC converter?tks...

author: Nerull
author_rank: Frequent Contributor
timestamp: February 27, 2019, 04:33:20 am
content: The opamp scales the voltage across the load from 0-20V to 0-5V so the ADC in the microcontroller can handle it. The MCU needs to sense the output voltage to adjust its regulation depending on the load, but it cannot deal with the output voltage of this circuit directly.If it was a SEPIC circuit than it would have two inductors and its output wouldn't be inverted.
doubt trigger rigol DS1104z - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: March 09, 2024, 08:03:51 pm
content: Hello, I have a Rigol DS1054z oscilloscope (conv. DS1104z), on the Rigol DS1102 oscilloscope, if I'm not mistaken, it had a trigger called toggle, which it did was alternate the two channels. On the DS1054z, is there any way to do something similar?in spanishhola, poseo un osciloscopio rigol DS1054z (conv. DS1104z), en el osciloscopio rigol DS1102 si no me equivoco traia un triger llamado alternar, que lo que hacia era alternar los dos canales, en el DS1054z hay alguna forma de realizar algo parecido??
Doubt with a schematic. Detecting the BEMF. - Page 1
Forum section: electronics / beginners

author: joelsrf
author_rank: Newbie
timestamp: May 03, 2022, 09:01:58 am
content: Can anyone help me with the schematic part of the BEMF voltage divider? Thanks. What do you think A0, A1, A2 and D6 are doing? I think that D6 detects when it´s a 0 crosing and A0, A1, A2 detect during all the time if they´re floating or if they are active phases. So then, knowing with phase is floating and knowing how the other two phases are, we can know wich is the next step sequence.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 04, 2022, 12:53:45 pm
content: R13, R16, R17 are the top side and R12, R14, R15 are the bottom side of a voltage divider to get the motor voltage into the range of the ADC.R20, R21, R22 take the average of the three motor phase voltages, and they mimic the "star" point of the motorThe microcontroller can now compare the phase voltages (A0, A1, A2) with the "star point (D6) to get very close to the zero crossing.ATMEGA328 has an analog comparator. Is this comparator connected to D6 (and configurable to have any of the analog inputs for the other side?

author: Picuino
author_rank: Super Contributor
timestamp: May 04, 2022, 01:31:33 pm
content: I join the thread
doubt with connection of elements to ground - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: November 03, 2019, 09:02:10 pm
content: Hi, I have a doubt, I have an Arduino mega 2560 connected to a PC which has a ground connection, and I also have a FY6900 generator and a Rigol ds1054z, without a ground connection, the three being connected to each other there should be no damage problems nothing, it is always one of the elements that has a ground connection, very rarely you see or almost never only when I test on the protoboard are floating FY6900, Rigol and protoboard without land.in spanishhola, tengo una duda, tengo un Arduino mega 2560 conectado a una pc la cual tiene conexion a tierra, y ademas poseo un generador FY6900 y un Rigol ds1054z, sin conexion a tierra, estando los tres conectados entre si no deberia haber problemas de dañar nada, siempre es uno de los elementos el que tiene conexion a tierra, muy rara ves o casi nunca solo cuando hago prueba en la protoboard quedan flotando FY6900, Rigol y protoboard sin tierra.
Doubt with formula in chapter 4x4 of the AoE X-Chapters - Page 1
Forum section: electronics / beginners

author: Atomillo
author_rank: Regular Contributor
timestamp: July 25, 2021, 02:29:03 pm
content: Hi!I was reading the X chapters when I arrived at chapter 4x4 and more specifically at figure 4x41, which I attach.Now, I understand that this compensation network creates a pole at the origin. In fact, this looks analogous to the Type I compensation network used in power supplies.However, why is it that the frequency that crosses unity gain is determined by Rc and Rg in parallel? Following the before mentioned type I compensation network theory, the op amp virtual grounds makes it so that all current that flows through Rf passes directly to Cc, so that the crossover frequency is 1/2*pi*Rf*Cc.How is the the Rf in parallel with Rg term determined? What is different from a type I compensation network?Many thanks!
How does copperless PCB wear? - Page 1
Forum section: electronics / beginners

author: BigBrother
author_rank: Regular Contributor
timestamp: February 16, 2013, 03:58:04 pm
content: I was thinking about making a case out of copperless PCB but I've never thought about how PCB wears down in a high physical (touchy) environment. Any ideas?

author: jeroen74
author_rank: Frequent Contributor
timestamp: February 16, 2013, 09:53:24 pm
content: Basically you are asking for the material properties of FR4, of which most PCBs are made. It's allhere.

author: BigBrother
author_rank: Regular Contributor
timestamp: February 17, 2013, 03:24:39 am
content: Quote from: jeroen74 on February 16, 2013, 09:53:24 pmSince it contains Bromine, it wouldn't be a good idea for day-to-day use as a split keyboard casing? might still be good for a Raspberry Pi case though, right?

author: jeroen74
author_rank: Frequent Contributor
timestamp: February 17, 2013, 08:24:34 am
content: Yes, that's what makes it Flame Retardant. It's part of the resin molecule, it's not in elementary form. I guess it's something you don't have to worry about.

author: burro
author_rank: Contributor
timestamp: February 17, 2013, 03:44:24 pm
content: Yes, sorry about that, I removed it.
Down the rabbit hole
Forum section: electronics / beginners

author: tifkat
author_rank: Regular Contributor
timestamp: August 21, 2020, 05:46:34 am
content: Starting a new topic, because the official thread is over 120 days old since last reply, and my questions feel like they fit better in the beginner section.I recently watch EEVBlog #1132, and I was interested in the font chips for a possible project, so I went looking on LCSC to see what was on offer. While looking at the datasheets for some of these little chips, I noticed a strange idea in the circuit hookup.Looking at the data sheet for the GT20L24F6Y (https://datasheet.lcsc.com/szlcsc/GT20L24F6Y_C126754.pdf) on page 25, I don't see a connection to GND. And there's a 3.3v connection, plus a 3.3v connection via a series resistor.This got me to thinking, are they using a voltage difference (the forward voltage of the resistor would make a lower voltage on the #HOLD pin, which I'm assuming is pin 2, or GND) to act AS IF the chip is connected to ground? Does this result in an over all lower operating voltage across the chip, say 1.2v or something? Like half of a voltage divider? So the 3.3v through series resistor has a lower potential than the un-modified 3.3v and thus it has lower charge and so acts like a ground?If this is the case, the charge must flow from the 3.3v, through the chip, and out to the resistor, where it is dissipated as heat, because where else can it flow? It surely can't flow back along the other 3.3v line going to the resistor.If this is correct, it raises another issue in my to-date understanding of resistors. Most people simplify the concept of resistors for the uninitiated by drawing a large dimeter water pipe, connected to a smaller diameter water pipe and explain that the water can only flow as fast as the narrower pipe will allow.This concept falls apart if you have 2 large diameter pipes pumping water against each other via the smaller diameter pipe, which seems to be a better representation of what the above circuit shows. If I've got it right so far, would it be more correct to represent a resistor as a soaker hose in the middle of 2 larger source pipes? Both pipes are pumping water towards the soaker hose, and the water escaping from the soaker hose results in very low flow, effectively from both source pipes? Of course the chip would be a 4th pipe, smaller than the supply pipes, but much larger than the soaker hose. Maybe a pipe with a couple of piercings which let some water escape. (The little rebel!)Please enlighten me if you really understand this concept.Alas, I never found a chip with a decent 7-segment font, but it did bring me to think that perhaps I can use a regular EEPROM to make my own font chip.tifkat

author: greenpossum
author_rank: Frequent Contributor
timestamp: August 21, 2020, 06:00:43 am
content: I think it's an erroneous schematic. There is no Hold# pin on the package.
DP832 for split rail supply - Page 1
Forum section: electronics / beginners

author: netdudeuk
author_rank: Frequent Contributor
timestamp: July 01, 2018, 12:23:16 pm
content: HiRigol states 'must use wire rated for 9A or greater to prevent damage or a possible fire hazard'. That's 12 AWG.https://rigol.desk.com/customer/en/portal/articles/2285140-how-do-i-connect-the-dp832-to-achieve--30v-on-channel-1-and-channel-2-That seems to fit in with the 3A per channel maximum but if the project is only a lower current one, wouldn't it be ok to use, say, 18AWG wire ?Thanks

author: Ian.M
author_rank: Super Contributor
timestamp: July 01, 2018, 02:32:40 pm
content: They are being over-cautious. However if you ignore their recommendation, use thin wire, short it at max current and as a result mar the front panel or melt a notch in a binding post insulator, you are S.O.L.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: July 01, 2018, 04:10:13 pm
content: Quote from: Ian.M on July 01, 2018, 02:32:40 pmI've located some ring mains cable to I'll use some of that.Thanks.

author: bson
author_rank: Unknown
timestamp: July 02, 2018, 04:35:40 pm
content: You don't need to handle more current than the total CC you set. For example 50mA each on the rails and 150mA on the digital section will need at most 250mA. And youshouldset CC limits; this is what will save your projects when you do something stupid.Just your typical lab 4mm banana jack equipped patch cables are fine, like basic Pomona ones. Pomonas specifically are rated to 20A.

author: Ian.M
author_rank: Super Contributor
timestamp: July 02, 2018, 06:03:33 pm
content: Personally, I'd get some stackable 4mm plugs and make up some short jumpers - 6" between plugs would be a convenient length. Alternatively, if you rarely use the binding posts to clamp wires, make up custom jumpers for each configuration with crimped fork terminals, with multiple ends depending on the number of terminals you need to tie.

author: Zero999
author_rank: Super Contributor
timestamp: July 02, 2018, 08:19:02 pm
content: Quote from: bson on July 02, 2018, 04:35:40 pmCan the constant current mode be relied on for protection against fire though? Is there a failure mode which could result in the full current being delivered in to a short circuit?My advice would be don't worry, the CC mode should be reliable enough, but I wouldn't leave it running, unattended.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: July 02, 2018, 08:57:09 pm
content: Quote from: Hero999 on July 02, 2018, 08:19:02 pmMy goodness. Is it that bad ? I have a nearly £500 lab power supply and I can't leave it hooked up ?Is this because we're talking all three rails here with the (pretty small) potential for the whole 9 amps to be dissipated ?Would this apply to other PSUs too ?I'll add that I did set up CC as suggested but at even lower levels.Thanks