hybridfree/eevblog-posts huggingface dataset:
Solid State Relay flashing when it should be off - Page 1
Forum section: electronics / beginners

author: bitshift
author_rank: Regular Contributor
timestamp: February 06, 2016, 11:49:32 am
content: Hey guys,I'm trying to use a solid state relay to switch a light bulb through the 230VAC mains. The relay is controlled with a 10VDC signal. I've connected everything as follows:The lightbulb turns on great when 10V is applied to pin 3 of the relay. When the control signal is turned off, the light bulb flashes on or off at around 1-2Hz. I've tried a 10k as well as a 1k pull down resistor.Any ideas as to what could be causing this?Hereis a link to the datasheet. The model I am using is on page 6.

author: Ian.M
author_rank: Super Contributor
timestamp: February 06, 2016, 01:00:14 pm
content: Use a real incandescent lightbulb not a LED or CF bulb!It only takes a minuscule leakage current to slowly charge up the LED or CF bulb's reservoir cap, and when the voltage gets high enough for the control chip to come out of UVLO (undervoltage lockout), it will switch on till the charge on the cap is used up. The result is a bulb that 'blinks' on briefly at intervals varying from a fraction of a second to several minutes depending on the leakage and the UVLO mode current consumption of the control chip. I've seen it happen just due to wiring capacitance on stair lighting with mechanical switches top and bottom. You could try adding a snubber network (Class X cap and low value series resistor) across the bulb to shunt the leakage current and keep the reservoir cap under the UVLO threshold.

author: bitshift
author_rank: Regular Contributor
timestamp: February 06, 2016, 02:05:31 pm
content: Ah those pesky parasitic parametersTried a incandescent bulb and it works as expected. Thank you Ian

author: Zero999
author_rank: Super Contributor
timestamp: February 06, 2016, 02:32:56 pm
content: But aren't incandescents inefficient, especially if you're living in a hot country such as South Africa?Try connecting a 100K resistor in parallel with the CFL/LED lamp. Also note the minimum load current so it may not work with very low power lamps.Another thing you could try is a solid state relay with a MOSFET output stage.

author: bitshift
author_rank: Regular Contributor
timestamp: February 06, 2016, 02:35:24 pm
content: What I'm actually doing is testing the temperature of the SSRs heatsink. I'm using the SSR to control the elements in my reflow oven. I built up the circuit and tested it with my desk lamp and was surprised when it was flashing on and off.

author: Seekonk
author_rank: Super Contributor
timestamp: February 06, 2016, 03:54:18 pm
content: Place a .47uF in series with a 220 ohm 1/2W resistor in series. May work with a .1uF. Caps should be X2 type rated for line voltage. That RC network should be placed in parallel with the lamp. That will shunt any leakage of the SSR without wasting energy.
Solid state relay question - Page 1
Forum section: electronics / beginners

author: Precious Roy
author_rank: Contributor
timestamp: December 26, 2016, 12:42:28 pm
content: Hello,You can buy there solid state relay boardshttp://www.ebay.nl/itm/5V-8-ch-Solid-State-Relay-Genuine-Keyes-Module-240V-AC-2A-Arduino-Flux-Workshop-/121957116913?hash=item1c6535ebf1:g:ZwwAAOSwKfVXEOsBAnd i think this is the datasheet for the relayshttp://www.rhydolabz.com/documents/29/Solid_State_Relay_g3mb_datasheet.pdfbut i am wondering I need to switch 24v ac and i get the feeling when reading the datasheet that they will not work for 24v accan any of you confirm or deny my suspicions?

author: snarkysparky
author_rank: Frequent Contributor
timestamp: December 26, 2016, 01:01:34 pm
content: It may not work for the low voltage you specify.The reason is outlined in this document on page 2-14http://literature.rockwellautomation.com/idc/groups/literature/documents/at/700-at001_-en-e.pdfThe output side uses the applied voltage to trigger the internal triacs. If it's below the design threshold it will trigger late or not at all.
Solid State Relay Schematic - Double Check - Page 1
Forum section: electronics / beginners

author: vidarr
author_rank: Frequent Contributor
timestamp: March 28, 2024, 01:50:06 pm
content: Hi, can someone please double check my schematic of a solid state relay for use with Arduino?It is a pretty straightforward circuit, but I want to be double sure because I am using mains power here.Also, I want to attach the TRIAC to an aluminum heat sink, but the main terminal 2 and the tab of the TRIAC are connected. This means I have no option but to put the whole thing into a "project box" correct?TRIAC BT137:https://pdf1.alldatasheet.com/datasheet-pdf/view/16764/PHILIPS/BT137.htmlOPTOCOUPLER DPC-817C:https://datasheetspdf.com/mobile/952198/KeepJump/DPC-817C/1THANK YOU!

author: pqass
author_rank: Super Contributor
timestamp: March 28, 2024, 02:24:45 pm
content: The optocoupler you've chosen has a phototransistor. You'll need a bidirectional triac driver; like the series MOC30xx (eg.MOC306xorMOC302x).Some in the series can turn on only at zero-crossing; others turn on immediately. The latter can be used for fine-dimming loads (bulbs or motors) but generates lots of noise since large current spikes can occur if turned on midway into the cycle. The former is used for switching on/off but can dim too but only in half-cycle increments (eg. 1/120sec). Since turn on occurs only at zero-crossing there is less noise/spikes and easier on the load.Also, if the load is inductive, you'll need a snubber resistor/cap.See attached.

author: Ian.M
author_rank: Super Contributor
timestamp: March 28, 2024, 02:32:25 pm
content: No good at all. The opto's phototransistor is only rated for max. 35VDC (or 6V if reverse polarity), so it will fail as soon as mains is applied.Pqass has already given good adviceFor the TRIAC, yes, you need a box, just to avoid exposed mains terminals, but the heatsink doesn't have to be (and shouldn't be) live. Either use an isolated heatsink mounting kit for the TRIAC, or (easier) get a different one in an isolated package. If the heatsink is accessible it must be grounded for safety.

author: vidarr
author_rank: Frequent Contributor
timestamp: March 29, 2024, 12:51:23 pm
content: I only need the circuit to turn On and Off, so the zero crossing will work.Thank you for the links!
Solid State Relay to power anything on car Non-Stock and avoid blow ControlUnits - Page 1
Forum section: electronics / beginners

author: dssence
author_rank: Regular Contributor
timestamp: March 26, 2014, 04:43:52 am
content: Hi guys , I have a Toyota 86 FT (same as Scion or Subaru BRZ) so to be short I wanted to add a led strip to my position lights (ones which light up when you turn on backlight on instrument panel) or a T10 led bulb to replace the ugly stock original bulb. I know you can easily screw up "Body System Integrated" units when diminishing the amperage going through that circuit, as most circuits are designed for resistive loads.So,if I take out the led bulb for instance which is a T10 format 5watts , and replace it with a led strip which draws 600mah I could easily blow up the driver of that circuit on my car.So take 2 scenarios-First Scenario (Adding led strips for position lights to each headlight, removing the original 5 Watts T10 bulbs )In this scenario a friend of mine came up with a solution to use a solid state relay opto coupled (IXYS part number LC717) to avoid damagin the driver. This is in theory how it would be connected. But I have many doubtsAs you see the output + of the SSR to switch both ledstrips go to the cars battery, and the Control line of the solid state relay goes to one of the positive lines of the position light harness, so when I turn on the knob on the instruments panel it lights upNow these are all my doubts1)We are lighting up an IR led diode with the positive line form the position lights which in turn is coming from a driver. I know it's not the same as plugging a resitive load there. But we're lighting up a led diode. So this could, well blow/damage the driver?2)Shouldn't we be emulating the original resistive load instead? rather than lighting up a Solid state relay IR led. By emulating the original load I mean, if the original position light was a 5watts bulb and if I measure it with a dmm and it's filament measure 150ohms, shouldn't I replace a 5watts resistor 150ohms in series with the led strip I want to place there?. All this instead of using a solid state relay?- Second Scenario (replacing the original 5 watts incandescent bulbs with LED bulbs T10 same wattage)Say I want to replace the original incandescent bulbs 5watts with led bulbs T10 same wattage , would this damage the Control unit. ? My friend said it could. Cause the circuit it's not designed to handle this kind of load which is not resistive.This is the kind of bulb I'm talking about .Should I have to use this load resistor instead? Or precisely on which case should I add a load resistor like this onehttp://www.vleds.com/resistors/parking-light-resistors/lr-park.html
Solid State Relays and Current Consumption - Page 1
Forum section: electronics / beginners

author: Veramacor
author_rank: Regular Contributor
timestamp: January 18, 2013, 01:48:57 pm
content: May be a stupid question but I'm asking anyway!I have a low power application that requires my microcontroller to be in sleep mode most of the time.I would like to turn on a wifi module that only needs to be on for a few seconds, then can be turned off.If I were to use a solid state relay to turn the wifi module on and off, would the solid state relay consume any power in the 'off' position?I have a wifi module that can go into 'sleep' mode and it consumes about 50 micro amps, I would like to get that number down further by using a solid state relay, but if the SSR consumes a lot of power in the 'off' state, its obviously not worth it!thanksJUPDATE: *** I may have answer my own question:The following SSR apparently has only 1 micro amp of off-state leakage current:http://www.clare.com/home/pdfs.nsf/www/CPC1002N.pdf/$file/CPC1002N.pdfNow that will work!

author: SeanB
author_rank: Super Contributor
timestamp: January 18, 2013, 04:38:14 pm
content: What about a P channel mosfet as a high side switch? Next to no power when off, and low loss when on. I assume the wifi and micro use a common supply voltage. You will just have to use a logic level one that will have a low enough loss at the required current and then you will have no problems.

author: Veramacor
author_rank: Regular Contributor
timestamp: January 18, 2013, 05:21:39 pm
content: Looks like the one I found does TTL level switching 2.2V and 2ma. Looks like it requires an LED? Or could I just hook it up to an output on the micro on pin 1 and pin 2 to ground?

author: vsholding
author_rank: Newbie
timestamp: April 28, 2013, 04:04:27 am
content: Electronic Design and Research Inc. makes many micro-consumption relays, both types SPST-NO, SPST-NC, SPDT, etc.http://www.vsholding.com/news%20release/news%20release%20for%20mSSR%20for%20website.pdf
Solid State Resettable Fuses??? - Page 1
Forum section: electronics / beginners

author: logancane
author_rank: Regular Contributor
timestamp: May 20, 2021, 06:23:55 pm
content: Hi everyone,I'm looking for a device or a circuit that performs the same task as a fuse but it must be:Solid State - Because it will have to operate in a vacuumSelf-resetting - Because it will be on a high altitude balloon, thus there will be no operator presentLow leakage - Because the whole system will be run on batteries, which due to weight restrictions I want to keep power loss as small as possibleSo far, the best thing I've found is a PTC fuse, but I don't like how they are resistive and thus have both a voltage drop and some power drain. Can we do better than that? Perhaps something to do with a FET? Any help would be much appreciated!Thank you in advance.

author: penfold
author_rank: Frequent Contributor
timestamp: May 20, 2021, 06:34:54 pm
content: Have you seen those such astheseeFuses from ST, other manufacturers (AD, TI etc) make similarI'd agree with your avoidance of PTCs, but more from the perspective that they are very thermally dependant and therefore will be quite unpredictable when subject to temperature, pressure and humidity variations. That goes for any lossy devices on a PCB to be fair and thermal behaviour will generally be quite unpredictable.

author: logancane
author_rank: Regular Contributor
timestamp: May 20, 2021, 06:47:49 pm
content: Quote from: penfold on May 20, 2021, 06:34:54 pmAwesome! Exactly the kind of thing I was looking for. It even has some of the other types of protections functionality that I was looking for.Thank you!
SolidWorks Electronics or others ? seeking recommendations  - Page 1
Forum section: electronics / beginners

author: Tomer
author_rank: Regular Contributor
timestamp: March 23, 2018, 10:43:23 pm
content: Hi All.I am a beginner and would like to create schematics and to design PCB. I have a lot of experience with SolidWorks but not with the electrical module.My questions are:1) Does SolodWorks "Electrical Design" is a good choose for creating schematics and design PCB's ?2) Would you recommend a different tool/program ?Thank you for your help and knowledge !Tom

author: rdl
author_rank: Super Contributor
timestamp: March 24, 2018, 05:16:01 pm
content: It looks like something that is intended to plan electrical systems for buildings and factories, not something you would use to design pc boards.

author: Tomer
author_rank: Regular Contributor
timestamp: March 25, 2018, 05:49:21 pm
content: Thank you for the replayAny recommendation for a suitable program ?ThanksTom

author: Farley
author_rank: Regular Contributor
timestamp: March 25, 2018, 06:00:40 pm
content: SolidWorks has a PCB design package which I believe is actually some flavor of Altium.https://www.solidworks.com/product/solidworks-pcbI've never used it.I use SolidWorks for mechanical design and DipTrace for PCB design. DipTrace will create STEP files that import into SolidWorks. It works quite well.

author: trevers
author_rank: Contributor
timestamp: March 26, 2018, 05:24:07 pm
content: If you truly are a beginner -http://fritzing.org/home/Free (as in beer) and very capable -http://kicad-pcb.org/Free (as a limited user) -https://www.autodesk.com/products/eagle/overviewYou probably did not get many answers for this as a simple search would have found the three that I mentioned above. IMHO all of the "ecad" packages from the major mcad vendors (PTC, Siemens, Dassault) (excluding Eagle) are not really intended for PCBs.

author: ericasdf
author_rank: Newbie
timestamp: March 26, 2018, 06:24:02 pm
content: SolidWorks PCB is a stripped down version of Altium. I do not know how stripped down it is, but when you start talking SolidWorks or Altium, you have to have fairly deep pockets. I use Altium for my day job and at home (the speed benefit pays for itself), and while I like it, it does have some quirks (and bugs). But I think that is common among all EDA packages; you will find things you love and things you will hate. If you are willing to spend some money, contact the vendors and get trials and demos of each before making your decision. If you want seamless integration into SolidWorks then either SolidWorks PCB or Altuim is your choice.Altium does have a free versionhttps://circuitmaker.com/#why_circuitmaker. I have never used it so I can't comment on how good it is.I have coworkers that use KiCad and DipTrace and love them. Eagle is a popular one, but I find it very unintuitive.
Solution for relative XY axis input device - Page 1
Forum section: electronics / beginners

author: PeterFW
author_rank: Frequent Contributor
timestamp: January 17, 2016, 09:49:35 pm
content: Hello!To reduce the "problem" to its simplest explanation. I would like to control the relative position of a dot on a LED matrix.That means it should wrap around when reaching the border.Most likely powered by an SAM3X8E µC since i like the simplicity of the Arduino IDE.That is not that big of a problem, either i could just simple push buttons or a miniature joystick.I would however prefer something more tactile/seamless and have a hard time coming up with a solution.My favorite so far would be re-purposing a USB trackball.It should be something with tactile feedback, so touch sensors are out of the question. Both X and Y should be useable with one "knob".Does someone have a creative idea?For every other control i use rotary encoders.Greetings,Peter
solution : how to judge the micro and type-c cable quality  - Page 1
Forum section: electronics / beginners

author: RD Tech
author_rank: Regular Contributor
timestamp: June 19, 2018, 09:30:32 am
content: UM25(C) Measure Type-C and Micro cable resistance same with UM24(C) and UM34(C))Use our tester to measure the cable resistance to judge the cable resistance good or not , it is very usefulMeasurement procedure:First, connect the USB Tester directly to the power supply and adjust the appropriate load current (recommended value 1A). Press and hold the "Next" button to begin recording data. The indicator prompt will stop flashing.Second, unplug the USB Tester and then reconnect it to the power supply via the data connection cable and adjust the load current to the same value as in the first step. Press and hold the "Next" button to begin recording data. The indicator prompt stops flashing and the Data Connection Cable resistance measurement test is completed and the value displayed.Note: If during the second step the screen turns black, this indicates that the voltage difference is too high and the tester will enter the 4.5V power-down state. The load current needs to be reduced. Then re-start the measurement from the first step. After the Data Connection Cable resistance test is completed, the Tester needs to be powered off and then on again to resume measurement.UM24(C):https://www.aliexpress.com/store/product/RD-UM24-UM24C-for-APP-USB-2-0-LCD-Display-Voltmeter-ammeter-battery-charge-voltage-current/923042_32845522857.htmlUM34(C):https://www.aliexpress.com/store/product/RD-UM34-UM34C-for-APP-USB-3-0-Type-C-DC-Voltmeter-ammeter-voltage-current-meter/923042_32880908871.htmlUM25(C):https://www.aliexpress.com/store/product/RD-UM25-UM25C-for-APP-USB-2-0-Type-C-LCD-Voltmeter-ammeter-voltage-current-meter/923042_32855845265.htmlLD25:https://www.aliexpress.com/store/product/RD-LD25-Electronic-Load-resistor-USB-Interface-Discharge-battery-test-LED-display-fan-adjustable-current-voltage/923042_32882318330.html

author: anishkgt
author_rank: Frequent Contributor
timestamp: June 19, 2018, 09:34:29 am
content: Sad these don't have an app for the IOS.

author: Ian.M
author_rank: Super Contributor
timestamp: June 19, 2018, 10:11:30 am
content: Personally, I'd rather use a bench multimeter + a set of breakout boards for all the sizes of USB A and B socket. That also lets you check the shield resistance is under 0.6 ohms, and the data pair resistance to confirm they are at least 28 AWG. If its got good low L and C ranges, you can also check if the data pair impedance is close to the 90 ohm spec.High shield resistance or out of spec data pairs are key signs of a crappy cable that wont be picked up by testing the power pair resistance or voltage drop in circuit.

author: RD Tech
author_rank: Regular Contributor
timestamp: June 20, 2018, 02:12:59 am
content: sorry, for now , there is not

author: RD Tech
author_rank: Regular Contributor
timestamp: June 20, 2018, 02:14:31 am
content: thank you so much for your reply, we only provide one way to measure ...
Solution to noise when using iphone power/audio splitter - Page 1
Forum section: electronics / beginners

author: euroclydon
author_rank: Newbie
timestamp: June 13, 2022, 12:48:06 pm
content: I bought a cable that has a male lightning connector on one end, and splits to male USB and male 3.5mm mini audio. When I use this in my automobile with admittedly a super-cheap cigarette lighter USB power supply, the noise in the music is unbearable (buzz, engine speed, etc).I'd like to build a 12v -> 5v power supply to solve this, and learn along the way, so practicality and expense (within reason) are not concerns.I think the problem is a ground loop, but not sure. Assuming it is a group loop, my first thought was to buy an isolated dc2dc converter and add in capacitance on the input and output if needed. I've even seen diagrams with an I/C circuit on the input side. But my concern here is that the isolated converters I find in the 12v->5v range are only rated for 5-6 watts, yet a recent iPhone probably wants up to 4x that much. I'm not sure what the max charge rate an iPhone can do when connected to a dumb circuit like this. If it's only 1A, then I guess this will be okay.Questions:1) What is causing the noise?2) What are some solutions I can build?

author: ledtester
author_rank: Super Contributor
timestamp: June 13, 2022, 01:41:10 pm
content: Just to be sure, is this your setup?cigarette lighter -> USB power supply -> iphone -> 3.5mm audio cable -> car's audio system

author: euroclydon
author_rank: Newbie
timestamp: June 13, 2022, 01:50:22 pm
content: [ Specified attachment is not available ]

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2022, 06:41:07 pm
content: Quote from: euroclydon on June 13, 2022, 12:48:06 pmThis is anextremelycommon problem in car audio, and indeed it's a ground loop issue. The solution is an audio ground loop isolator (an isolation transformer). (I don't think the quality of power supply makes any difference; I even had to use an isolator when I upgraded my first car's stereo from busted factory unit to a fairly high end Blaupunkt. I would assume it had a very clean power supply.)You want something like this (also in attached photo):https://catalog.pac-audio.com/catalog/audio-interfacing/sni-1-3-5It costs $12 on Crutchfield (one of the very best sources for car audio stuff):https://www.crutchfield.com/p_127SNI135/PAC-SNI-1-3-5-Noise-Filter.html

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2022, 06:46:36 pm
content: P.S. I kinda like this model, one of many available on Amazon, etc, because it's got fully removable cables, making it more flexible regarding your installation, and FAR easier to fix if the cable goes bad!https://www.amazon.com/Isolator-Eliminate-Buzzing-Completely-Playing/dp/B019FC6ZQQ/
Solution to replace 4-pin PWM RD fans - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: July 29, 2025, 12:17:05 pm
content: Hi,I'm not having much luck, I have an three 5yo inverters powering my house, their cooling system uses two DA08025B12UH fans, I want to source quality replacements.They're 4-pin PWM but they don't have a tachometer (FG) wire, it's rotation detect (RD) instead.Fans are:80x80x25mm12VDC (7.0~13.8VDC)4500 RPM0.35A67.21 CFM0.32 inch-H2O70000hrs at 40℃45.0dB MaxDual ball bearingDIYers have tried using fans with tach wires and they get FAN LOCKED errors.Any ideas, I'd only need a maximum 12 fans and can't find any on Digikey or Mouser?So the technical question, if I cant find RD fans, can I make a tiny circuit that takes the tach signal and converts it to an RD signal, or swap a component on the fan PCB?I found this:https://product.minebeamitsumi.com/en/technology/fanmotor/dc_cat_001-03.htmlThanks for looking.

author: mtwieg
author_rank: Frequent Contributor
timestamp: July 29, 2025, 01:15:26 pm
content: In my experience, tach outputs are basically the norm now, it's actually rare to find DC axial fans with simple locked rotor detection.Sure you could probably make a circuit to translate the tachometer signal into a an effective locked rotor signal. However, to get it to work with existing firmware, it might be more complicated than you'd expect. Depends on how the firmware assumes the signal should behave.For example, that website shows a couple different behaviors for the lock signal. Which one does the firmware expect?Also, if this fan's speed can be controlled down to zero with the PWM input (can't tell if that's the case for your fan), there's also the question of how the lock signal should behave in that case.

author: benj38
author_rank: Frequent Contributor
timestamp: July 29, 2025, 07:07:45 pm
content: I would hazard to guess that you still have the old fans, and that at least one of them still works well enough. Thus, why not make some measurements of the RD signal under different conditions?I am sure once this is done it would be quite easy to emulate this signal from a tachometer signal.
Solutions of book Electronic Principles 8th - Malvino  - Page 1
Forum section: electronics / beginners

author: leftek
author_rank: Regular Contributor
timestamp: March 20, 2018, 05:48:27 pm
content: Hello, know anybody if there are solutions of the book "Electronic Principles 8th" of Malvino?I am reading it, but i need to know if my solutions of problem is correct. He have only the half solutions on the end of book.

author: Unknown
author_rank: Unknown
timestamp: March 20, 2018, 06:43:32 pm
content: Here's what the textbook says, if you can't find a copy floating around the internet. Note, there is a solutions manual and lab exercise manual.Directions for accessing the Instructor Resources through ConnectTo access the Instructor Resources through Connect, you must rst con- tact your McGraw-Hill Learning Technology Representative to obtain a password. If you do not know your McGraw-Hill representative, please go towww.mhhe.com/rep, to nd your representative.Once you have your password, please go to connect.mheducation.com, and login. Click on the course for which you are using Electronic Principles. If you have not added a course, click “Add Course,” and select “Engineering Technol- ogy” from the drop-down menu. Select Electronic Principles, 8e and click “Next.”Once you have added the course, Click on the “Library” link, and then click “Instructor Resources.”

author: leftek
author_rank: Regular Contributor
timestamp: March 20, 2018, 07:33:10 pm
content: Quote from: steverino on March 20, 2018, 06:43:32 pmThank you for your information. I obtain printed book on Greek language and don't say these information.Do you mean this?https://www.amazon.com/Experiments-Electronic-Principles-Engineering-Technologies/dp/1259200116I think that is not solutions manual for the textbook, but only lab exercise manual.About this way (by connect.mheducation.com), they says that is for educator. Can i have access on this?

author: Unknown
author_rank: Unknown
timestamp: March 20, 2018, 07:49:43 pm
content: I don't know, I just happen to have a softcopy of the book and did a cut and paste. Access is probably restricted to instructors but I don't know how the publisher verifies.

author: rstofer
author_rank: Super Contributor
timestamp: March 20, 2018, 09:03:39 pm
content: The author doesn't want the extra solutions showing up on the Internet because it diminishes the value of the book for classroom use.What I have found is there is usually an answered problem very similar to an unanswered problem. The idea is to have the student solve BOTH problems and compare the answer for one of them. Yes, it's twice as much work!There won't be any problems that can't be solved with a knowledge of the theory and the use of Matlab. Perhaps "Solving DC and AC Circuits Using Matlab" can help. This may not be what the instructor wants the student to turn in so perhaps it is better to solve by hand and verify by computer.Also, symbolab.com and desmos.com may be useful. Perhaps the Electrical Engineering videos at Khan Academy.
Solve LED strip light flickering on shared rail with high current load - Page 1
Forum section: electronics / beginners

author: GreyArea
author_rank: Contributor
timestamp: September 19, 2021, 08:18:58 pm
content: A while ago I built an enclosure for my 3D printer including relay control from a Raspberry Pi and LED strip lights around the inside.The PSU is a Mean Well S-240-12 which outputs around 18A, more than enough for the load. The 12V rail is shared between the 3D printer (which draws about 9A of current) and the LED strip lights (about 1A), the attached schematic shows the layouut.The problem I'm trying to solve is that when the heated bed and the extrusion nozzle of the 3D printer reach a stable temperature, the controller switches into PWM mode, taking (or rather, not) gulps of current and causing the LED strip lights to dim/flicker at about 2/3Hz.I've never had a need to use an Inductor before but I was wondering if placing one in-line at the Pin 3 output of K1 would solve my problem.I placed my multimeter at the output (Pin 5) of the PSU and measured a DC current draw of about 9.67A, just within the rating of the meter. I switched the meter to AC mode on the 10A range and measured (I think) a ripple of about 3.5A.Some questions then:- Would placing an Inductor in-line at the Pin 3 output of K1 solve my problem?- Is my measurement set up correct (3.5A of current fluctuation)?p.s. I just realised I've labelled pin 2 of the PSU as Earth, I know it's not but.

author: Zero999
author_rank: Super Contributor
timestamp: September 19, 2021, 09:05:42 pm
content: The inductor would have to be huge to make a significant impact. It's not practical.How thick are the cables? It's highly likely they're too thin, resulting in excessive, voltage drop when the heater turns on.Increase the cross-sectional area of the cable, so the voltage, drops by no more than 0.5V, from full to no load. R = V/I = 0.5/18 = 0.028 Ohm

author: BrokenYugo
author_rank: Super Contributor
timestamp: September 19, 2021, 10:55:47 pm
content: Assuming you are already using fairly heavy wires (2.5 mm^2 or better), run a dedicated pair of wires directly off the PSU to power the LEDs (with it's own relay if needed), or modify the PSU for remote sense.That 3.5A ripple measurement does sound wrong. Note that cheap meters often don't like measuring AC with a DC offset.Also, minor thing, 2-3Hz isn't PWM, it's just switching on and off to keep the temperature in range, you wouldn't see the flicker (frequency too high) if the heaters had PWM control.

author: cortex_m0
author_rank: Regular Contributor
timestamp: September 20, 2021, 03:39:54 am
content: Even though the MeanWell supply is rated for 18A, that does not mean you will get the exact same voltage out of it at no load that you will at full load. The supply has a specification for "load regulation" of 0.5% That means over the output current range, the output voltage would be expected to vary by up to 0.5%.That's only 60mV, but if your problem is not the voltage drop through the cables, this would be the next thing to check, by measuring the voltage directly at the terminals of the power supply.
Solving bridge equation - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: March 04, 2015, 08:50:52 am
content: 1. I am using wheatstone bridge to measure change in resistance.2. Bridge is excited by IDAC instead of voltage source.3. I have made a equation for it in term of voltage output versus change in resistance. It is attached with circuit in pdf.4. Can anyone check if it ok.5. I have simulated the results with my equations & they are ok.
Solving current in transformer circuit. - Page 1
Forum section: electronics / beginners

author: MarkusAnd
author_rank: Contributor
timestamp: November 23, 2020, 01:10:48 pm
content: Hello!This is a part of a homework problem, so I'm not looking for the solution to the whole problem. But anyhow I want to solve the current Ir and my plan was to convert the current source to a voltage source. After that i would use mesh analysis to solve the current.My question is if I've done the source-transformation correctly and that J goes in the opppsite direction of Ir? Is the current J correct in my drawings?Picture attached.

author: mag_therm
author_rank: Frequent Contributor
timestamp: November 23, 2020, 11:30:13 pm
content: After doodling for a while I think you have reduced it correctly into two loops.E3 is the transform to the voltage source.dots of L's are at the topMagnitude of E1 is jwM*I2Magnitude of E2 is jwM*I1Check the polarities of E1 and E2.
Solving OPAMP circuit - need help - Page 1
Forum section: electronics / beginners

author: txescientist
author_rank: Regular Contributor
timestamp: January 19, 2014, 07:07:06 pm
content: Hi,I need help solving one circuit - ideas, methods, anything. Know how to solve basic opamp circuits, but this I can't solveAll parameters are known, I need to solve for Ip.Any help is very much appreciated

author: electronics man
author_rank: Frequent Contributor
timestamp: January 19, 2014, 08:23:59 pm
content: Need more information

author: txescientist
author_rank: Regular Contributor
timestamp: January 19, 2014, 08:48:48 pm
content: I don't have any more information. We work just with variables, no numbers. Need to find current trough Rp. Tried with node potentials, but can't get solution. Maybe use superposition - Vi1 = 0 and find part of Ip1 and then use Vi2= 0 and get Ip2, so Ip = Ip1 + Ip2. I study physics, so we rarely use real numbers, just get equations and relations.Thanks

author: Rudane
author_rank: Regular Contributor
timestamp: January 20, 2014, 08:09:41 am
content: I think he's hinting at what you are suppose to relate. Should the answer be only a function of V1, V2 and R?

author: txescientist
author_rank: Regular Contributor
timestamp: January 20, 2014, 08:39:45 am
content: That's right. Sorry for my confusing post. We only worked on class simple examples where inputs were not connected together and those examples are easy, but this I can't handle. Thanks

author: IanB
author_rank: Super Contributor
timestamp: January 20, 2014, 09:18:48 am
content: Label the unknown voltages at each of the nodes as V3, V4, V5, etc. (much as you did with V0).Write current balance equations around these nodes to get some simultaneous equations. Assume the voltages at the op amp inputs are equal to get another equation.Eliminate voltages from these simultaneous equations to get an expression for the unknown current Ip.There may be a shortcut way of solving this problem (I'm not sure), but the above way is the first principles method that should work. It is just a lot of algebra.

author: txescientist
author_rank: Regular Contributor
timestamp: January 20, 2014, 09:54:42 am
content: Solved it!Thanks for help!
Some advice on temp and help understanding  - Page 1
Forum section: electronics / beginners

author: Bensco
author_rank: Newbie
timestamp: June 15, 2019, 03:57:39 pm
content: Hi, I picked up an old technics sa-eh760 hifi system, it works great. I have a concern with a component getting very hot, it's a pcb with 3 transistors d2374 and 2 b1548's the service manual calls them regulator transistors. The 3 transistors are clamped down to the body of the amp, I'm guessing for heat dispersal. If it is a heat sink it's not very substantial and no sign of any thermal paste ever being used. So I would like to know what it is? A voltage regulator?And should it get hot? How hot is to hot.Many thanks Ben

author: soldar
author_rank: Super Contributor
timestamp: June 15, 2019, 04:03:42 pm
content: Complementary transistors.2SD2374,2SB1548

author: Audioguru
author_rank: Super Contributor
timestamp: June 15, 2019, 05:56:22 pm
content: The service manual with a detailed schematic was posted on the other website's forum.

author: soldar
author_rank: Super Contributor
timestamp: June 15, 2019, 07:40:08 pm
content: Yes, I found it easily online. After a very quick look it might be that those transistors are not part of the audio amplifier but part of the power supply. I did not look in detail though.

author: Stray Electron
author_rank: Super Contributor
timestamp: June 15, 2019, 07:44:02 pm
content: I would look for any capacitors that are on the output of the regulator circuit (or on the input to the audio amps which it powers) and check and see if any of them are starting to short out. They could be drawing too much current and overloading that regulator.

author: Bensco
author_rank: Newbie
timestamp: June 15, 2019, 08:02:21 pm
content: Thanks for the replies
Some doc about function generator use? - Page 1
Forum section: electronics / beginners

author: dds
author_rank: Contributor
timestamp: January 20, 2011, 08:14:32 am
content: Looking for a book or good tutorial about beginner function generator use. Any idea?Thanks!

author: saturation
author_rank: Super Contributor
timestamp: January 20, 2011, 02:16:03 pm
content: A commonly linked intro is B&K's pdf:http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBYQFjAA&url=http%3A%2F%2Fwww.bkprecision.com%2Fsupport%2Fdownloads%2Fguides%2FFunction_and_Arbitrary_Waveform_Generator_Guidebook%2FBK-Function-Generator-and-AWG-Guidebook.pdf&rct=j&q=function%20generator%20B%26K%20pdf&ei=O0M4TYfKFMXflgePz7HvBg&usg=AFQjCNFV6JGMLaMk_6y9pYgNYiw9wW0vug&sig2=3MTSKV0TAJTDkC0ipmuLgA&cad=rja

author: radiomog
author_rank: Regular Contributor
timestamp: January 09, 2015, 07:38:54 pm
content: Quote from: saturation on January 20, 2011, 02:16:03 pmthat link no longer works... this does as of a few minutes ago..http://www.testequity.com/documents/pdf/bk/BK-Function-Generator-and-AWG-Guidebook.pdf

author: devanno
author_rank: Regular Contributor
timestamp: January 09, 2015, 08:02:15 pm
content: Another "white paper" here:http://www.ni.com/white-paper/5514/en/
Some doubts about reading voltage and current with and ADC - Page 1
Forum section: electronics / beginners

author: senso
author_rank: Frequent Contributor
timestamp: August 29, 2012, 04:37:48 pm
content: Good afternoon, when dave started his PSU series, I grabed is rev B schematic, made some modifications and got some pcb's, after months I finally got some time for this project, and the voltage measurements are a bit off, like, the adc says its 1.00v, and the scope(Rigol DS1052E) measures 1.20v, usually its always a 200mV diference, in some values its a bit smaller.The current, well, it was suposed to be 1mA/bit, but for a 220ohm resistor at 1.00v(measured by the ADC), the current is about 9 counts, or as the expected 1mA/bit 9mA, but ohms law says it should measure 4.5mA.The schematic is in this pdf:https://dl.dropbox.com/u/30143255/power%20supply.pdfThe code to convert from the ADC readings to voltage is this:Code:power.vinf = (double)((power.vinRaw*2.048f*10.98)/4095.0f);power.voutf = (double)((power.voutRaw*2.048f*5.0f)/4095.0f);And the voltage reference measures 2.04v on the scope.Any thoughs on how to correct the measures, and whats is the correct calcs to get the current values?
Some Equipment Choices - Page 1
Forum section: electronics / beginners

author: AustinTxBob
author_rank: Contributor
timestamp: December 22, 2016, 10:08:47 pm
content: I recently acquired some test gear from the ITT auction. All of it is school grade stuff but since I didn't have some of these pieces, it's an upgrade.PSU - Currently I have an Elenco XP-720 with 10-turn pots. It works well except it does not have any meters. I acquired a B&K 1651, a GW Instek GPD-3303S, and a GW Instek GCP-3020. I was just going to keep the 3303S but should I hang on to the B&K also (it is silent)? (3 supplies total too many?) The 3020 is huge and the fan is so loud that I can't see keeping that one.Freq Counter - I got a B&K 1823 and a GW GUC-2020. I was planning on keeping the B&K.I made a mistake and bought a GW GOS-6112 scope but I already have a Rigol DS1054z. Any reason to keep the GW scope?Also I picked up a GW GDM-8135. Right now I only have my B&K 2709B handheld but I was planning on keeping the bench model unless there is a reason not to.Any thoughts?Thanks!Bob
Some fundamentals question - Page 1
Forum section: electronics / beginners

author: msuffidy
author_rank: Frequent Contributor
timestamp: March 12, 2025, 02:44:27 pm
content: I saw this in facebook and thought there are some issues with this. What it does is flash like a night bike warning. So in this example someone is running off of mains and has a high value resistor. A diode polarizes the flow to charge a capacitor. When the current is high enough, it switches a zener diode to let through the capacitor charge. Is there anything wrong with this circuit? Is the problem really that the LEDs have an effective resistance, and thus the voltage across them may exceed their limits? That is to say the 220V drop is between 1 resistor, 2 LEDs in series and two diodes, which the voltage levels have to do with the resistor values?

author: jmelson
author_rank: Super Contributor
timestamp: March 12, 2025, 03:48:47 pm
content: The Diac is not a Zener, it snaps on to conduct at some voltage, and stays on until the cap discharges to some level where the current stops flowing. There is no current limiting resistor in series with the LEDs. Depending on the trigger voltage of the Diac, this could lead to excessive current in the LEDs.Jon

author: msuffidy
author_rank: Frequent Contributor
timestamp: March 12, 2025, 05:10:32 pm
content: OK so in this case the part involving the capacitor is more like a power supply, and the discharge is the LED circuit. I guess there is a high voltage low amperage input to the capacitor, and that translates into a rising voltage in the capacitor during charging? It still probably does have to current switch the diac though, otherwise it would already be on? Does the capacitor and diode have effective resistances to determine their voltages?

author: IanB
author_rank: Super Contributor
timestamp: March 12, 2025, 06:29:56 pm
content: Quote from: msuffidy on March 12, 2025, 05:10:32 pmThe capacitor slowly charges up through the resistor and diode, until it reaches the threshold voltage of the diac. At that point, the diac conducts and discharges the capacitor through the LEDs. Then the cycle starts over again.The potential problem with this circuit is the lack of current limiting in the discharge path through the LEDs. They will see a short, high current pulse. This may be OK if the average power dissipation is low enough, but it might also be a problem.
Some good info from Renasas's FAQs - Page 1
Forum section: electronics / beginners

author: allanw
author_rank: Frequent Contributor
timestamp: March 07, 2011, 03:35:19 am
content: There's a lot of good general information at Renasas's FAQ page about op-amps, comparators, transistors, and other general design principles which might come in handy:http://www2.renesas.com/faq/en/f_op.html

author: VIPR
author_rank: Contributor
timestamp: March 07, 2011, 01:43:40 pm
content: Thanks for the info and link. Certainly one of the best FAQ's I've seen in quite some time with loads of valuable info--especially for beginners/hobbyist.Of course there is something similar at most of the major silicon manufacturers websites. One of my favorites is National:http://www.national.com/analog/training#overview
Some help to get my first PCB made - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: May 05, 2020, 01:23:02 am
content: Hello you very helpful bunch,Please PM me if you can spare a wee bit of time I want to use a Olimex ESP32-POE and connect that through a ULN2803A to six G6K-2P and 22 resistors, to make a networked relay volume control.RCA L/R pair in one side, through the R2R network to another RCA L/R pair at the other side.It's a hobby project for my Hi-Fi setup, I don't expect it done for nothing, happy to pay a bit. In theory I set the six GPIO's and I get a specific volume.Essentially I want to put the ESP32-POE into a socket on the new board, six of it's GPIO's will go to the ULN2803A inputs and the outputs go to the relays. Using PoE I should have at least 600mA @ 5V remaining for this circuit.Attached is the main part of the circuit, grabbed from some doco and gerbers I found onlinehttp://www.vaneijndhoven.net/jos/attenuator-calculator/index.html.Thanks for looking.CheersRichard
Some help with transistors? - Page 1
Forum section: electronics / beginners

author: robinsonb5
author_rank: Newbie
timestamp: April 02, 2014, 07:32:50 pm
content: HiI'm new to the forum and wondered if someone could give me a little help with transistors.I've been playing with one of those Gotek floppy drive emulators and figured that it needed some kind of audio feedback for that authentic retro feel! So I hacked together a little circuit using BJTs and a piezo sounder. The result works......sort of.Occasionally I get a parasitic oscillation that makes the sounder squeak when it's not supposed to. It goes away if I touch the sounder, so I put a capacitor across it, which helped but didn't get rid of it entirely. Since I don't have a massively solid grasp of transistors most of the component values here were selected by intuition or trial-and-error, and rather than just swap out yet another component in the hope of killing this oscillation, I figured it's time to ask whether there's a better way to achieve this.I want to keep the circuit as simple as possible since I'm "rats-nesting" it on the underside of the Gotek PCB.I've attached a schematic of what I've got so far - if anyone can suggest improvements or corrections I'd be gratefulVCC is 12v, taken from the floppy power connector. The step pin is pulled up to 3v3 by the Gotek (and loaded down a bit by my circuit), and triggered by a very brief low pulse (a few µs) - so T2 has to be a type with a very low storage time. The much higher storage time of T1 should have the effect of widening this pulse, which I presume is a good thing from the point of view of making the pulse audible.Any insights gratefully received

author: KJDS
author_rank: Super Contributor
timestamp: April 02, 2014, 07:38:09 pm
content: Put a 220R into the base of T1 and a cap, probably about 10n in parallel with R4.A decoupling cap on the supply would help too.

author: madires
author_rank: Super Contributor
timestamp: April 02, 2014, 08:09:57 pm
content: What kind of piezo buzzer do you got? There are different kinds, each with it's own driving method.

author: robinsonb5
author_rank: Newbie
timestamp: April 02, 2014, 11:24:38 pm
content: Quote from: KJDS on April 02, 2014, 07:38:09 pmOK thanks - I'll give that a goQuote from: madiresIt's a bog-standard piezo transducer, rather than a self-contained buzzer. This kind of thing:http://www.ebay.co.uk/itm/5-35mm-Piezo-Elements-Sounder-Sensor-Trigger-Drum-Disc-/360853719389?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item54048ec95d
some kind of strain relief - Page 1
Forum section: electronics / beginners

author: mike_mike
author_rank: Super Contributor
timestamp: September 05, 2021, 01:01:23 pm
content: Hello! What kind of strain relief do you recommend for using in a soldering gun case for the 230Vac cord ?In the case is very small space, and for testing, I used a 7mm cable gland which I cut into half, and I used the part that holds the cable. I mounted the cable gland onto the cable and placed it into the soldering gun's handle.Do you have any other recommendation for strain relief for the soldering gun ac cord ?