hybridfree/eevblog-posts huggingface dataset:
circuit simulation - Page 1
Forum section: electronics / projects

author: yalect
author_rank: Regular Contributor
timestamp: April 20, 2020, 06:37:21 am
content: Hi,I would like to ask you that I have problem with some circuits like this (attached picture) sometimes when I simulated it with Proteus 8 it shows me the message ( TRAN : timestep too small; timestep =0.00133113: trouble with instance Q1 and simulation stoped]).how to resolve or set that problem?timestep too smallthank you

author: JoeyG
author_rank: Regular Contributor
timestamp: April 20, 2020, 06:49:58 am
content: I'm not familiar with this simulator, but where is the Voltage (power source)?

author: Ian.M
author_rank: Super Contributor
timestamp: April 20, 2020, 07:23:26 am
content: Its more likely to be an issue with the switch in series with C2. When it initially closes it will cause a step change in Q2 Vbe, which may be problematic if the Q2 BC547 model is a macromodel.

author: SiliconWizard
author_rank: Super Contributor
timestamp: April 20, 2020, 02:04:53 pm
content: I don't know much about Proteus, I'm assuming it's a Spice-based simulator. In particular, I don't know about the base parameters for base parts.I would try adding some small ESR to C2 (if there is an ESR parameter for capacitors), or manually add a small resistor in series (like 1-2 ohm) with C2, and see how that goes.

author: Wimberleytech
author_rank: Super Contributor
timestamp: April 21, 2020, 01:52:02 pm
content: I suggest that you reduce the cap to 1uf or less and run the simulation.Is your switch starting in the on or off position?What is the on resistance and off resistance of the switch?

author: bson
author_rank: Unknown
timestamp: April 21, 2020, 06:27:40 pm
content: Is that thing that says "+88.8" supposed to be voltage source or a volt meter? Is R1(1) a measurement, or a power rail?'Time step too small' in Spice usually implies it's unable to converge while determining the DC operating point. With the capacitor open looped it would have to derive this from the BJT, but its internal model may not allow it to do that, or there may be a discontinuity - for example around where the base current transitions from zero to non-zero. It may be a model parameter, but it can't be found iteratively. If so the easiest workaround will likely be to put a 1G resistor between the base and ground.

author: Wimberleytech
author_rank: Super Contributor
timestamp: April 21, 2020, 06:51:23 pm
content: Quote from: bson on April 21, 2020, 06:27:40 pmNo, that is an error during transient analysis. For dc operating-point problems there is a different error message...but I cannot recall what it is because I have not had a convergence issue recently.
Circuit Specialists 75 Watt Soldering Iron? - Page 1
Forum section: electronics / projects

author: devin23b
author_rank: Newbie
timestamp: March 01, 2017, 07:02:39 pm
content: I am looking into getting a new soldering iron and found this one and though it didn't look to bad, but you never know nowadays, so does anyone know if this is a good one to get?

author: ebastler
author_rank: Super Contributor
timestamp: March 02, 2017, 09:54:26 am
content: Looks like a (probably Chinese) copy of the Hakko 936. You might be able to get a better price elsewhere.There just was a discussion on soldering stations in that price range in the Beginner's forum,https://www.eevblog.com/forum/beginners/is-the-velleman-vtss5-a-decent-soldering-iron/.

author: viperidae
author_rank: Frequent Contributor
timestamp: March 04, 2017, 07:00:57 pm
content: I've been using a 936 clone for 3 or 4 years now. It's been very good, except last night the heater coil failed. $3 for a new iron but it's going to take weeks to get here from China. It's been good considering it only cost me $15 from hobby king.
Circuit that reduces 12 volts to 3 volts - Page 1
Forum section: electronics / projects

author: electronicsstudent98
author_rank: Newbie
timestamp: January 13, 2025, 06:34:30 pm
content: Hello everyone. I need a circuit board connected to the car battery, that is, a circuit that reduces 12 volt energy to 3 volts, but the power can be adjusted, that is, a non-linear circuit. Can anyone help if they have an example video, picture, kicad or proteus file? I want to create a circuit based on the SY8113B datasheet. Thank you to everyone who helps in advance.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 13, 2025, 07:07:52 pm
content: https://electronics.stackexchange.com/questions/385998/sy8113-based-buck-converter-voltage-regulator-designsimple google fuu would have given you many designs to choose from ...

author: Konkedout
author_rank: Frequent Contributor
timestamp: January 13, 2025, 09:06:29 pm
content: Quote from: coromonadalix on January 13, 2025, 07:07:52 pmThis link above works OK but when I click on the next link I get "bad gateway". I cannot find SY8113 at Mouser or Digikey.How much current do you need? If the current is under maybe 200 mA and efficiency is not critical, then I recommend an LM317. This link will take you the TO-220 version from many manufacturers:https://www.mouser.com/c/semiconductors/power-management-ics/voltage-regulators-voltage-controllers/linear-voltage-regulators/?q=LM317&package%20%2F%20case=TO-220-3&instock=yThis will be inexpensive and use only a few parts. If power dissipation is significant then I recommend a heatsink and/or a "burnoff" resistor. Tell us minimum and maximum input voltage, maximum load current?

author: andy3055
author_rank: Super Contributor
timestamp: January 13, 2025, 09:33:02 pm
content: Get one of these. There are many different versions. You can replace the preset with a regular, linear control:https://www.ebay.com/itm/135090864371
Circuit to countdown after a given pulse - Page 1
Forum section: electronics / projects

author: SScattered
author_rank: Contributor
timestamp: November 17, 2022, 07:25:05 am
content: Hi,Please see the attachment.When I give input to opto-coupler it turns on the mosfet thus actuating the relays. Even after the power opto-coupler is removed, the relays will still be powered. So only way to reset this is to release the "Emergency Button".I can't use a microcontroller for this. What now I need to do is remove the "Emergency Button" and implement some sort of circuit which reset the circuit (Like emergency button does) automatically after a few seconds when the input to the Opto-coupler is removed.What I thought of to be used it a 555 IC timer, but I'm not sure how can I utilize it.Basically,1) Opto-Coupler is powered -> relays powered2) Opto-Coupler is not-powered -> relays still powered3) Timer circuit cut-off power to the relays after a certain time (Opening the circuit where emergency button is and the closing it)

author: robzy
author_rank: Regular Contributor
timestamp: November 17, 2022, 08:04:51 am
content: Quote from: SScattered on November 17, 2022, 07:25:05 amWhy not? Is there anything else you can't use?Why don't you just throw away the whole circuit and create something new?How will you be sure that the emergency button will still be safe?

author: SScattered
author_rank: Contributor
timestamp: November 17, 2022, 08:11:24 am
content: Quote from: robzy on November 17, 2022, 08:04:51 amActually this is for some project. Therefore cannot use a microcontroller in this case.Emergency button works. I already made a prototype and tested.

author: Benta
author_rank: Super Contributor
timestamp: November 17, 2022, 10:59:57 am
content: CD4541/MC14541 come to mind.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 17, 2022, 01:54:01 pm
content: Remove RL1 and add a 555 circuit between the optoisolator and MOSFET.
Circuit to detect polarity of RFID - Page 1
Forum section: electronics / projects

author: charliehorse55
author_rank: Contributor
timestamp: June 20, 2025, 09:23:29 am
content: I'm trying to detect which way an RFID card is placed onto a surface. Luckily, there is a nice theoretical way to do this - detect whether the amplitude of the carrier wave changes on the "rising" edge, or the "falling" edge. However, I'm not sure how to design a cheap/efficient circuit to detect this. I'm using LF RFIDs, in the <1MHz range (these ICs work well into the 10+ MHz range. I'm not using them at the stock 125kHz for other reasons).Here we can see the "top" changing first:With the card reversed, the "bottom" changes first instead:So far I tried a solution using passive filters, but I found that the frequency components of the amplitude change are all clustered tightly around the fundamental, so that's not really possible. My next idea was to setup two peak detectors, one for the min and one for the max. Then pass them both through differentiators to detect changes in peak amplitude, then finally some sort of pulse logic to determine which diff output pulses first. Unfortunately, that seemed rather convoluted. Ultimately, I'm trying to get the signal into an MCU, a WCH RISC-V clone of STM32. Perhaps there is a way to use the timer/PWM capture features to record which event happens first.The sine wave amplitude is a few volts P-P, with the amplitude changing about 5% showing up on the reader (as the tag modulates the field).Any ideas?
Circuit to measure power with respect to a reference for negative feedback? - Page 1
Forum section: electronics / projects

author: julian1
author_rank: Frequent Contributor
timestamp: September 05, 2016, 08:26:57 pm
content: We can use a long-tail-pair/differential-amplifier to measure voltage against a reference.And by employing a shunt resistor do the same for current.Is there a similar circuit that can measure DC power (voltage * current) with respect to a reference that does not introduce non-linearities, and that emits an output suitable for negative feedback?Ideally,Something simpler than an analog multiplier, or multiplying op-amp configuration.Perhaps ADC digital-sampling of both voltage and current and multiplying digitally would be the only way to achieve instrument level accuracy/ avoid non linearity?For moderators - I wasn't sure whether to post here or the beginners section, so please move if appropriate.

author: retrolefty
author_rank: Super Contributor
timestamp: September 05, 2016, 08:36:19 pm
content: Posting to follow.

author: dannyf
author_rank: Super Contributor
timestamp: September 05, 2016, 08:49:32 pm
content: referencing only changes voltage, not current.so if you want, measure the product of the two, or measure them individually and do the math offline.

author: uncle_bob
author_rank: Unknown
timestamp: September 05, 2016, 09:57:48 pm
content: HiThere are indeed analog multiplier circuits that you can feed both the voltage and current into. A Gilbert Cell is one of several approaches. You can then feed the output of the multiplier into your control loop. If you are dealing with a high frequency signal, there are interesting circuits that directly estimate the power without going through the current and voltage thing. A thermistor power meter is one way to do this, there are others.If you abandon the analog domain entirely (yikes !!!), then yes, you can digitize both the current and voltage. You then let your MCU do some math and away you go.The much more conventional approach is to do none of this.Most loads present a fairly constant impedance to the driving circuit. Because of this you can use either voltage or current to figure out what is going on. This is the approach taken in the vast majority of control loops out there.Bob

author: David Hess
author_rank: Super Contributor
timestamp: September 08, 2016, 06:03:17 am
content: Quote from: julian1 on September 05, 2016, 08:26:57 pmSome dedicated instrumentation amplifiers work this way. Check out the datasheet for the LM395 monolithic transistor pair which includes an example.QuoteLog-antilog multipliers can be pretty accurate but multiplication can also be done using switched capacitor circuits. Check out Linear Technology application note 3 for a 0.01% analog multiplier built using the LTC1043 switched capacitor building block. Switched capacitor circuits can also make precision instrumentation amplifiers.
Circuit to show relative strength of audio signal? - Page 1
Forum section: electronics / projects

author: level6
author_rank: Regular Contributor
timestamp: February 01, 2024, 08:10:00 pm
content: I would like to use an LED to show the relative strength of an audio signal. I know how to design a circuit that will light the LED if it reaches a certain threshold, but I want the brightness of the LED to vary, depending on the strength of the audio signal. How can I accomplish this?

author: pqass
author_rank: Super Contributor
timestamp: February 01, 2024, 10:40:33 pm
content: Lookup VU metering circuitslike thisand study how it was doneonce upon a time. The key is that audio strength is logarithmic; not linear.Maybethis simple circuitcan be adapted for your needs; replacing the meter with a 1k resistor (corresponds to 1V full scale) then use avoltage-to-PWM (ramp gen+comparator)or voltage-to-current (harder to tweakopamp+FET).

author: moffy
author_rank: Super Contributor
timestamp: February 02, 2024, 02:00:33 am
content: Quote from: pqass on February 01, 2024, 10:40:33 pmThe eye also is logarithmic so it automatically will compensate for the perceived loudness of music. Heard it said that the eye when fully adjusted to complete darkness can detect a single photon, but needs 5 to 9 photons in 100ms to trigger the brain.

author: donlisms
author_rank: Frequent Contributor
timestamp: February 02, 2024, 02:24:12 am
content: Elliot's page is a pretty reasonable conventional approach. I suspect, though, that your needs are simple and not very precise, or you would be using a display more complex than a single LED.The brightness of an LED is determined by the current, not the voltage, so you want a current source that is controlled by the input signal. The input signal is a voltage, so you want a voltage-controlled current source. Conveniently, a transistor does that. You'd want to bias and scale everything appropriately for the particular input signal and the desired brightness.A major issue with measuring audio levels is the time frame. If you had a very fast-responding display, it could track the waveform itself. That wouldn't really be very useful. If it responded slower, and you start to get some averaging, the display will tend to track with the perceived intensity of the music a little better. So there's probably a capacitor in there somewhere acting as a low-pass filter.

author: level6
author_rank: Regular Contributor
timestamp: February 02, 2024, 06:09:10 pm
content: Thanks to everyone for all their help and suggestions. I ended up using an LM393 comparator with the reference set to GND and the audio signal as the input. This provided a decent enough indicator for my application.
Cirrus Logic technical support rejected - Page 1
Forum section: electronics / projects

author: Debugging
author_rank: Contributor
timestamp: November 19, 2022, 06:16:06 am
content: Did you get any support from a (local) Cirrus Logic agent ?Trying to use a Cirrus logic chip and had a question about the circuit. Their chips are used by many audio companies.When contacting the local Cirrus logic agent they said no support is possible without a company registration in the chamber of commerce.Cirrus logic does not provide any email address or technical support ticket system like many other companies do.Any question goes to their local rep who can decide whatever they want and consumer must obey by their own defined requirementsWe tried to contact Cirrus Headquarter about what their policy is on support, but never got an answer other than "it takes times to get an answer"It seem Cirrus isn't interesed in designers unless buying lots of chips from them first before getting any support.Thus, you must first design, certify and sell a product with their chips or be a very large company before getting support.This seems quite a bit shortsighted. Do you have the same experience with Cirrus ?

author: jonpaul
author_rank: Super Contributor
timestamp: November 19, 2022, 05:43:37 pm
content: What part no, problem?Most IC mfg stopped support years ago.Their line of interface and digital audio ICS is well documented in openly available specs, app notes, papers.Similar parts may be from TI, AKM, ADI.Same situation.Bon courageJon

author: Benta
author_rank: Super Contributor
timestamp: November 19, 2022, 05:58:58 pm
content: I have this experience with almost all semiconductor manufacturers. They do not want to support hobbyists or small customers. Nor do they have the resources.That's why they have franchised distributors with educated engineers (FAEs). If you don't like those, try to get support from Alibaba or wherever you buy. Cheapness costs in the end.Sorry, but did you want cheese with that whine?

author: moffy
author_rank: Super Contributor
timestamp: November 19, 2022, 10:36:53 pm
content: My own experience with TI and NXP has been favourable, but mainly the support forums. But most of the really obscure issues you are largely on your own.

author: Debugging
author_rank: Contributor
timestamp: February 05, 2023, 02:37:21 pm
content: Sent a mail to Cirrus USA without expectations. After a few weeks or so an email popped up and they assigned another local Cirrus FAE and they were very helpful to answer any question without any prerequisites.
CISCO 341-0631-03/PS-2122-2S server PS - Page 1
Forum section: electronics / projects

author: Technotronic
author_rank: Contributor
timestamp: October 25, 2023, 04:56:44 am
content: Trying to re-purpose some of these as they have some pretty high current output at 12v.They have a strange blade type power connectors, I am guessing the small multi pin one maybehas a ps-on pin you short to get it going like other computer power supplies do, with a load hooked up- but cannot locate any info online.This is what one looks like:https://www.ebay.com/itm/304879725658Anyone have any idea how to figure out the hookup or perhaps the server they go to could have thehookup pinout?

author: Technotronic
author_rank: Contributor
timestamp: October 26, 2023, 04:20:18 am
content: Found this resource:https://www.rcgroups.com/forums/showthread.php?1292514-How-to-convert-Server-Power-SuppliesApparently you place 500 to 1k resistors on all the non power pins then remove one at a time.https://www.rcgroups.com/forums/showpost.php?p=18002964&postcount=570
Cisco C3K-PWR-1150WAC PSU Connection out of RPS2300 rack C3K-PWR-750WAC - Page 1
Forum section: electronics / projects

author: Robert763
author_rank: Super Contributor
timestamp: April 02, 2021, 06:58:36 pm
content: Following a discussion on the TEA thread I got a couple of Cisco redundant power supplies intended to power network swtches with PoE. These consist of a 1U rack unit, the PWR-RPS2300 with two slots that each take a 750W (C3K-PWR-750WAC) or 1150W (C3K-PWR-1150WAC) PSU module. Power input is 115/23V auto ranging by a IEC inlet on the front of each PSU module. The rack provides a cooling fan, supervision and switching of DC power to up to 6 switches with selectable priority in case of failure or excess power demand.The PSU modules have 2 outputs, 12.25V and 52V. When in the rack they are configured as +12.25V and -52V with 0V common to both outputs and the chassis ground. Outside the rack the 12v and 52V outputs are isolated from each other and chassis. This means the 52V can be used as positive WRT to common. The 1150W PSU has built in fans, 25A 12V and 16.4A 52V ratings.The problem is that these will not power up outside the rack and there is no published information on the interconnect that I can find. But I want a 800W+ >35V power supply for a project without the rack..... I got one of each PSU model and a RPS2300 and set to work finding a minimum configuration that worked. As these have serial communication I was not certain it was possible. The control connections are 16 square pins on a 4x4 0.1" matrix. I decided to make up some 4 way extension leads to run it out of the rack and then see which rows and then which pins were required to power it up.I narrowed it down to two pins which is good. It was likely to be a passive interface as the rack has no separate power supply and it's hard to do anything active with just two wires. I then investigated the matching connections on the rack. Long story short, to turn the PSU on you just have to connect a 1k resistor between pin 6 and pin 15The fans on the 1150W seem to respond to load and are very quiet off-load (on my unused unit at least) but I've not tested at full load yet. The hack will probably work on the C3K-PWR-265WAC PSU too.Marked up image below.
Clamp-meter and voltage - Page 1
Forum section: electronics / projects

author: cs.dk
author_rank: Unknown
timestamp: October 13, 2018, 04:18:58 pm
content: Hi,Got a Brymen BM-089, and it is safe for Cat III 1000V - I guess that only applies, if I use the input jacks?Is there any risk in measuring current (with the clamp) on say 1500VDC? Will the reading skew, will it cause damage to the meter? Other thing I have not thought of?The HVDC cable is safe to touch by hand, so no worries there.
Clamping voltage lower than working voltage? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: March 02, 2022, 06:32:24 pm
content: Hi,this spanned from a previous post but is a different one, a general one about TVS so I making a new post.I was looking into the specs of this TVS: PESD3V3X2UT datasheet here:https://assets.nexperia.com/documents/data-sheet/PESD3V3X2UT.pdfThe Vrwm is 3V3 but the Vcl (clamping voltage) is at 2V6, i.e. clamping voltage lower than the working voltage.There might be some data missing and/or some incorrect one. The datasheet:1) seems missing info about the clamping voltage at very low currents (2-3 mA instead of Amps). Am I missing it perhaps it is deductible form some graphs?2) seems missing infos about the recovery... i.e. at what voltage it reverts to if the current lowers to very low levels such as 5 mA (instead of the Amps of a surge). The clamping voltage is defined as "The voltage that the TVS diode will regulate to when exposed to a transient current". So it should be going back to 3V3 and not remain to 2V6. Correct?3) figure 3 on the datasheet shows Vcl (clamping voltage) higher than Vrwm and always increasing, never going to 2V6 mentioned in the table in the previous page. Isn't that incorrect?Thank you

author: uer166
author_rank: Super Contributor
timestamp: March 02, 2022, 06:35:20 pm
content: This TVS has a GDT-like bevahior: "The device uses an advanced clamping structure showing a negative dynamic resistance.This snap-back behavior strongly reduces the clamping voltage to the system behind the ESDprotection during an ESD even".That might explain all your issues.

author: uer166
author_rank: Super Contributor
timestamp: March 02, 2022, 06:57:52 pm
content: See the clamp waveform, seems like it clamps down to ~1.2V after triggered. There is also no current spec for a "reset" current, which means your pullups may keep it triggered indefinitely.

author: ricko_uk
author_rank: Super Contributor
timestamp: March 02, 2022, 09:41:56 pm
content: Thank you uer166
Clampmeters and voltage - Page 1
Forum section: electronics / projects

author: cs.dk
author_rank: Unknown
timestamp: November 02, 2018, 10:54:38 am
content: I hope someone can shed light on this topic.If I short a lab psu and measure the short circuit current, it will display it just fine. So down to almost 0V it is reading current fine.However, i'm involved in a solar setup. Can I safely measure lets say 1500 VDC with ie. a Brymen BM089? I think the input rating is for the jacks, not the clamp.

author: Zero999
author_rank: Super Contributor
timestamp: November 02, 2018, 11:53:13 am
content: Quote from: cs.dk on November 02, 2018, 10:54:38 amIf the conductor is insulated, then the clamp has no voltage limit, which only applies to the voltage between an uninsulated conductor and earth. The cable could have 10kV on it with respect to earth and it would be perfectly safe to measure the current using a clamp meter only rated to 1.5kV, so long as the cable is adequately insulated for 10kV. However, if the cable is uninsulated, then the clamp meter needs to be rated for the full 10kV.Quickly Googling for the specification of the BM089 shows it's only rated to 1000V, which I presume is both for the jack and clamp when used with an uninsulated conductor.https://www.tme.eu/gb/details/bm089/meters-and-acdc-clamp-probes/brymen/

author: cs.dk
author_rank: Unknown
timestamp: November 04, 2018, 06:44:27 am
content: Thanks. The conductors are insulated, so i'll try to get some measurements
Clapp Oscillator Problem - Page 1
Forum section: electronics / projects

author: ANTALIFE
author_rank: Frequent Contributor
timestamp: December 09, 2017, 07:01:55 am
content: HelloI have been trying to make a Clapp Oscillator from a JFET and some L/C/R's (see pic)With these values the circuit should be oscillating at ~40kHz but I am not getting anything? I have triple checked all connections, soldered it on veroboard, tried biasing Gate, and tried using a 2N5484 JFET but still nothing...Is there something else i'm missing?

author: danadak
author_rank: Super Contributor
timestamp: December 09, 2017, 11:01:29 am
content: C3 should be eliminated, so that inductor serves as bias connectionas well as part of tank.Or bias with additional DC path gate to ground high valued R -Regards, Dana.

author: rhb
author_rank: Super Contributor
timestamp: December 09, 2017, 08:46:04 pm
content: It looks to me as if you are missing a 1N194 from the gate to ground. The attached is from "Solid State Design for the Radio Amateur" by Hayward and DeMaw, which *really* should be reprinted by ARRL. I know of know equal.My understanding is that the Clapp is just a Colpitts with a capacitor in series with the inductor for tuning.

author: Cyberdragon
author_rank: Super Contributor
timestamp: December 09, 2017, 11:39:56 pm
content: You don't need a diode for it to operate, it's just there to adjust the gate bias. The lack of any bias at all is what's causing the oscillator not to start.

author: rhb
author_rank: Super Contributor
timestamp: December 10, 2017, 01:37:00 am
content: I see two issues, R1 is rather large and V2 is rather small.But my main purpose was simply to post the circuit. I don't recall ever building this, but I built several of the more basic circuits in the book. Sadly too busy finishing degrees and earning a living to spend more time on them. I'm working on my penance and reformation ;-)

author: CJay
author_rank: Super Contributor
timestamp: December 11, 2017, 03:01:44 pm
content: Quote from: rhb on December 09, 2017, 08:46:04 pmI believe there's a PDF copy on the CD included with the recent reprint of EMRFD from the ARRL?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 11, 2017, 06:35:48 pm
content: The tank impedance is rather low for the amount of bias current (and therefore transconductance (gain)) the JFET has.Try a smaller resistor.The gate bias comments are also spot on.Tim
Clapper Project - Page 1
Forum section: electronics / projects

author: ItsElliot
author_rank: Newbie
timestamp: March 02, 2014, 05:29:30 pm
content: As a project I am creating a Clap on / Clap off switch for my computer however the tutorial I am following is designed to toggle a relay on and then off, and I would like to make it pulse after detecting a clap; Is there a way to modify the code or the output for this? I will include links to the guide and the code:http://www.instructables.com/id/How-to-make-a-Clap-Clap-on-Clap-Clap-Off-switch-/?ALLSTEPShttp://www.electroniclessons.com/10F222TMPO.ASMIf I get this working, I have a friend who will 3D print a box that can fit in one of the 5.25" bays in the front of the computer and can link to pictures when it is finished.Thanks,Elliot
Clapper switch. - Page 1
Forum section: electronics / projects

author: lesserwords
author_rank: Newbie
timestamp: October 06, 2010, 01:33:36 pm
content: ok... I wanna make a clapper switch for my room that works with clapping no just any loud sound, so if you people out there can give me some designs or tips on how to make one plz and thank you.Ps. Dontmake it too expensive

author: scrat
author_rank: Frequent Contributor
timestamp: October 06, 2010, 01:55:12 pm
content: By analyzing the sound wave of a clap you should find something which characterizes it against other sounds, and then try to recognize it by means of some filtering (if it's quite complex, also digitally inside an MCU).There should be around many circuits to do this, usually electronic kit magazines offered them.

author: Zero999
author_rank: Super Contributor
timestamp: October 06, 2010, 03:21:12 pm
content: He asked the same question before, perhaps it's spam?https://www.eevblog.com/forum/index.php?topic=1440.msg19034#msg19034

author: scrat
author_rank: Frequent Contributor
timestamp: October 06, 2010, 03:31:21 pm
content: Perhaps I'm an ingenuous

author: allanw
author_rank: Frequent Contributor
timestamp: October 06, 2010, 08:30:20 pm
content: Probably just cross-posting.

author: Zero999
author_rank: Super Contributor
timestamp: October 06, 2010, 10:28:09 pm
content: Either way it's annoying when you've wasted your time responding to someone's question, only to find they've posted it elsewhere and someone else has already suggested exactly the same thing.Fair enough it's only he's only made a few posts so our gentle reminder should be enough but if he re-offends I'd suggest banishment but that's up to the powers that be.

author: lesserwords
author_rank: Newbie
timestamp: October 07, 2010, 12:07:27 am
content: I did and it was my second post forgot to put the question on the projects blog, and also the other one never checked it after i made it i came to these section and wrote it again.ps. no one has answer it yet so... yeah.

author: Zero999
author_rank: Super Contributor
timestamp: October 07, 2010, 08:10:37 am
content: If you'd bothered to read the replies you'll find that NiHaoMike suggested how it could be done and probably would've provided more information if you'd asked.What were you expecting? Someone to post a schematic, complete with code and a PCB design? How much are you willing to pay others to do your work for you?

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 07, 2010, 09:11:14 am
content: Quote from: lesserwords on October 07, 2010, 12:07:27 ammaybe the suggestion will be just to re-bump/reply the thread, it will automatically goes top ranking. or just delete it. you keep and care your own threads, make them tidy... and do make an effort on someone's suggestion, otherwise there is no point for the second thread. IMHO

author: lesserwords
author_rank: Newbie
timestamp: October 08, 2010, 12:01:13 am
content: I never saw the other one until today.
Class A headphone amp-Changing from +/-12v to +/-9v supply-Simulation help. - Page 1
Forum section: electronics / projects

author: djsb
author_rank: Super Contributor
timestamp: April 27, 2025, 08:41:39 am
content: I'd like to try running this class A headphone amplifier off of 2 x 9V rechargeable batteries. It will use 2 channels and consumes around 250mA for BOTH channels (not confirmed by actual testing/prototyping yet). It's designed for a +/-12v dual rail supply. I'm considering first trying to simulate the circuit in Kicad/Ltspice/Quc-s/ etc (starting with KiCad as I've the schematic already). Do I need to just make sure that the DC biasing/currents are the same if I change the power supply voltage? Or would I be able to get away with not changing any of the component values? I've attached a screenshot of the schematic for your consideration. I can supply the full schematic as a zip file if needed. Any help appreciated. Thanks.PS Corrected the current consumption from per channel to BOTH channels.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 27, 2025, 09:16:56 am
content: At a brief look, my guess is it will work at +/-9V, just that the idle current is huge for a 9V rechargeable.At 250mA/channel, a so called "9V" NiMH rechargeable will last only a few minutes. They are in fact a 7.2V battery, usually made of 6x1.2V NiMH cells in series, together in the shape and size of a 6F22 9V alkaline. Their typical capacity is very small, 150..300mAh or so. They are destined for much lighter loads of only a few mA.

author: djsb
author_rank: Super Contributor
timestamp: April 27, 2025, 09:30:56 am
content: I corrected the consumption figure to 250mA for BOTH channels. Still, it doesn't change anything much.Looks like I'll have to drop the 2 x 9v rechargeable idea. I wonder what else I could use?

author: Zero999
author_rank: Super Contributor
timestamp: April 27, 2025, 10:11:59 am
content: Quote from: djsb on April 27, 2025, 09:30:56 amDrop the idea of using a class A amplifier. It uses far too much power to run off a battery. Use a class AB amplifier.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 27, 2025, 10:38:03 am
content: There is a dedicated IC for headphone amplifiers, with specs hard to beat even by a class A.https://www.ti.com/lit/ds/symlink/tpa6120a2.pdfHas PCB layout examples, evaluation boards and design notes. If you use an university email address, TI might even send you a couple of IC samples for free:https://www.ti.com/product/TPA6120A2
Class A headphone amplifier - Which one to build? - Page 1
Forum section: electronics / projects

author: radoczi94
author_rank: Contributor
timestamp: May 30, 2019, 02:26:11 pm
content: One day I had an idea about building a headhone amp. Just because I can (and I have almost every part at hand necessary to build it in a decent-ish quality). Almost every device can drive a headphone nowadays. I figured, that because of the small-ish power, It's viable to build in class A. I started to dig around the web, and found these:https://sound-au.com/tcaas/jlhphones.htmI heard and read only good about JLHs designs, so I quickly settled by these. Now I can not decide which one I will build. Someone said that the first one has slightly lower distortion, but I really like the symmetry of the first one, I could make a beautyful PCB design for that.What are your opinions?

author: Audioguru
author_rank: Super Contributor
timestamp: May 30, 2019, 03:48:25 pm
content: The circuits you posted are very old, are their parts available today?Why not make a headphones amp with an audio opamp?What is the impedance of each side of your headphones?

author: radoczi94
author_rank: Contributor
timestamp: May 30, 2019, 04:27:31 pm
content: I looked for replacement parts for the second schematic, the BC184-214 combo can be replaced with BC550-560 the BD135-6 could be substituted by the TTC011B/TTB006B combo from Toshiba.I don't know. Easier for sure. Better? Maybe. I'm aware of the CMoy amp, which is basically a barefoot opamp. Will build one of that too, saw an article about one being built in freeform style and completely encapsulated in resin, it was really cool.The manufacturer specified 38Ohms impedance.

author: iMo
author_rank: Super Contributor
timestamp: May 30, 2019, 09:09:00 pm
content: Is the transistor's type in that amplifier so critical? Yo do not talk an ultra low noise preamp, but rather a final stage. I think any BCxxx and BDxxx would work fine there.PS: provided you would use oxygen free gold-plated copper wiring

author: radoczi94
author_rank: Contributor
timestamp: May 30, 2019, 10:12:21 pm
content: QuoteWhat is that?We're not talking about audiofoolery hereYes, would probably work with any kind of transistors. Just selected these types,mainly because they were low noise and not the most expensive ones available.I'd spare less than a dollar per tranny if I'd use BD139-40s. I only want to build one unit, so give or take 4 dollars, why bother? The toshiba complementer pair is meant to be used for audio purposes, and also notthatexpensive, less than a dollar each, good enough for me. And I only need to buy those.

author: Audioguru
author_rank: Super Contributor
timestamp: May 31, 2019, 12:01:46 am
content: If you buy the Toshiba transistors (or anything else) from ebay, Amazon, Banggood or AliExpress then they are probably fake.

author: radoczi94
author_rank: Contributor
timestamp: May 31, 2019, 06:21:38 am
content: Yes, probably. That is why I order parts from the local industry suppliers.
Class D amplifier as four quadrant Power Supply - Stupid idea? - Page 1
Forum section: electronics / projects

author: ulwur
author_rank: Newbie
timestamp: July 17, 2019, 10:06:30 pm
content: Hi! I have searched the forum for a topic like this but haven't found anything useful.I have an idea.. Trying to design a 4-quadrant power supply for my bench, and got the idea to use a Class-D amplifier circuit for the output stage to minimize the losses.Is this a good idea? Will it work? Have it been tried?Most of the time the supply will, ofcource, be working like a simple Buck voltage regulator.Ideas on how to create the PWM waveform? The resolution of the PWM would have to be something like 6000 steps to create +-30 volts with 10 mv resolution. The input to the PWM Circuit is analog so I cant use a Micro to create the PWM signal.Is it too complicated? Am I Better off with a traditional Class AB amp with switching buck pre-regulators to keep the losses manageable?

author: bitseeker
author_rank: Super Contributor
timestamp: July 18, 2019, 01:31:06 am
content: A four-quadrant power supply is able to sink as well as source power. In other words, it's both a power supply and an electronic load, depending on which quadrant it's operating in. So, you'll need to understand how both types of equipment work.A Class-D amplifier is a switch-mode power supply (SMPS). Search for that and you'll find lots of information. Note that they are more complex than linear power supplies.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 18, 2019, 01:47:52 am
content: Amplifiers generally are designed to supply predictable loads, not wildly varying ones.

author: David Hess
author_rank: Super Contributor
timestamp: July 18, 2019, 02:13:08 am
content: A bipolar (positive and negative, not transistor type) output class-D amplifier can make a great output stage for a 4 quadrant power supply with the usual caveats about noise and stability. Higher power units do exactly this when high power density is required.Just beware that when operating as a load, the power is transferred to the internal power supply which may rise out of bounds if not controlled.
Class D amplifier's gain. - Page 1
Forum section: electronics / projects

author: Els_Chaos
author_rank: Regular Contributor
timestamp: August 16, 2025, 01:47:07 am
content: Hi everyone,I'm doing a small assignment about class D amplifier, but I'm confused while calculating the gain of its. As my teacher said that the gain of class D only depends on the rail voltage, which is ± 150V in this case and the amplitude of the triangle Vtr should be larger than Vaudio_amp_peak about 80%. So with Vaudio_peak is about 46,5V (at t=), Vtr should be 80,5V. But when doing FFT (with the setting - Number of data points samples in time: 16777216 and Windowing Function: Flat-top), i know that Vtr also affect the gain of the amplifier.

author: mtwieg
author_rank: Frequent Contributor
timestamp: August 16, 2025, 12:01:59 pm
content: Voltage gain will basically be the supply voltage of the bridge output divided by the amplitude of ramp waveform used for your PWM modulator.

author: SteveThackery
author_rank: Super Contributor
timestamp: August 16, 2025, 12:28:15 pm
content: Is there no feedback loop from the analogue output on class D amps? I ask because that is what sets the voltage gain on an "ordinary" analogue amp.
Class D audio amplifer - Page 1
Forum section: electronics / projects

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: May 27, 2014, 05:01:17 pm
content: I've designed a class d audio amplifer circuit using SG3245 and i am feeding the audio signal from computer. I have shifted the input singal all to positive side using opamp summing network . And after demodulating or filtering out the signal at output ,I get the same amplifed shifted version of the input. How can i remove the DC part that I have used to shift the signal.

author: Deepak
author_rank: Regular Contributor
timestamp: May 27, 2014, 07:30:07 pm
content: Not a ton of information here - like what your desired bandwidth is.Have you tried putting a filter on the output? Something as simple as a series capacitor in your signal line and a resistor to common would remove the DC part.

author: kiran_shrestha
author_rank: Regular Contributor
timestamp: May 28, 2014, 03:24:02 am
content: I have thought of doing .. so but i think it will decrease the output power of the system when filtering out at the end. So now i am thinking to use trilevel pwm . But i dont know how to achive it .

author: nickm
author_rank: Regular Contributor
timestamp: May 28, 2014, 03:47:18 am
content: The cheap class d chips that are designed to work off single ended rails will either use the blocking cap or do a full bridge. The blocking cap will be big, like 1000uF if you want response down to about 20Hz. This is why most cheap amps use a full bridge since it just requires a little more silicon which is easier to fit in an ic than a huge cap. The blocking cap will not reduce the available output power (unless its a really bad cap).
Class D power amp - Page 1
Forum section: electronics / projects

author: tbj
author_rank: Contributor
timestamp: October 10, 2012, 08:18:22 pm
content: I decided to build a simple class D amp.Schematic:Triangle wave generator built from 1/2 a TL084 op-amp, LM339 comparator.Sounds pretty rubbish, but works.Video:Any suggestions for tweaks I can make to improve the quality?

author: DaveHardy
author_rank: Regular Contributor
timestamp: October 10, 2012, 08:52:54 pm
content: Try using full +15/-15v rails.
Cleaning digital signal for retransmission - Page 1
Forum section: electronics / projects

author: palindrom71
author_rank: Contributor
timestamp: May 31, 2022, 12:42:06 pm
content: Hi,I get a feeling that question I have is not that uncommon, but searching for it was a nightmare.My goal is reception of fairly good digital signal, conditioning it: amplification to some fixed logical levels, so it looks more like rectangles than potatoes. Denoise and dejitter are optional. That way I can daisy-chain a couple of devices and each node sends decent signal forward.I'm handling 1250 MHz Manchester data stream. I couldn't find a dedicated IC, most likely because I asked the wrong keywords.How can I attack that problem?Any help appreciated!

author: Marco
author_rank: Super Contributor
timestamp: May 31, 2022, 01:24:34 pm
content: Clock buffer? SN65LVEL11 for instance.

author: Terry Bites
author_rank: Super Contributor
timestamp: May 31, 2022, 04:11:08 pm
content: I think this is what you're after.https://www.analog.com/en/parametricsearch/10771#/sort=4671,asc

author: moffy
author_rank: Super Contributor
timestamp: May 31, 2022, 10:13:28 pm
content: Do you want to recover the clock from the stream and use that to resample the Manchester signal? I assume that is what you want, since it increases your BER enormously. You might want to use an FPGA if there are no dedicated chips.

author: palindrom71
author_rank: Contributor
timestamp: June 06, 2022, 07:20:45 pm
content: Wow, I was totally searching the wrong parts.The signal I'm handling is peculiar, as it looks like clock only until you search for glitches. It's Manchester encoded slowly varying signal.And as I expected, I was looking for wrong keywords here.-Thank you!
Cleaning up power supply noise - Page 1
Forum section: electronics / projects

author: SpiderElectronics
author_rank: Contributor
timestamp: July 11, 2012, 12:11:08 pm
content: HiI have an question for you power supply experts out there:-I have a sensitive audio device which is powered from +5V, there are several other devices on the +5V rail. Some of which introduce noise to the rail.This scope trace shows the noise I am seeing (with the DC portion removed)Any suggestions on how to clean the +5V at the input to the device?Currently it has a 100nf X7R 0603 ceramic capacitor across the rail and GND. This signal was measured right at the end of the capacitor.

author: Rerouter
author_rank: Super Contributor
timestamp: July 11, 2012, 12:14:25 pm
content: tried reconnecting your devices in a star configuration, that way noise from other sources becomes a far smaller issue, and if this audio device is primarily linear in nature, you could possibly throw a few hundred micro henry worth of inductance near your devices connection,

author: JuKu
author_rank: Frequent Contributor
timestamp: July 11, 2012, 12:16:30 pm
content: Quick fix might be a ferrite bead or an inductor from the 5V to the power input of the device (keeping the cap on the device side) and maybe similar arrangement at the noise sender power pins. If not successful, you need to look deeper in to it (power supply arrangement, separate supplies, PCB layout etc)

author: poorchava
author_rank: Super Contributor
timestamp: July 11, 2012, 01:31:04 pm
content: If you have access to GOOD scope or spectrum analyzer, then you may analyze spectrum to find what the noisy frequencies are. This has 2 benefits: will give you idea about a source (like main noise frequency component being equal to microcontroller clocking frequency) and will help you calculate appropriate filtering parallel capacitors and series inductors to remove this noise.You may also try to power the sensitive stuff directly from the main regulation unit.

author: SpiderElectronics
author_rank: Contributor
timestamp: July 11, 2012, 02:52:42 pm
content: Thanks for all the quick and useful replies.I will try out some of the suggestions. My scope does do spectrum analysis, but it's only a cheap scope (Picoscope 2500).

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 11, 2012, 07:20:02 pm
content: Quote from: SpiderElectronics on July 11, 2012, 12:11:08 pmAre you sure the noise is created by the other devices? It certainly looks like SMPS noise...
Cleaning up toner from board after toner-transfer etching. - Page 1
Forum section: electronics / projects

author: Alana
author_rank: Frequent Contributor
timestamp: October 05, 2012, 01:53:00 pm
content: What solvents or other methods do you use to remove toner from your PCB after you have etched them using toner-transfer method.I tried nitro solvent but it does not clean it, just helps to remove toner mechanically.

author: Psi
author_rank: Super Contributor
timestamp: October 05, 2012, 01:57:35 pm
content: Try turpentine, pretty sure that's what i used last time and the toner dissolved right off.

author: kripton2035
author_rank: Super Contributor
timestamp: October 05, 2012, 02:38:52 pm
content: acetone was working right away for me last week ...easier to find ?

author: RCMR
author_rank: Frequent Contributor
timestamp: October 05, 2012, 08:53:51 pm
content: For the Brother toner I use an aerosol can of brake-kleen -- however I suspect that acetone would work just as well.

author: miceuz
author_rank: Frequent Contributor
timestamp: October 05, 2012, 10:36:05 pm
content: acetone FTW or nail polish remover if you just want to go around the corner.

author: george graves
author_rank: Super Contributor
timestamp: October 05, 2012, 10:53:56 pm
content: Quote from: miceuz on October 05, 2012, 10:36:05 pmNail polish remover often has an oil or something in it as a moisturizer, and fragrance - and it's much more expensive.

author: nukie
author_rank: Frequent Contributor
timestamp: October 05, 2012, 10:59:00 pm
content: Go to a paint shop get some acetone.

author: Psi
author_rank: Super Contributor
timestamp: October 06, 2012, 12:29:49 am
content: Quote from: RCMR on October 05, 2012, 08:53:51 pmAnything designed to clean brakes will be very aggressive and not the sort of thing you want to use unless necessary.

author: george graves
author_rank: Super Contributor
timestamp: October 06, 2012, 02:26:14 am
content: Not to mention - that stuff has to be really bad for the environment.Sometimes I use some compressed air to blow off the pcb after cleaning with 98% IPA - I get noticeably cleaner boards that way.