hybridfree/eevblog-posts huggingface dataset:
Audio IC - Page 1
Forum section: electronics / beginners

author: awyeh1234
author_rank: Contributor
timestamp: April 22, 2015, 08:51:08 pm
content: Hello I have this older audio ic that is from the late 80's and i have no clue how to put this into a circuit. Can anyone help?I do have the pin-out diagram. i also have a power supply for it. I just don't know how to put it into a circuit.

author: jeroen79
author_rank: Frequent Contributor
timestamp: April 22, 2015, 08:57:58 pm
content: Do you know it's name/type/manufacturer?With these you can look up the datasheet which may contain some sample circuits.Otherwise it looks like a dual amplifier with a ripple filter which -depending on it's specifications- could be used as a buffer, headphone or power amplifier.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 22, 2015, 09:00:34 pm
content: What is the part number on the IC?How do you know that diagram matches your IC?There is not enough information in that diagram.For example we have not the slightest clue what the power rail voltages are?

author: awyeh1234
author_rank: Contributor
timestamp: April 22, 2015, 09:07:19 pm
content: its is an c1316c dual channel Amplifier IC and no it didn't have any sample circuits.

author: Rory
author_rank: Frequent Contributor
timestamp: April 22, 2015, 09:11:25 pm
content: You know, it's interesting just how easy it is to do a web search with 'c1316c' and find the datasheet, application notes and schematics of how to use it.That being said, here's a page (in russian) that has an example circuit.http://cxem.net/sound/amps/amp56.php

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 22, 2015, 09:11:44 pm
content: Google is your friend. The VERY FIRST Google hit reveals the full manufacturer's data sheet:http://pdf.datasheetcatalog.com/datasheet/nec/UPC1316C.pdfIt includes reference circuits and full specifications.
Audio line-out into an AMP, attenuation, impedance and other fun stuff - Page 1
Forum section: electronics / beginners

author: PeteAU
author_rank: Contributor
timestamp: June 22, 2014, 05:49:50 am
content: Hi,I'm trying to design a simple little audio circuit, but there's more to it than meets the eye (at least for me).I have an audio DAC outputting 2.1 Vrms full-scale and then an amplifier that cannot tolerate such a high signal.I'm trying to attenuate the signal to around 0.42 Vrms, just using a resistor divider, and a cap to ground (low-pass filter).Specs:DAC: Outputs 2.1 Vrms, with 1K source impedance.Amp: About 55K impedance (I think!), I measured how much it "loads" down my signal and calculated this. Needs 0.42 Vrms.What do you think, will it work? Will there be any unexpected effects, .e.g. from impedance mismatch?

author: TMM
author_rank: Frequent Contributor
timestamp: June 22, 2014, 06:16:42 am
content: It's possible to introduce distortion like this because the current draw of the amp might not be completely linear with the signal voltage.The ideal solution is to place a low output impedance buffer between the attenuator and the amp. If you don't require ultra-low distortion (much lower than even high end speakers are capable of) it should work just fine however.

author: Richard Crowley
author_rank: Super Contributor
timestamp: June 22, 2014, 06:24:19 am
content: I don't understand the use of any of the capacitors in your proposed circuit? You didn't present any need for frequency-shaping in your description.I would simply use a 10K log-taper ("audio") pot on the input of the amplifier. Then it would handle a wide range of levels, and it would be operationally adjustable. That is actually the more "normal" way of handling this.With a 1K source impedance, the need for any further impedance buffering seems superfluous to me.
Audio Noise on Breadboard - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: October 01, 2018, 12:11:31 pm
content: Hi,I'm troubleshooting a pedal circuit that is producing a lot of noise. I broke the circuit down (removed the actual function) to just the input jack connected to the output jack and am still getting the noise. As a reference, I run a 15 ft cable b/t a bass and a small amp. I hear some noise. but much less, at high volume.On my breadboard, I have T -> T and S -> S wired between the input and output jacks. My bass goes into one jack using a 15ft cable (same as my reference). Coming off the breadboard, I have a 6ft cable. The wires between the jacks are about 5mm.Is this expected from a breadboard set up?Thanks,Carl

author: eev_carl
author_rank: Regular Contributor
timestamp: October 01, 2018, 12:22:26 pm
content: I think it's the large breadboard. I used a very small breadboard with the same input and output jack breakout wiring and the noise went away.Here's a link to what I'm using.https://www.sparkfun.com/products/12046For anyone replying...Is this stray capacitances? Is there anything I can do to reduce this on my larger breadboard.

author: madires
author_rank: Super Contributor
timestamp: October 01, 2018, 01:14:00 pm
content: Most likely the noise is simply picked up from the environment by the large breadboard. The tiny one has less area, i.e. it picks up less mains hum and what have you. You could try to put the large breadboard into a metal can (maybe connected to signal ground). The breadboard's capacitance starts to matter when you play with RF or fast digital signals.

author: Ian.M
author_rank: Super Contributor
timestamp: October 01, 2018, 01:50:54 pm
content: You need screening. A tin plated steel biscuit tin would be reasonably good for a large multi-panel breadboard, if you sanded any paint or varnish off the top 1/2" of the sides and the insides of the edges of the lid for good metal to metal contact. Use chassis mounted connectors with a metal shell mounted to the tin for signals in & out to screened cables, and solder-in bulkhead feedthrough caps for all power connections.

author: FotatoPotato
author_rank: Regular Contributor
timestamp: October 01, 2018, 05:13:54 pm
content: For any sensitive projects, built on a breadboard, you will always encounter noise. It's just how it is. The best way to get rid of it is to use a soldering perf board. That should get rid of most noise.Good luck!
Audio Op Amp - Page 1
Forum section: electronics / beginners

author: jheatac
author_rank: Regular Contributor
timestamp: June 30, 2024, 10:00:17 pm
content: I'm learning...Car audio amplifier. Stereo in - mono outThe left and right low audio inputs go to a dual op amp on the + input of each. The - input is tied directly to the output. 15v rails.Leaving the output of each they are tied together through a resister.Is the purpose of those just to isolate the input signal?

author: Benta
author_rank: Super Contributor
timestamp: June 30, 2024, 10:12:51 pm
content: The right term would be "buffering". As you don't know the input signal characteristics (output impedance from the source, etc.), the buffers make certain that the dignal summing is under control at all times.

author: jheatac
author_rank: Regular Contributor
timestamp: June 30, 2024, 10:20:05 pm
content: Thank you. I'm starting to figure this out

author: jheatac
author_rank: Regular Contributor
timestamp: June 30, 2024, 10:27:59 pm
content: Just to confirm. In this application, the output is all but the same as the input?

author: Benta
author_rank: Super Contributor
timestamp: June 30, 2024, 10:39:35 pm
content: The opamps are configured for x1 voltage gain, yes.

author: BeBuLamar
author_rank: Super Contributor
timestamp: June 30, 2024, 11:46:33 pm
content: If you want stereo in and mono out it's best to configure the OP amp as a summing amp.

author: jheatac
author_rank: Regular Contributor
timestamp: July 01, 2024, 01:56:39 pm
content: I am walking myself through the audio path. I think the summing amp may be next

author: TimFox
author_rank: Super Contributor
timestamp: July 01, 2024, 04:19:23 pm
content: The simplest way to add two analog channels (L & R) together is with two resistors (say, 10 k each) to the mono output, but that increases the output impedance driving the next stage.A single op amp can either buffer the output of the two resistors (non-inverting) or sum the two resistors into a virtual ground (inverting); both choices give a normal low impedance to drive the next stage.
audio output transformer - Page 1
Forum section: electronics / beginners

author: christos
author_rank: Regular Contributor
timestamp: April 02, 2014, 12:50:52 pm
content: i bought a audio output transformerit says that 2 wires are 8 ohm but it only 1 ohmis it right or bought a wrong audio output transformer?

author: pa2ees
author_rank: Contributor
timestamp: April 02, 2014, 03:01:30 pm
content: We'd love to help, but you've got to give us some more to go on. If you could answer some or all of the following, we can probably help:What is the make/model of your audio output transformer?Where did you get it from?Where does it say that 2 wires are 8 ohm?How are you measuring the 1 ohm?Can you give a link to the datasheet?And how do you plan on using it?- Erik

author: linux-works
author_rank: Super Contributor
timestamp: April 02, 2014, 03:09:23 pm
content: are you trying to measure the dc resistance with an ohm-meter?you can't do thatthis is IMPEDANCE and it is an ac concept, with frequency.tell us more about what you are trying to do.
Audio panning circuit design help - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: August 14, 2023, 12:05:28 pm
content: Hi all,I was wondering how I could achieve a 50% volume to both ends with this widely used circuit.All I want is 50% when the pot is in the middle and full volume on either end when turned left or right.Is this possible?I would preferably want to use a 100kB pot instead of 10kB.The circuit is widely used so it's probably me that's going nuts with this one.See the "pan" pot on the schematic below or better the isolated circuit marked "panner2".I can't calculate the values for 50% and 100%. I don't care for restoring the original signal level I can do that afterwards with an opamp at the summing stage but 50% in the middle is crucial so both L and R to have equal volume..
Audio PCB - Page 1
Forum section: electronics / beginners

author: cbassett1000
author_rank: Contributor
timestamp: February 21, 2019, 01:43:12 pm
content: Hi all,I am creating an audio splitter/combiner unit with multiple inputs, outputs, stereo to mono, switched, etc. Attached is a schematic.I used a bit of information from here in my design.https://www.rane.com/note109.htmlNow I am on to PCB layout. The only issue I have, (note: this will not have high production volumes, maybe a sample set of 5) is doing single or double layer board. Because this is audio, I need to be aware of trace distances and maybe some coupling? Especially with a 2 layer board? Obviously interference and audio quality would make a difference here and is important. I can route with a single layer but the rotary switches definitely provide a challenge in that routing. Double layer would be much, much easier but again I am concerned with coupling. Any design rules to follow or suggestions would be appreciated. Thanks!

author: mvs
author_rank: Frequent Contributor
timestamp: February 21, 2019, 03:05:46 pm
content: Quote from: cbassett1000 on February 21, 2019, 01:43:12 pmUse one layer for horizontal and another for vertical routing, cross traces at 90 degree... I doubt that few pF will matter at audio frequency anyway.

author: Benta
author_rank: Super Contributor
timestamp: February 21, 2019, 05:39:47 pm
content: Use 2 layers, it's almost the same price as single layer. If you follow mvs' recommendation and do not make the traces immensely wide, we're talking about fractions of pF here.
Audio PreAmp - Advice - Page 1
Forum section: electronics / beginners

author: goldfinger
author_rank: Regular Contributor
timestamp: April 19, 2017, 04:40:09 am
content: Hi Guys,My preamp recently died and I'm looking to build a new one and was hoping I could get some feedback on advice on the best way to approach the build layout.I'm still relatively new and it's first build of a hifi pre so apologies in advanceSome info.I currently have two sources one is single ended with an output impedance of around 100ohm and another that has both single ended and balanced out which is 600ohm.The amplifier is balanced in and has input impedance of 40k.I have managed to get my hands on a balanced shunt stepped attenuator 10k which I would like to used. The issue is that with my setup once source can't seem to drive the amp enough passively so I will need to look at an active circuit with moderate gain.I do have a pair of drv134 I can use in build. But I have a few questions I was hoping I could get some feedback and advice on.- The input impedance of the drv134 is 10k, now whilst that is seemingly enough to drive both my sources issue is the output caps on one source is tuned for >22k for proper bass response so I'm assuming I will need to place a buffer in front of the line driver?The line driver does a touch under 6db gain I believe which is close but I think I probably need another 3-4db from another stage to drive the input of amplifier well.I suppose my main questions are:1. What is the best way to achieve the preamp stage with stepped attenuator? Stages and sequence?Source -> op buffer/gain-> line driver -> stepped attenuator - outputSource - > op buffer/gain -> line driver - > stepped attenuator-> buffer - > output2. Any suggestions on good op amps which will work well for audio preamp? I'm sure there is a lot but given my suggested outcomes and individuals experience would be great to hear people's thoughts.I'm using a good volume attenuator so want to ensure I do it justice by using quality op amp, Open to discreet as well I've just stuck to op amp for convenience I suppose3. Any other thoughts or considerations you might have I need to think about/take into account.Any feedback or thoughts would be really appreciated.Thanks all!
Audio preamp circuit for microphone input. (solved) - Page 1
Forum section: electronics / beginners

author: Jim0000
author_rank: Contributor
timestamp: October 11, 2020, 10:11:12 am
content: I have a small audio amplifier designed for automotive application. I want to use it to make an electronic stethoscope of sorts. I plan to use a cheap microphone from Banggood and drive a small speaker.The purpose is to assist me to locate vacuum leaks while vacuum bagging composite parts (fibreglass, epoxy and other composite materials).The plan is to place the microphone over the vacuum line where it exits the vac bag. If there is a leak, the air rushing into the hose can be heard when I put my ear close. However, the leak might be up the opposite end of the bag, requiring my attention while listening at the same time.I figure a device like this would be a great aid for this.Accordingly, can somone direct me to a simple mic pre-amp circuit to drive and little audio amplifier at line level please?Jim.

author: Zero999
author_rank: Super Contributor
timestamp: October 11, 2020, 11:31:05 am
content: What sort of microphone is it?

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 12, 2020, 01:16:31 am
content: You'll probably be using an electret mic since they are ubiquitous, cheap and quite sensitive. There are a bazillion circuits that will do what you want, from extremely basic to quite sophisticated.For example:https://www.electronics-lab.com/project/low-noise-mini-electret-microphone-preamplifier/

author: tooki
author_rank: Super Contributor
timestamp: October 12, 2020, 09:16:05 am
content: If you're gonna order from China anyway, why not just order one of those little mike preamp boards that use a mike amp IC, and either have a mike on the PCB already, or include one you can mount off-board?Or, instead of using sound, why not use a pressure sensor on the vacuum hose? If there's a leak, the vacuum will not be as strong as if the seal is airtight.

author: Jim0000
author_rank: Contributor
timestamp: October 27, 2020, 03:51:57 am
content: Thanks for the replies.I found one here:http://www.circuitdiagram.org/microphone-preamp-circuit.html
Audio processor IC Swap - Page 1
Forum section: electronics / beginners

author: andrewlapham
author_rank: Contributor
timestamp: July 02, 2020, 11:01:32 pm
content: I have an 8277l android head unit that has two revisions, one supports the BD37033 the other, TDA7719. both revisions of the board are almost identical apart from some of the traces to the chip and support components. I, unfortunately, bought a BD37033 instead of the TDA7719 but i do have some breakout boards for the chip. looking through the datasheet for each IC, 90% of the pins have a match on the other chip and I plan to use the breakout board to wire in the new ic and update 3the support components.I've uploaded a picture I put together matching the pins up and have put a red dot on the pins I'm unsure about. I'll also include the datasheets if anyone wants to help me out.Cheers.also, i have the firmware the will run this revision and it does successfully flash to the device.BD37033 -https://pdf1.alldatasheet.com/datasheet-pdf/view/575595/ROHM/BD37033FV-M.htmlTDA7719 -https://au.mouser.com/datasheet/2/389/cd00164982-1796539.pdf
Audio signal "blinker" - Page 1
Forum section: electronics / beginners

author: sandros
author_rank: Newbie
timestamp: April 01, 2015, 01:53:14 am
content: Hello,I have a self-made blinker stuff for audio signals. The leds lights up when the input signal is high enough.This should work with phones too, but it's not. To see the leds blinking I have to attach it to my HT amplifier.I'm using BD243C instead of TIP31, because we don't have any of them. I'm also using 2 regulator ICs: 3V for the leds, 9V for other use.Question: How can I boost the input signal to work with phones too? I'm looking for a simple solution.(I have a BC 546 B. Can I use this amplifier transistor?)Thanks!/ c1.gif: original, c2.png: current, power source: 230V/12V DC adapter, 1A output /
Audio signal analysis with Rigol DS1054Z - Page 1
Forum section: electronics / beginners

author: devriv
author_rank: Newbie
timestamp: March 11, 2019, 05:29:19 pm
content: I need to see (as with eyes) about 1-second worth of audio sampled at 8KHz (16-bit PCM if that matters). The object is a single 1-second frame, with distinguishable boundary characteristics. There are multiple frames, all a bit different, it's fine if I can see a randomly (approximately) chosen one.So far I used Excel to plot the samples, but it is painfully slow manual process (dump samples, import in Excel, plot.)I was wondering can I use Rigol to capture the analog audio and 'see' it.I am not a scope expert, so questions that come to mind are:- general settings for this frequency range- triggering - manual is OK, but then I'd need 2-3 seconds worth of samples to spot a full frame.All feedback welcome!

author: Bicurico
author_rank: Super Contributor
timestamp: March 11, 2019, 06:31:09 pm
content: Why don't you just use the freeware Audacity software?Also, I imagine there are far better audio analysis tools for a PC using the soundcard than a regular oscilloscope.RegardsVitor

author: devriv
author_rank: Newbie
timestamp: March 11, 2019, 06:53:39 pm
content: I'm using Audacity for other stuff - it may work here, but the problem is getting the signal in - it's far easier with scope than computer.To clarify - this all happens on embedded platform, not on a computer: I can get debug output and analog out, but I can't run arbitrary software on it (like Audacity). I would have to put some kind of audio pre-amp in-between.Plus, scope is much cooler

author: rstofer
author_rank: Super Contributor
timestamp: March 11, 2019, 07:15:15 pm
content: Can you bash the embedded code to output a sync signal and use it to trigger the scope in one-shot mode?

author: devriv
author_rank: Newbie
timestamp: March 11, 2019, 07:55:01 pm
content: Good point - I could create a filter on the computer that receives the debug output, then say NOW, on the computer. But I have no means of I communicating "NOW" from the computer to Rigol. The setup is very limited as it is now.Instead of expanding hardware for this essentially one-time use, I wonder if I could simply continuously monitor the audio out in manual trigger mode, then push Rigol button to capture 2-3 secs of audio, then observe the signal at leisure. I just don't know how to setup the Rigol thing without spending hours understanding its operation. In particular - is it capable of memorizing 2-3 secs of audio sampled at 8 KHz (which comes to 30-50Kb in 16-bit resolution.) Can it even do such low sampling rate ? (16-32 kilosamples per sec are also OK - the memory requirements go up though.)

author: Gyro
author_rank: Super Contributor
timestamp: March 11, 2019, 08:08:03 pm
content: It's worth remembering that you are going to be feeding the audio into an 8 bit resolution scope.
Audio signal conditioning / protection circuit recommendations? - Page 1
Forum section: electronics / beginners

author: cincin
author_rank: Regular Contributor
timestamp: March 18, 2024, 05:56:03 am
content: I'm starting to play with audio signals and filters and I'd like to use my computer's on-board sound card to do some frequency analysis Bode plots. I'm concerned about connecting my experiments directly into my computer, in fear of sending in DC or over-voltage by mistake.I'm looking for an audio signal conditioning and protection circuit that would protect my sound card from my inevitable blunders. I've looked around, but signal conditioning is a broad subject with diverse applications, and I couldn't find a clear answer.I know this will involve a 0.1uF to filter out any DC... and something like a 1V Zener to keep things under 1V (line level), is that even a thing? Do I need resistors or input and output impedance? I'm in the Beginners forum, right? goodAny help is greatly appreciated.Good resources on that subject, or good places to search for circuits also appreciated.

author: DimitriP
author_rank: Super Contributor
timestamp: March 18, 2024, 08:25:43 am
content: Fancy front end :http://www.pmillett.com/ATEST.htm

author: CountChocula
author_rank: Unknown
timestamp: March 18, 2024, 01:28:57 pm
content: Rod Elliot's websitehas a lot of good information on this subject (well, really, onanythingthat has to do with audio,includinginput protection).A couple specific examples:Input Protection CircuitsandPC Oscilloscope Interface, the latter of which I think does exactly what you're looking for.—CC

author: cincin
author_rank: Regular Contributor
timestamp: March 18, 2024, 03:39:12 pm
content: Thank you!Off to read all of that with my morning coffee.

author: John B
author_rank: Frequent Contributor
timestamp: March 20, 2024, 09:10:49 pm
content: Quote from: cincin on March 18, 2024, 05:56:03 amGet that pesky AC out of my audio signal!But seriously you'll probably just want to make a buffer op amp with input protection.http://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgoqoQFMBaMMAKACUQAWQzkbbQnzR8BUcFyrCq06AhYAnLjxGDC+FWLDxILACYhCGFBsPHOYQcd10AZgEMArgBsALnoPrzqz8Ushr9s4uDABedAB2dPLuply+BkZcFiBWto6uoRFRMZ7JangaqYGuLADuHgX8qolVUGUVcdVm8ToA5g2c8fkUYMbSLADGIDiCtSONmowFhLDYKOZk2BZ4GJBgxFCwa-WxnYLje3XlsWOitToA9gYGvFSckKQpMnCEKEiS19gs2AVUAGIQKgMYTCJggABqF1cdladBYQASomething like this has always been sufficient for me. In your instance you may not even need a 1N4148 in series with a zener diode, 2x 1N4148 in series will clamp your voltage to somewhere around 1.2 volts.

author: cincin
author_rank: Regular Contributor
timestamp: March 20, 2024, 09:58:06 pm
content: Quote from: John B on March 20, 2024, 09:10:49 pmDerp! hahaha yea, YOU KNOW WHAT I MEANT! haha. I'll go correct the original post to save what's left of my dignity.Also, I love Falstad links. Thank you!
Audio switch - Low pass filter - Page 1
Forum section: electronics / beginners

author: zathrasb5
author_rank: Contributor
timestamp: October 14, 2020, 11:24:14 pm
content: Hello,I am working on an audio switch. In summary, it will be spliced into an existing car radio on the FM line between the radio and the amplifier.So far, I have, starting with the FM line, a high pass filter (16 hz), a voltage bias to Bring the line up to 4V, the Switch (Max 4053), and another High pass filter (to pull the 4V back out). The signal then goes on its merry way back into the amp.A though occurred to me. I may need a low pass filter between my input signal, and my output signal, to bias the signal back to whatever the radio has it biased at.1) For this low pass filter, assuming I construct it with an RC, what is to stop the low pass filter from wiping out my signal on my output line? 2) Do I need a resistor on either side of the capacitor (R19).3) If so, is this the full resistor value for the filter, or 1/2 of the value that I otherwise calculate?4) Am I making my life more complicated than it need be?
Audio Voltage biasing - Page 1
Forum section: electronics / beginners

author: zathrasb5
author_rank: Contributor
timestamp: August 29, 2017, 06:36:32 pm
content: Hello.I have been working on an audio switch, using a 4053, and have breadboarded my design so far. One of the problems I am having is that none of the low frequency is passing through the IC.I have attached a simplified version below. Basically. Line level comes in, and a high pass filter filters out the existing DC. I then add in my VBias, and run it through the switch. On the other side I have another high pass filter on the other side.What I think my problem is, is that I have a problem with my math. The formula f=1/(2piCR) should calculate the cutoff frequency, which I know I want to keep much lower than 20hz.I have two theory's of what is wrong.a) because I have two resistors on each high pass filter, is 1/R=1/R1+1/R2?, orb) Is it actually 1/R = 1/R1+1/R2+1/R3+1/R4, orc) Am I completely wrong.I know the practical answer is just increase the capacitors and resistor values until it sounds good, but I would like to understand my error.

author: Benta
author_rank: Super Contributor
timestamp: August 29, 2017, 06:59:50 pm
content: If the switch is open, you have a)If the switch is closed you have b)(disregarding switch resistance)

author: zathrasb5
author_rank: Contributor
timestamp: August 29, 2017, 07:11:24 pm
content: Thanks, that's what I thought my problem was. Just based on the sound quality, and where it was cutting off. Hard to tell for sure, but the correct formula (b) gives the cutoff frequency that I have right now as 63Hz, which is way too high. Time for a redesign. Need to order more caps.-Z

author: Ian.M
author_rank: Super Contributor
timestamp: August 29, 2017, 07:29:02 pm
content: Why not just increase the resistors by an order of magnitude?

author: Benta
author_rank: Super Contributor
timestamp: August 29, 2017, 08:03:22 pm
content: When doing AC analysis like this, VCCand ground are the same.

author: zathrasb5
author_rank: Contributor
timestamp: August 29, 2017, 08:14:13 pm
content: Ian, The main reason I am changing the caps, and not the resistors, is I actually already have a resistor array that I am going to use, to save space. I could also change the design to use two resistors to get my Vbias, and then an resistor array feeding off that to each line, and reduce the number of resistors to 8 overall, from 12, but the resistor array should still be smaller, overall.Benta, Thanks. That's what i found out. Not mentioned in any of the audio guides on the internet though. Definitely a trick for new players.-Z
audioNoob wants to build Bluetooth speakers using 10watt speakers he salvaged. - Page 1
Forum section: electronics / beginners

author: buck converter
author_rank: Regular Contributor
timestamp: August 16, 2017, 07:54:56 pm
content: I salvaged 2 6-ohm speakers from my grandfather's TV. What is a good amplifier? I thought the PAM8610 modules available everywhere would be good, but they are 10w for 8 ohm and 15w for 4 ohm. I don't need the full 10 watts of volume but something more than the standard 3 watts would be finehttps://www.parts-express.com/pam8610-2-x-10w-class-d-audio-amplifier-board--320-604?utm_source=google&utm_medium=cpc&utm_campaign=plahttps://www.diodes.com/assets/Datasheets/PAM8610.pdf

author: Paul Rose
author_rank: Regular Contributor
timestamp: August 16, 2017, 08:43:12 pm
content: 2x PAM8302 ?https://www.adafruit.com/product/2130

author: buck converter
author_rank: Regular Contributor
timestamp: August 16, 2017, 08:56:16 pm
content: Quote from: Paul Rose on August 16, 2017, 08:43:12 pmat least 3 watts?

author: Paul Rose
author_rank: Regular Contributor
timestamp: August 16, 2017, 09:04:12 pm
content: There are pam8406 5w+5w modules, but it looks like you have to go to amazon/ebay

author: Audioguru
author_rank: Super Contributor
timestamp: August 16, 2017, 10:41:38 pm
content: Haven't you guys seen the spec's that say 10% distortion?Have you ever listened to horrible 10% distortion? It sounds awful.The "10W" amplifier produces only 5W into 8 ohms or a little more into 4 ohms with reasonably low distortion when the supply is 12V.A heatsink is needed if the speaker impedance is less than 8 ohms.But I think the salvaged speakers will also sound awful.
Audiosonic CL-131 Alarm clock Retro tune? - Page 1
Forum section: electronics / beginners

author: @Ampere2001!
author_rank: Newbie
timestamp: February 11, 2019, 08:22:17 pm
content: Dear Sparkles of the universe!I've recently got my hands on a Audio Sonic CL-131 Alarm clock.It is looking very retro in fact some people may call it trash but i like it.Now my question is do you any of you know if it is possible to solder an AUX wire somewhere so i can wake up with a retro tune from an MP3 PLayer.I know the alarm clock is old but i love the look of itIt is so old it doesnt eaven has FM-Band only UHW and MW.By the way i live in the Netherlands so my apoligies for any bad English.Regards,@Ampere2001!

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2019, 08:40:14 pm
content: You need two things, one is switched (alarm) DC power for the MP3 module and the second is audio input to the amplifier in the alarm clock radio.If you know the clock IC used (i.e. LM8560, MM5316 etc), look for the ALARM output. It usually goes to a transistor to switch power on to the radio, usually around 9VDC. This is probably too high for the MP3 module 5V?.You can add a switch between radio/MP3 by taking signal at the volume control potentiometer.Any pictures can help to tell more. It can be done. I added Bluetooth audio to an old 1970's Randix cube clock radio.

author: @Ampere2001!
author_rank: Newbie
timestamp: February 11, 2019, 09:06:33 pm
content: Dear Floobydust.I have found a datasheet and some pictures i want to upload them but they won't show up.i will try one more time.I would like to hear from you about the best solution!

author: @Ampere2001!
author_rank: Newbie
timestamp: February 11, 2019, 09:09:54 pm
content: Dear Floobydust,I am thinking about taking pin 24(ALARM OUTPUT). and solder an MP3 Module?Maybe i have step down the voltage?also can i directly solder the speaker to the Module?

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2019, 09:55:00 pm
content: Which one is your MP3 module? Something like WTV020-SD-16P needs 3.3V power.So the clock IC output is too much voltage, you will need to add a voltage regulator IC.

author: james_s
author_rank: Super Contributor
timestamp: February 12, 2019, 11:44:12 pm
content: A simple way to interface pretty much anything you want is to use a reed relay or small SSR connected to the alarm output. Then you can power the load with whatever it needs.

author: @Ampere2001!
author_rank: Newbie
timestamp: February 18, 2019, 08:40:00 pm
content: Dear,Thank you all for your help.Also the replies are great!My apologies for being so slow.I am an Electrician in the Netherlands and electronics is my hobby.I was wondering about the SSR relay or a step down module.I now what to look for so thank you all for that!I am still wondering about an case to put the module in.Any creative ideas or suggestions?I would like to keep the alarm clock as one unit.So i was thinking about maybe a connector or a simple 3.5MM jack for AUX.As you might see i am not a long member of the forum but i like it already!Regards,@Ampere2001!
Aurel 433Mhz module, antenna pull to ground - Page 1
Forum section: electronics / beginners

author: savril
author_rank: Regular Contributor
timestamp: December 09, 2015, 12:34:39 am
content: Hi,I want to make a similar circuit to theRFLink gateway.I choosed a RTX MID 5V as the RX/TX.But in theAurel user manual, I found something that I don't understand (schema included as attachment).Why is the antenna pin pull to ground ? Is it to prevent damage if no antenna is connected ?Another question, the manual does not provide a value for the 5V module, only for the 3V module. Am I right if I use something like 82 kohm resistors instead of 47 kohm (47*5/3=78) ?

author: ataradov
author_rank: Super Contributor
timestamp: December 09, 2015, 12:45:19 am
content: Where do you see pull to the ground? Antenna pis is free floating in the schematic.

author: savril
author_rank: Regular Contributor
timestamp: December 09, 2015, 01:22:07 am
content: F***, you're right. It's late there, time to go to bed... Imyself...I was looking at AN-OUT which is for Analog Out.From the manual :"Output analog for test purpose.Connect resistor network for squelch function.(See data-slicer description in the receiver section) "So ... the problem as we say in french int IT was between the chair and the keyboard...Thanks.
Autel KM100 Key Programmer USB C port replacement - Page 1
Forum section: electronics / beginners

author: kambo-Rambo
author_rank: Newbie
timestamp: May 20, 2025, 04:56:40 am
content: Hello I have attempted to replace USB C port on my Key programmer cause it was no longer able to charge and maintain connection.. I managed to remove the Old USB C port off carefully but as carefully as I should have .. I knocked off some resistors I believe , and need to know if they are required to be put back on cause i did lose them as well , I have picture of what they looked like as well as video of the location where they went missing from .. here is the videohttps://youtu.be/8SItoSoOWfcPlease help Identify these resistors as I was not sucessful and there seems to be no one else that have dared to do this

author: kambo-Rambo
author_rank: Newbie
timestamp: May 20, 2025, 04:58:18 am
content: Links to photoshttps://ibb.co/V0NdVvyjhttps://ibb.co/ptzfyVw
Auto door project - Page 1
Forum section: electronics / beginners

author: doggo240
author_rank: Newbie
timestamp: January 31, 2015, 08:08:09 am
content: I am a complete novice at electronics and would much appreciate some help with this simple project.I am making a 12v auto door closer for my fowl house. It consists of a battery, a photoswitch and a car door lock actuator. The actuator is a sealed unit but I am pretty sure it consists of a 12v motor and some gears.The load from the photoswitch is connected to the VCC terminal of the delay timer with a loop to the common terminal of the module. Under test but with no load the device works fine. When the light drops to the appropriate level the power flows to the delay timer which switches after the set number of seconds.However when I connect the actuator to the NC terminal of the delay timer module it does not switch and keeps powering the actuator. The same thing happens when I try to run the actuator directly from a 12v digital time switch. The relay component of the delay timer is a Songle SRD-12vDC-SL-C and it is supposedly rated for 10 amps at 30V DC.The actuator pulls in about one second and then continues to draw 1.8 amps (I think - on the 10A setting the multimeter reads 1.Would a 30A 12v automotive relay added in series help?Thanks. I hope this question is not too dumb.

author: SL4P
author_rank: Super Contributor
timestamp: January 31, 2015, 09:02:57 am
content: First guess - is the driver capable of driving the motor/solenoid?Can you post a pic or quickie schematic of your setup?

author: doggo240
author_rank: Newbie
timestamp: January 31, 2015, 02:24:41 pm
content: Thanks SL4P. What I don't understand is how the relay can be rated at 10 amps and yet not be capable of driving a 1.8 amp load.I will try to post a rough schematic.

author: SeanB
author_rank: Super Contributor
timestamp: January 31, 2015, 03:00:21 pm
content: The photocell also has to deliver the motor current. You probably would be better to use the delay switch normally open contact and use the timer as a pulse generator with the common fed directly from 12V. What timer module are you using, for this simple application you can even use a very simple RC timer consisting of a 4700uF 25V capacitor in series with the relay coil, and a 1k resistor across the photocell output to discharge it.

author: SL4P
author_rank: Super Contributor
timestamp: January 31, 2015, 11:42:07 pm
content: @SeanB is correct.The way your schematic drawn, the + supply passes through the photoswitch to the relay [ hence the current limit is capped by the weakest series component (the photoswitch?)Both proposals are valid - you've chosen the first, it just needs tweaking in the implementation.
auto polarity in digital multimeter - Page 1
Forum section: electronics / beginners

author: Fatih
author_rank: Newbie
timestamp: July 08, 2013, 09:11:08 am
content: Hi everyone, I have decided to join this forum hoping that I will improve myself in electronics.Currently, I am trying to understand how a digital multimeter works and searching over the internet, but I could not find how auto polarity in digital multimeter works. What is the mechanism for this function in digital multimeters?I appreciate any effort.Fatih

author: Paul Price
author_rank: Super Contributor
timestamp: July 08, 2013, 04:39:47 pm
content: Have faith, if you google "How to use voltmeter" or "How to use DVM" or search using "DVM" on Youtube you will find plenty of info and tutorial.Any multimeter can tell the difference if the input positive probe is more positive or negative then the other ground probe and then whether it is positive or negative, the auto-polarity circuit is just reacting to that and changing the display readout to notify you what polarity it detects.So how does the auto-polarity get sensed? Usually a very high sensitivity circuit called acomparatoror anoperational amplifierdoes the job.In a comparator the output is switched ON or OFF depending on the relative voltages at the PLUS and MINUS inputs of the comparator. The inputs are quite sensitive and a difference of only a few millivolts between them will cause the output to turn on or off.google or Youtube the words "comparator" to get more info.

author: Fatih
author_rank: Newbie
timestamp: July 09, 2013, 06:23:10 am
content: Thanks for your help. I will do as you suggested.
Auto-ranging circuitry for an ADC on a microcontroller (Arduino) - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: May 01, 2012, 12:03:06 pm
content: I need to measure DC signals that can vary from about from about 6mV to 10v to an accuracy of about 5%. This is for measuring the current and voltage across a salt water chlorinator.The Arduino has a built in switchable reference for 1 or 5 volts.Would a voltage controlled amplifier or op-amp and programmable attenuator be the way to go?The limiting factor is the number of microcontroller pins as half are already assigned for driving a display etc.The Arduino doesn't have a DAC, so generating analogue control voltages is limited to resitive dividers on digital outputs or feeding a PWM signal into a low pass filter.Mike

author: Kremmen
author_rank: Super Contributor
timestamp: May 01, 2012, 04:41:47 pm
content: Yes, that is the way i would start looking into the signal conditioning. My recommendation would be to look into some of the I2C-interface parts that need just the SDA and SCL signals, i.e. 2 pins from the Arduino to set. What is best, if you need say 2 components (attenuator and amplifier, both can use the same I2C bus.Arduino has the library for I2C or TWI interface but i haven't really used it, so no experience there.

author: Fox
author_rank: Regular Contributor
timestamp: May 01, 2012, 07:23:25 pm
content: Hi,have a look at the Design Note 339 from Linear Technology, i attached, for a general overview how autorangeing can be realized.In your case would need an PGA which can switch between a gain of 0,5 and 1, or a switchable voltagedivider.Or you could use just use a fixed 1:1 voltagedivider to reduce your max. 10V to 5V and switch your reference Voltage to 1V when your input Voltage goes below 2V.This would be the cheapest and easiest way to do it, with an 10Bit ADC and 1V Reference that would be 0.97mV per Bit.Therefore your input voltage resolution is 1.94mV per Bit.So you have to decide if this resolution is good enough for your application or not.
Autodesk Eagle PCB cutouts - Page 1
Forum section: electronics / beginners

author: csheldon
author_rank: Contributor
timestamp: December 27, 2018, 09:44:54 am
content: Hi all,Some help for a noob here pleaseI want to be able to do two things:1) I want a slot-like trace cutout of preffered length and shape on the pcb2) I want to cut out piece of pcb on the edge...basically something like defining board shape..but it's not shape rather it's simple cut out.How can I do these two things..?

author: Chriss
author_rank: Frequent Contributor
timestamp: December 27, 2018, 10:03:08 am
content: Hi!I assume you will do the cutting with a cnc?Sent from my GT-I8260 using Tapatalk

author: westfw
author_rank: Super Contributor
timestamp: December 29, 2018, 08:52:39 am
content: QuoteThis is normally more dependent on the the board fabricator than on the PCB editor.I would draw lines/shapes on the "routing" layer, using a width equal to my tool width. But most board fabs seems to want an outline of the actual slot, usually in the dimension layer, sometimes with a drill hole in a starting position. (The one time I tried to get slots (for a USB connector) done in a board, it didn't come out :-( ) Check your board vendor's web page for info on "internal milling."Quoteusually you can do that just by modifying the "dimension" layer - there is no reason that it has to be a rectangle.
Autodesk Eagle Workflow - Page 1
Forum section: electronics / beginners

author: csheldon
author_rank: Contributor
timestamp: November 26, 2018, 09:29:43 pm
content: Hi all,If somebody here is using eagle, can you please explain the workflow when trying to get 3D PCB design along with fusion 360.Their managed libraries system sucks really hard, so basically, I want to download my preffered libraries and use them locally, but I would also like to get my 3D PCB at the end.As far as I've seen solution is to export components used in project to single library and then individually map those components to 3D packages. Problem is, If I use something from a huge library like rcl.lbr for example, the script extracts all those unwanted devices in to my exporeted library, which is silly really ,, and tedious to delete all those unnecessary devices every time.SO maybe I am missing something, can someone please share their bulletproof method in making this simple.Sadly I must say eagle is crap, and I would really never use it, but it is free, and comes with bunch of libraries, which is the only reason why I am giving it a shot.Could also try kiCad, which i heard is significantly frendlier and better, but not sure if it's library count is as big as eagle's?

author: csheldon
author_rank: Contributor
timestamp: November 27, 2018, 08:33:21 am
content: anyone?

author: level6
author_rank: Regular Contributor
timestamp: November 27, 2018, 02:53:58 pm
content: I just finished my first board using Eagle and was able to get the 3D board just fine. But I just used the built in libraries and any parts I had to add I added to my own managed library. I didn't really have any problems with it. This was my first experience using Eagle and any problems I had were quickly resolved using Autodesk's forums.

author: csheldon
author_rank: Contributor
timestamp: November 27, 2018, 03:19:44 pm
content: Hi, thanks for the response. When you say you used built in libraries, do you mean you used offline libraries that came with Eagle?If so, do they even have the proper 3D Models mapped from the start(or only solid squared things?), or do you first need to update them through managed library option?Thanks in advance for your response!

author: level6
author_rank: Regular Contributor
timestamp: November 28, 2018, 12:47:59 am
content: I used the standard libraries that came with Eagle, which I believe are also managed. Some of the parts I used had 3D models, such electrolytic caps SOT3 and TO-92 forms. The accurate 3D rendering was not as important to me. Even if the part had no 3D model, the default shape that was the same size as the part footprint was okay for me.
"Automagic" window roller control - Page 1
Forum section: electronics / beginners

author: PinheadBE
author_rank: Regular Contributor
timestamp: January 06, 2020, 12:28:15 pm
content: Hi there,I'm looking for a commercial solution to replace the manual up/down switch of my rollers with an automated one which should be able to open/close the rollers based on, for example, the official dusk/dawn times for my location (manually override able)I've seen some fairly inexpensive switches (less than 50 EUR), which are programmable through an Android app, but I don't know if I need something else in the infrastructure for them to work (a server of some kind or whatever...)--> Is such a switch, connected to the WiFi enough to work independently once programmed through the App, or does it need something else ?--> Do you have, based on your experience, some examples of fairly reliable models to guide me ?Any advice welcome !Thanks a lot !
Automatic eprom identification using pin A9 - Page 1
Forum section: electronics / beginners

author: tridentsx
author_rank: Regular Contributor
timestamp: December 02, 2015, 09:17:25 pm
content: How does eprom programmers auto detects eproms ?As I understand it by putting a higher voltage on pin A9, an ID can be read from the chip, but eproms comes in many packages and A9 can be on different places in the ZIF socket. Is there a way to see which pins has been connected to "guess" what type of package is inserted and that way "guess" what pin in the socket is A9?
Automatic Gain Control - exercise from 'The Art of Electronics'. - Page 1
Forum section: electronics / beginners

author: FullBridgeRectumfire
author_rank: Newbie
timestamp: April 14, 2017, 07:51:23 pm
content: Hi all.Anyone fancy to help me out with this very simple exercise?The VN13 has an ON resistance (VGS = +5V)of 15 ohms (max). What is the range of amplifiergain in the second circuit (assume that thecurrent sink looks like 100MOhm)? What is the low frequency3dB point when the FET is biased sothat the amplifier gain is (a) 40dB or (b) 20dB?How to find the lowest drain-source resistance of the MOSFET? How to find cut-off frequency knowing only a value of the emitter cap or how a change of Rds value affects frequency response?

author: danadak
author_rank: Super Contributor
timestamp: April 14, 2017, 09:01:50 pm
content: Assuming the bipolar is high beta, then Ie =~ 1 mA. Vemitter = 6V - Vbe =~ 5.3V. Re then looks to be 5.7V / 1 mA = ~ 5.7K. You can then compute the ~3db from 1 uF and 5.7K.Make the same calcs when the bias changes.Regards, Dana.

author: FullBridgeRectumfire
author_rank: Newbie
timestamp: April 15, 2017, 10:40:02 am
content: Your solution does not include changes of mosfet's characteristic acting as a voltage controlled resistor.