hybridfree/eevblog-posts huggingface dataset:
ADC design for 16bit / 48Khz audio - Page 1
Forum section: electronics / projects

author: cncjerry
author_rank: Unknown
timestamp: August 11, 2024, 05:25:06 am
content: I need help selecting ADC chips. I would like to build a couple ADCs for 16bit 48Khz coding with AES/EBU output. Balance or differential input would be key. I would like word clock input and output. A stereo channel pair would be ideal. There must be a single chip solution, no? Way back I know Crystal Semi made a single chip codec, but I don't think it had word clock and was made for consumer CD. I've looked around at eval boards but those I found where higher priced than I wanted. I use Crystal Semi eval boards for DACs today but I was given them by Crystal Semi years ago. I know people are using different TI chips. I'm looking at their product selector and I was hoping someone who knows those chips could narrow the selection for me or maybe point me at other choices. I can code a micro if needed for setup but would love it to run standalone with pushbutton selections. As some of the data is headed to either ADAT or TDIF, I know there are custom ADAT chips available for up to 8 channels I was thinking of incorporating too.ThanksJerry

author: boB
author_rank: Frequent Contributor
timestamp: August 11, 2024, 08:23:01 pm
content: I would take a look at AKM in Japan. They are one of the biggies in this area.https://www.akm.com/us/en/products/audio/They had a fire a few years ago but I think they are all caught up with that.AKM was starting to make A/Ds and D/As like the Crystal Semi parts but were cheaper back around 1990 as I remember.I just tossed my old Crystal Semi eval boardsYou can also enter some of the terms into parts search engines like...https://octopart.com/

author: zapta
author_rank: Super Contributor
timestamp: August 13, 2024, 01:14:58 am
content: Search Digikey for I2S ADC. There are a bunch of them, including with 2, 3, or 4 channels. E.g.https://www.digikey.com/en/products/detail/asahi-kasei-microdevices-akm/AK4385ET/5182185
ADC Design for AC Voltages Across a Current Sense Transformer - Page 1
Forum section: electronics / projects

author: Haeden
author_rank: Newbie
timestamp: June 06, 2023, 03:41:11 am
content: I am trying to measure the voltage across a burden resistor attached to a current-sense transformer using a differential ADC.The current sense transformer will operate at ~250 KHz.My current design is based on Figure 2 on page three of "Driving High-Speed Analog-to-Digital Converters" (https://www.ti.com/lit/an/slaa416a/slaa416a.pdf) from Texas Instruments.I am planning to use the ADC100651) Is tying the COM pin to an external reference bias voltage the correct way to interface the ADC10065 with a current transformer?2) Is there a better way to measure AC voltages from a current sense transformer?

author: moffy
author_rank: Super Contributor
timestamp: June 06, 2023, 05:24:04 am
content: Your circuit looks reasonable and the Vcom biasing seems good. The data sheet:https://www.ti.com/lit/ds/symlink/adc10065.pdf, shows 18R resistors instead of 5R, and a 25pf cap across the ADC input.P.S. What sort of BW are you looking for around the, I assume, center frequency of 250kHz?
ADC Input Track Layout - Page 1
Forum section: electronics / projects

author: geo_leeman
author_rank: Regular Contributor
timestamp: May 29, 2016, 04:34:58 pm
content: Hi all,I'm working on a project that uses the MAX11040K 24-bit ADChttps://www.maximintegrated.com/en/products/analog/data-converters/analog-to-digital-converters/MAX11040K.html](https://www.maximintegrated.com/en/products/analog/data-converters/analog-to-digital-converters/MAX11040K.html). I have some sensors that are driven with a 250 Hz square wave and I read their output voltage on the high and low segments to determine their value (that's a whole other story). The sensors output goes though a LMC6482 as a buffer, then to the ADC. My question is do I need to worry about impedance control on the ADC tracks? The buffer should drive the ADC just fine without much thought to this right? After much googling I didn't find much design advice for the input traces, just lots of information about routing the digital and analog separately/at right angles, etc.* ADC Input Impedance ~ 130k* LMC6482 Output Impedance ~ a few hundred ohms?Thanks!

author: Yansi
author_rank: Super Contributor
timestamp: May 29, 2016, 04:54:19 pm
content: Worry about what? Track impedance at 250Hz soft-transitioned analog signal? Really no.You should be well more worried about your grounding system on the PCB, or using the differential inputs from the ADC correctly. Otherwise, with a bad layout and a few sources of EMI you can easily reduce the effective resolution you could get from the adc to below16 bits in some extremes due to induced noise.

author: nctnico
author_rank: Super Contributor
timestamp: May 29, 2016, 05:14:52 pm
content: A 24bit ADC which has no ENOB specification should make alarm bells go off. Also using an external buffer will probably do more harm than good (offset and non-linearity). Did you look at TI's offerings? TI has 24bit ADCs with an internal buffer which can also be taken into account when the device self-calibrates.When it comes to routing the signals: make sure there is no current flowing in the traces between the ADC what is being measured.

author: JPortici
author_rank: Super Contributor
timestamp: May 29, 2016, 05:31:33 pm
content: Quote from: nctnico on May 29, 2016, 05:14:52 pmwhich is also a maxim part. or has thing improved recently?

author: geo_leeman
author_rank: Regular Contributor
timestamp: May 29, 2016, 05:49:39 pm
content: Quote from: Yansi on May 29, 2016, 04:54:19 pmThanks for the input. I have Rev.A of the board and don't really have any signal integrity issues, so that's a good sign. The measurements have been rock solid.Quote from: nctnico on May 29, 2016, 05:14:52 pmThis isn't an ideal part, but was the only thing I could find on the market that did what I need - many kHz sampling of 4 channels at 24-bits. As for the buffers - I have to provide a very high impedance input for the sensors. They are electrochemical and any dc bias/current will eventually harm them (hence the square wave driving and buffers).
ADC input voltage confusion - Page 1
Forum section: electronics / projects

author: jmdejoanelli
author_rank: Contributor
timestamp: July 27, 2012, 04:18:53 am
content: Hi all,I'm designing a RF receiver and data logger. The RF signal is mixed down an intermediate frequency of 30kHz or there abouts and some filtering and such is done at this point as well.The resulting signal is then to be converted using an ADC, a PCM1802 (datasheet attached), so that the signal can be recorded on the data logger.My question, and where I am confused:Does this ADC take a bipolar signal? I.e. does it take a signal centered around zero volts? I have searched around the datasheet and found that it accepts a 3Vp-p input, but does this mean it must be centered around zero?I'm sorry if this is a silly question, but I've been racking my brain for hours and I just can't get a straight answer.Thanks,Josef

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: July 27, 2012, 04:39:14 am
content: HiI'm no expert on ADC chips but it says to capacitively couple the input channels.This will mean no dc component will get through to the ADC from these inputs.Just make sure the amplitude is within the limits 3v p-p you said and you should be right.the example in fig 29 shows unipolar caps for R-ch in and L-ch in , if you use unipolar double check the orientation.You can suitable bipolar as well.

author: jmdejoanelli
author_rank: Contributor
timestamp: July 27, 2012, 04:53:12 am
content: Ah yes that makes it clear then doesn't it.Cheers mate!
ADC is only positive in single ended mode!!! - Page 1
Forum section: electronics / projects

author: v8dave
author_rank: Regular Contributor
timestamp: July 28, 2016, 04:00:52 am
content: I have a design with an ADC using the MCP3428 and I have 2 of them. 1 is connected to the common ground of the system and the other is isolated with it's own DC-DC supply. The ADC is specified to work with -2.048V to +2.048 input.The isolated one has the + and - connected to the external connector and can range from -2V to +2V but the other ADC has the + connected to the input and the - to the same GND as the VSS pin so is set for single ended input. This input is supposed to be -5 to +5 so I have a potential divider to drop the 5V input to within the range of the ADC's +-2.048VThe isolated input can measure the -2V to +2V input and I can read this from the output but the non-isolated ADC only seems to measure 0-5V. If I input -5 I get a reading of approx -1.17V from the ADC. From this it appears that this ADC only works with positive input voltages and not negative if we use the single ended input mode?This appears to happen because of the diode protection on the input if the -Ve is connected to VSS. If floating and in differential mode it seems to work.Would someone please confirm what I have found?

author: tombi
author_rank: Regular Contributor
timestamp: July 28, 2016, 04:15:18 am
content: Datasheet says (top of page 5)Absolute Maximum Ratings†VDD...................................................................................7.0VAll inputs and outputs ............. ..........VSS –0.4V to VDD+0.4VI think it can read voltages that are negative w.r.t channel X minus but the input must always be > VSS-0.4.So if you wire Channel1 minus to vref then voltages between 0 and Vref will be negative (i.e. return negative numbers) and Vref-Vdd will be positive. But the voltage musn't go below VSS-0.4. Depending on your gain settings it will likely max out in less than that range however.Tom

author: v8dave
author_rank: Regular Contributor
timestamp: July 28, 2016, 04:25:16 am
content: Thanks TomThe same datasheet shows above that, that the full scale differential input is +-2.048/PGAThe isolated input doesn't have the the -Ve input connected to the supply ground so this one can actually measure the -2V to +2V input from the sig gen. Thankfully this is the one I needed pos a neg inputs on and can live with the 0-5V input.It tripped me up as I have used other ADC's where I can do this but like you mention, the -REF is connected to a negative reference. The MCP3428 does not have any ref pins, it's all internal.
ADC reading garbage SAMD20 (No ASF) - Page 1
Forum section: electronics / projects

author: matthew_zammit
author_rank: Newbie
timestamp: May 04, 2018, 05:14:32 pm
content: So, I have an ADC which is software triggered every 30ms via the RTC interrupt handler. The problem is that the ADC produces garbage results no matter the voltage applied at the input. Am I setting it up wrongly?Code:void init_ADC(){//ADC INPUT PIN INITPORT->Group.PINCFG.reg = PORT_PINCFG_INEN | PORT_PINCFG_PMUXEN; // INPUT ENABLE AND PERIPHERAL MULTIPLEXING FOR ADC_INPUTPORT->Group.PMUX.reg = PORT_PMUX_PMUXE_B; // ENABLE ANLOUGE INPUT FOR ADC_INPUT//Clock ADC by GCLK0REG_GCLK_CLKCTRL = GCLK_CLKCTRL_WRTLOCK |GCLK_CLKCTRL_CLKEN |GCLK_CLKCTRL_ID_ADC |GCLK_CLKCTRL_GEN_GCLK0;REG_PM_APBCMASK |= PM_APBCMASK_ADC;// enable ADC APB clock BUSNVIC_SetPriority(ADC_IRQn,0); // SET TO HIGHEST PRIORITY INTERRUPTNVIC_EnableIRQ( ADC_IRQn );// enable interrupts for ADC// 1.65V reference Voltage and (Reference buffer gain compensator -- REMOVE COMMENTS TO ENABLE)REG_ADC_REFCTRL |= ADC_REFCTRL_REFSEL_INT1V;// | ADC_REFCTRL_REFCOMP;while(ADC->STATUS.bit.SYNCBUSY); //wait for synchronizationREG_ADC_CTRLB |= ADC_CTRLB_PRESCALER_DIV4 | ADC_CTRLB_RESSEL_10BIT | ADC_CTRLB_LEFTADJ; //| ADC_CTRLB_CORREN;while(ADC->STATUS.bit.SYNCBUSY); //wait for synchronization//INTERRUPT SET FOR WINDOW MONITOR or result is readyREG_ADC_INTENSET |= ADC_INTFLAG_RESRDY;while(ADC->STATUS.bit.SYNCBUSY); //wait for synchronizationREG_ADC_INPUTCTRL |= ADC_INPUTCTRL_MUXPOS_PIN12 | ADC_INPUTCTRL_GAIN_1X | ADC_INPUTCTRL_MUXNEG_GND; //PIN MULTIPLEXING FOR ADC INPUTwhile(ADC->STATUS.bit.SYNCBUSY); //wait for synchronization//Use this to calibrate Adc --- REG_ADC_CALIB = ADC_CALIB_BIAS_CAL() | ADC_CALIB_LINEARITY_CAL();//This can be adjusted post testing -- REG_ADC_SAMPCTRL = ADC_SAMPCTRL_SAMPLEN(SOME SAMPLE LENGTH);REG_ADC_CTRLA |= ADC_CTRLA_ENABLE; //ENABLE ADCwhile(ADC->STATUS.bit.SYNCBUSY); //wait for synchronization}The Result register is read in the ADC interrupt handler. I've also tried enabling an LED at different Voltage thresholds but still no luck.

author: ataradov
author_rank: Super Contributor
timestamp: May 04, 2018, 08:43:19 pm
content: Please don't cross-post. The other topic is herehttps://www.eevblog.com/forum/microcontrollers/adc-not-working-correctly-samd20-(no-asf)/
ADC Sample rate for e-bike power meter - Page 1
Forum section: electronics / projects

author: Axk
author_rank: Regular Contributor
timestamp: January 07, 2019, 05:34:24 pm
content: What current sample rate is enough for accurate (e.g. 5% accuracy) consumed power measurement given the current waveform on the screenshots attached?I've recorded the waveform with no load applied to the wheel accelerating from 0 to full throttle. Used a thin wire as the shunt with the voltage across the shunt amplified with an om-amp (100x if I remember correctly), not sure if this measurement setup is correct. I was not interested in absolute values, just the shape of the current waveform.It looks like 1 Msps should be enough for this, but I wonder if I could get away with a lower rate of e.g. 100Ksps and a low-pass filter and still keep the accuracy within 5%.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 07, 2019, 05:41:27 pm
content: Since there is so much noise, and the current ramp is quite slow (about 100 msecs), if you decide to do 1 Megasample/sec then you will require to significantly average the readings.Like 1000 averages.Another is to low-pass filter the input waveform prior to the ADC, and sample at a much slower rate.
ADC, SPS, Bandwidth and Antialias help - Page 1
Forum section: electronics / projects

author: baoshi
author_rank: Regular Contributor
timestamp: December 04, 2015, 03:27:55 pm
content: This question is about signal bandwidth, sample rate and design practice.I have a analog frontend with design specification of 100khz bandwidth (-3db)I need to design ADC system capable of sample the signal at 12bit.So here is the calculation:For effiecive 12bit accuracy, the stopband of anti-alias filter needs to be at least -72db in order to limit aliased signal below 1LSB;Try using Filter Wizard athttp://www.analog.com/designtools/en/filterwizard/,for butterworth response,Cut-off Frequency ADC Sample Frequency Filter order Filter Stages230kHz 460ksps 10 5282kHz 564ksps 8 4399kHz 798ksps 6 3795kHz 1.59Msps 4 26.4MHz 12.8Msps 2 1It seems if I want to limit the anti-alias filter to be 1 stage Sallen-Key filter, I need to sample at 12.8Msps for 100kHz bandwidth.Anything wrong here? I can't recall I saw any design like this.Thanks!Baoshi

author: dom0
author_rank: Super Contributor
timestamp: December 04, 2015, 04:09:27 pm
content: QuoteDo you? This is rarely necessary, because in most systems there is additional band-limiting before the anti-aliasing filter, i.e. you already know beforehand that you'll never see a 0 dBfs signal beyond your 100 kHz at the AA filter input. Only if that's possible you will need the "full" anti-alias filter.At 100 kHz signal bandwidth and 12 bit resolution you might end up using some audio converter. Those are almost always oversampling and don't require as steep anti-alias filters as non-oversampling converters. Check the datasheet of the converter you are going to use, then design and match the filter to the converter.

author: dom0
author_rank: Super Contributor
timestamp: December 04, 2015, 04:42:59 pm
content: I assume by "compensate" you mean oversampling and subsequent digital filtering?

author: baoshi
author_rank: Regular Contributor
timestamp: December 05, 2015, 02:30:44 am
content: Quote from: dom0 on December 04, 2015, 04:09:27 pmGood point. The frontend probably has -10db at 1MHz. That reliefs the attenuation requirement a bit. The signal will contain pulses that makes up wide sprectrum. I probably have to use a 3-order filter and sample at 2MHz, then digitally filter and down sample to 200kSPS.
[SOLVED] ADC7476 confusing SPI timing diagram  - Page 1
Forum section: electronics / projects

author: Dmeads
author_rank: Regular Contributor
timestamp: July 27, 2021, 04:21:48 am
content: Hello!I am writing a SPI master for the ADC7476 in VHDL for a project.I am confused about the last bit sent out over the MISO/SDATA line. in the datasheet here:https://www.ti.com/lit/ds/symlink/adcs7476.pdf?_ga=2.119868360.1926354315.1627190855-336353978.1613715017, it says that the 12-bit adc ( the one i am using), does not clock out trailing zeros like the 8 bit and 10 bit versions. (pg. 16), so, on the last bit conversion, it is valid after the 16th falling edge of SCLK.if you go up to pgs 9 and 10, you will see the timing diagram for the 12 bit ADC, and timing requirements.There is a time window (t4) where you are allowed to access/sample the data after the falling edge of SCLK/data is clocked out. However, on the last falling edge, there is a much smaller amount of time (t8) before the SDATA line goes into high-z. This amount is minimum 6 ns @ 3.3V, where as the data access time on the other edges is 40 ns.Does this mean I will only have 6ns after the last negative edge where I can sample the last bit?I suppose I can create my FSM to sample RIGHT on the falling edge of SCLK, but I am just wondering. Thanks!

author: ataradov
author_rank: Super Contributor
timestamp: July 27, 2021, 05:19:48 am
content: Their diagrams are confusing. T8 is after the negative edge after the lat bit. You sample the data on the positive edge. So you have half the cycle.So interpret it as you actually have 3 dummy bits in the beginning, then 12 bits of data, and then one transition that you ignore. And you will be fine.
ADCMP60* hysteresis pin - Page 1
Forum section: electronics / projects

author: aiju
author_rank: Newbie
timestamp: January 05, 2018, 10:30:33 am
content: I'm quite confused why the ADCMP60* datasheets (e.g. ) claim there is an internal 70 k? resistance when that seems to be inconsistent with everything else in the datasheet.The only reasonable interpretation of the 70 k? figure, that I can think of, is that the equivalent model* is a 1.25 V voltage source in series with 70 k? (i.e. basic Thevenin equivalent).The hold mode activates around 1.1 V at the LE/HYS pin, so we don't want more than 0.15 V drop across the resistor. 70k? would limit the current out of the pin to 2?A which is an order of magnitude below the 25?A cited in the datasheet for maximum current out of the pin. There is tons more examples like this in the datasheet that make no sense given this equivalent model and the 70 k? figure.Is this just a typo or am I mistaken about this model?It bugs me that all the numbers come out right with 7 k?...I've tried to ask this question on the analog devices support forum but no luck. Same with their "report error in datasheet" form.http://www.analog.com/media/en/technical-documentation/data-sheets/ADCMP606_607.pdf* Yeah, it's clear from the datasheet that resistance is a lot higher above 1.25V, but we don't care about that. And there is ESD clamping diodes, obviously, that kick in at the edge of the supply range.

author: David Hess
author_rank: Super Contributor
timestamp: January 05, 2018, 03:13:33 pm
content: You are right, the datasheet is misleading or just plain wrong. Maybe nobody at Analog Devices knows what it means either.Figures 8 and 9 are consistent with a 70 kilohm external resistor operating against a 1.25 volt voltage source and this conflicts with the +/-0.1 milliamp specification for input low of the latch enable function and operation with an open drain/collector driver which could leave the part latched off permanently.
add a transistor to my DC-DC converter for 1.5A output - Page 1
Forum section: electronics / projects

author: ElectronicFanatic1
author_rank: Contributor
timestamp: December 06, 2010, 07:44:22 pm
content: Hi i want to add a transistor to my DC-DC converter for 1.5A output but im not sure how or what transistor (mosfet) to use? can anyone help me?

author: Psi
author_rank: Super Contributor
timestamp: December 06, 2010, 09:34:53 pm
content: not without a lot more information about your design.

author: tyblu
author_rank: Frequent Contributor
timestamp: December 06, 2010, 11:07:17 pm
content: Which DC-DC converter? Are you planning on using the transistor in parallel with it as a linear regulator? It isn't possible to increase the output power of a DC-DC converter directly, but you can bypass it and use its output to regulate a linear regulator.
Add automatic tip power off to soldering station - Page 1
Forum section: electronics / projects

author: thomasa88
author_rank: Newbie
timestamp: April 19, 2024, 05:51:51 am
content: I have a soldering station bought at a local reseller which I think is a Zhongdi white label station. It was bought 2020.It works quite well, but I tend to sometimes start thinking and then forgetting the iron on for some minutes before I solder the next joint and I tend to have to use tip cleaner on the tips quite after a few soldering sessions. I have seen that more expensive stations automatically lowers the temperature when you put the pen in the stand. Do you think it would be possible to mod my station to have the same feature?Ideas:Add a long-tongued switch to the stand, that is pressed when the pen is put in it which* cuts the power to the whole circuitry,* cuts the power to the heater (I guess this will make the regulation try to raise the temperature),* indicates a very high temperature to the temperature sensor (If I see temp 500C, I know that the heating is paused),* makes the + and - temp buttons be pressed for x seconds when pen is inserted or removed.Ideally, I think I want the heating to not turn of completely, just lower the temperature to a "safe" one.Thoughts?

author: Teledog
author_rank: Regular Contributor
timestamp: April 21, 2024, 01:45:07 am
content: JBC irons do that, ..but horrendously expensive.For a low-buck unit, .. I use a wind/clock timer mechanism in an electrical box for my hot glue guns (I always seem to leave them on)ie:https://www.aliexpress.com/item/32950908666.htmlAdd an indicator light & input/outlets & good to goNote:This is for OFF-ON only though! ..no warm stateG'Luck!

author: JustMeHere
author_rank: Frequent Contributor
timestamp: April 21, 2024, 02:11:24 am
content: I'd put this and a wall socket in an out door electrical box.https://www.amazon.com/Honeywell-RPLS730B1000-7-Day-Programmable-Switch/dp/B004SOZHXYGet an appliance replacement cord.And make this:https://m.media-amazon.com/images/I/71QzvlwE9PL.jpg

author: inse
author_rank: Super Contributor
timestamp: April 21, 2024, 05:37:32 am
content: Additional sensing idea: a contact spring or brush that touches the metal sleeve of the iron in the stand. Assuming the iron is grounded, you should be able to check a ground loop being closed.Without modification on the base unit, maybe a ‚time relay‘ circuit switching the entire unit on for a couple of seconds and off for a couple of more seconds to achieve the desired temperature reduction.And completely off after x cycles, so microcontroller required or logic gates…
Add Fiber Transceivers to TP-Link router? - Page 1
Forum section: electronics / projects

author: Bluestreak66
author_rank: Regular Contributor
timestamp: February 01, 2015, 08:45:33 am
content: Would there be an easy way to connect a fiber Transceivers like this:http://www.finisar.com/sites/default/files/pdf/VnkbAPFTLF8524E2xNySpecRevG.pdfto and off the shelf router?The routers I'm specifically targeting are the ones using the AR9331 chiphttp://www.openhacks.com/uploadsproductos/ar9331_datasheet.pdfas there seems to be a lot of information and support availible for the TL-WR703N.I have the schematics for that router and I'm modifying it into different form factor with the additional ports. It would be nice to use one port for fiber, However I have yet to see anyone doing anything similar and almost no info other than the data sheets.

author: helius
author_rank: Super Contributor
timestamp: February 01, 2015, 09:05:49 am
content: No, that SOC has 100BaseTX Ethernet PHYs on chip and only exposes the physical signals (on the board they would go through a pulse transformer and then to the RJ45 connectors).To use optical transceivers you need to interface to them at a higher level. For 100 megabit that would be MII, and for gigabit speeds there's GMII, XAUI, et cetera.

author: Bluestreak66
author_rank: Regular Contributor
timestamp: February 01, 2015, 06:04:06 pm
content: I've seen these used in alot of switches and media converters:Marvell 88E1112http://www.marvell.com/transceivers/assets/88E1112_Technical_Product_Brief.pdfDo you think it would be possible to connect this directly to the SOC without going through two sets of transformers?I'm building the first few of these for a "proof of concept" with the well documented AR9331. I would like to switch to a gigabit SOC. I have tried to find info on the AR9340 which looks like a good candidate but can't find any info on it other than the initial specs. The AR8327 looks like the best candidate so far, as it does show in the documentation support for RGMII and SERDES as well.https://lafibre.info/images/doc/201106_spec_AR8327.pdfIf anyone has any suggestions for a SOC I'd like to heard them, my basic requirements are:4 port Gigabit Ethernet1 FiberLow power 3.3vSupported by DD-WRTIt does not need to have wifi, it will probably never be used.I'll most likely stick with the AR9331 for the first few and then change to the New SOC if I decide to make a lager quantity. The fiber is meant for distance not speed. The object of this is to make an all-in-one card that fits into a server neatly, adding an external media converter defeats the purpose.

author: Stonent
author_rank: Super Contributor
timestamp: February 02, 2015, 11:50:22 pm
content: Not really, the normal way is to use something like a McBasic to convert the media from Ethernet to Fiber.
Add-on garage door IR safety sensor - Page 1
Forum section: electronics / projects

author: Peabody
author_rank: Super Contributor
timestamp: November 13, 2017, 05:48:32 am
content: I just need to check my thinking on this. I have a vintage 1972 Sears opener, model 139.654000, which still works quite well. I just have to replace the start capacitor every couple decades. But while it has obstruction reversal in both directions, that's not particularly sensitive, and it doesn't have the optical sensors that more modern openers have.So I thought I would look into buying a replacement sensor set, but use it as an add-on, and rig up a circuit for it. The existing remote receiver, key switch, and push button all work by shorting two terminals on the opener panel. So my circuit could do the same if the light beam is broken, but I would have to figure out a way to limit this function to the period when the door is closing. Otherwise, I would initiate a closing when walking into or out of the garage.I've come to the conclusion that this probably isn't a good idea. So far as I can tell, there are no add-on kits sold for this purpose except for use with openers designed to use them, all of which appear to have four terminals instead of just the two I have. My guess is that's because it isn't easy to make these things work with openers not designed to use them, and because this is a safety item and an invitation to a bunch of lawsuits if not installed correctly. And if I rig up a DIY version of such a kit, then sell my house at some point, I would be at risk for a similar lawsuit if anything goes wrong, whether it's my fault or not, and that's even if my DIY sensor would pass inspection in the first place. So it looks like it would be necessary to replace the opener to get this safety function.It would be fun to work it all out, but I just think this may be a case where DIY isn't a good idea. Well I just wondered if anyone else sees this differently.
Add process alarm to an ERSA I-CON 1 - Page 1
Forum section: electronics / projects

author: fipse
author_rank: Newbie
timestamp: February 10, 2019, 09:38:09 pm
content: hi,I've recently bought an ERSA I-Con1 soldering station and i love itBut:There is a small thing that buged me. Since that was the cheapest model (0IC113A) the process alarm feature was missing. I mean it is described in the manual and the firmware have it too but there was no buzzer.So i checked the net and searched for pics of the i-con 2 because they have the same pcb and the buzzer installed.And after a quick test it was clear to me, that ersa simply safed a buck and didn't install the buzzer on a €300+ stationSo if you also want this i've made some pics of the installation.The buzzer is an el-cheapo 5V type from my bin

author: kony
author_rank: Regular Contributor
timestamp: February 10, 2019, 09:59:00 pm
content: Nice mod, thanks for posting it.

author: Hel385
author_rank: Newbie
timestamp: May 27, 2021, 11:26:03 pm
content: Thank you !!
ADDAC87D-CBI-V help - Page 1
Forum section: electronics / projects

author: lusher00
author_rank: Newbie
timestamp: December 17, 2024, 03:09:01 pm
content: I have an ancient board my client says doesn't work. The board has a socketed DAC I am trying to test but it appears dead. I believe I'm doing everything correctly but I want to check with the internet before I invest $400 and 13 weeks in a new DAC.I am supplying -15V to -Vs, +15V to +Vs, 0V to COMMON, Vref out is tied to REF INPUT, I have a microcontroller that shares a COMMON and I am driving BIT 1-12 with 5V GPIO. I have a 10k load resistor on Vout but the output is stuck at 15V regardless of my parallel data. The rest of the pins on the DAC are floating. Is there something else I might need to do to get this thing to work? Datasheet says I should have 6.3V on Vref which I do. -Vs is drawing about 20mA, +Vs is drawing 0mA. I have tried +/- 5 & 10V with no changes to the behavior aside from I can't get a 6.3V reference with 5V but the output is following the +Vs rail rather than the reference.I've attached a photo of the chip as well as the datasheet.

author: xvr
author_rank: Frequent Contributor
timestamp: December 17, 2024, 04:35:59 pm
content: QuoteYes. See table III in datasheet for additional connections. Without them output Opamp will be in saturation, this is that you got

author: lusher00
author_rank: Newbie
timestamp: December 17, 2024, 06:41:48 pm
content: Many thanksI figured I was missing something with those pins but I should have spotted that table. I have 15 tied to 18, 17 to 21 and 19 floating now but the output is stuck at 0V. I feel more confident it's a bad DAC but still not 100%. Confident enough that I ordered a new one. Thanks again for taking the time to read my post as well as the datasheet.
Added another calculator (and stuff) - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 25, 2016, 02:35:05 am
content: See:http://seventransistorlabs.com/Calc/index.htmlThermistor Data and Functions is the latest addition. More of an Article really, as it discusses the work and thought process behind the development I did on the subject.Speaking of articles, I added a new section as well:http://seventransistorlabs.com/Articles/index.htmlI have a couple of other lengthy would-be forum posts that will wind up here shortly.Tim
Added yet another impedance calculator - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 21, 2023, 12:42:48 am
content: In my ever-growing series of inductor measurement tools, I've added one with a series matching capacitor topology, so you can get more power into the tank from a function generator:https://www.seventransistorlabs.com/Calc/RLC.html#cmatchKinda fun to actually palpably heat up a large-value inductor just under signal generator power.Let me know if you find any discrepancies!Tim
Adding 100Mbps ETH to an R&S ZVx Network Analyzer - Page 1
Forum section: electronics / projects

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: December 21, 2019, 12:21:47 pm
content: I would really like to add 10 or better 100mbps ETH to my Rohde Schwarz ZVR VNA.There is a R&S option for it, however it's only base10, not available used and likely obsolete and or too expensive soThe instrument runs Win NT 4 which I have zero expirience with so far. On the bright side, the backplane / mainboard / plugins do have 3x ISA extension slots so should be straight forward(ish).At the moment I would be interested in pictures of ZVx's with installed ETH options as a reference

author: george.r
author_rank: Contributor
timestamp: December 23, 2019, 06:17:26 am
content: What a delightfully weird piece of gear. Seems like it runs on an Eurocard SBC. WinNT4 looks like a crossbreed between W98 and W2k (because that's what it essentially is - a W9x-ish interface tacked atop an NT kernel, Windows 2000 being NT5). You won't find too much difficulty fiddling with it. NT4 lacks a device manager, but that's the only major weirdness (or so have I found). Something like a 3Com 3C515TX ought to work. The Ethernet card R&S originally installed is an SMC 8416 EtherEZ. But anything with the proper NT4 drivers should work.
Adding a differential dc bias to a fully differential amplifier - Page 1
Forum section: electronics / projects

author: electronx
author_rank: Regular Contributor
timestamp: February 07, 2024, 08:03:18 am
content: How do I add dc bias to a fully differential amplifier? I cannot add it with Vocm or Vref pins because the receiver system also has a differential input and the offset common mode signal I add to the Vocm or Vref pins will be accepted and deleted.In this case, should I add (DC bias /(2 x G)) to the non inverting terminal and -(DC bias /(2 x G)) to the inverting pin for the dc bias I want to add?

author: jbb
author_rank: Super Contributor
timestamp: February 08, 2024, 12:35:38 am
content: I guess so… you should be able to simulate the situation which helps.One wrinkle which comes to mind is that the DC injection you want is differential mode, but feeding in a reference from a single-ended DAC (and other wire tied to ground) you’ll inject differential mode and undesired common mode. I think this would result in the input signal source seeing a (slightly?) changing common mode input equivalent circuit.If you want to keep really stable common mode input performance you’d need a proper differential DC injection source. Which could be a normal single-ended DAC and an opamp configured for G=-1.

author: electronx
author_rank: Regular Contributor
timestamp: February 09, 2024, 11:14:40 am
content: Actually, I can add dc bias this way, but I don't have a vref pin. In this case, this added offset will be added to the differential signal, but when we examine it on its own, it may create common mode noise and cause differential noise for the opamp.And also, this added DC reference will be constant and will not be multiplied by the gain. Maybe I can add a reference signal that is multiplied by the gain by adding gain to the Vref signal with an external opamp.

author: magic
author_rank: Super Contributor
timestamp: February 09, 2024, 02:28:38 pm
content: If you have a pair of well matched resistors, you could connect them in parallel with R1,R3 to any differential DC voltage and it will simply be added to the signal.Particularly so if R1~R4 are already discrete resistors, so not extraordinarily matched, and adding another pair of discretes won't compromise CMRR too badly.

author: avandalen
author_rank: Contributor
timestamp: February 12, 2024, 12:09:58 pm
content: Maybe my article about this will help you.https://avdweb.nl/tech-tips/electronics/general-summing-amp
adding a load shut off circuit to a basic PSU-is it possible? - Page 1
Forum section: electronics / projects

author: GreyWoolfe
author_rank: Unknown
timestamp: November 11, 2013, 03:47:30 am
content: I see a lot of the higher end PSUs have a load shut off switch. I've tried to find information on it on the Internet but I haven't been successful. Is there a circuit that is fairly easy to implement? I built and modded an Elenco XP720K and I think that is something I would like to add. I also have an Agilent E3610A PSU on the way that I would like to add the circuit to. Has anyone done this and can you point me in the right direction?Tom, NW0LF

author: tsmith35
author_rank: Frequent Contributor
timestamp: November 11, 2013, 07:53:28 am
content: Possibly similar to the automatic load shutoff for a UPS? When the battery charge falls below a user-specified level, the UPS will shut off power to the load while still remaining active.

author: TMM
author_rank: Frequent Contributor
timestamp: November 18, 2013, 02:29:35 pm
content: You can simply add a switch or relay on the output but then you have to deal with contact bounce - look up RC snubber circuits. Also the PSU itself may produce some undesirable effects if it is suddenly connected to a load (under/overshoot).A better solution would be to simply have a switch that sets the PSU voltage to 0V. Obviously there is no 'one circuit fits all' solution for that, you have to reverse engineer the PSU to find out how the voltage is being set.

author: nctnico
author_rank: Super Contributor
timestamp: November 18, 2013, 04:46:18 pm
content: Just put a switch across the volt setting potmeter. Shorted means the output goes to 0V. I recently modified one of my HP6024A PSUs with such a switch.
Adding a second Zener diode to power supply - Page 1
Forum section: electronics / projects

author: Kadotus
author_rank: Newbie
timestamp: April 02, 2022, 05:55:39 pm
content: Hiya everybody! I've got a power supply in an old (1985) synthesizer that has some issues.It uses a transistor to switch +/-15V down to +/-6V, and then Zener diodes for the +/-5V.From the factory it was adjusted to about 5.8V for the 6V output, so the circuitry wanting 6V is undervolted.However, even at the 5.8V, the 5V Zener is overworked. Others that have adjusted the 6V output to actually give 6V have burned out the Zener.So my question is, can I simply replace the single Zener with a pair of matching ones to split the load and heat dissipation?

author: ledtester
author_rank: Super Contributor
timestamp: April 02, 2022, 06:27:13 pm
content: FWIW, attached is the data sheet for the HZ-series zener diodes. The datasheet says they are 500 mW devices.I think I would look into replacing the zeners with a modern LDO voltage regulator. Being 80s tech it shouldn't be too hard to install one and if you have to buy parts then shipping will basically make both solutions cost the same.

author: bdunham7
author_rank: Super Contributor
timestamp: April 02, 2022, 06:35:38 pm
content: Quote from: Kadotus on April 02, 2022, 05:55:39 pmNo, that will work poorly as they won't share the current equally at all. The simplest solution, without any re-engineering, is to use a 5W 5.1V zener like the 1N5338BG (if you can find one...) and raise it up off the board a bit if possible.

author: Kadotus
author_rank: Newbie
timestamp: April 02, 2022, 07:20:05 pm
content: Quote from: bdunham7 on April 02, 2022, 06:35:38 pmIt seemed like it would have been too easy a solution. Slight difference in internal resistance and path of least resistance, right?A 5W diode would probably be much more appropriate. Thanks!

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 02, 2022, 07:28:10 pm
content: The temperature coefficient is the issue with paralleling diodes, forward voltage drops as temperature rises, the slight differences device to device just knocks over the first domino.

author: TimFox
author_rank: Super Contributor
timestamp: April 02, 2022, 10:25:24 pm
content: Unless you go to a huge amount of trouble to balance the currents, it is generally a bad idea to put identical diodes in parallel.
adding a time delay to ac transfer switch - Page 1
Forum section: electronics / projects

author: michaelmrc
author_rank: Newbie
timestamp: April 07, 2014, 02:19:08 pm
content: i have built a simple transfer switch for my rv with a 40 amp dpdt contactor relay to switch between my rv's generator and its inverter. problem im having is there seems to be a very slight switching delay which causes things like my computer to shut down during the switch. i would like to add some sort of time delay or buffer that would keep power to the load during the switch but im not sure where to begin. any suggestions? thanks everyone

author: ejeffrey
author_rank: Super Contributor
timestamp: April 07, 2014, 04:46:12 pm
content: Is it just the computer? If so, the easiest (and probably the cheapest) solution is to put the computer on its own small UPS. The UPS will switch fast enough to its internal inverter to avoid causing problems, and then switch back once the supply has stabilized.
Adding an LED power indicator to vintage circuit - Page 1
Forum section: electronics / projects

author: gkmaia
author_rank: Frequent Contributor
timestamp: May 18, 2019, 07:39:53 am
content: I would like to add an LED to a vintage circuit as an indicator it is powered on.My plan would be to add on a 12v rail that comes out of T1 pins 9 and 10.Add a couple resistor as a voltage divider to bring the voltage down. By my calculations I will get about 2.04v at the LED with the divider.Can someone with more experience let me know if its a good plan? Or any drawbacks of my idea with some viable suggestions?

author: StillTrying
author_rank: Super Contributor
timestamp: May 18, 2019, 09:10:00 am
content: "My plan would be to add on a 12v rail that comes out of T1 pins 9 and 10."There's already a LED there, or is that the one you've added.SuperBright LEDs are bright enough as an indicator at 2 or 3 mA, so you can connect them almost anywhere there's DC."Add a couple resistor as a voltage divider"A LED only needs one series current limiting resistor.The polarity of C104, C105 and D107 look the wrong way around to me.

author: gkmaia
author_rank: Frequent Contributor
timestamp: May 18, 2019, 09:18:31 am
content: The LED you see is the one I added.That rail runs 12v. My LED runs 2.5v. Without a divider I may end up burning it or not?Yes, they were wrong. Just fixed it thanks.

author: Benta
author_rank: Super Contributor
timestamp: May 18, 2019, 09:25:08 am
content: You mention that is's vintage eq. In that case, I'd install a neon lamp across the 240 V line (don't forget a series resistor). Much easier.

author: pwlps
author_rank: Frequent Contributor
timestamp: May 18, 2019, 09:53:21 am
content: Quote from: gkmaia on May 18, 2019, 09:18:31 amA LED is a diode: you drive it with a constant current, not voltage. Just put a resistor in series, for example to get 10mA it will be (12V-2.5V)/10mA that is around 1k.

author: gkmaia
author_rank: Frequent Contributor
timestamp: May 18, 2019, 10:25:35 am
content: Went with a neon as per L101. Thanks for the tips!
Adding Aux input to solid state guitar amp - Page 1
Forum section: electronics / projects

author: ccnw
author_rank: Newbie
timestamp: May 25, 2017, 05:52:44 am
content: I'd like to tap in just before the TDA2030H power amp chip to insert backing tracks from a phone or mp3 player. (Amplifier schematic attached) From what I understand I could insert a resistor in the existing preamp line and place a similar resistor in line with the additional incoming line, tie them together and send them into the existing power amp input, creating a summing point Just a guess from what I understand and can google. Are the resistors actually necessary or could I just put a healthy sized cap in the incoming and line and hack it in? The other alternative I'm wondering about would be to bring the auxiliary input in at the negative input (labeled input 2). Might this work? Please school me here. Thanks!

author: P90
author_rank: Frequent Contributor
timestamp: May 25, 2017, 07:53:37 am
content: Another option would be to get a multieffects pedal, such a a zoom g1on and plug into the built-in aux jack...

author: ccnw
author_rank: Newbie
timestamp: May 25, 2017, 04:39:54 pm
content: Thanks, but in this case I'm trying to go minimalist and not bring out anything from my typical overstuffed "gear closet".
Adding Bluetooth 4.0 to your Arduino Project [IoT] - Controlled by Smartphone - Page 1
Forum section: electronics / projects

author: IoTaLabs
author_rank: Newbie
timestamp: January 03, 2016, 05:57:21 am
content: I noticed a lack of proper documentation on this subject as I was messing around with BLE in the past. I made this guide to help other people out. For some reason it seems BLE hasn't quite gotten the love it deserves. Let me know if it's useful!http://doteverything.co/blog.html
adding bluetooth audio to my pioneer amp/tunner - Page 1
Forum section: electronics / projects

author: m3vuv
author_rank: Super Contributor
timestamp: September 06, 2021, 08:17:13 pm
content: Hi all,i have an old pioneer tuner/amp unit,also have some hc05 is it bluetooth moduals,i just wondered if it would be a big job to add a bt modual to it so i can stream stuff from my ipod or phone to it,just wondered whats involved like adc dac etc.

author: David_AVD
author_rank: Super Contributor
timestamp: September 06, 2021, 08:31:37 pm
content: The HC05 is a simple serial BT module so not suitable.You can buy BT audio receivers cheap that will plug into a spare aux input on the receiver.
Adding C-Wire to OLD system (without modern circuit board) - Page 1
Forum section: electronics / projects

author: ITSecGuy
author_rank: Newbie
timestamp: December 10, 2017, 11:15:02 pm
content: I've seen a couple of discussions on this subject, but my greatest challenge is that I don't have a modern circuit board on my HVAC... I share with you the same silly question I PM'd to someone, with the hopes that you someone might be able to talk to me like I'm stupid while also helping to construct a solution that doesn't include a new HVAC unit...Fair warning: I rocked out of electronics school after Ohm's law, so I know enough to be dangerous, but not much more than your average idiot at Home Depot.I have an old system - it doesn't even have a circuit board (at least not one that is easily recognizable). I am trying to add a common-wire to it (it's worth noting that the thermostat is on the other side of the wall from the air handler, so if it's possible to do this without the Venstar gadget please let me know)Right now - I've rigged my thermostat to use the Emergency Heat (which my unit does not have) as the "C" wire. Which worked just fine for the past seven months while the AC was on... but now that the heat is on, my thermostat resets every time it tries to draw power (every few minutes). It should be noted that I don't want to run it off the compressor as I don't want to create an Energy Vampire, or put undue stress on an older system.I've attached the diagram of the air handler. I suspect that giving you this challenge would be like someone asking me to fix their computer (which I love to do), and I greatly appreciate your help/assistance!https://drive.google.com/open?id=104N3e1Yhn5IePzj6kXeQOt5caJnuJHAc

author: ajb
author_rank: Super Contributor
timestamp: December 11, 2017, 02:37:31 am
content: On that diagram the blue wire is the common wire. You might just need to pull an additional wire from the air handler to the thermostat.