hybridfree/eevblog-posts huggingface dataset:
Sensing mains input current in offline SMPS - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: July 21, 2018, 11:06:23 am
content: Hello,We sometimes monitor the input current to our offline SMPS’s by using a diff probe and scope to observe the voltage across a sense resistor at the input to the SMPS (as in the attached diagram).Why is it that the reading is always more noisy (and this is seen as ‘more ‘fuzz’ on the scoped waveform) when the sense resistor is placed in the Live line as opposed to the Neutral line?

author: Gyro
author_rank: Super Contributor
timestamp: July 21, 2018, 11:25:03 am
content: Neutral, being near earth, making less demands on the probe's CMRR?Either that or the parasitic capacitance between your circuit and ground (bench?) is providing some HF filtering.

author: dmills
author_rank: Super Contributor
timestamp: July 21, 2018, 11:52:54 am
content: Seems likely, UK practice has the neutral bonded to earth (In most installations) at the supply company terminal, so while this is not to be relied upon there will usually be less common mode voltage measuring in the neutral.Regards, Dan.

author: ocset
author_rank: Super Contributor
timestamp: July 21, 2018, 01:45:51 pm
content: Thanks,If the sense resistor is placed just downstream of the mains rectifier bridge, (as in the attached schamtic) then it shouldn’t matter whether the sense resistor is placed in the [DC Bus –ve] or the [DC Bus +ve]. Either place should be equal from a noise point of view, since each node alternately connects to mains live then mains neutral.However, even in this case, I always seem to see less noise when the sense resistor is connected into the [DC Bus –ve]. Do you know why?
set transistor bias - Page 1
Forum section: electronics / beginners

author: Axtman
author_rank: Regular Contributor
timestamp: May 03, 2025, 10:26:20 pm
content: I currently repaired a Randall RB100 bass amp. This amp uses two MJ15003 NPN output transistors with 0.6 ohm emitter resistors. I have not been able to locate the schematic diagram. How do I set the transistor bias? Thanks.

author: Xena E
author_rank: Frequent Contributor
timestamp: May 03, 2025, 11:42:13 pm
content: Service information available for download from Electrotanya web site.The bias adjustment is performed with the 250Ω pot
setpper motor - Page 1
Forum section: electronics / beginners

author: abdullahseba
author_rank: Frequent Contributor
timestamp: April 17, 2014, 10:32:05 am
content: is there a stepper motor controller that has a switch for making the motor going forwards & backwards without using any programing

author: Simon
author_rank: Unknown
timestamp: April 17, 2014, 10:41:59 am
content: You mean you want a forward / reverse pin ? yes I think they do many of them. The pin can be brought high or low by am MCU or a simple switch.

author: GeoffS
author_rank: Unknown
timestamp: April 17, 2014, 10:44:35 am
content: Most stepper motor drivers have STEP, ENABLE and DIRECTION lines as input.More detail of your intended application may help.

author: poorchava
author_rank: Super Contributor
timestamp: April 17, 2014, 01:24:02 pm
content: Stepper motors are typically used when positioning is needed. If you only need to spin motor forwards and backwards, perhaps you should pick a normal DC motor?

author: Witention
author_rank: Contributor
timestamp: April 28, 2014, 10:43:47 am
content: I assume that the stepper motor has gears that reduce the 45 degree movement of the armature to only 1.8 degrees of movement on the drive shaft.The gear down ratio is 25 to 1, amplifying the drive force between 20-25 times - including friction loss. Am I correct??

author: tjb1
author_rank: Regular Contributor
timestamp: April 28, 2014, 11:18:50 am
content: Quote from: Witention on April 28, 2014, 10:43:47 amNo, they work with magnetics.

author: Kremmen
author_rank: Super Contributor
timestamp: April 28, 2014, 12:00:11 pm
content: Quote from: Witention on April 28, 2014, 10:43:47 amLike tjb1 stated - no gearbox. The most common type i.e. variable reluctance motor has both rotor and stator equipped with protruding square teeth (looknig along the motor axis). The number of teeth is different such that when one phase the stator coils are energized, say A, some teeth align providing a minimum reluctance magnetic path through the rotor. When the next phase B is then energized, a successive set of teeth is puuled into alignment causing torque on the motor shaft. Next reverse energize A and you get the next step and so on and so on. The number of teeth is cleverly calculated to provide just the desired angular displacement per step.Read alla bout it here:http://www.pcbheaven.com/wikipages/How_Stepper_Motors_Work/?p=0

author: poorchava
author_rank: Super Contributor
timestamp: April 28, 2014, 12:42:42 pm
content: Quote from: Witention on April 28, 2014, 10:43:47 amWhat you are referring to is called 'a servo'. It's typically a motor with a gearbox, an encoder and a position controller. Type of controller and motor vary. RC servos typically swing within limited range and are driven by pulse train with constant frequency and variable on-time. Industrial servos can typically spin around like a normal motor and they utilze wide variety of motors: DC, AC, brushless. Other types too, but more rarely.
Settable Hysteresis in this example - Page 1
Forum section: electronics / beginners

author: alank2
author_rank: Super Contributor
timestamp: October 05, 2015, 02:58:40 am
content: I've been playing around with a MAX997 as an input stage to a frequency counter. I used a pot to set a trigger point and fed that to the - input and fed the signal t the + input. This works pretty well, but I wondered - can you use a dual version MAX962 to be able to set both an upper trigger and a lower trigger? What type of circuit could accomplish that? If you just doubled the single example and had a pot for each comparator and fed the input signal to both + inputs, then the outputs might be:HHLHHLLLHH you would want to be high, LL you would want to be low, but you would want LH or HL to remain unchanged. What type of circuit would accomplish that taking the two comparator outputs and turning them into a single one?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 05, 2015, 03:33:00 am
content: Take a look at the internal diagram of a 555. It's a window comparator, but instead of wired-OR outputs, an RS f/f is used to provide hysteresis.If you like threshold +/- (hysteresis band)/2 better, that can be done with a traditional bistable multivibrator (which might be what you have already?) where the +FB resistor is adjustable.Tim
Setting a logic output high (or low) depending on presence of a sine(ish) wave - Page 1
Forum section: electronics / beginners

author: Infraviolet
author_rank: Super Contributor
timestamp: March 13, 2022, 02:52:07 pm
content: I've just been contemplating about circuits to take an analogue sine wave input and give an output of a low or high constant voltage depending on if it is present.I know one can use a peak detector circuit with a diode and op-amp, which charges a cap fast when the sine wave goes high, then discharges slow enough the the putput is still high by the tie the next sine peak comes along, but are there ways with less component count which would take up less board space? And without relying on any specific specialised IC which might suddenyl become impossible to source.Thanks

author: Ian.M
author_rank: Super Contributor
timestamp: March 13, 2022, 03:00:25 pm
content: DIY Vactrol?(grain of wheat bulb, a subminiature CDS photocell, black heatshrink and a little black potting compound to fill the ends)Edit: The disadvantage is of course if you need it to discriminate between AC and DC, as the high value non-polar series capacitor required to do so with a Vactrol is large and expensive.

author: IDEngineer
author_rank: Super Contributor
timestamp: March 14, 2022, 08:06:23 am
content: Schmitt Trigger driving a one shot.Or, analog comparator driving a one shot.Easy, simple, inexpensive, bulletproof.Edit: There may be one shots with ST inputs, giving you a single chip solution with a few discrete to set parameters.
Setting the gain of an instrumentation amplifier to 1 - Page 1
Forum section: electronics / beginners

author: AQUAMAN
author_rank: Regular Contributor
timestamp: January 25, 2017, 04:25:40 pm
content: In a lot of instrumentation amplifiers it seems difficult to get the gain to equal 1 unless you have a 1Meg resistor for the gain setting, and even then its always 1.05 or something.I would like to use an instrumentation amplifier with a gain of 1.In the AD8429 datasheet,http://www.analog.com/media/en/technical-documentation/data-sheets/AD8429.pdf,it claims that by not using a gain setting resistor, that the gain will default to 1."The AD8429 defaults to G = 1 when no gain resistor is used.Add the tolerance and gain drift of the RG resistor to thespecifications of the AD8429 to determine the total gain accuracyof the system. When the gain resistor is not used, gainerror and gain drift are minimal."Has anyone any experience of this? I presume it means to leave both the terminals for the gain resistor floating.

author: tron9000
author_rank: Frequent Contributor
timestamp: January 25, 2017, 04:46:11 pm
content: well page 15 shows that:G= 1+ (6k/Rg)so if Rgis O/C (infinite) then G >> 1. or near as damn it.why is it vital that you get exactly 1 (0dB)?

author: AQUAMAN
author_rank: Regular Contributor
timestamp: January 25, 2017, 05:29:47 pm
content: Quote from: tron9000 on January 25, 2017, 04:46:11 pmI want it at 1 because its calculating power loss across a transistor

author: tszaboo
author_rank: Super Contributor
timestamp: January 25, 2017, 05:38:23 pm
content: Yes, you can just leave it "floating". Though it is not really floating, becuase it is driven internally through a resistor. This is also probably the most accurate way to do A+B-C calculation for analog voltages.
Setting the output voltage of SMPS using TPS62088 IC - Page 1
Forum section: electronics / beginners

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 02, 2025, 06:19:32 pm
content: I'm not clear what to set R1 and R2 to if I follow the datasheet. They say choose R2 that is 100K or less, ok, I get that. But in their example, if Vfb is set to 0.6 (taken as typical value from the table in the datasheet) and I want an output voltage of 0.6V, then R2 becomes 0. Is that correct?

author: benj38
author_rank: Frequent Contributor
timestamp: March 02, 2025, 06:36:17 pm
content: Quote from: newtekuser on March 02, 2025, 06:19:32 pmVfb is not exactly "set" to 0.6V. Inside the IC there is a reference voltage that is 0.6V, and the IC compares the value at the FB pin to this reference voltage. The IC increases/decreases theoutputvoltage to make the Vfb equal to the internal reference. Hence, if you want an output of 0.6V, you need Vfb to be equal to the output voltage, i.e., an R2 of zero ohms.There is nothing wrong with the equation in the datasheet: if you want 0.6V output, R2 is simply a short; lower output voltages are not possible, and for higher output voltages increase R2 according to the equation (e.g., for Vout=1.2V, R2=R1).

author: newtekuser
author_rank: Frequent Contributor
timestamp: March 02, 2025, 07:05:15 pm
content: Quote from: benj38 on March 02, 2025, 06:36:17 pmThanks!Didn't know that was possible (i.e.: having zero ohms in a resistor divider network, or not having an R2).
Setting up a scope for flyback measurements. - Page 1
Forum section: electronics / beginners

author: cs.dk
author_rank: Unknown
timestamp: July 02, 2017, 04:33:42 pm
content: Sorry, I know this may be so basic. But I can't get a flyback measurement.I took a relay without resistors or diodes in parallel. I can't measure any flyback, which wonders me. What am I doing wrong?The only spike my singleshot trigger captured was the powersupply turn on spike.Any hints? I have attached some screencaptures with rising and falling triggers.First two is powersupply turn on, just zoomed in/out.

author: Benta
author_rank: Super Contributor
timestamp: July 02, 2017, 05:50:30 pm
content: If you're just turning the power supply on and off, you're not going to see much. The output filtering and general low output impedance of the PSU will absorb anything the relay throws at it.You need to put the scope directly over the coil, and then turn it on and off with a switch to the coil.

author: cs.dk
author_rank: Unknown
timestamp: July 02, 2017, 07:24:30 pm
content: Quote from: Benta on July 02, 2017, 05:50:30 pmThanks - It was in my mind to put a switch in. But the scope should be fast enough to register an overshoot? Or what am I missing?.

author: Benta
author_rank: Super Contributor
timestamp: July 02, 2017, 07:51:00 pm
content: I already told you. The coil is still attached to the PSU output, which will kill the transient.
Setting up a scope in ungrounded environment - Page 1
Forum section: electronics / beginners

author: cte7ds
author_rank: Contributor
timestamp: November 12, 2012, 01:25:10 pm
content: I recently got a Rigol DS1052E and now I'm wondering how to wire it. I'm using 230VAC CEE 7/4 extension cords with protective earth tabs but they are connected to wall sockets that don't have protective earth tabs. So essentially all the gear in the lab is sharing a floating ground which has quite a bit of potential difference in respect to earth ground because of the filter capacitors that power supplies have.

author: Zero999
author_rank: Super Contributor
timestamp: November 12, 2012, 02:36:14 pm
content: Sounds dangerous.All exposed metal surfaces should be earth-bonded unless they have class 2 insulation.

author: c4757p
author_rank: Super Contributor
timestamp: November 12, 2012, 03:57:26 pm
content: Quote from: cte7ds on November 12, 2012, 01:25:10 pmTo ground. Please,pleaseground the lab.Quote from: cte7ds on November 12, 2012, 01:25:10 pmThis is not good.

author: david77
author_rank: Frequent Contributor
timestamp: November 12, 2012, 04:16:27 pm
content: Why are your sockets not grounded?Do yourself a favour and get an electrician in to fix that for you!

author: nanofrog
author_rank: Super Contributor
timestamp: November 12, 2012, 05:31:44 pm
content: Quote from: david77 on November 12, 2012, 04:16:27 pmLikely due to the existing wiring was installed before outlet grounds were mandated by code.Same situation in my current home, so I've added ground rods and GFCI's to get grounded outlets.
Setting up ESD workstation - Page 1
Forum section: electronics / beginners

author: 3rj4
author_rank: Regular Contributor
timestamp: July 13, 2020, 09:59:59 pm
content: I have just built a wooden workbench for my electronics workstation. I plan to drill thishttps://www.oritech.com.au/bench-mounted-grounding-fixture.html(1M resistance) into the bench, and connect it to the power outlet via thishttps://www.oritech.com.au/clipsal-esd-earth-plug.html.I will then connect my (1M resistance) wrist strap to this bench mount. As matting for the bench surface, I will use thishttps://www.oritech.com.au/dual-layer-esd-mats-techspec.html(recommended by Dave in one of his videos), which will require thesehttps://au.element14.com/desco/09864/universal-snap-mounting-kit/dp/4973501?MER=sy-me-pd-mi-alte, and will be attached to the bench mount. And since I am working with ESD sensitive devices such as laser diodes, I will also be using thishttps://www.oritech.com.au/esd-table-mat-with-ground-cord-techspec.htmlas an ESD floor mat, which I will also have to connect to the ESD bench mount.My problem at the moment is that the bench mount only has 2 banana jack spaces. However, between the wrist strap, the bench surface mat, and the floor mat, I need 3 jack spaces, right? So how am I to connect all of these correctly? I have been reading thishttps://www.rs-online.com/designspark/6-steps-to-choosing-and-installing-an-esd-working-surfacedocument, which contains thisimage. However, as you can see from the image, the bench and floor mats are actually connected to the ground separately, rather than through the bench mount (which presumably only contains the wrist strap). So how exactly should I go about setting all of this up?I would greatly appreciate help with this.

author: 3rj4
author_rank: Regular Contributor
timestamp: July 13, 2020, 11:38:56 pm
content: Thishttps://blog.correctproducts.com/2015/12/11/how-to-set-up-an-esd-workstation/blog has thishttps://correctproducts.files.wordpress.com/2015/12/esd-workstation-set-up.jpgimage. This seems to imply that I can attach the wrist strap and bench mat to ground via the bench mount, and then attach the floor mat to the grounding plug directly via thishttps://au.element14.com/desco/14213/cord-kit-common-point-ground-10mm/dp/5808406. Would this be acceptable?
Setting up experiment problem-No Waveform - Page 1
Forum section: electronics / beginners

author: gotwood
author_rank: Contributor
timestamp: May 08, 2013, 11:53:42 pm
content: I need a 10 mV AC supply for an amplifier circuitMy function generator only goes down to 100mV pp.I figure I would use resistors as a voltage divider or a variable pot.Well, the bigger problem is my Agilent 54645D Mixed-Signal Oscilloscope is not reading a sine wave at that low of an amplitude.Any ideas of what I could be doing wrong?I've only had 2 resistors or the variable pot hooked up to the FG.And the oscilloscope hooked up at the same ground and divider junction.Forgot to add.....1KhzPot is 5K ohm

author: croberts
author_rank: Regular Contributor
timestamp: May 09, 2013, 12:15:00 am
content: You probably want to use a 1x probe (not 10x)?

author: gotwood
author_rank: Contributor
timestamp: May 09, 2013, 12:21:32 am
content: I'm using some mini grabbers...pamona brand

author: croberts
author_rank: Regular Contributor
timestamp: May 09, 2013, 12:28:45 am
content: How are you connecting those to the scope BNC connectors ?

author: gotwood
author_rank: Contributor
timestamp: May 09, 2013, 12:32:14 am
content: Yes, they are purchased as such

author: croberts
author_rank: Regular Contributor
timestamp: May 09, 2013, 12:45:12 am
content: Can you provide a schematic of your test set up? What exactly are you seeing on the scope screen? A straight line or no line. Are you AC or DC coupled?

author: gotwood
author_rank: Contributor
timestamp: May 09, 2013, 12:56:19 am
content: Both couplings look the same......not sure how to describe except looks like bunch of lines packed together with intermittent spikesGround|. |FG 100 mV pp Oscilloscope|. |R1. R2. -ground
Setting up Flir e4 wifi - Page 1
Forum section: electronics / beginners

author: p38vtol
author_rank: Newbie
timestamp: April 09, 2018, 12:48:26 am
content: I'm new to the site and also to these cameras I've looked on the site to try to find the info I needed and strangely couldn't find it so I need to ask where I should look for the full instructions on using the wifi in it.As I say I'm a newby so if anyone could explain the process or any extra software I need I'd appreciate it.Also the best place I might be able to find the answers for further missions?

author: p38vtol
author_rank: Newbie
timestamp: April 09, 2018, 12:53:59 am
content: I forgot to mention it has been updated to e8 version

author: p38vtol
author_rank: Newbie
timestamp: April 10, 2018, 07:08:39 am
content: Although I haven't learned how to do it yet I did locate the manual online, can't believe there was nothing in my package , I had believed none of the cams had come with a manual or disk ?By chance anyone know if 2 batteries would normally be in a new Flir 4 package ?I got cam, 1 battery a usb cord and assorted plugs for different voltages.
Setting up triggers - Page 1
Forum section: electronics / beginners

author: eTobey
author_rank: Super Contributor
timestamp: April 16, 2024, 12:06:09 pm
content: I was about posting here to get help to set this up, but then it dawned on me. But i think it may help others too, so i post it anyway.I started to write two words, but then i thought: "Wait a minute... could it be, that...". And yes, sure enough it was (again) that the trigger level was at zero. The thing that got me confused was, that it triggered well with other settings of the pulse trigger, but it did not so with negative pulse trigger when between two values.It may be a bit embarrassing, but if it helps others, i am fine with thatThe followong may only apply to siglent SDS800 series:I like to mention, that after a scope restart, trigger levels of channels that were not active in that particular trigger, are set to zero if activated.

author: Psi
author_rank: Super Contributor
timestamp: April 16, 2024, 12:16:07 pm
content: Quote from: eTobey on April 16, 2024, 12:06:09 pmThe trigger system on scopes can be quite confusing sometimes.Not confusing in what it does, or the trigger settings, but confusing in the odd behavior you often see because behind the scenes it's doing some pretty complex stuff, or some pretty hacky stuff, or both.
Setting up simple wireless moduals to arduino - Page 1
Forum section: electronics / beginners

author: Beamin
author_rank: Super Contributor
timestamp: November 05, 2017, 01:20:56 am
content: I'm going off this video to start. I noticed he has uarts connected. Is he doing this just to see the data easier on the computer? He says you don't need them. What I want this device to do is blink 4 leds sequentially so I can see the signal is being sent from tx to rx. I'm going to try putting 1/4 wave antennas on these little things which will look ridiculous but I just want to experiment with antennas.Will the arduinos do the Manchester encoding with the library? So I just connect one data pin?https://youtu.be/txSrx5druXgAlso when hooking up the antenna can I hook the outside of the shield to the GND pin on the unit? Or is that not an RF ground? The units have solder points for a simple wire antenna and I want to hook up 75 ohm coax.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: November 05, 2017, 09:18:20 am
content: Seen this ?https://youtu.be/3Rs3SJBsiYE

author: Beamin
author_rank: Super Contributor
timestamp: November 06, 2017, 01:25:28 am
content: Yes I did. I'm trying to figure how I can just use one gpi/o pin to feed and read each modual. I think in the first video he has soe go into a uart.I really just want the led to blink on the other Arduino if its getting a signal at this point.

author: Beamin
author_rank: Super Contributor
timestamp: November 06, 2017, 01:30:24 am
content: Code:Well my lap top just stopped letting me copy and paste. Never seen that before. This is going to make things hard. Very hard. :wtf:....

author: Beamin
author_rank: Super Contributor
timestamp: November 06, 2017, 01:32:56 am
content: Hmmm when I click the right mouse button it lights up the reload sign in ms edge and the keys start controlling things. WTF?I could right click and copy though just not for paste? No menu that grayed out just nothing.
Setting up phase data for calculating the Allan deviation - Page 1
Forum section: electronics / beginners

author: Masku
author_rank: Newbie
timestamp: January 20, 2019, 08:25:01 pm
content: Hi!I'm having a project where I'm measuring the concentration of carbon dioxide gas with an infrared sensor. I need to find the optimal averaging time for the signal, the one that minimizes the Allan deviation. I have a code that calculates the (overlapping) Allan variance using this formula:sigma^2 = 1/(2*n^2*tau^2*(N-2*n)) * sum_(i=0 to N-2*n-1) (x_(i+2*n) - 2x_(i+n) + x_i)^2),where N is the number of data points, n is the averaging multiplier, tau is the averaging time and x is the phase data pointHowever, I'm not sure what I should use as phase data. The signal is a time series of ppm values - should I transform it into radians somehow, like defining the minimum as 0 and the maximum as 2pi? Or could the raw data be passed as "phase"?

author: iMo
author_rank: Super Contributor
timestamp: January 20, 2019, 08:38:31 pm
content: Try to play with TimeLabhttp://www.ke5fx.com/timelab/readme.htm

author: awallin
author_rank: Frequent Contributor
timestamp: January 21, 2019, 06:02:01 am
content: Quote from: Masku on January 20, 2019, 08:25:01 pmwhen 'misusing' ADEV (and similar) for other things than time/frequency you almost certainly want to use your measurement data as frequency data.so either convert your measurements to 'phase' bydifferentiatingintegrating - and use the phase ADEV formula.or use your measurements directly as 'frequency' - and a formula for ADEV that takes (unitless) frequency.whether you want to normalize your measurements (divide by the mean) or not can be discussed... usually in time and frequency the frequency is always normalized before calculating adev.allantools is a python library for this, if you don't want to use the free windows-binaries available (timelab or stable32).
Setting up Tune Voltage Circuit - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: December 03, 2018, 09:18:46 pm
content: Hi All,I am controlling the tune voltage of an oscillator with a 16-bit PWM DAC out from Arduino (from the Lars DIY GPSDO project).My oscillator needs a smaller tuning range than 0-5V, probably 1-3V or less would be fine. The current tune voltage is about 2.1V. I figured I can wire the DAC out to a 10k trimpot (simulated R1-R4) and use the center tap to the tune pin to increase effective DAC resolution.Is there an equally easy way to improve noise and temperature stability? I was wondering if a 2.5V voltage reference could be easily used. I probably won't consider anything too complex, including op amps, etc.

author: David Hess
author_rank: Super Contributor
timestamp: December 05, 2018, 12:23:08 pm
content: Improving the noise will mean adding an active low pass filter and removing any ground loops. Improving the temperature stability will require a stable reference, stable gain, and stable offset.Potentiometers do not make good precision voltage dividers; a pair of precision resistors should be used instead.A great improvement could be made by doing the PWM switching closer to the oscillator with the 2.5 volt reference but it would require an analog switch or logic gate.
Setting up USB Eye Diagram - Page 1
Forum section: electronics / beginners

author: caliper15
author_rank: Contributor
timestamp: April 23, 2013, 06:53:08 am
content: I want to check the signal integrity of the USB signals on my board using an oscilloscope but I'm unsure on how to go about testing it.Would I need a third party software to generate a test signal?

author: amyk
author_rank: Super Contributor
timestamp: April 23, 2013, 07:01:00 am
content: http://www.usb.org/developers/docs/#comp_test_proceduresDo you have one of those scopes listed? Then you can just follow the test procedure there.

author: caliper15
author_rank: Contributor
timestamp: April 23, 2013, 07:33:12 am
content: Quote from: amyk on April 23, 2013, 07:01:00 amUnfortunately I don't have any of the scopes listed. It also seems like I need Matlab..
Setting Vmax of AP3032 LED driver? - Page 1
Forum section: electronics / beginners

author: Pugbutt
author_rank: Contributor
timestamp: April 24, 2016, 04:58:26 pm
content: Hi Everybody.I'm wanting to use a Diodes Incorporated AP3032 LED driver in a design. (http://www.diodes.com/_files/datasheets/AP3032.pdf) The datasheet says that, by default, you can just hook the OV pin to the output to set the max voltage to 27V. The example schematic though shows a voltage divider there though, and the resistors are unlabeled. This implies a variable setting to me, but there is no more detail given.A similar (but much more expensive) part is a Linear Technology LT1618. (http://cds.linear.com/docs/en/datasheet/1618fas.pdf) They have a pin serving the exact same function, and they were nice enough to specify the relation between divider ratio and cutoff voltage.Does anyone see how I can set a specific cutoff voltage on the AP3032? 27V feels way too high for my application. I'd rather set ~5V.Thanks,Craig

author: michaeliv
author_rank: Frequent Contributor
timestamp: April 24, 2016, 06:07:37 pm
content: If you connect the OV to the output and get 27V, any voltage divider will only increase the maximum voltage.I guess the only way to know for sure is to see what happens if you connect OV to output directly.A work-around is to trick the current feedback with a resistor divider and a extra schottky diode, like attached. You do the math for the resistors.

author: Kilrah
author_rank: Unknown
timestamp: April 24, 2016, 06:42:29 pm
content: Quote from: Pugbutt on April 24, 2016, 04:58:26 pmYou're probably looking at the wrong chip then - as mentioned in the datasheet this one is specifically intended for driving 7 white LEDs in series, so around 20-25V output.
Settings for 861DW rework station? - Page 1
Forum section: electronics / beginners

author: ryanmills
author_rank: Unknown
timestamp: July 11, 2019, 07:53:38 pm
content: Any guidance on the settings for a Quick 861DW? I heard around 200 for solder paste but I'm having to use it around 300 with the air speed at 40? I'm using MG Sn63/Pb37.

author: thinkfat
author_rank: Unknown
timestamp: July 11, 2019, 09:27:35 pm
content: I don't have the same hot air station, but on mine I usually go for 270-300 for leaded paste. No idea about the airflow, I set it so that no parts fly off the board.Gesendet von meinem Nokia 6.1 mit Tapatalk
Settings for Sealed Lead-Acid on Imax B6AC? - Page 1
Forum section: electronics / beginners

author: FrankE
author_rank: Regular Contributor
timestamp: March 04, 2018, 12:23:52 am
content: I got myself a genuine IMAX B6AC v2 last week to try and recover my Makita batteries.That done, I'm going through my Yuasa, Yucel and other sealed lead acid stock 3.2Ah up to 17Ah.I've got a LA charger but it's 10A which I have a gut feeling is too high for smaller SLAs.What settings does one use on the Pb programme for sealed lead acid.It asks to input the Current (0.1A increments up to 6A) and Voltage (obviously the battery voltage)What does one set the current at on a Pb relative to the battery Ah capacity?

author: helius
author_rank: Super Contributor
timestamp: March 04, 2018, 12:40:34 am
content: Assuming your SLAs are the compact 6V type, the voltage setting would be 7.38 (plus 0.015V per degree C below 25°C). You can charge an SLA at a rate of 6C or more (so, 18A for your 3.2Ah) as long as the battery is balanced. If the balance is not known it's safer to charge at a lower rate like C/3 and then seeing if the battery reaches the expected voltage endpoint with a load test.

author: FrankE
author_rank: Regular Contributor
timestamp: March 04, 2018, 12:48:27 am
content: Sorry, it asks for nominal voltage which the settings menu expresses as 12.0V(6P)My batteries are all 12V nom except one 6V nom.Still 1/3C to 6C?

author: floobydust
author_rank: Super Contributor
timestamp: March 04, 2018, 02:34:16 am
content: Quote from: helius on March 04, 2018, 12:40:34 amI think 6C is very high and too aggressive? I would first check the battery manufacturer's datasheet. It's just there's no temp sensor on the battery if anything goes wrong.For datasheets, I found some AGM can take higher rates 3C, but not older SLA's which must be what I am used to at C/3.

author: FrankE
author_rank: Regular Contributor
timestamp: March 05, 2018, 06:33:55 am
content: Well that was a bit of a waste of time. The Yuasas are still holding their charge after ages in storage and are load-testing fine.

author: paulca
author_rank: Super Contributor
timestamp: March 05, 2018, 09:54:49 am
content: My Yusa deep cycle SLA quotes about 1/3C as max charge rate. It's 26Ah and quotes 6.5A as max current.If the charger is asking for the nominal voltage that would mean it will manage boost, cycle and possibly equalisation. Unless you change those settings be aware they are often different for different types of LA battery. Flooded cell often accept up to 15V boost, 14.4V float where as SLAs are sometimes lower at 14.5V boost, 13.8V cycle or similar.Sometimes these settings are hidden in the preference menu.
Seven Segment LCD Reflector Type - Working Principle - Page 1
Forum section: electronics / beginners

author: 2X
author_rank: Frequent Contributor
timestamp: May 13, 2025, 08:56:34 pm
content: Hi,from the below post where I found it says:"So, the dark segment where the eye see is the shadow on the reflector sheet which is created because of the light blocking by the rear polarizer?"I have the same query about how why see tha black segment. When the segment is engaged and the ambient lightis not polirized 90 degreesthe reason we see the black colour it is because the light is absorbed from the rear panel and not because we see the shadow on the reflector sheet which is created because of the light blocking by the rear polarizer?Source 1:https://electronics.stackexchange.com/questions/736835/seven-segment-lcd-reflector-type-worksSource 2:https://www.smorescience.com/how-do-we-see-colors/
Several devices on same I2C bus - Page 1
Forum section: electronics / beginners

author: Yaroooo
author_rank: Regular Contributor
timestamp: October 22, 2019, 04:07:50 pm
content: I've a question about level-shifting using mos. In my case I've several my devices that works at 3v3 and communicate between them using I2C bus. I must modify my board to communicate between them, but allowing to connect external boards (not from me) that use 5v as voltage level.Schematic will result like this:I'm sure I'll not have problem to interface 3v3 and 5v.With two 3v3 I'll have something like this:It should work with same principle. Can someone just check and (in case) confirm?

author: magic
author_rank: Super Contributor
timestamp: October 22, 2019, 05:00:41 pm
content: I think it would work, even without 5V pullup on the middle segment, as drawn. Maybe try in in SPICE or on breadboard to be 100% sure.But it's more complex than it needs to be. You can use one 3.3V bus segment for all the on-board devices and add just one level shifter to bridge with the 5V system.

author: Yaroooo
author_rank: Regular Contributor
timestamp: October 23, 2019, 07:59:50 am
content: Thanks for your answer. This 5V devices are already commercial boards with a connector on them, I can't modify them. On other side, create a special adapter will add additional logistic complexity and cost.

author: aries1470
author_rank: Regular Contributor
timestamp: October 24, 2019, 01:59:46 am
content: Hi,Have you looked at the i2c level shifters?They are small and cheap. You can have all the 3p3V ones on one side and the 5V on the other?You can use as many of either one before and after the shifter.I have attached a rather rudimentary drawing on how to do this and a couple of links to ebay for these devices, of which are fairly cheap too.Search for items on eBay - Australia:https://www.ebay.com.au/sch/i.html?_from=R40&_nkw=i2c+5v&_sacat=0&LH_TitleDesc=0&_sop=15https://www.ebay.com.au/itm/Two-Channel-5V-to-3-3V-TTL-I2C-IIC-Logic-Level-Converter-Bi-Directional-Module/262664199077?hash=item3d28019ba5:g:51sAAOSwZJBX-Ju8https://www.ebay.com.au/itm/2Pcs-4-Channel-IIC-I2C-Logic-Level-Converter-Bi-Directional-Module-5V-3-3V/301924606812?epid=778328238&hash=item464c1be35c:g:NvIAAOSw5VFWJwmjAll the best.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: October 24, 2019, 04:02:03 am
content: Look for something just like this:http://www.ti.com/product/PCA9306Level shifter IC for I2C.http://www.ti.com/product/TXS0102Bidirectional level shifter that's faster.

author: mikerj
author_rank: Super Contributor
timestamp: October 24, 2019, 08:23:48 am
content: Quote from: JustMeHere on October 24, 2019, 04:02:03 amNote that the TSX0102 level shifters take some liberties with the Vol levels that degrades noise immunity. The TI LSF0102 parts appear to be better in this respect.
SG marking on PCB component  - Page 1
Forum section: electronics / beginners

author: made2hack
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:13:30 pm
content: Hey all,What does SG mean on a component definition on a PCB?If R = Resistor, C = Cap, D = Diode, L = Inductor, what is SG?The component in question is cylindrical / axial about the size of a 0.5 W resistor, no bands, just pink bands over the transparent looking package?Sorry, I don't have a photo, if need be, will take one.

author: radioFlash
author_rank: Regular Contributor
timestamp: September 30, 2014, 05:27:24 pm
content: Perhaps spark gap? What kind of device is this component in?

author: made2hack
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:36:23 pm
content: It is in the beam circuitry from an old CRT Monitor.

author: SeanB
author_rank: Super Contributor
timestamp: September 30, 2014, 06:12:03 pm
content: Spark gap for sure then. Used to protect whatever silicon is driving the CRT if the tube flashes over for any reason. In many cases you find a regular neon lamp used in this application if the voltage is under 50V above the cathode voltage. You will often find the CRT base in colour sets also has a built in set of spark gaps on all electrodes, and very high voltage ones on the focus and A1 voltage connections, as they have up to 5kV on them.
SG3525 or KA3525 - Page 1
Forum section: electronics / beginners

author: Nickk2057
author_rank: Regular Contributor
timestamp: January 08, 2015, 08:14:52 am
content: I am trying to figure out of how i can make a inverter circuit with these SG3525 or KA3525 chips. i know it can be done since i took them out of old inverters and/or car amps.but how do they work? and how can i reverse engineer them to use as a homemade setup? what i want to do with them is to have them set up to run at 60Hz frequency.any ideas?Nick

author: jlmoon
author_rank: Unknown
timestamp: January 08, 2015, 05:00:06 pm
content: Nickkk,How about starting with a data sheet on that 3525, study the minimum and maximum ratings and the recommended operating conditions. 60hz "f_osc" is a tad below the minimum oscillator conditions.
SG3525 Oscilator current - Page 1
Forum section: electronics / beginners

author: aless2056
author_rank: Contributor
timestamp: May 30, 2021, 03:21:59 pm
content: Guys, just to be sure, since I'm not very familiar with the datasheet.Is the SG3525's oscillator current 5ma? Esyou thinking of using an AD5220 as RT, the maximum current of the variable resistance is 20mA?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 30, 2021, 03:47:27 pm
content: Even easier, just use a variable current sink. It doesn't need to be a resistor.Tim

author: aless2056
author_rank: Contributor
timestamp: May 30, 2021, 04:27:47 pm
content: I will use the AD5220 with RT and the CT will be a fixed value capacitor. I will use the AD5220 to vary the frequency of the PWM
Sg3525 PWM Output - Page 1
Forum section: electronics / beginners

author: mustafayilmaz
author_rank: Contributor
timestamp: August 02, 2024, 11:35:39 am
content: I will use this integrated circuit to operate a motor with a 5-6 ampere maksimum current. The motor belongs to a spraying machine used in agriculture.As far as I know, each output (Qa and Qb) can reach up to 50% duty cycle. For this reason, I am thinking of combining the outputs via a diode. Is there another method? I also want to understand whether a mosfet driver is needed. The pwm circuit will operate around 300-400Hz.Another question is that a tiny switch potentiometer will be used to turn this circuit on and off. Since the power of the switch will not be able to handle large currents, I am thinking of turning the integrated circuit on and off directly. The gate leg of the mosfet will therefore be connected to chassis with a resistor. The existing circuit was a 555 circuit and was working with a tiny pot. Will this cause a problem?

author: Andy Chee
author_rank: Super Contributor
timestamp: August 02, 2024, 01:08:14 pm
content: If you want 0-100% PWM duty cycle, you have selected the incorrect chip.A better chip would be IR2153.

author: David Hess
author_rank: Super Contributor
timestamp: August 02, 2024, 08:05:00 pm
content: Combining the outputs with two diodes or transistors will work, but then a driver might be required. The SG3524 has uncommitted outputs which can be combined directly in parallel.Quote from: Andy Chee on August 02, 2024, 01:08:14 pmThere is nothing wrong with combining the outputs to achieve >50% duty cycle, and it is even recommended in the application notes for this type of controller, although the SG3524 would be preferred.

author: Xena E
author_rank: Frequent Contributor
timestamp: August 02, 2024, 08:44:47 pm
content: Hi Mustafa.What about just using 2 mosfets each driven by its own Q output on the 3525 chip! Then parallel those to control the motor, they're cheap enough.If the control voltage is within the capability of the gate of the pass mosfets then all you will need is a small (series) gate resistor, say 68ohm to stop fault propagation.Just use your pot switch to switch the 3525, the power to the motor/mosfets need not be switched.RegardsX
Shaded pole motor - Page 1
Forum section: electronics / beginners

author: Wytnucls
author_rank: Super Contributor
timestamp: May 03, 2015, 10:28:51 am
content: 220VAC 50Hz shaded pole motor.I understand the principle of operation of the motor, but what seems strange is that I can generate a small AC voltage in the winding by turning the rotor by hand (15Hz 170mV).Any idea how this works?

author: Yansi
author_rank: Super Contributor
timestamp: May 03, 2015, 10:45:18 am
content: Simple. remanent magnetization trapped in the rotor.http://en.wikipedia.org/wiki/Remanence

author: SeanB
author_rank: Super Contributor
timestamp: May 03, 2015, 11:07:48 am
content: The same thing with the original car generator, where the remnant magnetism in the field winding is what starts the voltage generation when you start the car. This then gives the initial voltage required to pull in the charge relay to start charging the battery. That is why you have to briefly short the F terminal to battery positive when converting the car from positive to negative earth, otherwise it will start out with a negative voltage generated, and when the regulator connects it to the battery it will flatten it very fast.Also used with making 3 phase generators out of an induction motor, you typically will have to place a slight magnetic bias in the rotor by passing a high DC current through one winding if there is not already a bias present from manufacturing or use.

author: Wytnucls
author_rank: Super Contributor
timestamp: May 03, 2015, 11:38:43 am
content: Thanks. Doh, should have thought about it.Now I understand how this free energy works:

author: SeanB
author_rank: Super Contributor
timestamp: May 03, 2015, 11:50:54 am
content: Note where he brakes the rotors the light goes out just before. I will guess there are 2 48SWG wires leading off to the sodes to provide the AC power to the system, hidden by the low resolution camera and the background. Switch off then brake, and you can see the RHS stopping slower as it slips on the rubber band.Bet both of those shading rings were hot as well.You saw Dave in his unboxing video with the 2 steppers doing the same by connecting the stepper wires, to make a simple selsyn system.
Linear shafts and ballscrews in the UK - Page 1
Forum section: electronics / beginners

author: abdullahseba
author_rank: Frequent Contributor
timestamp: May 22, 2014, 02:13:22 pm
content: where can you get linear steel shafts & spiral shafts in for cnc applications the uk

author: roboticsound
author_rank: Newbie
timestamp: May 22, 2014, 04:58:53 pm
content: www.zappautomation.co.ukIt's a while since I used but they were pretty friendly and helpful

author: abdullahseba
author_rank: Frequent Contributor
timestamp: May 25, 2014, 08:07:55 am
content: Quote from: roboticsound on May 22, 2014, 04:58:53 pmits very cheep is there any hidden prices

author: GeoffS
author_rank: Unknown
timestamp: May 25, 2014, 08:26:17 am
content: Here's a good local site to get more info:http://www.mycncuk.com
Share a simple circuit...LED ON - OFF - Page 1
Forum section: electronics / beginners

author: SYOM
author_rank: Newbie
timestamp: May 13, 2025, 08:39:15 am
content: Completely beginner. If I'm missing anything or doing something wrong...

author: LazyDebug
author_rank: Newbie
timestamp: May 13, 2025, 09:05:39 am
content: Beware, you are creating a short circuit across the battery when pushing the button.

author: squadchannel
author_rank: Frequent Contributor
timestamp: May 13, 2025, 09:28:03 am
content: Check the datasheet for the tactile switch.(OMRON B3F clone)First, it is not a 2-circuit switch, it is a 1-circuit switch.you probably built when pushed, the switch disconnects and turns off the light. But to be precise, that when pressed, causes ashortcircuit that turns off the light.

author: JOSDHO
author_rank: Contributor
timestamp: May 14, 2025, 03:43:28 am
content: i think you are right, the led goes off because a short is created in the power rails. XDSimple fix tough, Cathode of the led directly to gnd, Anode of led to resistor, resistor to one leg of the button, other leg of the button to 9v and done.
Share any simple illustrations that are really help in understanding electronics - Page 1
Forum section: electronics / beginners

author: BravoV
author_rank: Super Contributor
timestamp: May 09, 2016, 04:42:22 am
content: While browsing for caps on the net, noticed how nice they made the illustration on the ESR and ESL of the capacitors with a glass vs bottle like below attached picture, I really like it, kudos to the creator.Wish I saw this when I was trying to learn and understand it long time ago.Post here if you think you have others that is good to help and visualize electronics subjects.At Taiyo Yuden MLCC caps portal ->http://www.yuden.co.jp/ut/solutions/mlcc/property/

author: tautech
author_rank: Super Contributor
timestamp: May 09, 2016, 05:31:46 am
content: One that SL4P found and stuck in this thread:https://www.eevblog.com/forum/beginners/ohms-law-the-lighter-side/

author: sjd.aliyan
author_rank: Contributor
timestamp: May 09, 2016, 08:44:30 am
content: I think this could help everyone!

author: paulhm81
author_rank: Regular Contributor
timestamp: May 09, 2016, 06:43:52 pm
content: I’m just going to leave this here
MCLK of I2S shared with multiple slaves, how to keep signal integrity? - Page 1
Forum section: electronics / beginners

author: hitech95
author_rank: Regular Contributor
timestamp: March 14, 2021, 01:57:54 pm
content: I have the following architecture on a project I'm creating:The source is bus master, the MUX and the AMP are slaves.Both the AMP (tas5731m) and the MUX (pcm9211) requires the MCLK clocks.The Mux also require an external 24.576Mhz clock. This can be provided by both a crystal or an external source.The i2s data source is in a baseplate and each baseplate have different slots for more AMP boards. (One source is a I2S ADC and the other is a USB CODEC)Right now the I2S busses of the baseplate have a buffer after the source to give the bus enought drive strength to all the slots. (there are 5 slots)The bus is series terminated and it should be 50 Ohm impedance matched.What would be the best way to archieve this?Would it be a good idea/easier to use a clock driver and share the 24.576Mhz clock with all the slot in boards intead of having a crystal on each board?For reference design I'm using:https://www.ti.com/lit/df/tidrt10/tidrt10.pdfhttps://www.ti.com/lit/an/scaa082a/scaa082a.pdfhttps://www.ti.com/lit/ds/symlink/tas5731m.pdfhttps://www.ti.com/lit/ds/symlink/pcm9211.pdf

author: hitech95
author_rank: Regular Contributor
timestamp: March 17, 2021, 10:46:00 am
content: Does someone have some info on PCB routing of I2S signals?

author: hitech95
author_rank: Regular Contributor
timestamp: March 22, 2021, 06:57:11 pm
content: No one?