hybridfree/eevblog-posts huggingface dataset:
Using an AWG to generate signal for an H-bridge driver - Page 1
Forum section: electronics / beginners

author: igo762
author_rank: Newbie
timestamp: January 31, 2021, 04:28:51 am
content: I would like to use the output from a function generator to supply a signal to an H-bridge driver. For example, the L297 driver requires two inputs, IN1 and IN2, where:IN1-high, IN2-low: ForwardIN1-low, IN2-high: Backward(high=5V, low=GND)Since the function generator has only one channel (OUT and GND), what is the easiest way to "split" its output OUT to get IN1 and IN2 that can both be low/high during one cycle?

author: ledtester
author_rank: Super Contributor
timestamp: January 31, 2021, 04:35:00 am
content: You could use a TTL or CMOS inverter gate.An NPN transistor configured as a logic gate inverter might also work:http://www.learningaboutelectronics.com/Articles/Transistor-inverter-circuit.phpThese days I'd juts use an Arduino -- it's a lot easier to create the exact signal waveform that you want.

author: ledtester
author_rank: Super Contributor
timestamp: January 31, 2021, 05:16:24 am
content: QuoteDid you mean the L298 instead of the L297?I've been researching what precautions should be taken to prevent shoot-through on the L298 and found this:https://forums.parallax.com/discussion/153464/l298-dead-timeand this for consideration during power-on and off:https://electronics.stackexchange.com/questions/368537/l298-data-sheetIn the Arduino libraries for the L298 there is no special timing code to sequence the transition between forward and reverse -- except that they use "digitalWrite()" which is very inefficient and can take upwards of 2 us to execute. Direct pin access would be able to switch the output of both pins in a couple of clock cycles.https://www.arduino.cc/reference//en/libraries/l298n/

author: igo762
author_rank: Newbie
timestamp: January 31, 2021, 10:28:18 pm
content: Correct, I did mean L298.Thanks for your reply - I will try the Arduino route. In terms of operating the L298 most efficiently/as fast as possible, is the library you mentioned (https://www.arduino.cc/reference//en/libraries/l298n/) the recommended one?
Using an Electronic Load to measure a power supply with negative output - Page 1
Forum section: electronics / beginners

author: 50aprojects
author_rank: Newbie
timestamp: April 30, 2018, 08:16:02 pm
content: Hi,This may be a really stupid question but how can you use an electronic load to test a power supply that has a negative output? We have a power supply with +12v, +5v, GRND, and -12v outputs and are using a BK precision 8601 electronic load to measure the current. Can we just hook up the + input to the GRND output of the power supply and the - input to the -12v for testing? Thanks!

author: Cerebus
author_rank: Super Contributor
timestamp: May 01, 2018, 02:15:14 am
content: You ought to double check that the electronic load is floating with respect to earth, but I would expect it to be. A simple continuity check ought to take care of that. With that proviso, yes, you should be able to wire it up the way you suggest.

author: edpalmer42
author_rank: Super Contributor
timestamp: May 01, 2018, 02:40:44 am
content: A quick check through the manual doesn't give any clues whether the negative input is grounded or not. If it was floating I would expect to see a maximum voltage rating between the load terminals and ground.I've seen one electronic load where a BNC monitor jack was isolated from the chassis. The chassis was grounded and the BNC jack was tied to the negative output. We put it on a -48V telco supply. You know the type. 48V of big lead-acid batteries. Short to chassis. Hilarity ensued. Luckily the BNC jack was the only casualty.Move carefully....
Using an LM2596 as a gate driver? - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: September 18, 2014, 06:01:57 pm
content: Would it be possible to use the output (pin 2) of an LM2596(S) through a dual latching, inverting/non-inverting gate driver IC to the gates of much more powerful FETs then put the standard diode/inductor/cap on the output of those fets with feedback from the output of this stage back to the LM2596 through the standard voltage divider? If so it seems a much simpler way to achieve high power output than some of the PWM controllers I've looked at. The LM2596 is very very simple and cheap as well compared to most PWM ICs which are very expensive and complicated.Would this be feasible or not, I'm probably missing something glaringly obvious.

author: planet12
author_rank: Regular Contributor
timestamp: September 19, 2014, 03:01:37 am
content: You can't really do it with this chip; the main switch is built-in, as is the current sense resistor. Trying to put an external switch on it, while "possible", is not going to work well at all - the current mode control loop will not function properly, and this will then break the built-in control loop compensation, likely leading to oscillation.By the time you finish mucking about with this and deciding it's not going to work acceptably well, you could have paid for and learned to use a modern SMPS controller with built-in gate drivers.Another option that you may want to consider - if your requirements are not too tight but your budget is - is to use a hysteretic controller such as the MC34063, which can be set up with an external switch, and get away with it due to the control loop technology in use.

author: Unknown
author_rank: Unknown
timestamp: September 19, 2014, 04:15:00 pm
content: Thanks, I'll investigate both options you mentioned.

author: David Hess
author_rank: Super Contributor
timestamp: September 24, 2014, 06:05:44 pm
content: Based on the LM2596 datasheet, it does not appear to be a current mode controller. Peak switch current is only monitored to implement a lower oscillator frequency at high currents and for cycle by cycle current limiting. The output current is never compared to the oscillator ramp.As far as your question Boltar, I think you could do this but I suspect there are better alternatives depending on what switching regulator type you are implementing. A boost regulator for instance can be used to drive a flyback transformer through a high voltage transistor cascode and keep all of its switch protection features like current limiting intact.
Using an N-Channel mosfet to control current in a regulated power supply - Page 1
Forum section: electronics / beginners

author: SharpEars
author_rank: Unknown
timestamp: October 21, 2016, 02:26:24 pm
content: Is the idea in the subject line sound? For example, let's say I want to accurately limit my power supply's current output to a range of 0-500 mA. If I use an N-Channel enhancement mosfet in its saturation region and vary Vgs with for example a DAC between the threshold voltage Vth and Vdd - X, where X represents whatever voltage will cause the current to be limited to 500 mA, I should be able to accurately control current for a load, assuming that Vds (i.e., the power supply output) is relatively constant.Is this sound?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 21, 2016, 03:10:02 pm
content: Using just the MOSFET curve to do current limiting gives a crude, not very accurate limiting of the current. Close to the maximum set current the voltage will already drop by something like 0.5 - 1 V. The current output for a given gate source voltage depends on temperature. So the current will depend on temperature.In case of a short the full voltage will be at the MOSFET and thus there will be quite some heat produced. No all MOSFETs can handle that, especially at higher voltages like 20 V. An MOSFET large enough to handle the heat can have quite a steep curve. So small changes in the gate voltage can change the current quite a lot. It will thus be difficult to get an accurate setting.

author: Kalvin
author_rank: Super Contributor
timestamp: October 21, 2016, 03:13:04 pm
content: Adding an op amp would give better current regulation. Here are some ideas:http://www.ti.com/lit/an/sboa046/sboa046.pdfSee section "Current Sources and Sinks and Current Mirrors Using an Amplifier and a Series Pass Element" on page 7 onwards.

author: SharpEars
author_rank: Unknown
timestamp: October 21, 2016, 03:50:51 pm
content: Quote from: Kalvin on October 21, 2016, 03:13:04 pmWow, thanks for that link. It's a treasure trove of ideas for current limiting...
Using analog switch for SPI MOSI signal - Page 1
Forum section: electronics / beginners

author: ieeeHuseyin
author_rank: Contributor
timestamp: May 15, 2024, 09:30:22 am
content: Hello,I am experimenting with RGB leds (like ws2815)I use SPI over RPI to control the RGB leds.I want to control two separate led groups.I had problems with SPI1.I am thinking of using SN74LVC1G3157DCKR to control two separate led groups with SPI0.The datasheet says it can be used with SPI.Is it a problem to use an analog switch for a digital signal?https://www.ti.com/lit/ds/symlink/sn74lvc1g3157.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1715693632860&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fsn74lvc1g3157

author: tszaboo
author_rank: Super Contributor
timestamp: May 15, 2024, 09:36:31 am
content: It's not an issue, you can do it. You can also use logic gates, but analog switches today are often times smaller and cheaper.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: May 15, 2024, 09:47:20 am
content: Most modern MCUs have several SPIs, it would be wiser to learn how to use them correctly.In addition, you can use the software SPI (serial out) on any pins.External switches will require control/selection, and this is the same output that can be used directly.

author: xvr
author_rank: Frequent Contributor
timestamp: May 15, 2024, 09:59:51 am
content: You could use this switch, but it worth to add pull down resistors to its outputs. Because when you switch one RGB string to SPI output other RGB string input left floating.PS. ws2815 can be cascaded without any switches. Are you really need a switch?

author: ieeeHuseyin
author_rank: Contributor
timestamp: May 15, 2024, 11:10:24 am
content: Quote from: xvr on May 15, 2024, 09:59:51 amI have shown the connection diagram below.The leds will be connected in two separate places.

author: ieeeHuseyin
author_rank: Contributor
timestamp: May 15, 2024, 11:12:59 am
content: Quote from: S. Petrukhin on May 15, 2024, 09:47:20 amI cannot use software spi because I am sending data at high speeds.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: May 15, 2024, 11:20:48 am
content: Quote from: ieeeHuseyin on May 15, 2024, 11:12:59 amThe SPI can adjust the speed.But that's not what I was talking about.You will need a pin that switches the transmission direction for the external switch.But you can leave the output for the first line of LEDs alone and output data there, and use the pin that should be used for switching in the same way for another part of the serial output.External switching makes sense when you have many directions and you choose them in binary code.
Using both lines on a MAX232 TTL->RS232 line driver simultaneously - Page 1
Forum section: electronics / beginners

author: Keex
author_rank: Newbie
timestamp: September 29, 2017, 07:40:17 am
content: Hi,I am currently building an application that interfaces two RS232 devices with an Arduino using the hardware serial ports and in my prototype I am currently using two individual TTL->RS232 converters. I need both to send to and receive from both of the devices.I now want to build my own version of the converters using a MAX232 chip, but I am getting a bit confused by the specifications. The package has two RX/TX lines, so on first glance it seems to me that I need only one of these chips to work with the two devices independently. However, spec lists of the chip say the following:Number of line drivers 1Number of Receivers per Line 1I am not experienced with the lingo involved, so this sounds to me that I can only use one device at a time. I can't find a clear statement anywhere if the two RX/TX channels of the MAX232 can be used completely independently from another.So to summarize the question: Can I use just one MAX232 to talk to two independent RS232 devices without interference or do I need two of the chips?Thank you.

author: newbrain
author_rank: Super Contributor
timestamp: September 29, 2017, 07:52:21 am
content: I don't know where you found that information, but thedatasheetclearly states that you have "Two Drivers and Two Receivers".No problems in using those for separate RS232 channels (I did)!

author: Kleinstein
author_rank: Super Contributor
timestamp: September 29, 2017, 07:57:28 am
content: Old style RS232 used extra handshake lines too. So they needed a second driver and receiver for a single RS232. However the extra Handshake lines are not always used. So the max232 is good for one channel with HW handshake or 2 channels with only rx/tx.

author: Keex
author_rank: Newbie
timestamp: September 29, 2017, 08:08:30 am
content: Perfect. That is the information I needed. Good to hear that you have used it yourself @newbrain, and thank you for the additional explanation @Kleinstein.
Using both switch-mode and linear supplies in one application. - Page 1
Forum section: electronics / beginners

author: medical-nerd
author_rank: Regular Contributor
timestamp: April 19, 2017, 08:54:42 am
content: HiyaAre there any problems that I should be aware of if I use both switch-mode and linear power supplies for one application or one board?I have a low noise switch mode supply for +/-12V 2A +/-5v 8A but a few items need in addition +24V or -24V which will be up to 1.5A for all of them - for which I plan to use a simple linear supply not supplied from the existing switch-mode.I'm using salvaged microwave/rf modules from the 80's that need the multiple voltages and don't want to release the magic smoke.Do I just connect all the 0V of the supplies? Can I assume that they will be at the same potential?CheersSteve

author: medical-nerd
author_rank: Regular Contributor
timestamp: April 19, 2017, 12:53:17 pm
content: Many thanks evb149 for your comprehensive reply.They are a mixture of circuit blocks on pcbs and separate shielded boxed modules.I like the idea of using multiple regulators to reduce the current in each - I certainly have enough to do this and will.I will work through your links this evening.CheersSteve
Using buck-boost converter as flyback converter? (XL6008 vs LM2588) - Page 1
Forum section: electronics / beginners

author: LinuxHata
author_rank: Frequent Contributor
timestamp: November 26, 2022, 09:33:57 pm
content: Hello.As old school IC's like LM2588, LT1370 and others are getting rare, expensive and less efficient, thinking about replacing them with something more modern, cheap, but still in beginner-friendly physical packaging.My task is to get from 5VDC input, 200VDC output at 20mA (4 watts).I have built such circuit with LT1370 or LM2588 and some Coilcraft transformers and they work just fine. But both components are quite expensive, so I'm thinking about going into cheap side. What about replacing LM2588 with XL6008 ? they both appear to have similar circuits in datasheet, so should work without any issues, but what are these CDC capacitors for XL6008? they needed for SEPIC operation? what if I remove them, since my Vout is always larger than Vin ?

author: m k
author_rank: Super Contributor
timestamp: December 03, 2022, 09:27:56 pm
content: Is your always a really always or just mostly always.
Using current-limiting resistor on Vcc pin of IC - Page 1
Forum section: electronics / beginners

author: coaxialgamer
author_rank: Contributor
timestamp: December 07, 2017, 08:49:39 pm
content: Couldn't find a clear cut answer when looking through google.Im using 74F ICs, and while i do know that you need to put pull down resistors on inputs, and that you should use current limiting resistors on inputs as well, according to datasheet. Should i use a resistor on the Vcc pin to keep the IC from burning up, or does it so that on its own?

author: hermit
author_rank: Frequent Contributor
timestamp: December 07, 2017, 08:54:38 pm
content: You should not need resistors on the power inputs. If they were needed the datasheet would have them listed/recommended. As long as you have the proper voltage you are good. The chip draws the current it needs.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: December 07, 2017, 09:00:23 pm
content: The above is correct. Also the "current limiting resistors" on the inputs are simply to protect against accidental over/under voltage. The IC has built in diodes to clamp inputs to the rails (inputs are not allowed to go more than one diode drop below ground or one drop above Vcc), but if you try to force the pin higher or lower with a low impedance source, you can burn out those diodes and damage the chip. The current limiting resistors prevent that, but unless you actually try to drive the pin above/below the rails, they won't really do anything.

author: Gyro
author_rank: Super Contributor
timestamp: December 07, 2017, 10:04:48 pm
content: It used to be common practice to put series resistors in the supplies of 4000 and 74C series CMOS devices in military gear 'back in the day'. These were to protect against latch-up during unpleasant events.These days CMOS logic devices are so resistant to going into SCR latch-up, due to excessive current on the inputs, that it's pretty much a non-issue. Series resistors to limit current on inputs that go external to the board or may exceed the supply rails are all that are that are needed. The Absolute Maximums section in the datasheet will give you the appropriate information.
Using voltage to current transmitter to ADC pin flawed? - Page 1
Forum section: electronics / beginners

author: Wize93
author_rank: Newbie
timestamp: March 31, 2022, 04:58:39 pm
content: Hello, my design consists of talking voltage signal and converting it into a current signal, and measuring a voltage drop across a resistor to read it into an ADC pin. My issue consists of output impedance, since it going to be high this not going to work I assume? To fix these issues I assume I have to put a voltage follower at the point where I measure my voltage? I would measure me I have attached my design, the application note, ADC pin internals below, and the datasheet for the xtr11m chip since the website is down?

author: mikerj
author_rank: Super Contributor
timestamp: April 01, 2022, 12:43:55 pm
content: You already asked this on your other post and got answers, what is the problem? The impedance seen by the ADC will be whatever the value of your sense resistor is.Also the schematic showing the potentiometer shows the +5v, 0v and ADC input all shorted together so that's not going to work.
Using cursors on a Scope - Page 1
Forum section: electronics / beginners

author: Bryan
author_rank: Frequent Contributor
timestamp: July 10, 2014, 05:26:23 pm
content: All:Okay, this may be a dumb question but just have to ask. When using cursors on a scope what is the correct way of aligning the cursor with the trace. It may be splitting hairs. But let's assume you have a completely straight horizontal trace on the scope. Would you align the bottom of the cursor to the top of the trace, or the top of the cursor to the bottom of the trace, or superimpose the cursor directly on the trace.Cheers

author: grumpydoc
author_rank: Super Contributor
timestamp: July 10, 2014, 06:08:19 pm
content: Superimpose the cursor on the trace

author: Bryan
author_rank: Frequent Contributor
timestamp: July 10, 2014, 08:22:35 pm
content: Thanks, much appreciated.
Using custom waveforms on an arbitrary waveform generator - Page 1
Forum section: electronics / beginners

author: jokkydee
author_rank: Newbie
timestamp: December 19, 2014, 03:09:16 am
content: I'm using a 4000 series Rigol arbitrary waveform generator. I have in excel, a normalised waveform of one period (=100 points) which I want to load into the arbitrary waveform generator and be able to adjust the frequency. Using Rigol Ultra Station, I try to create a new waveform, but it is set at 16383 points. How do I get my 100 point waveform to fill across one period for use in the arb generator? Do I need to scale it exactly to 16383 points in order to have my waveform repeat without a huge gap between each period?

author: HalfSpace
author_rank: Regular Contributor
timestamp: December 19, 2014, 09:51:46 pm
content: Hi jokkydee,I can’t help you with this but maybe asking the question under the Test Equipment section of this forum may get you an answer.HalfSpace
using DMM to trouble shooting electronic components - Page 1
Forum section: electronics / beginners

author: gowhar
author_rank: Newbie
timestamp: March 18, 2013, 06:56:34 am
content: Sir,your videos on EEvblog inspired me to go deep in electronics and in this regard i purchased a DMM Fluke 87 V to start trouble shooting common electronics around me. Now, my question is that i bought 3 laptop and earlier i have purchased 2 Desktop computers which i bought for my kids are now out of order. i just want to know how to check voltage etc on these computers and what ever i can check with my DMM to trouble shooting laptop motherboards with my DMM. i want to see it practically. if there is any video on this topic. i shall be highly obliged if you let me know.thanking you

author: dimlow
author_rank: Frequent Contributor
timestamp: March 18, 2013, 10:53:33 am
content: You will find we already answered your questionhere
Using ESP8266 with Google Home - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: May 14, 2019, 09:59:09 pm
content: I have a Google Home Mini, and I would like to use this:www.ebay.com.au/itm/ESP8266-ESP-01S-Serial-WIFI-Wireless-Transceiver-Module-Send-Receive-AP-STA/232741403454in combination with maybe a DHT11 to measure the temperature outside. I want to know whether this is possible, to configure the ESP8266 to appear to the Google Home as a temperature sensor (or another device, I'm kind of doing this as a learning exercise). My aim is to be able to ask the Mini, "What is the temperature outside", and it would tell me, getting the measurement from the sensor.While I'm here, what is the difference between a NodeMCU board and an ESP8266? Also, what's the difference between the ESP8266 board I've linked above, and this ESP8266?www.ebay.com.au/itm/Wireless-module-NodeMcu-v3-v2-ESP32-D1MINI-Lua-WIFI-development-board-WL/233208928513. This one says ESP32 in the title, but it looks physically different to the more expensive ESP32... Also, I'm assuming that everything I can do with the ESP8266, I can do with the ESP32?
Using fft on DSO - Page 1
Forum section: electronics / beginners

author: Dan Moos
author_rank: Frequent Contributor
timestamp: December 31, 2016, 09:08:13 pm
content: I have a Rigol 1052e. I have some questions on setting up my scope properly for fft.My biggest question is how to set the time base for the channel I'm running the fft on. It seems to me that I get better "looking" results with longer horizontal time per division on the scope channel. I also seem to get freq info lower than the fundamental with longer times.I guess I just don't know why that happens, so I don't know what the trade offs are with different time per division settings.

author: w2aew
author_rank: Super Contributor
timestamp: January 01, 2017, 05:25:11 am
content: Quote from: Dan Moos on December 31, 2016, 09:08:13 pmTwo things to keep in mind:1) the maximum frequency in the FFT is equal to 1/2 the waveform sample rate.2) the frequency resolution is inversely proportional to the time duration of the waveform recordThis video might help:

author: Dan Moos
author_rank: Frequent Contributor
timestamp: January 01, 2017, 06:05:13 am
content: Thanks! Btw, your videos have single handedly inspired me to tackle Rf duff for the first time. Thanks for the good work! I could fill a book with the questions I could ask in the matter. Perhaps you should write it!
Using FY3224 Signal Generator on Ungrounded Mains - Page 1
Forum section: electronics / beginners

author: quaternion00
author_rank: Contributor
timestamp: March 15, 2019, 07:34:57 am
content: Hi guys, i bought FY3224 signal generator recently. I read/watched that there is large AC voltage appearing between the ground andand the neutral.The mains in the house is not grounded, just two prong My question is will the problem appear even the mains is not grounded? Thanks.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 15, 2019, 08:25:47 am
content: The problem will be the same without a ground pin.The source is from small caps from the output ground to both lines of the mains input. These are kind of required to meet EMI requirements for a switched mode supply. So you should find this with many other parts, when there is no ground.So not have ground connection can cause a similar problem with other instruments too, that are normally grounded.

author: beanflying
author_rank: Super Contributor
timestamp: March 15, 2019, 08:41:05 am
content: There is a monster thread on the FY6600 herehttps://www.eevblog.com/forum/testgear/feeltech-fy6600-60mhz-2-ch-vco-function-arbitrary-waveform-signal-generator/msg1343235/#msg1343235There is some simple low cost fixes I did to mine to bring it under control over the next few pages. Basically Feelcrud now hiding under their new name of Feelelec still haven't sorted out their power supplies

author: quaternion00
author_rank: Contributor
timestamp: March 15, 2019, 12:31:28 pm
content: I read that one of the solution is to tie the ground of the bnc's to the earth ground. In my case, my mains is not grounded so I can't use that fix. Is replacing the switching power supply by linear supply the best solution in my case?I measured the voltage between either of the two main prongs and the bnc ground and its 92Vac. Is that a effect of switching power supply? Thanks in advance.

author: beanflying
author_rank: Super Contributor
timestamp: March 15, 2019, 12:44:17 pm
content: Depending on your setup can you pickup a metal waterpipe or drive an earth into the ground at a minimum? Not just for the Feeltech but for other gear and even your safety allowing Earthing of metal cases. You could look at a change of supply but a lot of the Chinese options are a crap shoot for where they sit.

author: quaternion00
author_rank: Contributor
timestamp: March 16, 2019, 11:47:23 am
content: How can i measure the leakage effects of the switching power supply? Where should i probe for leakage signals?Thanks .
Using Hakko 472B as regular soldering station - Page 1
Forum section: electronics / beginners

author: tino_so
author_rank: Contributor
timestamp: May 08, 2015, 05:53:45 pm
content: I recently acquire a couple of well used Hakko 472B Desoldering stations with one complete 807 Iron each (as per photo). They both seem to need new ceramic filters (S & L), new tips and so on.My question is, would any of the "knock-off" 5 pin regular Hakko irons sold on eBay work with this base? I mean just the iron, without the suction (e.g. similar to Hakko 907), so I could refurbish one for de-soldering and one for soldering?Thanks in advance,Tino

author: HalfSpace
author_rank: Regular Contributor
timestamp: May 08, 2015, 09:48:38 pm
content: Hi tino_so,If you only need one desoldering station then why not sell the other on ebay or where ever and with the money you get buy a good soldering station?HalfSpace

author: tino_so
author_rank: Contributor
timestamp: May 08, 2015, 11:24:33 pm
content: Hello Halfspace, I was thinking that at some point, I will have to sacrifice one to grab parts to fix the otherbut that is a good idea too.

author: tino_so
author_rank: Contributor
timestamp: June 11, 2015, 03:32:57 am
content: Well, after spending my $7 to get a Hakko 907 clone from the far east, I had a face palm moment shortly after plugging it to one of the Hakko 472B stations. Before turning the base on, I realized I could possibly fry this 907 iron if the pinout was not the same as the 807!!I had recently downloaded the 472B and 807 manuals and there was a pinout for it. Surely there would be a similar one for the 907, oh if I had only thought of that before ordering, or even before posting the initial message.Turns out the pinout for the 807 and the 907 are very different:807: 9.2 ohm between pin 1 and 3 (Heating element) and 54 ohm between pin 2 and 4 (sensor)907: 2.5-3.5 ohm between pin 4 and 5 (Heating element), 43-58 ohm between pin 1 and 2 (sensor) and under 2 ohm between 3 and the tip.So to answer my own question, I should read the manuals first then if in doubt post the question, and finally, no, the 5 pin Hakko 907 will not work as a replacement of the 807 iron on a 472B base, although it might after I re-solder the leads on the 907 to match the 807Update: scratch that, it really does not work even if tinkering with the leads.Cheers,Tino
Using K type probe with multimeter - Page 1
Forum section: electronics / beginners

author: sahko123
author_rank: Frequent Contributor
timestamp: May 20, 2021, 06:57:46 pm
content: I've recently got a k type thermocouple (namelyhttps://docs.rs-online.com/a128/A700000007069821.pdf) and have hooked it up to a Rigol DM3058E. I selected the KITS-90 setting in the sensors tab and get wildly out readings. Datasheet claims an accuracy of 1.5 degrees C and yet I'm reading around 10C in ice water. Am I doing something wrong with the probe or the measurement of the probe? I assume the KITS-90 standard is for reading k type probes. I also tried measuring the voltage output using the mV range and it read around -0.800mV in ice water.

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 20, 2021, 07:25:14 pm
content: It appears that the thermocouple isn't of the correct type. The ITS-90 with voltage of -0.778 is 10C which is what you got.
Using Kirchoff's Voltage Law to your advantage - Page 1
Forum section: electronics / beginners

author: Richardcavell
author_rank: Contributor
timestamp: May 16, 2024, 01:36:47 pm
content: Hi. I have been wondering whether it is possible to use KVL in this way:If I have a series circuit where there are a number of components in series, but the voltage drops are difficult to calculate, or variable, and I want to ensure what the voltage is at a certain node (perhaps to make sure that there is a certain voltage available at a part of a circuit), I could place at least two resistors parallel to this circuit as a voltage divider.I've drawn what I mean. Select A and B to ensure an adequate supply to the bottom two components.Richard

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 16, 2024, 03:05:10 pm
content: Let’s discuss the actual problem you’re attempting to solve, not your proposed solutionVoltage dividers are not power supplies. You reference/measure that voltage, not supply current to a device/circuit with that series chain. To supply current, you only need a single resistor, not a divider chain..

author: PlainName
author_rank: Super Contributor
timestamp: May 16, 2024, 03:16:52 pm
content: QuoteThe 'any components' will introduce a load in parallel to the resistors. Think of those 'any components' as simple resistors and you can see you can easily affect the junction voltage but changing one or more of the 'any components' apparent resistance. You will have two parallel strings of series resistors.If they are not simple resistors - for instance, LEDs or any component with varying current requirement - then it gets quite complex, but that makes it even simpler to see that your idea won't work

author: SteveThackery
author_rank: Super Contributor
timestamp: May 17, 2024, 09:11:08 am
content: Apparently you want to control the voltage at the mid-point (the junction of A and B) by choosing appropriate values for resistors A and B? For example, making them equal would set the mid-point voltage to 2.5V - is that the idea?It will only work if there is no current to or from the other half of the circuit (the four 'other components'). And the only time that will happen is when the mid-point isalreadyat 2.5V.Any current flowing in that horizontal wire - leftwards or rightwards - will alter the voltage at the junction of A and B away from what you calculated.You need to think aboutwhatyou are trying to achieve, and then come back to us with questions about how to achieve it.
Using Labview to show the data of a sensor via HC-05 - Page 1
Forum section: electronics / beginners

author: Naxmouk
author_rank: Newbie
timestamp: June 10, 2020, 09:48:52 am
content: Hi !I have a DHT11 connected to an Arduino uno, a HC-05 is also connected to the Arduino and is sending data via bluetooth.I would like to know if it's possible to receive the data and show it on LabVIEW with a computer and a USB dongle.Thank you in advance !

author: RoGeorge
author_rank: Super Contributor
timestamp: June 10, 2020, 10:08:13 am
content: Yes, it is possible.

author: Naxmouk
author_rank: Newbie
timestamp: June 10, 2020, 10:10:28 am
content: Thanks for your reply !Do you have any idea how to do it ?

author: RoGeorge
author_rank: Super Contributor
timestamp: June 10, 2020, 10:17:01 am
content: HC-05 can implement a serial COM port (USART) over Bluetooth.Search for LabVIEW examples for how to read and displaying data coming from a COM port.

author: Naxmouk
author_rank: Newbie
timestamp: June 10, 2020, 10:35:49 am
content: Okay thanks !And is it possible to connect multiple HC-05 to one computer and show the data of the various HC-05 simultaneously ?

author: RoGeorge
author_rank: Super Contributor
timestamp: June 14, 2020, 01:18:00 pm
content: It depends on the computer, or the dongle. At most, you'll need a computer dongle for each HC-05.Not sure why you choose HC-05, in the first place, Bluetooth is only for very short range radio links, and needs to be paired with another device in order to work, also is pretty expensive when compared with other 2.4GHz options.ESP8266 or ESP32 should be able to read the sensor themselves, without an Arduino, and transmit data over Wi-Fi, but they are also power hungry and not the cheapest option.If you want very cheap, very low power and good range, try a nRF24L01+ connected to an Arduino instead of a HC-05. Instead of PC Bluetooth dongle, for the PC receiver side you'll need yet another Arduino with a nRF24L01+ attached. Apart from the one to one link, nRF24L01+ can natively do some sort of mesh network of upto six slave devices and one master, they call it MultiCeiver™. There are plenty of schematics and code examples online to inspire for a meteo/weather station with DHT11 + Arduino + nRF24.https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf

author: Naxmouk
author_rank: Newbie
timestamp: June 14, 2020, 04:23:26 pm
content: Thank you very much ! I'll check the nRF24L01+ option !
Using Lenovo laptop PSU as general purpose PSU - Page 1
Forum section: electronics / beginners

author: vk3em
author_rank: Contributor
timestamp: June 10, 2023, 03:37:36 am
content: I grabbed a 20v 10A DC PSU from the waste bin thinking I might be able to use it to power a bank of 12v battery chargers that need 18v DC input. Checked it on my Lenovo docking module and it works fine. However, disconnected from the docking module there is no dc output on the rectangular connector.Have searched but can only find reference to laptop PSU with constant voltage output. Wondering if there is something I need to satisfy to enable the output like a minimum load. Have not probed it on a CRO yet. Any ideas would be welcome.

author: abeyer
author_rank: Frequent Contributor
timestamp: June 10, 2023, 05:59:18 am
content: Perhaps you need a sense resistor per this:https://www.thinkwiki.org/wiki/Power_Connector#slim_tip

author: Jwillis
author_rank: Super Contributor
timestamp: June 10, 2023, 06:32:56 am
content: Centre pin is Called an ID pin. Some say its for the laptop to identify if the correct supply is connected , Others say its to power up the supply when connected to laptop. I think it does both. Ran into that issue fixing a friends lenovo.By connecting a resistor from ID pin to the Ground (-) the power supply should start . I'm not certain of the value of the resistor.

author: vk3em
author_rank: Contributor
timestamp: June 10, 2023, 06:34:45 am
content: Connector does indeed have center pin - will try the sense resistor to ground. Many thanks.
Using LQ065T5CGQ1 TFT-LCD - Page 1
Forum section: electronics / beginners

author: ZZT
author_rank: Newbie
timestamp: March 03, 2021, 04:47:05 am
content: Howdy,I want to use this LCD in a project because I have alot of them, but I naively expected this to be simple.From what I figure, I need to find an IC that I can use to drive this LCD via serial or something.How would I go about finding one, or interfacing with this LCD?Sorry for the lack of information I don't really have any.

author: m k
author_rank: Super Contributor
timestamp: March 07, 2021, 09:28:59 am
content: Start looking old Siemens industrial control panels.With luck you'll find a ready solution.

author: amyk
author_rank: Super Contributor
timestamp: March 07, 2021, 11:27:48 pm
content: That's an LCD designed for NTSC/PAL composite video. Is that what you are planning to use as an input signal?
Using LT6230CS-10 instead of LMH6702 - Page 1
Forum section: electronics / beginners

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 03:26:58 pm
content: I am trying to build this circuit over here for a differential probe:https://github.com/wingel/diff-probe/blob/master/diff-probe.pdfI don't have access for LMH6702 instead I have access for LT6230 and I was wondering if I can use it instead of the LMH6702 and would the circuit need a lot of changes to do this replacement.(regardless of the package difference)Thanksproject page:https://github.com/wingel/diff-probe

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: June 02, 2017, 04:18:32 pm
content: Hi,The LTC6230-10 will not work well in most of these circuits. The-10version is uncompensated and is only stable in circuits with a gain greater than 10.The is shown as Av > 10Regards,Jay_Diddy_B

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 04:29:35 pm
content: Quote from: Jay_Diddy_B on June 02, 2017, 04:18:32 pmI want to work with signals <= 100Mhz, would that make difference?Also, I am not sure what do you mean by uncompensated, can the circuit be modified to handle this behavior?Excuse my ignorance.

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 04:36:03 pm
content: Quote from: blueskull on June 02, 2017, 04:12:22 pmI actually don't have a problem buying from the States, only the time and shipping fee is not the best.It usually takes 2~3 weeks for the items to arrive, I am using a local shipping forwarding company in the States to ship my stuff to my country which works fine in most cases.Currently, I am buying my things from TME, they are usually very fast 3~5 days to have my stuff. The only disadvantagethat they don't have a lot of things that I may need, that's why I have to search for alternates a lot to avoid buying from the States.Thanks

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 05:30:29 pm
content: Quote from: blueskull on June 02, 2017, 04:45:20 pmOk, I will pretend that I have understood this, so the question is what is the problem if I set the gain for the LT6230 to avoid the things that you mentioned(if there is a relation between the gain and the things you mentioned). or add external compensation to the opamp if possible (which I am not quite sure how to do this or where!)Also another question, if this circuit design is not suitable for LT6230, would it be suitable at all for the LT6230 to do the same thing in a different design and the why I am asking because I am about to buy it relatively cheap and if it is not going to work either way I will not buy it and buy the LMH6702 later.

author: nour
author_rank: Frequent Contributor
timestamp: June 02, 2017, 08:06:16 pm
content: I think I will just cancel them if this project will not work with the current design or the current design will require a lot of changes, I just go and buy the LMH6702.Hopefully, someone would confirm that so I would cancel them and don't regret it later because I have them for a good price!
using MC33151 with Arduino  - Page 1
Forum section: electronics / beginners

author: hussamaldean
author_rank: Unknown
timestamp: July 21, 2018, 07:13:13 pm
content: Hi all,I want to use this mosfet driver with arduino or other 5V logic IC to driver IRF150 or IRF510. However, once I apply the signal, nothing happen like there is no input signal at all and I can see clearly with oscilloscope the pwm signal is working fine while the output is maintained at the applied voltage.is there something wrong or the IC is burnt ?note: I connected the output directly without any resistor or capacitors

author: JS
author_rank: Frequent Contributor
timestamp: July 21, 2018, 07:27:35 pm
content: Mosfet drivers usually need two separate rails to provide the floating power for the output of the driver.JS

author: hussamaldean
author_rank: Unknown
timestamp: July 21, 2018, 07:41:43 pm
content: Quote from: JS on July 21, 2018, 07:27:35 pmcould you please elaborate ?

author: JS
author_rank: Frequent Contributor
timestamp: July 21, 2018, 10:45:46 pm
content: Quote from: hussamaldean on July 21, 2018, 07:41:43 pmNot much right now, but floating mosfet use driver with a secondary power source, for now go to de datasheet to check, when I can I could elaborate a bit moreJS

author: hussamaldean
author_rank: Unknown
timestamp: July 22, 2018, 09:50:10 am
content: Quote from: JS on July 21, 2018, 10:45:46 pmI am using 12V for the mosfet to drive the load while the mosfet driver is powered via 5V and share same ground

author: HB9EVI
author_rank: Frequent Contributor
timestamp: July 22, 2018, 10:26:53 am
content: the driver doesn't work with a supply voltage of 5V, since it has an undervoltage lockout of 5,8V. Also it doesn't make much sense to supply it with 5V - then you could drive the fet directly with logic output of the mcu.you can simply take a logic level fet and spare you the driver

author: hussamaldean
author_rank: Unknown
timestamp: July 22, 2018, 07:51:13 pm
content: I scraped the idea of using mosfet and mosfet driver and used L293D instead and it does work wonderfully
Using  MELF  resistors  with  3W power rate ? - Page 1
Forum section: electronics / beginners

author: freddy114234
author_rank: Newbie
timestamp: March 25, 2016, 06:36:22 am
content: I recently got an catalog from an manufacturer in Taiwan. And find out this company produce 3W MELF resistors with an huge size. Does any one really use this kind of resistors?

author: TheAmmoniacal
author_rank: Unknown
timestamp: March 25, 2016, 07:30:07 am
content: Would they fit in fuse holders? O0Send me some!

author: SeanB
author_rank: Super Contributor
timestamp: March 25, 2016, 11:15:19 am
content: Most likely in use for the voltage rating rather than the power dissipation. Likely in use for overload withstand rather than continuous power rating.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 25, 2016, 06:24:28 pm
content: What do they mean by "Ws", or "Wss" for that matter?"Ws" == J, a unit of energy, but that's not very useful for a resistor, and doesn't seem like the intent.Tim
Using mismatched LED panel and driver - Page 1
Forum section: electronics / beginners

author: sjetmand
author_rank: Newbie
timestamp: August 28, 2014, 04:21:44 pm
content: I've listened to The Amp Hour for a few years but this is my first forum post, so please forgive me if I lapse on any rules.For reasons out of my control, I am stuck using a particular LED driver and LED panel for a project.This is the 3w / 300ma driver:http://www.ebay.com/itm/New-85-265V-300MA-1-3x1W-Watt-High-Power-LED-Light-lamp-Driver-Power-Supply-/111344223557?pt=LH_DefaultDomain_0&hash=item19eca20545And this is the LED panel :http://www.ebay.com/itm/310934992692?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITThe panel is happiest at around 11v 150ma. When I hook the two up as is, the panel gets 13v, gets crazy hot, and invariably begins to flicker.From what I can muster, this is the driver's circuit layout (attached). Using an SM7523B IC. I tried replacing the resistor at the CS (current sense) input with a slightly higher value (4.7ohm vs 2.1ohm) without much luck.Any ideas of how I could either modify the driver to output less current, or the panel to draw more safely?Thanks everyone.
using multple power supplies - Page 1
Forum section: electronics / beginners

author: funkimunky
author_rank: Contributor
timestamp: November 09, 2012, 03:16:01 pm
content: I want to learn how to use transistors and op amps. I would like to use 3 separate power supplies to get +15v -15v and a input signal of around 2v. Is it ok to use 3 different power supplies one for each required voltage? if so what is the way to do this?

author: jeroen74
author_rank: Frequent Contributor
timestamp: November 09, 2012, 03:51:55 pm
content: Yes, as long as they are all floating.
Using My O'scope To Troubleshoot For The First Time - Page 1
Forum section: electronics / beginners

author: bullet308
author_rank: Frequent Contributor
timestamp: September 13, 2012, 10:31:48 pm
content: Hi:I have one of the Viz WP-702A power supplies I am selling right now on the bench and one side of it is very wonky, wit the needle twitching chaotically back and forth over what appears to be a 5v range.. When I hook it up to the Hameg HM-605, I get a waveform like I tried to capture below. I make it at about 16 Hz from peak to peak about 15v from peak to trough. The PS board appears to be switch-mode (mostly caps and diodes) and seems to have been repaired before. The other sides output is far smoother. So, cap or diode? or transistor? Cant find a manual or schematic for it. :-/TIA

author: MikeK
author_rank: Super Contributor
timestamp: September 14, 2012, 12:20:52 am
content: A little pricey, but available:http://www.etestmanuals.com/Search.aspx?Mfg=VIZ
using my solartron 7075 voltmeter - Page 1
Forum section: electronics / beginners

author: p.larner
author_rank: Frequent Contributor
timestamp: January 01, 2024, 04:21:13 pm
content: ia there any wat i can use this for setting up radio s meters,ie measure 50uv of rf? as it can test down to 1uv.

author: Gyro
author_rank: Super Contributor
timestamp: January 01, 2024, 04:58:33 pm
content: You haven't specified the frequency. Check the meter AC frequency specifications in the manual. Best guess without reading it and knowing the RF frequency - no.Edit: After RTFM, the spec goes to 100kHz.

author: CaptDon
author_rank: Super Contributor
timestamp: January 01, 2024, 05:17:51 pm
content: Probably not, and even worse if you are using long radiating test leads. Most DVM's have an accurate A.C. voltage frequency limit of 100KHz to about 1MHz. Beyond that range you are looking for an R.F. Voltmeter or spectrum analyzer.

author: p.larner
author_rank: Frequent Contributor
timestamp: January 01, 2024, 05:38:13 pm
content: what if the rf was rectified and smoother to give a mean value and vack calculated?,i think the solarcons max ac freq is 1Mhz.

author: Gyro
author_rank: Super Contributor
timestamp: January 01, 2024, 06:15:43 pm
content: A diode type RF probe won't work at the uV level.

author: tggzzz
author_rank: Super Contributor
timestamp: January 01, 2024, 06:25:47 pm
content: Quote from: p.larner on January 01, 2024, 04:21:13 pmRTFM.The specification is complete and authoratative.

author: p.larner
author_rank: Frequent Contributor
timestamp: January 01, 2024, 11:38:39 pm
content: didnt think of that chris DOH!.