One of the best electronic channels

Your channel is one of my favorite one, the dc load project was a state of the art, and now this one, I am imagining how wonderful should be your shop.

I am impressed by the tutorials you give, I find them very useful. They are fully understandable. Thankyou.

Thanks for all your hard work and attention to detail on these instructional videos.

Enjoying your well done videos and projects, thank you for the excellent quality, theory, testing, and techniques. There are a handful of providers doing this and you are one of those in the "Top Ten" in the world from my view. I had a thought that maybe a revisit to this concept would be great for those using "old school analog VOM/AVO". Many of the analog devices typically use 50ua 250mv for example in a Simpson 260, or a 60ua in a Triplett 300 series VOM.

PARTS LIST 1 x LT3092 - Linear Technology 200mA Programmable Current Source I.C. (SOT23) [This I.C. is also available in a SOT223 - 4 pin package which you may find easier to solder, but it is usually £1 more expensive] 1 x SOT23 to DIP8 PCB adapter (can be easily found on eBay) 1 x Male Header Pins Strip - 8 Pins required for SOT23 adapter PCB ABS Plastic Box (Black) - size to suite project about w83 x h53 x d35 (mm) 1 x Matrix PCB Prototyping Board - cut to size (can be easily found on eBay) 2 x 1K - 25 turn preset resistor (good quality one if possible i.e. BOURNS) 1 x 3 Pole 4 Way Rotary Switch (silver contacts) - [only using 3 of the 4 way] 1 x Black Pointer Knob (Chicken Head Pointer) 2 x 39K resistor (1% tolerance) 2 x 100 ohm 0.1% Metal Film Resistors (used in series for the 200 ohm resistor) 1 x 100 ohm 0.1% or better Metal Film Resistors (used to calibrate the unit) 2 x 10 ohm 0.1% Metal Resistors (used in series for the 20 ohm resistor) 1 x Black 4mm Banana Socket (any type will do - but I used gold plated one) 2 x Red 4mm Banana Socket (any type will do - but I used gold plated one) (I used HIRSCHMANN TEST AND MEASUREMENT 930176700 SOCKET, 4MM) 1 x Battery holder for 2 x AAA Batteries with Flyingleads 2 x AAA 1.5 volt Battery OPTIONAL: (Not really required) 1 x Green LED (low power 2 mA) 1 X Plastic LED Holder 1 x 560 ohm 5% Resistor

Really enjoyed your presentation. Great job!

Excellent as usual. I hope all is well and we hear from you very soon. Take care.

I appreciate the time and effort you put into this tutorial. THANKS David Lee.

Brillant video from start to end. Excellent teaching !! Many thanks !!

Very interesting video. Thanks for taking the time to educate us all. Cheers Dave.

A good project and excellent theory in this tutorial. So many videos and tutorials out there presented by other people, but very few manage to produce the quality in the presentation, the value in the theory and the skill with which you impart the knowledge. The world is concerned about global warming! There is a far greater danger that threatens society, and that is the irreplaceable loss of GOOD EDUCATORS.

Really enjoying your videos. I'm currently going for my electronics technology degree and these videos are actually helping me out.

Awesome tutorial and seems approachable.

Very nice project. I have just made one myself. Thank you very much for this. The next project is your 5V reference which I combine with the constant current box in one project box. So I have a nice feature to check my multimeters.

After many years I have designed / got manufactured / populated a circuit board for this project, also with 100mA range available. It has a calibration/operation switch which either provides a closed circuit over 6x120ohm resistors (20ohm effective) to measure 20mV/200mV/2V at a test point, or switches them out for the normal test points with which to source current. I also used 3 x AA batteries. I found 120ohm 0.05% resistors available at the time, but 5x100ohm might be the easiest for public to build. I was quite interested that to get 2V compliance I had to go almost to the end of my 1k pot! Thankfully not all the way to the end. I'm quite pleased that its my first semi-complicated circuit board I designed and it appears to work first try :D Thank-you for your project videos. 💕

I have watched your videos and I must admit I am impressed. I am an RF cell engineer with +20 years experience in product design. I have not found other videos which are as pleasant to watch as yours. You also like LT parts which gets my vote. You are doing a great job. I am looking forward to more videos soon. Thanks Adam

Nice video I find them very useful and thank for the excellent theory

Thanks for sharing your knowledge.

Excellent, keep it up. Thank you.

very professional. loved it !

I was wondering at the start how you would deal with the accuracy of resistors (1-0.1% can be quite a big deal) and the 10 micro amps, great solution. Also, I am pretty darn jealous of your workshop. Really enjoyed the presentation style and detail.

Nice video and a really useful project. I like this mini project format that u are using for your videos its excellent. Looking like a very good channel I cant wait for the next one. a basic cost for the projects would be helpful but I really like the way u explain things. Thanks

Hats off to you Sir. Excellent

I always like your videos!

Nice and detailed video for hobbyists, thanks

Well done sir.... Well done! 😀

Very nice project!! I am using the LT3092 for use in a milli-ohm meter project Im using.

Handy little project, thanks.

A really useful and informative video.

Excellent video, thanks

Awesome.....cheers.

That was great! Thank you.

Very nice project. By the way your current source is already very accurate. Here's how ,while watching the calibration part, one idea came into my mind . Why don't you just measure the output current of your current source and at that moment adjust the preset ( I mean trim it down until you see 1 .000mA and 10.000mA .) Its just that easy. If i am wrong please correct me. But iam pretty confident that this trick will work .

can we power this project with 5vdc through a micro usb and maybe a pc usb port (or a cell phone adapter)?

Excellent video .how to make a variable o to 20 ma source with this?

Another fine project for me. :)

can i use rout 2 ohms and to make 100mA ? and after that parallel 4 such sources to get a 400 mA current source ? will i get this much accuracy and tollerence ?

Excellent

Great, thank you

Thank you

Is the minus terminal of devices in GB on the right hand side? We have it on the left hand side in Germany.

I really enjoyed this project video! It would have been nice to see some testing with an oscilloscope to check ripple and performance under load - just a suggestion.

Very well done, every step is discribed with clarity and i really like the rather clever 100R test resistor :-D. I also like the 10 turn trim presets, they cancel out the 10uA ref (as you said) and null out the operating/drive current of the op-amp, brilliant :-). I dont suppose a 10 million ohm (or more) volt meter would have much effect on the 100 ohm test resistor, too many decimal places down the line. So when are you going intp full production and competing with "dmm check" ha ha just leg pulling :)

Nice videos you are producing. Keep up the good work. I have a question concerning the LT3092. Do you think it is possible to control the output current with a voltage on Vset from 0 to 200mV? I am starting a project for a calibration unit which today using LT3092 using trimpotentiometer to control the current. I want to develop the system by replacing the potentiometer with a microcontroller generating a 0 to 200mV with a PWM output. Do you see any problem with this solution? The datasheet for LT3092 says that Iout=Vset/Rset.

Thanks for the video! One quick question around the 10:00 mark, when you add the 100 ohm resistor on the output to measure the voltage drop across it, wouldn't that change the effective resistance you see on the output of our current source? Effectively changing the output current from the 1ma we want? Thanks in advance for any help! Edit: I see I think I see what you are trying to do, you are putting in that 100 ohms and monitoring the drop across it so that you know WHEN you have tuned the circuit to output 1ma, I thought you were putting it in to test IF it was outputting 1ma like it should and thought the resistor would screw that up. Am I following your design logic correctly?

The quality of your videos is excellent, congratulations. which camera you use? I would love to have that quality in my videos but surely can not buy that camera. regards

Very useful video sir. I have 100microammeter analogue pls get to convert to digital reading,as in internet I searched all are measuring above value

For calibration, can you simply measure the voltage at pin 5 for 200mv while adjusting the 2 adjustable resistors?

Would the accuracy of the unit be improved by meassuring the exact value of this uniqe shunt resistor and calibrating to the calculated voltage drop? In this case, also a resistor with higher tolerance can be used?

Great job, thank you. Not to be picky, but... at 12:22 you have drawn your third set of switch contacts incorrectly, that set should be in the middle position also. :)

Your mechanicals are much nicer than mine. It must be the Harbor Freight tools I'm using? Handy little tester for sure.

I'm fairly new to electronics and have just soldered my first SMD for this project. After I'd soldered it I thought I had shorts between pins 7&8 and 2,3&4. I was there for about half an hour trying to clean the solder up and testing for continuity when I suddenly remembered that these pins are connected internally. DOH! So I'm assuming I don't necessarily have to connect these pins externally as was mentioned in the tutorial? I have now ordered the items for the low current reference project. Keep the projects coming please :-)

dear sir , excellent project ! may i ask a simple question if you dont mind : cant we power these instruments you make from a power supply and not batteries ?

Can you make a video on how we can design a 4 to 20 mA circuit? just for testing a new module or PLC cards. Thanks!

Checking the capabilities of the chip, it shows it can handle 400mA - i am wondering how we could add a third level for 100mA - and i would really like to add 1.000A - but do not know where to go with that (or if it is possible) . Ultimately i would like a 2.0000A or even 1.90000 reference for checking multimeters. have obtained 2 of the chips so can build a second unit. Currently using a GW121 (EEVBlog DMM on KZfaq) . also obtained an 8W 100 ohm 0.01% 4 leg (kelvin) resistor from the UK - please let me know, i cannot find a multimter than has

Hi there, nice project. Very useful. Can you tell me from where can I get 0.1% resistors?

I want to make it for my milliohm meter project .

Brilliant tutorial. Thank you very much. This is better than Dave Jones ;-) Can this circuit be adopted for controllable variable current source?

One little trick when calculating voltage/current/resistance. I like to round them to whole numbers, but make sure they are all the same magnitude. So if I want to calculate resistor from 200 mV and 10 uA values I convert the mV to uV. So it's 200 000 mV or 200*10^3. Then I divide 200 000/10 and it's 20 000 Ohms. If you are ok with working with power of 10 then it's even easier - 200*10^3/10 = 20*10^3 -> 20kOhm

What process do you use to create the templates for the project box? I've been looking for ways to do this easily on Linux. Is the software you use a CAD package, or is it some other software or is it some drawing package like CorelDraw?

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Where we can use this?

Anyone have a copy of the front fascia they could share with me?

I like!

Do you have any good suggestion for a 10A constant current source circuit?

Why didn't you calibrate the unit by measuring the current rather than the voltage across the 100R?

I need a DC current source (range 10 to 200 uA). Will this work?

And a suggestion. To make the calibration more accurate I would use high accuracy resistor. But these are too expensive to solder inside. What I've done is I made a resistor box with few very accurate resistors (0.005%) - from 200 ohm to 2 MOhm. Then you can use the resistor box outside of the current source box. Once calibrated you don't need the shut. For 1 and 10 uA you don't even need 4 terminal measurement.

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dear sir, great video sir... I need 100mA constant current source. by changing Rout resistance to 2ohm, will I get 100mA constant current source?

is this keithley so accurate that you use it to calibrate other instruments?

hi, can you please post a link for smd to dil adaptor very good explaining. thank you

Very well presented. I am guessing you teach electronics/engineering ?

I think you should have calibrated your current source with multimeter in current mode, unluess you are using really precise resistors

there is a samsung phone dying there:) how long it will last on batteries? I'm guessing pretty long... just curious.

respected sir.....this is not related to video. i have a simple question,i damaged 50k pot while removing the radio set,i found 1k pot in my cupboard ,and i need to convert this for 50k pot so started connecting parallel resistor iam unable to find solution for this,pls share some idea how i can convert this 1k pot to 50k pot and i dont want series resistor to connect along with 1k pot.

Sir I did't find this IC in my local market. Can i make a precision current source using . TL431 Precision voltage refrance for opamp and mosfet for constant current mode.

Anyone interested can download an actual size image of the front panel template in PDF format. Link below: www.scullcom.com/Scullcom_Constant_Current_Box_Template.pdf

Nice project, but soldering that small thing would be a pain in the butt.

I have a little Circuit you might be interested in.

You've drawn this in a very confusing way. According to how it is drawn, the input voltage is wired and soldered directly onto the points marked as set and out.

if u really want accuracy u need to use 0.1% resistors.

Everyone else uses a dot to signify a soldered join.

Dont you have ZERO in your vocabulary? “0” isnt called KNOT or NOT. It is ZERO. Why cant you say ZERO? THANKS. And “Al-you-mini-yum” is a goofy way to say aluminum. Al-lum-i-num.

Why didn't you calibrate the unit by measuring the current rather than the voltage across the 100R?