A DIY Current Source Demonstrating Ohm's Law

A DIY Current Source Demonstrating Ohm's Law - DC To Daylight

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Күн бұрын

In this episode, we take a look at the shortcomings of measuring low resistances with a standard digital multimeter. We demonstrate measuring a small resistance using both the two-wire and four-wire kelvin methods. Then we build a standalone current source that will be used in conjunction with a standard DMM, allowing us to make four-wire measurements, without an expensive benchtop meter: bit.ly/30t9dKj
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#0:00 Welcome to DC to Daylight
#4:33 The Circuit
#7:51 Build It
#10:39 Test It
#12:00 Give Your Feedback
#ohmslaw #currentsource #DIY #4-wiremeasurement

Пікірлер: 17

@graemelinsdell2361 2 жыл бұрын

The prototype solution is excellent , I have never seen before,.

@oakspines7171 6 ай бұрын

Thanks. Very helpful. Quite some work and dedication you put into this video.

@Lokalaskurar Жыл бұрын

The parts where the maker says "The issues I faced were" are my absolute favourite

@Mr.Beauregarde 2 жыл бұрын

More of this guy in my future watch history. Very nice

@MrAshwindersingh 8 ай бұрын

Today I learnt new idea to prototyping thank you sir really appreciated

@Workshopshed 2 жыл бұрын

Great explaination of the 4 wire measurement, I've never dug into why that was needed before.

@vobbertbecking3598 2 жыл бұрын

You should fit the diode before the capacitors, if that is a 22uf electorlytic it is not protected from reverse polarity.

@AmRadPodcast 2 жыл бұрын

Facepalm. Rookie mistake - you're absolutely correct. Let's just call that cap a "reverse polarity notification device"! 😉

@barry2718 2 жыл бұрын

The prototype method is a great idea. Beats veroboard or matrix board for smaller circuits.For quick small circuits I have used stiff cardboard and a pin to make the component holes. Just push component through the cardboard and bend leads at back and solder. Great video, very well put together and educational.

@radman999 2 жыл бұрын

Great presentation style. Excellent work!

@mnoxman 2 жыл бұрын

Use Enhancement mode FETs to switch in resistances. Your minimum resistance is 5000 mohms and the RdsON of 4mOhms if you were using a 2n6661 would be insignificant by comparison worst case (0.08%). It would also be consistent (wouldn't change from switch click to switch click). Using a push button, a schmitt trigger in to a toggle flip flop to a 4066 would let you do this "the old school way". You could do it all in a PIC chip for a more modern take.

@GeorgeGraves 2 жыл бұрын

LM317 is cool. But boy I wish someone would make a Keathly 225 knock-off with modern parts and decent accuracy. It can't be that hard right? Right?!?!? (hehehe)

@GeoffryGifari Жыл бұрын

how big are the lead, contact, and jack resistances compared to 10 Ohm resistor, in most cases?

@dicko195 2 жыл бұрын

@7:14 2,270 ohms? Not 2,027? TY great video and info.

@RaviKumar-xx7gi 11 ай бұрын

Hi I have made the circuit of LM317 on bread board. I am generating a constant current of 100mA. The input to the regulator is 3.3vdc. 100mA constant current is fed to a resistor of 100 ohms. I should measure a voltage across resistor of =10mA x 100= 1000mV=> 1V, but the voltage across the resistor I am measuring is 3.3vdc. why so? I want to use the constant current source to find the unknown resistor using current and voltage How can I do this?