The LM317 is quite bad as a current source. Its internal reference is only good to a few percent and as it warms its self up from the current it will have some temperature drift. Regulating from the 9V battery to 5V with an added regulator device will make this better.
@pault65335 ай бұрын
I used a heat sink to reduce the VREF drift inherent to the LM317 when it rises above room temperature. I also used two different power sources using powerbank modules which do not shut off during low current draw, supplying 5V for constant current and the other the voltmeter. This enabled me to use 4-wire kelvin alligator connections. These improvements do not detract from this awesome video which shows the baseline requirements for making a circuit like this.
@kensmith56945 ай бұрын
@@pault6533 Yes, a heat sink helps a lot but making the reference and the pass element two different packages is a better way to go. You can get regulators that drive transistors to do this.
@pault65333 ай бұрын
I like this little monster! If you cover the decimal point with black paint inside the display, then the reading on the screen is millivolts and no more confusion. The dropout voltage of the LM317 determines the highest resistance that can be measured. For 100 mA current, the highest resistance is given by the equation Rmax=10*Vin-30. For 5V, you can measure up to 20 ohms. For 9V, maximum is 60 ohms. However, power to your resistor is W=R/100, so heat will change reading. A 60 ohm resistor would receive 0.6W! But that isn't possible with a 9V rectangle heavy duty cell, they instantly drop to 5 or 6 volts under 0.1 A load. Alkaline cells would drop to about 7-8 volts under the same load.
@MCsCreations5 жыл бұрын
Pretty beautiful job, dude! Really well done! 😃
@Ozzy33333332 жыл бұрын
Thanks for sharing. I would make it a 4 wire setup, so longer leads are much more useful.
@CoolDudeClem5 жыл бұрын
This is not a good way of measuring such low resistances. The 4 wire measurement method is better. The resistance of the probe connection and the test lead resistance is going to through this off.
@freddiemortos85195 жыл бұрын
Yeah,4 wire measurement is better than this..you can also use LM317 as a current source and the supply of the meter should be independent on the supply of the resistor being measured.
@FabiusKadett5 жыл бұрын
This is equivalent as the 4 wire method. Here you don't need the ammeter because you already set the LM317 as a constant current source of 100mA. It does not matter the series resistance of the cables because no matter the total resistance 100mA will pass though it all. And since you are measuring the voltage drop across RX. Is the same as using the 4 wire method. Don't see what all the fuss is about.
@maxwarfield66993 жыл бұрын
I’m just a hobbyist but, most of the unwanted resistances from the probes, wires, and the clips, will disappear/be “nulled” out, during calibration - am I wrong? If so, please clarify. I want to learn. Thank you
@JUANKERR20005 жыл бұрын
Great idea, many thanks.
@qzorn44402 жыл бұрын
very nice video. 🤓🥳 the test resistors workout well and 1% values or less make a great indication. 🧐 thanks a lot. 🤩🙂
@fredlllll5 жыл бұрын
i dare you to make a terraohm meter :D just so u can measure resistance of wood and other insulators. i found that discharging a tiny tiny capacitor can be helpful. for example a mosfet gate. i was able to rapidly discharge it by connecting it to wood, but only very slowly through my fingernail.
@avejst5 жыл бұрын
Night and simple design Thanks for sharing👍😀
@Bharathdbs5 жыл бұрын
Hi Myself bharath. A big fan of your channel. Am sorry am not good in English, sorry. I request you to make a device, I mean DC backup for my wi-fi router. Kindly make a backup using lithium batteries or 12 volt lead acid battery and output 12 volt 2 amperes. And it should work like uninterrupted power supply. Am requesting you to make this because always power failures at my home and no internet. If you make a uninterrupted DC power backup, it'll be very useful to me. I guess most of the people need such device. I have charging modules, step up modules and step down modules but always I fail when I make a circuit with such modules. Hope you understand my English. Thanking you.
@electronic79795 жыл бұрын
Nice project 👍
@deyviperez72465 жыл бұрын
Eres un maestro enceñanos hacer un capasimetro
@josephmaughan16355 жыл бұрын
Remember everyone when your measuring resistance is that low even resistance of the alligator clips is and can be significant some positive method of clamping tight is preferable so that you know that you're not introducing error into your measurement
@kensmith56944 жыл бұрын
4 terminal measurement works better. One pair carries current and the other connects to measure the voltage.
@josephmaughan16354 жыл бұрын
@@kensmith5694 yes like well made meter shunts where the main current passes through large bolted terminals and the metering is picked off the side
@tubeDude485 жыл бұрын
How about a part number for the volt meter? Also, was the meter connected during calibration?
@stevenchiverton484 жыл бұрын
very well done video and explanations
@ciprianpopa1503 Жыл бұрын
That led display would drain the battery like there's no tomorrow.
@jeanyvespochez5 жыл бұрын
do you have any link for the 5 digits led display ? thanks
@wi_zeus67985 жыл бұрын
Search for Mini Digital 0.36inch LED Display 5 Bits DC 0-33.000V Voltmeter Panel Volt Voltage Meter Tester Detector with Case for Car Home
@lusinpro86945 жыл бұрын
here it is got.by/3a5v5h
@vipinpurohit5 жыл бұрын
Thanks for the idea can you please make some simple device like this to measure low value capacitors and inductors.
@AmplifierWorld5 жыл бұрын
Can I measure resistance from 50 micro ohm to 200 micro ohm? Actually I want measure contact resistance of 400kv circuit breakers
@user-bu3ss4hm8t Жыл бұрын
In digital micro- ohmmeter how to troubleshoot. Not getting reading
@maxwarfield66993 жыл бұрын
Are using a 13 Ohm resistor or a 470 Ohm resistor? I see a 470 Ohm resistor in the video but you say it’s a 13 Ohm, or do you mean that you set the 470 Ohm resistor to 13 Ohms? Pardon my ignorance, I’m new to electronics but I want to learn. Please clarify. Thank you
@johnkemas73443 жыл бұрын
this was a multiturn 470 ohm resistor set 13 ohms
@maxwarfield66993 жыл бұрын
@@johnkemas7344 Ok, thank you kindly. Be safe.
@naf44942 жыл бұрын
Sir, watt of this resistor?
@dahamalanzy13535 жыл бұрын
ممكن تصنيع اوعمل عدادفوليته بواسطة لدات ماهو الايسي المستخدم وهل يوجد مخطط للعداد
@samhsavdr96475 жыл бұрын
Kasyan calibration bad ...low prescion ...
@mre38205 жыл бұрын
Would this be suitable as an ESR tester for capacitors?
@jeanyvespochez5 жыл бұрын
no it measures dc ohms. esr meter needs to measure using an ac current.
@hyperhektor77334 жыл бұрын
try the famous "transistor tester" from ebay ~7$ it can a measure ESR, and many other components
@siavasharash54483 жыл бұрын
Possible to use this as a capacitor ESR meter?
@amkp40technology5 жыл бұрын
Good
@netten20572 жыл бұрын
can you pls make a good esr meter
@shopehome17003 жыл бұрын
We can find bord short in this divide
@jenpau02695 жыл бұрын
Where is the zener tester did you delete it?
@hyperhektor77334 жыл бұрын
yes since youtube marked its as +18/nudity , the usual political censorshit
@Ahmadnaweed7862 жыл бұрын
This is only as accurate as your amp meter and voltmeter which you are relying on.
@abarytoimin33903 жыл бұрын
How many
@tonyvarghese755 жыл бұрын
Nice
@SnipeR-025 жыл бұрын
Old voice, please? ;(
@ernestclarkjr7493 Жыл бұрын
Schematic diagram
@ddhimanhr3674 жыл бұрын
Hi mam
@necoisidois75705 жыл бұрын
6:00 ? 0.05 =/= 0.005?
@MrMihanaha5 жыл бұрын
Reading voltmeter 0.005 V. Current through resistor is 100 mA=0.1 A . R=0.005V/0.1A=0.05 Ohm
@ghasemmadah86835 жыл бұрын
سلام
@ProtonOne115 жыл бұрын
Out of personal experience, looking ugly does effect the work... (2:51)