Build this Variable Constant Current Supply. LED light tester, Christmas lights and much more

This Variable Constant Current Source has a multitude of uses and is cheap and easy to builf.

I work in collaboration with:
The Electronics Channel (with Carlos and Detlef)

Gran Canaria Uncovered

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TEST METERS
Aneng AN8009
KM601
VC480C+
MESR-100 ESR METER
XC6013L CAPACITOR METER
TM-902C TEMPERATURE METER
LCR-T4 LOW COST COMPONENT ANALYZER
FNB58 USB ANALYZER
PCI POST ANALYZER
TL460S Plus PCI_E ANALYZER
TOOLTOP ET829 SCOPE METER
MULTIMETER PROBE KIT KET05
OSCILLOSCOPES
FNIRSI 1014D
FNIRSI DSO-TC3
FNIRSI DPOX180H
BENCH PSU
NPS3010W
SOLDERING
T12 Station with M8 9501 Handle
M8 9501 HANDLE
T12-BC3 Tip
SUGON T26D
QUICK 861DW
PROS'KIT SS-331H
SS-331H Spare Parts
THERMAL CAMERA
Infiray P2 Pro
MICROSCOPES
Amscope Optical Microscope (copy)
ANDONSTAR AD407

EEPROM Programming
TL866 II+
CH341A
1.8V ADAPTER
CONSUMABLES
NC-559-ASM FLUX
DESOLDER BRAID (I use size 8045)
MECHANIC HX-T100 Solder 63:37 (I use 0.6mm)
ESD-11 TWEEZERS

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Thank you
Richard

[mikepanchaud]

That's great. If you don't have spare probes you can use old plastic pen barrels with some 'hot snot' to fix the wires in.
It could also be used as an led tester.

[darrenwardell]

Absolutely brilliant video. Very well explained and i have learnt so much👍👍

[Lightrunner.]

Nice Tool Richard and pointed sharp measurements 👍👍👍👍👍👍👍

[cuanhogan]

A needle fits great into a banana plug connector, in the centre of the "cross" on the connector.. fits snug with no soldering

[SWoods]

I really like this. Unlike commercial probing devices, a sewing needle hole is basically self healing as it’s so narrow.

[justmc]

Fantastic tutorial Rich .. love these DIY devices .. As always I appreciate all that you share with us .. On a side note ... you mentioned in the past that you would prepare an Op-Amp tutorial .. hope that is still in the works ... 😎

[andrew_koala]

Fund the smallest connector block possible -
and there are some quite tiny variants available -
then remove the brass connector away from the plastic insulation..
After the sewing needle is fitted - put some heat shrink over the
brass connector -- the result is a neater appearance.
It is in such a method I replaced the thermal fuse in our Freezer.
Thus it was not necessary to crimp the thermal fuse into the wiring
that feeds the Freezer Defrost element --
This method also makes it very simple to replace the thermal fuse
if required in the future.
No stuffing around with crimps and a crimping tool =
Just a very small brass insert and a very small screwdriver -
and of course some heat-shrink tubing

[turnipofentropy]

Excellent. Great videos Rich. Many thanks.

[SkippiiKai]

Speaking of soldering onto probe leads I recently soldered small alligator/crocodile clamps straight onto a number of my test probes, set back a bit (1 or 2 cm) so you still have the pointy tip, but also can use them to clamp into anything. One of the mods I ever did to my multimeters (along with a little plug and charger circuit for the battery.)

[tonysheerness]

Sewing machine needles would fit better as they have a thicker shank. Another good practical next to nothing project.

[TheElectronicDilettante]

Awesome build!! As you were mentioning potential applications and voltages, how difficult will it be to add a “preset voltage “feature to the tool?

[knightwar]

So this "short tracer" can be used for testing leds without worrying about the current from the bench psu that's nice i need to build the second version too. Great content as always

[kriswillems]

Another interesting circuit is the "2 transistor current source".

[willthecat]

I doubt the needles will stay in those terminal blocks. (Spot weld to the regular metal probe tips?)

[sigworth]

I don't understand. Why is the reference voltage 1.25? How did he come up with that number?

[andymouse]

If you only have access to a fixed supply on your repair bench this would be invaluable but if you have a variable supply you can set voltage and current with that and then the nice little hack to make pointy probes comes in handy as thats a nice idea, very quick and clean to make and Bingo !! job's a good 'un....cheers.

[RetroUpgrade]

Told you it would solder 🤣😂, benefit being poor and a cheapskate 😋 you test things like this
Btw i usually use Shewing machine needles instead they are usually sharp and more resistant to breaking and they have a flat side so you can solder even easier .

de circuit its self is really useful :)

now make one for LED TV lights 😝 300V+ should be interesting XDD