As part of some recent competition prizes I included a little hand-made LED tester and some LEDs. For those who wish to make one themselves, here's how it's made.
You'll need a PP3 battery snap - It's usually best to get a pack of them. A 330 ohm resistor - the standard quarter watt type is fine. A bit of heatshrink sleeving to cover the resistor and a two pole socket connector of your choice to stuff the LED leads into. I used a Molex style connector, but you could use a two pole Dupont one too. Remember to make sure you get the inserts for your connector as they are often sold separately.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and LEDs at:-
http://www.bigclive.com/coffee.htm
You'll need a PP3 battery snap - It's usually best to get a pack of them. A 330 ohm resistor - the standard quarter watt type is fine. A bit of heatshrink sleeving to cover the resistor and a two pole socket connector of your choice to stuff the LED leads into. I used a Molex style connector, but you could use a two pole Dupont one too. Remember to make sure you get the inserts for your connector as they are often sold separately.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and LEDs at:-
http://www.bigclive.com/coffee.htm
I've got a whole bunch of cheap LEDs and I have no clue if they work or not…definitely making one of these when I get home today!
First time seeing the Helping Hands on the bench, lol. Currently mine is an amputee….had to borrow it's hands for something I was tinkering with. I kinda feel bad too because sometimes it looks as though it is waving it's nubs at me to remind me of what I did🤭
KISS
Would it work with a single AA cell and a joule-thief, if I wanted a more compact design?
This is very interesting and I'm interested in the calculation you did to determine the resistor value. It mostly made sense but how did you know the current you were after is 20mA?
Simply perfect. 🪛👍
If you don't fancy crimping, you can buy pre-wired connectors.
Thanks 👍
I think your 330 ohm resistor might be a bit on the low side.
I have some IR LEDs, which have a forward voltage of just 1.33 volts.
I've found IR LEDs to be quite delicate, so I'd be inclined to go with 390 ohms, or even a bit higher.
I made one with 2×2032 cells and heat shrunk the wires onto them. I tried soldering the wires on but no matter what I tried, it wouldn't stick to the battery. So I just soldered on a little folded up bundle of thick wire to the end of each lead then heat shrunk then either side of the battery. Then, buoyed by the success of this project, I made a USB powered one.
Ohhh nooo! After all the trouble Big Clive went to show us how a Joule Thief works, he digressed to using a 9V battery! Horrors! 😱😱😱
I built a Joule Thief with a socket like he used for the LED. But the JT must not be left open circuited with no LED because the voltage will rise very high and can damage the transistor. So I connected a 6.8V zener in parallel with the socket so the voltage can't rise above 6.8V.
One point: the typical 5mm LED and most others, too have a reverse voltage rating of 5V maximum, so if you insert the LED backwards, you are putting over 9V in reverse across the LED. I have never found that the LEDs I've tested have been damaged by this, however it is excessive voltage and should not be done.
Does anybody here have any advice for an electronics beginner who's colorblind? I can tell red from black and fairly obvious differences in colors (even if I cant identify the color) but the stripes on those resistors drives me up the fucken wall… Is there any way for me to learn this stuff without depending on those color codes?
So i am just learning this side of eletric world and your great at teaching. But as a car guy. I use a old style Mac tool wire striper. Looks like this one you use but has a block of sides on it. So you stick wire in appropriate hole and grip handles together. And it strips for you. Do you think this would be a better way to go. Or are the small wires very easy to break.
After watching this video, I went ahead and purchased a crimping tool, sort of like that, but with 3 sizes instead of the 2 as yours has. I am amazed at how often I use it, I had ordered a set of Dupont type ends for it, and ran out of the male type, had to order more of them, and have also purchased a set of the type you use in this video, while I don't use them as often as the Dupont, they are indeed very handy for many projects as well. You are correct in that it takes some time to learn exactly how to use it properly, but once you have it, it seems to come naturally thereafter. Thanks a million for the video!
This bring back memory. I had one such 9V tester. But the 9V was too expansive to replace. So I switch to 3 x NiCd AA batteries. It works fine and cheap but does not hold charge after several months. I guess I could solder Alkaline batteries? But I moved on with LED projects. I bought a number of LEDs on eBay. It is cheaper to buy vs. make my own.
Save the tops from dead PP3 batteries. These can be used as PP3 battery clips.