Big Dim Bulb Tester with Variac and Isolation Transformer
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- เผยแพร่เมื่อ 25 พ.ย. 2014
- Here is a large dim bulb tester and variable AC power supply that will provide up to 240 Volts. It current limits at "Around" 1 amp at 120V, and 500mA at 240V with the bulbs switched in. This is a dangerous build. If you build this, it's at your own risk. I suggest you don't build this power supply!... Unless you know what your doing.
- วิทยาศาสตร์และเทคโนโลยี
Yes, we are all waiting for the Vedolyzer sequel like Christmas. Therefore I have been forced to watch reruns of all MrCLab videos. And you learn new things every time. Thanks and wish you lots of energy for the darkest weeks of the year.
I built one kind of like that in my lab, I do have all connections covered . I used a variac, isolation transformer and a three bulb vanity fixture, so I can unscrew bulbs to lower the current, now after watching this I may revamp mine a little. great video!
I have watched so many of your videos! always enjoyable and I always learn. I saw this unit in 1 of your recent videos and was very curios. Today I searched and found this video.
Great stuff! I have been Interested in ham radio for some time. (that's how I found your channel) You make things that seemed scary , understandable which makes them a lot less scary or intimidating. This seems much better than any "isolating" transformers that are readily available. Thank you for sharing your seemingly endless knowledge.
I am thinking of rebuilding the current limiter I built yesterday adding in my variac plus a Power On lamp. Nice job, Sir.
Mr. Carlson, I recently stumbled across your channel and I have been delighted by your work, wit and ingenuity. I attended a technical school here in the states and studied digital electronics. During the first phase of the courses we learned about LCR, RF, and basic electrical circuits before we dove into logic and processors. That was back 35 years ago and my career path diverged wildly from electronics. Since a young age I experimented with electronics and your channel has renewed my interest and I am currently digging out my old power supply and test meters. Thank you for your very informative and entertaining videos.
Best Regards,
Gary
Thanks for your kind comment Gary!
Great job! The only suggestion I have would be to replace the light switches with old knife switches to complete the old look.
More CRAZY STUFF!!!... Lovin it Mr C, thanks for your time :-)
Thanks for the time and effort you put into these very excellent videos. You're not only a first rate tech, but also a very masterful craftsman. This project is as awesomely steam punk as it is useful. Kudos comrade ! Your work is a thing of beauty.
+Тимоти Блокер
Thank you for the nice comment!
Very cool. I have a separate section in my lab that is HV, Variacs, 10KV Hipot, 2KV DC Supply and etc. I like to keep all the HV isolated to it's own circuit and bench. Cool build!
That's a safe thing too do (separate bench). I'm running out of room.... Now using wall space :^/ Thanks for the comment Eric!
Dear Mr. Carlson,
As I continue focusing on repairing that tube radio, I remember seeing this video, and, realizing how serious it is to take safety precautions when testing such a radio, I decided to build a dim bulb tester of my own. So, I went to an electronics surplus store and managed to find in stock a 120V/100VA isolation transformer (with power and female cord attached) and a 5A variac which happens to not come with any housing, and so I decided to build one out of scrap wood and mount that and the whole system on a scrap board base. And I also made a three-inch wooden handle with eight finger slots and a chicken head pointer which I glued on top of the handle and mounted it on the arbor of the variac.
I also bought a 3-prong to 3-hole extension cord, a light switch, two sockets, two 150W light bulbs, and some electrical boxes. And then I made it in three stages. The first stage is the isolation transformer, of course. The second stage is the variac with the 3-prong end of the extension cord wired to it and another length wired from that to the third stage. The third and final stage is the switch, light bulb, and female end of the extension cord. I set it up so that if the switch is in the off position, current limiting begins as the current is bypassed through the two light bulbs hooked in series so that they do not get too luminescent to balance the current load properly. With the switch turned on, the switch provides a _direct_ path to the female end of the cord. I plugged a small drill into the new device and used it to test the thing and it works!!! :) I also used a voltmeter to test that the voltage goes from 0 to 120V with or without the current limiter system, making sure that no voltage registers if one or the other bulb is unscrewed.
The only thing is that light bulbs tend to stop electric drills from spinning. I hope electric drills just require more power than tube radios. If so, then, provided I manage to fix the radio, I can use the new device to test the radio. :) :) :)
Thank you for detailing this for us. I really like the current limiting aspect.
Glad you like it!
Thanks for sharing this - I really liked the look and the schematic was a huge bonus! Off to the bench 😃 to make mine!
It does look cool... You have developed the unconscious habits that keep you out of trouble. If I do a version of this, you bet I am using an isolated enclosure! Many thanks!
amazing tool, you inspired me to build one for my own :) .... I suggest replace the on-off switch with a relay, making a 'set-reset' to bypass the lamps instead of the key, so you will never need to remember to turn of the lamp bypass switch as it will be disconnected every time you turn off the AC, putting the lamps in series...
Very nice use of the lamps for current limiting - thanks for sharing
Cheers
Jim
+Jim Oates
Thanks Jim!
Your is the best I have seen yet! Love your vids. They are very analytical and in depth! I love them👌
Thanks Mark!
I really like your design. Thank you
Nice tool :-)
I suddenly get the urge to yell out "it's alive it's alive"
+smbrob Finally somebody yelled it, now I can release frankenstein...LOL!
Nicely done, I like the looks of it too.
Mr Carlson, thanks for this explanation and schematic. 😎
Mr. Carlton’s understanding even shines through with this simple but practical test set up.
It reminds me of things as seen in 1950s era popular science magazines or QST’s varnish 2X4 antenna projects.
Perhaps there is an influence derived from the first Westinghouse generating station at Niagara Falls. Large knife switches meters and pilot lights, and if you’re stupid enough to put your hand on open switch or terminal you deserve a shock.
(No disparity meant to lawyers) but why are instruction manuals written with 1 page of technical information and 10 pages of warnings like don't use your hairdryer in the bathtub.
Thank you Mr. Carlson keep up the good work
Great job on this thanks for producing it.
Mr carlson. The more I watch your videos. The more I understand. Your level of intelligence. I am only 32 years old. But wow. It's people like you who keep the world working. I work as a machinist. But have a passion for electronics. It's hard for me to understand stuff at times. When I can't see it. But you have a great way of explaining what you are doing. It's really sad how trades people who know what they are doing can't teach in a public school system. Because they don't have a masters degree here in the us. The us is just making every one stupid. And they think every one is going to push a pen around.
You echo my thought exactly. Paper is paper, lets get the job done!
So does the EU , they don't teach children and adults to think but to obey and to repeat ( the lies )........future slaves who think they are intelligent and free .
Knowledge and experience doesn't count anymore, just like a fabulous cook can't work because he has not the papers .
Thanks you sharing your knowledge and also for mentioning that a variac does NOT isolate from the mains , to many are not aware ...
Our youth are not taught anything ! They are brainwashed and indoctrinated with what the elites want them to know. It is coming to a time when they will realize that their paper diplomas aren't fit to wipe their asses with !
People need to simply stop hiring people with indoctrinated papers! People will start hiring people with actual hands on experience ! Times are changing folks !
Nice video - thanks for the work!
thank you paul''''i really like how you cover & recover to make sure we get it'''''that is very nice of you'''''its great and your a great'''''''class act''''
My pleasure!
Steam punk cool! One thing I would change is to turn the dual gang box 90 degrees so the outlets are up and down. Maybe omit the 220 Volt trans. unless your in Europe!
Keep it safe. Cover the business below the top bulbs with a clear acrylic plastic. Awesome Paul!
Variacs have always fascinated me.
Fantastic as always!
Paul, thank you for this video, very informative ..
Your welcome Amado!
Very nice. I built a much simpler version of this that serves my purposes. I just have one bulb i can change of necessary.
One suggestion i would make is to have a double pole switch for complete isolation on your primary so you don't have to unplug the DUT every time you go to solder or move things. 😊