DIY Deluxe Dim Bulb Current Limiter

[@Ezzell_]

This is the best dim bulb setup have seen! You have a new subscriber!

[@jmanatee]

Thanks

[@carlosjorgefernandes1050]

kzbin.info/www/bejne/eGmZeJdjncmIbcU

[@lord_haven1114]

That’s so awesome! I love it. Thank you for providing it all for free

[@jmanatee]

You are so welcome!

[@scottthomas3792]

Two jobs ago, I had a very simple version...a basic extension cord from K-Mart, cleat socket from the shop junk pile, and a clear 100 watt bulb, all on a piece of scrap wood. This place was old and still had fuses, so a dim bulb tester was pretty much a necessity.

[@jmanatee]

Its a good tool to have!

[@williamwoo1437]

Very nice and thoughtful design 👍 Only concern is the banana jack power leads that can be dangerous for those being careless. But then again, one could argue that careless practitioners shouldn't even be near such works

[@jmanatee]

Doing any work on AC is dangerous. The point of this is to limit the current that can power the device or hurt operator. And it is fused to help protect you more.

[@sanelleric6121]

Made similar one a few years a go, working a lot on power electronics, such as power supplies and motor drives (mostly DC inverter air conditioner boards). Life savior. I've put and AC contactor and connected all 3 contacts as one, which bypasses bulbs when I push button for direct connection, after making sure there's no short. Also, 3 bulbs, each with it's switch, so I can make few combinations (7) of limiting input current.

[@jmanatee]

Very cool. I think anyone who regularly works on power electronics should make some kind of current limiting device. This has saved my butt a couple times.

[@sanelleric6121]

@@jmanatee Mine too. Ever since electrolytic capacitors blew in front of my face (long time a go, when I was a newbie), I was scare to death working with SMPS. I accidentally set switch for 110V input, and plugged it to 230V, back in the days on AT SMPS.

[@nekoizmase9969]

​@@sanelleric6121 do you have scematic / jel imas shemu da okacis link?

[@nekoizmase9969]

​@@jmanatee your webpage is offline?

[@sanelleric6121]

@@nekoizmase9969 Nemam kulturno nacrtanu, samo u svojoj teki za praktični rad.

[@acestudioscouk-Ace-G0ACE]

Nicely done, thanks for sharing.

[@jmanatee]

Thanks for watching

[@electronbob6676]

Your video is most appreciated, very helpful! I'm assuming that this setup would not be good for testing/troubleshooting an old microwave oven? .. thanks!

[@faceboxtv4789]

What is the formula to calculate the bulb wattage needed related to the device?

[@jmanatee]

Watt = (E / R) * E Where E =Voltage and R = Resistance

[@GlenBeer]

Great idea & video! The way you handled the live leads scared me .

[@jmanatee]

Thank you, Because its current limited when I have accidentally touched the leads it doesn't hurt... very slight tingle.

[@el_sturlo]

Brilliant design, thank you

[@jmanatee]

Thank you

[@cookcrazy]

Well - Thanks for the Schematic - Finished building this design today - Looks almost identical as I used the same project box. I decided I really didn't want the Banana jacks so I left those out, and rather than the duplex receptacle I used a range type snap in receptacle (Qualtek# 738W-X2/03). I don't have a 3D printer so to mount the 3 light bulbs I simply used 3 Leviton# 8101 Porcelain 2 part Lampholders - they fit perfectly across the top.

[@jmanatee]

Very cool! I Like the changes you made. I should have gone with the snap in receptacle....

[@PosthumanKindergarten]

this reminds me of a contraption i made, the "ballast board", in other words i screwed a bunch of different size fluo ballasts on a fiberboard and select em with hairdrier switches, you can configure up to like 200W and limit the current on a load, it has only two wires coming out, it seems silly but it's fairly useful, instead of finding the correct ballast or for adjusting the power finely

[@jmanatee]

Sounds interesting.

[@karljay7473]

Would there be an advantage to having the 40 automatically trigger on the 60 and the 60 automatically trigger the 100 with a current sensors or some other switch so that it self adjusts to the current that is being pulled thru it? I'm new to these and it seems you have to know in advance that the device would pull a certain current amount in order to select the right combo for the most protection... However, if you make it so that the weakest of the bulbs had a trigger of some sort, if it were consuming too much current, it would instantly trigger another bulb. Maybe a trigger that measures current and only acts IF the bulb is on. That would make it fully automatic so you don't have to know which combo is best. Also, what gain do you get by using the 40 sometimes vs the 100, is it better protection? Then maybe having an auto trigger setup, you could have 10 20w bulbs in a row, each on triggering the next ONLY if needed.

[@jmanatee]

The reason to limit the power is to protect the device you are working on and give you an indication that the device is using 40 or 60, etc watts

[@karljay7473]

@@jmanatee So what is the advantage of using one wattage over another wattage? Would using 100W all the time be better than sometimes using 40W and what happens if it draws a lot more than the 40W bulb will consume, doesn't the device still run the risk of damage? That was my whole point. If you don't know what the current will be in a short, you select too low of a wattage bulb, then you still have damage. If you select too high of a wattage, you don't get much light.

[@karllaun2427]

I like this design. Will the relay still function if you feed the AC through your variac at a lower voltage?

[@jmanatee]

relays will usually clamp at a lower then rated power, But once activated they will usually stay energized at a much lower voltage. If you are using this with a variac and bringing the voltage up slow you would probably want limit mode anyway

[@MichaelB-wm5cg]

Great explanation. Here in the UK we can't buy incandescent filament bulbs anymore. I wonder what could be an equivalent as simple current limiter?

[@jmanatee]

They are getting harder to find here in the USA too.... Can you order them online?

[@PBoard]

Yes we can, you just have to look

[@Crimsomnia]

Are halogen bulbs good for this purpose?

[@jmanatee]

You can use halogen bulbs but there wattage will be equivalent so a 100w halogen may only be 70watt

[@ultimateworkshop2000]

Hi there nice job, I like the way it defaults to current limit every time, but I didn’t understand it from the diagram how will it stay latched how comes its AC not DC, I really don’t get it 😊? Are those 120V LEDs ready made or you added a resistor to normal ones?

[@jmanatee]

They are regular LEDs I added a resistor to. The coil of the DPDT relay is 120v when you energize it one set of the relays switches powers the coil through a normally closed switch so as soon as the relay is energized it self powering the coil. Its "Latched" until power is lost or you press the normally closed switch (opening it) breaking the feed to the coil

[@ultimateworkshop2000]

Ok I got it interlocking relay I will search for one here in my country, hope the price is good, thank

[@PBoard]

I've got most of the parts to build this now, but what LED's did you use, please?

[@jmanatee]

Just regular LEDs with resistor inline

[@PBoard]

@@jmanatee Thanks, having read through the feed I found the answer, and found a few design alternatives since.. Can it be substituted with a 230v LED?

[@martyaussie4538]

@@jmanatee the resistors that were left off your diagram ;-) - Hopefully nobody has built from the diagram verbatim and then blown LEDs into the sky without the necessary dropping resistors. ;-)

[@PBoard]

I like this very much and want to build one. However, I'm slightly confused. When I look at the diagram vs your list of components. The SPSTs in your list are 2 pin, yet what I assume are the 2 switches on the diagram, those just above the relay, are 3 pin. Could you clarify this, please?

[@jmanatee]

the relay is a double pole double throw, the two switches are labeled NO and NC

[@PBoard]

@@jmanatee Thanks for your reply, I see that now 🙂The other contacts on the diagram are those of the relay? I have an Omron LY2NJ 10A DPDT, which I intend to use for this project.

[@larrymcnair6249]

How are you all getting incandescent bulbs now? All I can get locally is led.

[@jmanatee]

I got Rough Service Shop Light Bulbs on Amazon... I think you can still find regular bulbs on Amazon too

[@armmargret1970]

Clever tester design, I like the auto switching and the combination of different power levels. Not sure what your mains voltage is, but the way you handle the alligator clips is frightening. Is there a difference in getting electrocuted with and without power limiting?

[@jmanatee]

No difference

[@cookcrazy]

Very nice - Any chance that we can see inside? Would love to see how you have the relay hooked up - I am not quite picturing it from the schematic. The Momentary Push Button Switches and the Contactor got me a little bit guessing. Thanks for sharing...

[@jmanatee]

Well I am a bit embarrassed by the wiring on the inside but when I get home (on vacation) I can post a few pics on my website of inside

[@cookcrazy]

@@jmanatee No need to be embarrassed - Sure it cannot be worse than my rats nest wiring jobs LOL - Looking forward to seeing that contactor and latching - may get some ideas on how you got the LED& and resistors put together etc to make it a little neat.... I seen some nice pre-made units on Fleabay today all done up with the mounting bezel, LED, resistor, and wire pigtails, all shrink wrapped nice and neat.... always nice to see other's way to approach projects like this... always good ideas to be found...

[@carlosjorgefernandes1050]

kzbin.info/www/bejne/eGmZeJdjncmIbcU

[@paulperano9236]

Do you use an isolation transformer too ?

[@jmanatee]

Yes, absolutely, especially when using my oscilloscope, its a tripp-lite isolator IS-1000

[@jameswarren1831]

Is it possible to use the small HV halogen bulbs to save space and make it more durable?

[@jmanatee]

You can use halogen bulbs but there state wattage usually is the Equivalent watt rating not the actual rating (ie a "75w" halogen is actually around 55w) Also halogen bulbs run much hotter and usually they are more expensive

[@jameswarren1831]

@@jmanatee I totally forgot about the output verses actual consumed power. Thank you for the response!

[@martyaussie4538]

Is there a reason to actually need 3 bulbs? I have a dim-bulb tester with only 1x 100W lamp, and it indicates any piece of equipment with a short circuit (or very low resistance) in its circuitry. So, i'm trying to reason WHY i would ever need lesser resistance filaments in the 40W & 60W bulbs for equipment testing? Obviously the resistance of the 100W bulb allows enough current for fussy switchmode power supplies to startup which also gives me reason to NOT need the 40W & 60W bulbs. Maybe there's a scenario i haven't experienced yet?, but my dim bulb tested has been fine for all the valve radios, guitar amps, vintage hi-fi and computer power supplies over the decades of restoring & repairs that i've experienced. with thanks.

[@jmanatee]

No this is a luxury, I used a single bulb current limiter for a long time. I just wanted to improve it. I always start with 40watt bulb to get an idea of how the repair is going.

[@jjoeygold]

If my motor/power supply is 500W what would be the suggested globe wattage?

[@jmanatee]

It isnt what your supply is it is what the load needs so If the motor requires 500w then you would need 500w of bulbs

[@jeffnay6502]

I have a vintage IMSAI 8080 computer that appears to have two shorted diodes. So when I apply power the 5A fuse blows. I could simply replace these diodes and the system will more then likely work. However I have just purchased a Dim bulb current limiter and want to test the effectiveness of this device to see if it will limit the current and allow me to apply power to the power supply and test the 3 output DC voltages, to see which voltage is working and which is not working. The IMSAI is a valuable piece of history, so as I have never used one of these testers before, I am a bit concerned that it could case further damage to the power supply that already has a short circuit. I did pick up a couple of 15W and 25W bulbs for the tester, as it ships with a 100W bulb. Which is probably too high. All the computer boards have been removed and power has also been removed from the main (bus) board. So just the power supply will be effected. Which is mainly a large transformer, 3 large capacitors and several diodes and that is about it. Should I be concerned with apply power to this system with the known short on the two diodes controlling the -16V rail??? Could any problem arise from the shorted diodes that would effect the capacitor or the transformer of this system???

[@jmanatee]

You could start with the lowest wattage bulb to see if it is enough to test the voltages

[@leonardpeters3266]

I really like this design. Best part is that it comes up in limited mode. I would appreciate the relay part number and the current limiting resistor sizes for the LEDs. If you could provide those I would appreciate it.

[@jmanatee]

The relay is Omron LY2-UA-006244 Relay... I can't remember the exact resistor but I think it was either a 5.6k or 10k 5watt in series with a diode. Although the LED is a diode it can have trouble with the reverse current thats why I added the diode.

[@vernonbosshard9317]

I like this design, plus you showed the diagram, in other videos I have to stop the video at a certain point to get a small glimpse of it, frustrating. The sound on the video is good, no echo or low volume. I would add an output voltage and amp gauge. I might add a GFCI outlet, just in case of a dead short to ground. I've used one before and it saved my fuse and my ass.

[@jmanatee]

Thanks, I have the schematic and 3d print files on my web site. I like the ideas for GFCI and gauges Version 2?

[@HIDLad001]

This is definitely better than the ones that just use a socket adapter and a regular outlet,

[@jmanatee]

Thanks I agree

[@carlosjorgefernandes1050]

kzbin.info/www/bejne/eGmZeJdjncmIbcU

[@a2phil]

I'm a newbie, forgive the possible stupid question, can this be used in place of a variac, or (even better??) with a variac? KE8NFK

[@jmanatee]

it wont replace a variac but can be used with a variac

[@johnfitzpatrick2469]

G,day from Sydney Australia. Wow fantastic invention. Would another way for the same purpose; Bench power supply LCD of V and Amp with a meter between cables to appliance measuring Amps? You could limit or set V and detect if a short exists because no amps are passing through the short? 🌏💫

[@jmanatee]

Bench supply works great for DC applications. With AC you could use a variac and amp clamp but a dim bulb is a quicker more protective way

[@mixinginthebox]

Nice ty!

[@jmanatee]

Your welcome

[@t1d100]

Nice project.

[@jmanatee]

Thanks

[@garygranato9164]

why not a bulbs with clear glass so you can see the filament ?

[@jmanatee]

That's a good idea but due to new laws, incandescent bulbs are getting hard to find in the USA

[@Tysman909]

I want one, right now just use a variac and isolation transformer for vintage electronics

[@jmanatee]

They are very helpful

[@amsoiltek]

@@jmanatee How does the relay get along with the variac? I'm sure it won't stay latched.

[@jmanatee]

@@amsoiltek It will stay latched at 70v and fall off at 60v

[@electrolatif]

You get new subsrib 😊 great job If you use bulb G5.3 your bulb tester will be smaller, just order today my G5.3 bulb 50w hope will be work fine I will try do like your tester but smaller😅

[@jmanatee]

Thats cool but I think g5.3 bulbs are halogen and the actual wattage is less then there stated wattage just so you know when using them

[@electrolatif]

@@jmanatee i will update to you after i try them🙂 also i will check also actual wattage

[@RGD-Games]

Ahh, so you have 3 bulbs. All of different wattage, for more or less current to the device? So a 40w gives the device connected, less power? And 100w gives most power? So when testing an amplifier for a short… the 40w bulb would severely limit the power that the amplifier receives, compared to the 100w bulb?

[@jmanatee]

Correct but you can also do combination 40, 60, 100, 140, 160, 200 watt by using single and multiple bulbs at the same time, I also have a couple 150w bulbs if need be for up to 400w 2x150 1x100

[@chiraldude]

Do not rely on a current limiter for safety! 10ma is enough to cause uncontrolled mussel contraction "can't let go". 100ma and above across the heart will interfere with heart function which means high probability of death!

[@jmanatee]

You do understand that this device is to assist in working on AC devices. Doing this by its very nature is dangerous. If you do not feel comfortable working with electrical devices. Don't.

[@garygranato9164]

i doubt that 10mA will cause you to lose muscle control

[@breakthru3000]

nice tool but handling AC mains like that is dangerous. always unplug the power cord when touching live wires (dont trust the on/off switch).

[@jmanatee]

I have heard that before...

[@andydelle4509]

I noted you are using a switch mode power supply to demonstrate your dim bulb project. But I think the audience here needs to know that switch mode power supplies and dim bulb testers are often a bad mix. As a switch mode power supply is non-linear, it doesn't work well with a linear current limiter. It may not start up but rather pulse on and off. As there is a line operated rectifier and large capacitor on the front end, even reduced current can still easily take out the switch transistor or MOSFET due to capacitor storage. This warning also goes for UPS units and motor VFD drives. The primary use of dim bulb testers is older pre 1990s electronics that used linear power supplies. And most calss B audio amplifiers which still mostly use a linear power supply.

[@jmanatee]

Although I was just using that SMPS for demoing the dim bulb I built. Current limiting an unloaded SMPS during repair is not uncommon. A lot of SWPS use some form of current limiting to ease the inrush current during power up. Something like a series NTC (negative temperature coefficient) thermistor.

[@mikeadler434]

👍👍

[@jmanatee]

Thanks

[@fed9096]

you should sell yours, I would buy one! 😅

[@jmanatee]

Thanks,...

[@craigs5212]

You do realize a 40W, 60W or 100W LED bulbs don't draw 40, 60 or 100W. That is just fake number that represents the equivalent light output of normal old time filament light bulb. In rough terms the actual wattage of those LED bulbs is only about 10% of those numbers. Most LED bulbs have switching power supplies built into the base and are not just plain resistive loads and useless as a current limiting device.

[@jmanatee]

I do know that, Thats why I used incandescent light bulbs The kind with plain old resistive filaments. The LEDs the previous comment was talking about were the indicators for Full or Limited power

[@jjoeygold]

@@jmanatee Can Halogen Globes be used (assuming they have the same real wattage as incandescents)?

[@jmanatee]

@@jjoeygold Yes as long as you know the real wattage

[@barryandersen1]

Please change the name of your channel. When searching "jmanatee" all that comes up are manatee videos.

[@jmanatee]

I know its a problem but I have had this for decades.

[@misterbonzoid5623]

Don't you have Safeblocs in America? Those banana plugs and croc clips are hideously dangerous, uninsulated and right in front of you.

[@jmanatee]

This is used for testing and repairing electronics Yes it is dangerous but so can testing and repairing electronics.

[@stevenbliss989]

You love to live dangerously! Holding onto the two alligator clips horrified me, and I think BigClive would also freak out!

[@jmanatee]

Sorry, Living more like ElectroBOOM

[@stevenbliss989]

@@jmanatee :), ...stay safe man!

[@jmanatee]

@@stevenbliss989 Thanks will do

[@richardplatko7532]

Lol funny. Oh yeah shout out to Big Clive and Electro boom. Thanks again for the contest, jmanatee. And thanks to all the other channels that I love. You guys are the best!