I think the point of the dim bulb tester is something workable for those who cannot afford a Variac - they're relatively expensive. 100s of $ retail, last time I looked.
I could connect mine downstream of my AC isolation transformer, though my digital AC watt meter - with voltage and current displays.
Some still would like to fix or scope something's condition out without all that 100s of $ expense - after all safety, convenience, accuracy are expensive. But, you dont have to be stuck without spending on it.
2nd hand or in like surplus stores, I have seen them often sold for less than 25-30 bucks in the US.
Bought one about a year ago.
New on Amazon, they are about $50-70. Or similar priced for higher power 2nd hand ones for better quality.
see:
https://www.surplussales.com/Variacs/index.html (great store btw, I order there as well! 🙂 )
https://www.amazon.com/s?k=variac&rh=n:16310091,p_72:1248921011&dc=&ds=v1:giFmE1Kd7Lh4zO/wIuT0gIfonaMjLCmHhlkIEdCQQWA
There are plenty of others.
So I have no idea why you say they are hundreds of dollars, because they are simply not?
But if you talk about safety, working on such equipment without a VARIAC (better in combination with an 1:1 isolation transformer) is a no-no anyway.
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simple ones don't cost as much.
I know my Sencore one was expensive. But I paid that premium price long ago in the heyday of television repair. It also has other functions like the leakage test for neutral bonded chassis. The musician idiots call them "death caps" because some guitar amp manufacturer didn't use a polarized cord like they should have and their customers got a 50/50 chance of getting a small electrical shock when their cap started to fail. There was nothing wrong with that circuit. The manufacturer just didn't use the correct power cord. Nor I think the techs in that sector knew what us television repair guys knew about them.
I assure you I didnt pay that for the units I have. I did sell one that was new and got good money for it on ebay.
The ones I use/used at work were also proper ones.
Those are pretty $$$$ yes.
Also up to 5kW or something crazy.
At home I really can't be bothered.
Got some very cheap one 2nd hand, wiring was of factory horrendous;
https://www.diyaudio.com/community/threads/warning-about-cheap-variacs.370831
The transformer itself however is just totally fine.
So build a nice case around it, put some fuses and meters with it and you're done for cheap.
If you don't wanna put all the effort and time in it, find some wooden box or whatever somewhere.
At my family in the US it was even cheaper, since I just wanted to have some fun in the summer with some old tube radio.
So got a little VARIAC for I think $15-20 at the local surplus, and literally put it in a plastic yoghurt container.
Measured the output, drew a scale on it with a marker, put a fuse in it and found a knob that fitted.
It ain't pretty, but does the job fine
A bit of creativity can bring you very far.
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Totally believe you, but you made it sound that they are very expensive in general. 🙂
Here is another idea, get something like this;
https://www.amazon.com/NOYITO-Current-Detection-Sensor-Module/dp/B07HWDS121
(Just an example, you can also make it yourself!)
Desolder the little multi-turn pot, put a regular pot on it and make a little scale.
Change the threshold value accordingly to the power of the amplifier.
Maybe need to modify it a bit, since 5A is a bit much (especially for EU standards).
Also a softstart might be handy in combination, otherwise it might trigger to quickly.
You could also use it in conjunction with like a big fat resistor or PTC.
Or use multiple ones.
https://www.amazon.com/NOYITO-Current-Detection-Sensor-Module/dp/B07HWDS121
(Just an example, you can also make it yourself!)
Desolder the little multi-turn pot, put a regular pot on it and make a little scale.
Change the threshold value accordingly to the power of the amplifier.
Maybe need to modify it a bit, since 5A is a bit much (especially for EU standards).
Also a softstart might be handy in combination, otherwise it might trigger to quickly.
You could also use it in conjunction with like a big fat resistor or PTC.
Or use multiple ones.
To each his own. I never even bought a Variac, ever, always lightbulb limiters.
My point being they are automatic , not requiring my attention which is focused in something else: the broken Amp I am trying to repair.
Many times something starts "working", sort of, and then suddenly shorts or something inside plain explodes, a cap bursts, transistors in series in a totem pole output stage short in succession (one shorts, the one in series can't take it and also shorts).
I am not that fast when dropping everything (I might be soldering something, holding meter probes on a high voltage spot, etc.) to grab Variac wheel and turn it down.
Bulb filaments have no thermal mass to speak of and react in a second or less.
There are also amps which "start fine" ... until you apply signal or plug something at the input or warm up ... or ... or ...
I do not feel protected against that by a Variac, at all.
So in my case, speed and "automatism" win the race, big time.
Others may differ, of course.
Ps: almost forgot, they also work beautifully as a soft start, by definition, and as "never burn" fuses.
My point being they are automatic , not requiring my attention which is focused in something else: the broken Amp I am trying to repair.
Many times something starts "working", sort of, and then suddenly shorts or something inside plain explodes, a cap bursts, transistors in series in a totem pole output stage short in succession (one shorts, the one in series can't take it and also shorts).
I am not that fast when dropping everything (I might be soldering something, holding meter probes on a high voltage spot, etc.) to grab Variac wheel and turn it down.
Bulb filaments have no thermal mass to speak of and react in a second or less.
There are also amps which "start fine" ... until you apply signal or plug something at the input or warm up ... or ... or ...
I do not feel protected against that by a Variac, at all.
So in my case, speed and "automatism" win the race, big time.
Others may differ, of course.
Ps: almost forgot, they also work beautifully as a soft start, by definition, and as "never burn" fuses.
Over here in Germany they have banned incandescent lightbulbs a long time ago and they are still available for a price - even at 300 Watts.
bulb
While I haven't read the law in its details I am pretty sure there will always be exemptions for scientific, military and other special applications. I am sure the incandescent lightbulb will never truly die just like vinyl or petrol cars.
bulb
While I haven't read the law in its details I am pretty sure there will always be exemptions for scientific, military and other special applications. I am sure the incandescent lightbulb will never truly die just like vinyl or petrol cars.
40W appliance bulbs are readily available -- and there are heavy duty incandescent available if you search.
(i was an early adopter of LED bulbs, now I find that when you have multiple LED bulbs, such as a dining room chandelier, they all flicker like a strobe.)
(i was an early adopter of LED bulbs, now I find that when you have multiple LED bulbs, such as a dining room chandelier, they all flicker like a strobe.)
I'm annoyed at the number of components in LED lamps that just go into landfill once they don't reach their claimed lifetime. I have an open set of ceiling lights in the kitchen that uses R50 style bulbs. Have tried both halogen incandescent and LED, but neither lasts longer than the old incandescents, so although they may use less energy, the other claims are BS. They need to produce better designs to handle the thermal side of things and MAYBE they might get tens of thousands of hours of life...but not while the electronic components are sealed in small, unventilated housings.
Yes, temperature/ventilation is most important, and built in heatsinking is marginal, it needs all the help it can get.
I get long life out of generic supermarket sourced lamps BUT since I need strong white concentrated light I routinely remove plastic diffuser bulb, that already increases ventilation, specially of the aluminum backed PCB where LEDs are mounted, and also use them in open fixtures, never in enclosed ones.
That makes all of the difference.
Here I cut the plastic bulb all around leaving a 10 mm skirt for easier handling but worst case you can remove it fully.
They literally last forever.
Notice they are basically screwed into open ceramic sockets.
No reflectors or screens needed since bare LEDs emit light forward in a narrow 60 degree cone.
Yes, white bright light can be harsh, and blinding if you stare straight at the naked LEDs ... simply don't 😉
I get long life out of generic supermarket sourced lamps BUT since I need strong white concentrated light I routinely remove plastic diffuser bulb, that already increases ventilation, specially of the aluminum backed PCB where LEDs are mounted, and also use them in open fixtures, never in enclosed ones.
That makes all of the difference.
Here I cut the plastic bulb all around leaving a 10 mm skirt for easier handling but worst case you can remove it fully.
They literally last forever.
Notice they are basically screwed into open ceramic sockets.
No reflectors or screens needed since bare LEDs emit light forward in a narrow 60 degree cone.
Yes, white bright light can be harsh, and blinding if you stare straight at the naked LEDs ... simply don't 😉
Getting off topic talking about led lamps but I do the same and cut off the diffuser, I est you get almost twice as much light out and allow them run much cooler. I am finally getting to the point where the older compact cfl are eol and time to replace with LED
The older LED bulbs had a driver board behind the LED board, they could use a drilled hole for ventilation, the tapered conical housing is usually a functional heat sink.
The new ones are driver on board, and if you wish, a few holes / slits in the diffuser can be made for ventilation.
Prices are now down to 4 cents for 9W driver on board assemblies, in bulk quantities.
Considering the amount of parts and work involved, it seems difficult to achieve, the more expensive ones are 15 cents.
And durable if properly used, I have LED bulbs running since 2016, in open air, not inside housings, and indoors.
At 900 lumens, about the same as a 2 foot fluorescent (20W + magnetic choke = 30W) and 11W CFL (27W with magnetic choke, cos phi is 0.4), even 11W on electronic ballast will draw about 13W, and last less than LED, because of filament start currents.
Attempting to repair a 4 cent part is futile, best put a MOV or other high voltage limiter on your mains, that helps a lot.
The new ones are driver on board, and if you wish, a few holes / slits in the diffuser can be made for ventilation.
Prices are now down to 4 cents for 9W driver on board assemblies, in bulk quantities.
Considering the amount of parts and work involved, it seems difficult to achieve, the more expensive ones are 15 cents.
And durable if properly used, I have LED bulbs running since 2016, in open air, not inside housings, and indoors.
At 900 lumens, about the same as a 2 foot fluorescent (20W + magnetic choke = 30W) and 11W CFL (27W with magnetic choke, cos phi is 0.4), even 11W on electronic ballast will draw about 13W, and last less than LED, because of filament start currents.
Attempting to repair a 4 cent part is futile, best put a MOV or other high voltage limiter on your mains, that helps a lot.