But leds will break as short circuit and a neon bulb will just not light up at all while being highnimoedance. So it‘s much safer with the neon lamps I suggest 🤔
I assume this is the same as what I was taught. One hand gripping my belt behind my back. Should any current be induced in the body that hand would hopefully clench up and be prevented from closing the circuit across the heart.
Left hand in the pocket was allegedly begun by Nikola Tesla (I don’t buy it myself) because even while he was working, it was known that current passing through the heart could stop it, and avoiding current passing into the left hand lessened the possibility of stopping your heart.
There is no such rule! It's advice! And it's a pretty dangerous one if you are on ladders, fault finding some lights on a ceiling, as you can lose your balance and fall off with one hand in your pocket! Pretty daft idea!
Clive, don't forget that a neon has a 50v strike voltage. So with a neon, it'll only light when above 50v. With 3 leds, it'll light up at any voltage above around 10v. Yiu need a zener in there... 😀
Interesting. I'd like to see some measurements for both versions. Actual current for a start, if you've got a meter sensitive enough, both grounded and non-grounded. Also voltage drop across the screwdriver and across your body when grounded. I've a feeling the neon drops a higher voltage than the LEDs, so would be considered "safer". Using ordinary 3 or 5mm LEDs instead of the tape might give better all round vision, although the neon ones tend to have a little "lens" over them so you can see the tiny glow better.
I think the Neon lamps are safer and last forever in such application. The fact that diodes fail short is disconcerting. Neon lamps have two plates separated by gas, not much can go wrong there.
Even if the LEDs fail short it would still be safe. That's why it's better to use the version with several resistors in series to spread the voltage and keep it safe even if a resistor is shorted.
I was thinking the same thing. Some circuits I have seen, which take a voltage reference from the mains, do so with a whole stack of resistors in series for safety. The classic neon screwdriver uses just one resistor, and my thinking was that neon bulbs added the additional protection.
Yes, the problem with a series string of diodes is that they don't share reverse voltage equally or in any specified way since it depends on the leakage current vs reverse voltage curve. Your third option with three independent groups of LEDs looks more attractive.
In re green LEDs being the most efficient: it's also the colour to which our eyes are most sensitive. I did an SYS project on this and having got the wrong answer during my interview I will never, never forget that the wavelength which appears brightest to human eyes is 555nm.
Green LEDs are actually among the least efficient in terms of actual light output. The high brightness per watt is purely down to our eye's sensitivity. From memory, blue LEDs are the most efficient by far (largely driven by the huge demand for efficient white LEDs).
Here's a true neon screwdriver tale: I had a close call being up on a ladder many decades ago in a friend's factory in London checking to see if a 440V panel is dead or not before ripping it all out and redoing the connections. On that day I didn't have a neon tester so instead I was using a multi-range tester, holding the black and red probes one in each hand while leaning forward to the electrics to stay on ladder. I carefully dabbed the probes to various places but didn't get any voltage reading at all, it didn't make sense and it completely messed up everything I had planned out. All I got was the reading briefly just tiny jump slightly from zero when I made the probes contact. I wanted to confirm the voltage was there first then shut off that circuit only. So I just came back down from the ladder, very puzzled, I then packed it in until the next day. Next day I came back in to repeat and then I noticed.... the tester was switched to DC VOLTS instead of AC. DOH! I was THAT close to a major calamity but my '6th sense' + logic had saved me. If I had instead a Neon Screwdriver in one hand then I wouldn't had needed to have a 6th sense + logic to protect me. = much safer.
@@jor7137 Very good point..... if the metal ladder I was up on had been instead made of insulating plastic, but a wooden ladder that's more feasable. I'd still be puzzled all the same why a neon hadn't lit up for me first before I'm ready to cut the power, then I wouldn't had proceded any further by default. I just now remembered all those decades ago when I used a wooden ladder: I would leave a reel of insulated cable down on the ground and then carried up the loose end with me still insulated. Then came out in the 80s the non-contact LED 'volt-stick'. I guess if I'd used that the combined wood together with proximity acts like an almost short-circuit impedance? This all just neatly proves: *the most sinister and deceiving failure of a safety feature - is the one which is believed to be reliable*
@@jor7137 By the way had you seen that YT video of the HV (500 kV?) line worker on a platform attached to a hovering helicopter, clipping on dampers one at a time to each live phase wire. There was a huge long spark in front of him as he approached. He definitely wouldn't had needed a neon tester!!
@@jor7137A neon tester would still work even if the ladder was insulated . They work even if you are wearing electricians safety shoes. If the path to ground is blocked by an insulator such as a wooden ladder , neon testers will use the capacitance of your body to function. Any insulation such as rubber soles or wooden ladders, become the dielectric of a big capacitor where your body acts as one plate and the Earth as the other. Try it , you can jump in the air while one of these things is glowing , and as long as it stays connected to the live, it will continue to glow.
The thing to remember is that even with the good old Martindale tester you were still instructed to test it on a known live source before using it! Worth remembering if it is hardly ever used and gets damp/corroded in the bottom of an old tool bag and goes o/c! Common sense and a little electrical knowledge can go a long way!
The neon bulb has high enough resistance to prevent a lethal shock even if the megohm resistor fails short circuit. The neon also has other uses checking for microwave leakage or standing waves on an antenna circuit. LED’s offer no protection, hence your suggestion of using three resistors in series. Fifty years of using neon screwdrivers as a quick sanity check gives me a degree of faith in these simple devices that I don’t have with the all singing and dancing high tech solutions today. Yes, you do need experience of how to use them properly and appreciate that no light never means a guarantee of no voltage!
The impedance of a neon lamp once struck is quite low. Certainly low enough to carry enough current to be dangerous, tens of milliamps if not more just for a small indicator lamp. It would be highly dangerous to rely on the neon to protect you if the current limiting resistor failed short.
Nice video there and interesting as well. I prefer the definite brightness of the LEDs as I have found on occasions it is difficult to tell if tge neon has lit up or if it is a reflection off something else. There will be the traditionalists out there that will prefer neon over anything as that is what they have used for the last 20 years but they fail to remember that before these testers we used apprentices to test for live wires, if they made a mig of tea afterwards it was safe to work, if you needed the plasterer to repair a human shaped hole in the wall it was still live 🤣 Obviously the last part is a joke but the traditionalists will still favour neon 👍
It's a nice idea. Much though I love neon testers, and believe that alongside their great value as a cheap and simple diagnostic tool, they are invaluable as safety equipment. I have heard tell of - and experienced personally, countless instances where their ease of deployment has given timely warning of an unexpected live. Some people bang on about them being electrocution hazzards, and sure, this may well be possible if one plays submarines with them before use, but I haven't heard of one electrocution occurring via these devices , yet I've heard as I say, of countless instances where danger was averted due to them. Their greatest drawback , is their dimness , which makes them unsuitable for use in bright daylight. Making such a tool brighter as you have done, has to be a good idea. Another drawback they (neon testers) have , is that they are limited in the voltage they can safely handle. For most home DIY ers this is not a problem, as most of us will only be probing 240VAC. But they can cause electric shock if inadvertently used on voltages higher than their rating. As an edit. I'd like to add that although as I said, electric shock could occur if neon testers are used to check voltages higher than their rating. I mean shock - electrocution even so would be difficult. If we consider the ballast resistor in the tester to be 1Meg ohm, than to pass a current of 7mA , which the smallest current known to be fatal (across the heart ) , 7000 volts would be necessary.
The green light usually indicate that something is acceptable. In this case it can indicate that it is acceptable to touch the wire which is currently tested. Some other color could be better in this application.
Our eyes are very much more sensitive to green light. If one were to observe a green and a red laser beam of the absolute same power levels, the green beam would look MUCH brighter to our eyes, even though the beams are both the same in terms of output.
Very informative video, doubt I’d touch the end on live connection, I will stick to vde 1000v compliant test gear, but respect to Clive, and respect the beard 👍🏻
Used to love proper neon screwdrivers, they're great for detecting the presence of high frequency AC, you just hold the body of it near to the source and if it's energised the neon glows. Dead handy for working on old CRT tellies and radio gear because it takes a good whack of radiated energy to light it up..
The neon has a much higher threshold which could be useful. To duplicate the effect a couple of back to back zeners in the 68V range in series could be added.
@@pjeaton58 Transzorbs are much better for transients and less accuracy on the point at which they start to conduct. In this application I'd stick with zener diodes.
Very good led conversion you made there Clive. The LED's are a lot brighter. I thought that most LED strips are power hungry. A high efficiency LED can glow at currents well below 1 mA.
If I recall when I was working on human interface with mains voltage we had to allow for any direct path where humans could touch live would require a limiting resistance. We had to assume a resistors could become s/c or o/c. Safety resistors were too expensive, and not all approval bodies would accept them other than the ww type. So in order to say create a 330k resistor, we would need to use 4 resistors (a parallel pair of 330k and then another 330k parallel pair in series). The ww fusible resistors only went up to about 1k, and you needed to limit current to a few uA. This meant you had to use around 1M for a 253V AC rms (240 + 5%). Fun fact neons need a few photons to cause the gas to initiate the flow of current between the electrodes, even after the striking voltage has been reached. If you wanted to use a neon in a dark /sealed environment (relaxation oscillator or as a voltage regulator), you needed a small light source near it or to cover the inside of the neon bulb with a bit of phosphorus that will glow due to electron radiation from one of the charged electrodes.
Interesting. Mine has a different design. It contains spring which is connected to the red cap and is pushing to a glass fuse where the fusible wire was replaced with a neon and a resistor inside. But sadly the transparent plastic cracked and the red cap fell off and when I glued it back the glue covered the fuse with a white film overtime and slowly terminated the connection between the spring and the "fuse" so the neon won't turn on anymore. I hope they will make these simple test screwdrivers with LEDs instead. And it looks nice with the green ones. But I like the neon variants too.
Although it could be seen with green only, having different colors for each polarity would quickly tell you the direction of flow or if it is AC vs DC current.
I built a tester after getting new green LEDs, It works great, even in a lighted area. Being that I am only using this on 120 vac I reduced the current limiting resistor to 220k. Tested it with one finger on the tester and an adjacent finger directly on a ground, absolutely no sensation of shock. It stays below the 400uA threshold for sensation
I still use a neon or a volt stick when pulling a switch or socket off the wall in an unknown house, it’s amazing what you find, and I don’t like finding current with my skin. ( Why the hell is it always the tender skin on the inside of my elbow !?)
The LED version is probably better by all accounts, but I prefer the neon one just because it’s neon and I prefer the aesthetic. (I own a Nixie clock for that reason too).
I really like the LED version much better than the Neon just due to the fact that they are way brighter...especially when on a grounded source...easier to read in a bright environment. Have you thought about making a small batch of these tester replacement boards...maybe even recording the process too? I have been missing your longer videos...I even rewatch several of them over & over again :)
LED is bright & easy to see. But neon is indestructible! Won't fail ! And Even if a high voltage is applied it won't electrocute you! Raj (Chennai) India.
I must defend the the much maligned neon screwdriiver and your improved LED version. I was brought up on this device when Avos other testers were too bulky to carry on a push bike and providing you understood the limitations as you must with all. test gear. I was once sent to investigate why shocks were being given from a cold water tap, the neon tester lit when placed on the tap! Of course the tap was not alive but the floor was, reaching in through the doorway and digging the neon screwdriver into the wooden floor there it was. The floor was soaked in moisture and chemicals and was conducting from a faulty heater next door
FWIW: When I was a kid I did just a bit of 'messing around' with a couple of small neon bulbs. {This was back in the 1970s.} I had {and think I still have} a small hand-cranked surplus magneto generator I would hook to one bulb to light it. I also THINK at one time I had one bulb attached to a wire or small antenna {or SOMETHING} outside my bedroom window that would illuminate when a thunderstorm was nearby. Living in Saint Petersburg, Florida {USA}, afternoon summertime thunderstorms were a fairly common occurrence...😊
It may be easier to do an LED version that fitted in the larger version of those electrical test screwdrivers. If a pair of RGB LEDs was used, they could be configured in inverse-parallel with a resistor for each pair. The resistances could be chosen to give a particular colour, possibly including one approximating a neon.
Great video, thanks Clive! If I might add: I think the neon being a tad safer as their failure mode is generally open cct whereas LEDs is a more 'direct' connection. Either way its 'only' mains voltage.....(he said while schmoke billows from his brightly glowing ears and now badly burnt nostrils, hair on fire) 😂 Also: money shouts louder than safety: neon wins due to being the very cheapest implementation of this design!
Reminds me of the "significant hit" I had from a (probably Chinese) VERY cheap Neon tester decades ago! Made a very basic version of this using two red LEDs in inverse parallel, and a 500k resistor. Bright enough to almost read a book by , and I wonder where that device is now -= somewhere in the garage I suppose 😀
500k will deliver letal current when used on triphasé 400v. Also you probably used a 250V resistor which will arc on the 310v part on the top of the wave, which can kill you in 0.2 s.
Never thought it would be this simple to use LED's in one. It makes me wonder whether one couldn't make a nice little decorative light without a neutral connection. Super simple design and looks really nice with the slight flicker.
That's called the antenna effect. It's technically capacitor efect. I see it every day when leds are used with very long wires, they glow even when switched off.
@@memejeff It happens in most wall switches that include a witness (the witness may light in the wrong situation) (Legrand Mosaic, Celiane, or Plexo using LEDs like 067686 ), or alarms like Legrand 076671. It also used to happen with LED bulbs used with halogen regulators: even switched off, leakage current could still light the lamp; recent regulators now fix this issue. You can also fix the issue on the bulb side by adding a parallel 0.1uF X2 capacitor (X2 does not means times two, but the letter hix two is the capa classification).
Clive, you can get 350 volt resistors type MFR4-1M0FI from uk Farnell (code 1100042): Through Hole Resistor, 1 Mohm, MFR, 500 mW, ± 1%, Axial Leaded, 350 V I normally use this type for the start-up resistors in SMPSUs. Usually 2 x 47k.
In the old days, the neon bulbs are brighter and lighted bulb can be seen easily. Nowadays the neon bulbs are poor illuminated that may be seen as no high voltage and caused electrical shock. For safety, I use clamp meter with NCV for AC high voltage non touching testing.
I was taught to keep a hand behind my back working on TVs as a lad. Nobody mentioned it during my later education, even though most professors had long white beards. I still automatically do it if I'm poking near dodgy voltages.
In general, electrical engineers and contractor frown on neon test screwdrivers as being dangerous and unprofessional. I personally have always found them useful, provided they are used with caution and with awareness of their limitations, such as not probing excess voltages above 400 volts peak breakdown voltage, so basically limited to mains 230 volts. Though in my day it was 240/250 volts A.C.. In their heyday, the neon bulb was constructed like a fuse, with a glass tube with two end caps. The series resistor was specified to provide a good margin of flash over protection. The neon was designed to strike when the voltage between its end caps was between 60 to 90 volts, though they might start glowing at voltages as low as 42volts. They were specified to light at 100 volts. I suppose the main weakness, was that the glow was not that bright, and depended on the user providing a good earth with their finger touching the end cap of the screw driver. In the days of valve TVs, there were some times used in the highly dangerous practice of detecting the CRT EHT field, this did not require touching the end cap. Their greatest virtue was simplicity, not an a attribute that could be used to describe the very dubious modern alternatives, that require a stack of button cells, and contain a microprocessor circuit. The advantage of the neon bulb over an led solution, is that it operates at a high voltage, but very low current. The little neon fuse like bulbs were once common components. My very first stroboscope was made with one of these neon bulbs mounted in a bicycle front light reflector It worked, but was not very bright. I think you should flash test your LED version, as that is the critical parameter. I certainly prefer your version to anything containing batteries. Not sure that such test screwdrivers have much of a future. Their reputation has been damaged by the cheap Chinese imports, that use inadequate components, that make them very unsafe to use. Professional electrical engineers want such testers banned, so they may disappear as a result of some EU directive.
Also another thing these devices are useful for: to find which conductor is the phase. Yes, in an ideal world conductors have the proper color and everything, in the real work you open a derivation box and you find all black conductors, or colors that make no sense at all. This is why in my country this device is called "cercafase" that is phase finder. Another less common use case is to touch appliances to know if they are grounded correctly. If you touch the metal case of an appliance and the earth is not connected the neon will glow slightly. This is because the filter capacitors let some current (not enough to be felt or to trip an RCD) to ground, that is enough to illuminate the LED. Or in general to know if a ground is good, for example if you touch with the scredriver the earth and the neon illuminates it means that that earth is not really connected to ground. That could indicate a break in the cable. Of course these are not scientific tests, but a cheap test to do to find potential problems, that then will need to be investigated with the proper testing tools.
I feel like there could be functionality added to this with a couple transistors so that a green would show 12v (ac or dc), yellow could be 120v, and red could be 240v. I don’t know how to design that, but I bet Clive could.
That would be pretty cool but the idea here was to be stupidly simple. Actually im pretty sure its not possible to get 12vdc to show up wireless like this, you need a ground wire.
@@snigwithasword1284 Yeah - I was unclear on the operating principle of the light. I didn't think it was using HUMAN FLESH as a virtual ground. Maybe it would be possible with some sort of boost converter? It's quite possible that I have no idea what I'm talking about.
It would be interesting to read the current in µA. The green LEDs are acting similar to LED lamps that continue to glow dimly after the power is shut off due to leakage currents.
Good quality Green LEDs need only a few hundred microamps to look reasonably bright. It depends a lot on the quality of the LED; there are so many shysters selling LEDs with defects, especially ones with bubbles in the clear epoxy. If you buy LEDs that are not mounted on tape, there is a high probability they're factory culls.
I've experimentet quite a bit with leds and ultra low currents to recreate tritium keyfobs. Green doesn't work that well. White (warm white as low as 1800k 3535 leds) are by far the best. They can be seen at normal room brightness at as low as 2μA. Green takes ~10μA to be as visible. The second best are blue and ice blue leds followed by some kind of pink. Red and yellow are the worst taking >20 μA to be even visible at lower light conditions.
I'm sure you must have used the older ones that had a screw on end cap, which was always handy so you could tip the water out of them after picking it up out of the puddle of dirty water you'd just dropped it in, that would have been shortly before your teeth were rattling around in your head 😮
I would feel quite safe using this LED one because I've no problem in slightest touching via 1 MegOhm to mains voltage, but there's only one thing which I wouldn't do, even though it was safe and that was touch to an earth to get a brighter signal. It's because there's a 6th sense inside me inhibiting me do that even though in this case unlikely anything bad would happen.
Speaking of neons, I was originally thinking of using blue neons for my "vintage style" VFD clock (mostly because blue LEDs wouldn't be "period correct" since I'm using soviet era VFD tubes from Ukraine) for the ":" between the hours, minutes and seconds. However I wasn't sure they'd be happy about switching on and off every half second, or if they'd be bright enough to match the VFD tubes. Then I thought of getting some of those tiny grain of wheat bulbs used in model railways and etc. and painting the bulbs blue or using a blue filter film. So I tried a blue alcohol ink pen, and rubbed off far too easily. Next I got some blue filter film from the art store and that did almost nothing to tint the bulb light blue. The only other option for the bulb is to try a piece of blue tinted acrylic, but I fear that would be much the same as the filter film unless I can find a dense enough blue coloured acrylic. So I'm looking again at neon bulbs, and I'm not totally comfortable using mains voltage in my design. So I'm wondering if there's a way to use them similar to the way they're used in that screwdriver, at at lower voltages with sufficient brightness to not look out of place next to the VFD tubes?
Perfect timing, Clive, good sir! I'm currently having a sort of online debate/car crash with internet experts who claim that nobody uses neon test screwdrivers because they cause the Coming of the Dark Lord, or something.
I think the LEDs benefit on apparent brightness by being much more a point light compared to the neon. As for the future? LEDs will probably take over in time. But as you note it isn’t going to be something that happens quickly.
In any case, to indicate „off“, always check the tester with a live line before/after. If you work on a line with a switch, that especially easy to do. And for professionals: yes, such a tester is not to prove the connection could hold 16A (that what your „Duspol“ is for. Sorry, only know the German term), but the very opposite, that there is not the slightest connection to life wire.
Would be interesting to plot some measurements and see how they vary with dry vs wet skin etc. If there is a reliable gap between grounded and non-grounded thresholds, could the circuit be improved by setting a couple of comparators at those levels - then you would have a logic signal you could do anything you want with (like light LEDs at full intensity :P )
You can feel the difference. Hot sweaty environment can make it a bit tingly. The ol' "testicle pensicle" has saved many a lecky from unexpected live ones. In bright light you feel it before you see it. 240 / 415 VAC control circuits are still around.
The LEDs might be a little too sensitive. I get a green LED to dimly light in my house, by holding one leg and touching the other to an earthed object, such as a tap or radiator. Putting a 75V zener diode in series and a high value resistor in parallel, would make it less sensitive, but it should still work with the mains.
A key feature of the good neon probes is missing. Any indication means voltage tested is above the safety limit of about 50V . This prototype reacts around 10V . Adding an apropriately sized Diac or extra LEDs could fix that . Another key feature is polarity indication, traditionally by lighting only the electrode connected to one of the poles . In the LED design, different colors could do the same job , just remember to compensate for voltage differences .
But is that really a good feature? I think the ionization voltage is usually around 90 volts which is well above the safety limit. It's definitely better to have false positives than false negatives.
@@eDoc2020 Still somewhere around the danger level . Getting a faint glow around half mains is still relevant when the main dangers are around 220V above ground . Of cause there's always feeling that voltage as a slight tingle while working on it .
Neat. The only very minor nitpick I can come up with is the LEDs are only visible on one side, while the neon one can be seen from any side. Probably a very easy fix with something as easy as twisting the LED strip so an LED can be seen from just about any side.
I would try using one or two LEDs taken out of some damaged light bulb. The high voltage kind, the one that glow at about 40V. They should be much better (brighter) than neon at a current typical for a voltage probe. I made a small pcb with few dozens of those in series to make a very high voltage lamp and played with static electricity. Surprisingly bright. I was going to try to light it up under high voltage lines and perhups leave it there as a modern equivalent to Will-o'-the-wisp kind of thing. A small light glowing in the middle of nowhere.
We apprentice electricians many decades ago used to short the resistor and leave the tester around. No one complained as this was an electricity board and these testers were strictly verboten.
-Facom already sells led testers since over 5 years.- They also use a black plastic tip ( with high level of carbon - french patent design to electro paint cat bumpers).
clive i know very well that you know what you are doing but i think the light sticks are safer. years ago a sparky left his e-z scan above a suspended ceiling in a high-rise office building. some time later we had the job doing a total stripout including the ceiling. the e-z scan fell out of the ceiling and has been mine for more than 30 years. the same model is still available. a row of leds allow you to locate live wires, more leds light up the closer you are. ive shown it to qualified sparkies who had never seen such a thing. and some of them cant see how it has any advantage over the common light stick.
The advantage if the LED tester is that neon indicator has a high voltage threshold and doesn't work well under 100V, but the LED has a treshhold about 6 -10V
The neon has the advantage that it drops 50 to 80 volts, well to strike anyway. it can also detect very high voltages just by being in the proximity. holding the neon near the ignition leads will often ionize the gas. I think I am right in saying if you hold the voltage just below the striking voltage of the neon it will act a a flame detector, they can be used as high voltage 'Zeners'. Long live the neon, bring back the ECC83. where is my 71/2 digit vacuum tube voltmeter, damn those peasty leds and new fangled OC71 transistors.
Flashing lights are easiest to see, especially in dark environments. Since one wouldn't want to have a point during which no lights are lit, it'd make a lot of sense to have two (or more) alternating lights.
I think the biggest drawback on the LED version is the viewing angle "benefit" that the Neon bulb has, you can see if it's lit or not from any viewing angle. Perhaps that can be dealt with with some form of fresnel lens, or super efficient double sided but super-narrow PCB layout to restrict the viewing angle blockage...
In Germany these devices are also called „Lügenstift“ (lying pen) and their usage is strongly discouraged, because they a notoriously unreliable. But I also understand if someone uses them for a long time and knows of their limitations. Still, the only really reliable device for this job is a two-pole voltmeter.
I still have a couple or more of old style live wire checkers with a "glass fuse style bulb" 20mm and 32mm neon lamps and even longer capped leadless resistor (neon wasn't so demanded in semiconductor production and soviets supplied enough of it not to be greedy of used amounts).
One has to be very careful with those neon testers.... if the inside of the screwdriver is wet, or very humid, you could get a HELL of a zap when you use it, as the mains current can bypass the high value resistor and go much less unimpeded through the moisture around the resistor.
I don’t know how efficiency of different colour LEDs compares but as I understand it green is the best colour for eye sensitivity - for a given energy output (proportional to voltage and current leakage = scariness) you will see green as being brighter. I don’t know what the threshold for visibility/danger is with neon but green LED in particular should add some safety margin.
Complaint or not, as an electrician you have to use a 2 pole voltage probing device to test for voltage on wires to work on them. No test screwdriver, and also no multimeter. Because if the coworker you always make fun of on breakfast time plugs the test leads in to the amps range without you noticing it, you will jump of that ladder from the bang and break your neck. It is not always current or voltage that kills you, but the fall, or 3 degree burns from standing 1m away from the big short And for the screwdriver: This thing will not indicate anything if you would probe an outlet in an ER for example, which might be completely insulated from earth. this also could be the case on an insulated ladder, but then you could touch the ground of something nearby. But you can never be sure that there is no voltage present, if it does not light up. If it lights up, you can be sure there is something, but if it doesn't, its a maybe and has to be proven by properly measuring (with a 2 pole tester) so if you have to carry a proper device with you anyway, you can just forget about the screwdriver al together
One issue or not is that this one already lights up at lower voltages, while the neon one only lights up at "dangerous" voltages - those that can send a dangerous amount of power through your body given usual body resistance. But this is obviously fixed easily by not using 3 but like 30 LEDs in series. May also make it more visible. Or maybe not, as this one is also nice and helpful in automotive usage.
A test screwdriver is perhaps an electrician's hammer. Hammers must be simple and without any vajazzling whatsoever. Proper clean, simple and great design!
What about using some clear gel LED filaments? There's so many dies in them you may be able to get more brightness for the same voltage as a neon, like you did a while back in the LED vs neon indicator video
I did consider that, but even with two in inverse parallel there's a risk of exceeding the reverse voltage of individual chips depending on whether the reverse leakage currents are matched. It's a fairly low risk though.
