Test screwdriver with microcontroller!
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- เผยแพร่เมื่อ 7 ก.ย. 2024
- This is NOT the product I was expecting. The functionality is probably the same, but the circuitry is very different, and it seems ridiculous that a microcontroller could be used in this application. Especially when you see how they detect the voltage thresholds.
I get the impression from the ludicrous 100Mohm resistor that the circuit is just using a simple threshold system where an internal weak pull-up is used on a digital input so that a test voltage of two distinct thresholds will be detected for continuity and high voltage.
It's quite odd that one LED goes to positive and one to negative. But there are lots of oddities about the design, which could easily have been implemented on a single sided PCB.
Quiescent current is spectacularly low, so the cell stack should last a reasonable amount of time.
Although the standby current of 7uA drops to near zero after about 9 seconds when the chip goes to sleep, it was notable that a noisy electrical load in the vicinity kept it awake and drawing about 20uA.
The microcontroller seems to waken and check the inputs briefly in standby, as tapping the end of the driver is not initially detected until it coincides with a wake-up and the microcontroller goes into sense mode.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- www.bigclive.c...
This also keeps the channel independent of TH-cam's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
As a former theatre electrician I consider the proper function of these devices is for opening the small tunes of paint I used to identify my kit.
As an ex NHS specialist hospital Electro-mechanical engineer...I fixed things in a slightly different theatre... and my little voltage detector did it's job... my colleagues, my boss laughed at me... I said that's live, my pens lit up... I'm not touching it 😂 (I refer to a proper Megger one, not those neon screw drivers)
And believe you me, many, many moons ago, in my other life as a Musical Instrument Technician: I've been thrown across a room by several thousand volts, from an old 100W PA Valve Amp, and lived to tell the tale 😂
Agreed. I smash them into little bits and bin them when they come in a kit as I have proper teaspoons for stirring my tea.
I never knew how dangerous a the average phase tester could be until I began learning electronics. Never again will I put one into a socket.. ⚡️💀
No, double down no... (of course, we learn the hard way zzzp)
@@keithking1985 I use the neon testers, but make sure I'm insulated from ground first.
Yet another reminder of how old I am when you said the originals just had a single LED.
I used the neon versions for decades, never got so much as a tingle on 120V or 240V. Got a very mild tingle using one as a field probe for my first Tesla coil. I can imagine a few scenarios in which they’d be hazardous but in long line DC use, the microprocessor isn’t going to save you.
I don’t really consider the use of a microprocessor “obscene” in this application. Silly, overkill, a ridiculous flex maybe, but I think of other products you’ve shown us with microprocessors built in and I just shrug. The trend probably started when a fresh design hire was tasked to design something simple and they decided to put their newfangled programming skills to use by flow charting the device’s functions and crowbarring them into a jellybean micro. One one level it makes sense; micros are intended to be sort of electronic multi tools that can replace discrete parts thus bringing BOM costs down. On another they obscure circuit operation within proprietary, undocumented and unhackable code. On the gripping level, profit overrides all other considerations. I wouldn’t be surprised to see a hammer with a micro these days.
Not surpising, there was a Kurig coffee maker, that wanted to take a photo, to verify an authentic coffee pod was used😂.
@@aware2action Gah. My wife wanted one of them so we got one. No camera verification gizmo in that model but we got rid of it when I figured out that you can’t drain the internal tank. Companies locking you into their ecosystem is one thing but that’s a health hazard IMO.
@@markfergerson2145 Unfortunately, When companies develop products, they are a bit altruistic, but later realize, its not going to work, in keeping the cash flow, leading to all sorts of convoluted schemes. The same goes for a lot of "Ch"eap products that initially look, as good as a reliable one. They could be as durable, if not for that "one" thing that breaks, to make it a disposable one. Rechargeable gadgets most always fail with bad batteries, followed by other cheaper parts inside(not replaceable unless someone is stubborn!). Unfortunately, externally, the products look identical, and may be from the same factory!. Gone are the days, a product is made to last, as the raw materials allow!. Sadly Programmed Obsolesence is what makes the new economy. The main culprit is the lack of continuing innovation, after the initial product launch/success. Just some 💭
@@markfergerson2145 Actually Kurig pulled the model from market, after they lost legally from preventing other coffee pod makers to circumvent(by just duplicating the barcodes) it. Nespresso has been clever, in making their pods difficult to make(sealed aluminum with nitrogen under pressure), while also making their machines bullet proof. Also refilling is not worth the effort(due to small size and high pressure). Best option is to use a old Kurig, with a reusable filter, in which you grind(using single serve manual burr grinder) and fill starbucks wholesale beans got at a discount(stored in another vacuum glass jar gizmo, that uses a rechargeable? battery-will open it to fix when fails!). For the non-drainable tank, I use distilled water made from my trustworthy non-digital Sears-Kenmore water distiller. Again it is just my way to fight the Programmed Obsolesence. Just some more 💭
I still have two neon ones I use
That npn-pnp combo has the same current gain as a darlington, but only requires 1 VBE to turn on, not 2 like the darlington.
That's the explanation I was waiting for! Clive didn't bother to explain WHY it ain't no Darlington.
@@derludditus2758 Because it's a Sziklai pair.
Beautiful!
This video has educated me on the Sziklai pairs advantages.
Interesting devices, even though whenever testing for voltage I do like the things to be as simple as possible to avoid surprises caused by failure of the electronics.
Or flat batteries
Yep this is why we're expected to prove our testers before AND after use
That's why I use 2 testers minimum always. Indeed the batteries near the touch side is an X factor to say the least. Leaking batteries will make things even more unpredictable.
You don't just use a proper DMM to check voltages?
You test a known live first
The first one uses a darlington configuration called a "sziklai pair". I've seen them used in push-pull audio amplifiers before where they need to keep the output driver transistors similar. The pull up darlington uses a PNP followed by an NPN that's matched to the pull down pair that uses NPN-NPN.
Interesting. I only remember the old style of these, where it was just a neon lamp and a resistor, so you could only check for the live connection by using your finger on the end to provide a path to groung. Not sure if I like this new style, seem to over-complicated. But I have not used one in a long time, I rather like to use a proper meter, as these can be quite unreliable, depending on the quality.
I remember the neon screwdriver well. I/we all had a decent size neon screwdriver that was used for tightening almost anything and used for testing fuses. This was nearly 40 years ago now, not much to go wrong with them, neon and a high-value resistor. No one ever got killed in our factories using a neon screwdriver unless they fell on the pointy end, ha ha.
@@getcartercarpark. The only issue I have ever had with those was that they were poorly visible in bright daylight (trying to find the live wire on the side of a building while hooking up a light fixture with an IR sensor).
@@getcartercarpark.A friend of mine go a nasty surprise of one that had compleatly filled with water after being left in a tooltray out in the rain.
@@Ranger_KevinThere was a professional version in black bakelite with a shielded window to the neon and a solid probe tip that wasn't a screwdriver . It could be easily turned away from the sun and the neon poles were clearly associated with separate ends to show polarity of DC power over 50V .
@@johndododoe1411 Interesting, I have never seen that here in Germany. Sounds way better than the classic "transparent screwdriver" type.
The older versions of these were actually pretty safe. The series resistor was a spiral cut carbon on ceramic type, providing 15mm of separation. Mine stopped working a couple of years ago and I assumed that the battery had expired but on taking it apart after seeing this video I discovered that it was just a dirty contact and it now works again. The nice thing about them is that you can test that they are working simply by putting your fingers across them before and after you use them for detecting voltage. Almost as good as an electrician's proving unit.
@petehiggins33
Is that you Peter? I thought I saw Phil on YT a few weeks back
@@jagmarc Yes Mark it is me. I haven't seen Phil on TH-cam but he's the only person from Astrium that I'm still in touch with. The rest of them have all died of old age. Sorry to read about your illness, good luck with your treatment. Frankly I was surprised to hear that you're still alive.
@@petehiggins33yes I've been hiding! When I left I wanted to make sure fully off recruitment agency headhunters radar, and today I still live on this tropical island.
Wouldn't it be great if Dave S, Steve C, Andy M , Mark C, GLG etc. showed up here too, I'm sure they tune in to this channel too.
I heard Brenda R passed in 2021 she had it much worse than me
@@jagmarc😂
Not what I expected; Hot screwdriver-on-screwdriver action
That NPN PNP design is called a "Sziklai pair" and it is way more sensitive to input vs a Darlington pair
The old ones without electronics but with a glowbulb were called "Phasenprüfer" in German.
That's literally translatet: checker for phase, as L1, L2 and L3 are called "Phase", while Neutral is called "Null" (zero).
Ground is "Erde" (earth or soil).
Phase tester = Phasenprüfer
@@connclissmann6514 Did I write anything different? 🤔
@@u.e.u.e. Yes, your explanation proved to me that german is unneedingly long winded. But so am I sometimes so you get a pass THIS time.
I like the band Null Positiv
That's an odd way to spell Lügenstift.
FWIW, that configuration is called s "complimentary Darlington pair", aka a "Sziklai pair". Not terribly common these days, but they used to be pretty common. It lets you reverse the control polarity. Not sure why the power transistor is PNP-that's rather odd.
If it wasn't for the PWM bit, I would have suspected that chip of being a pair of Darlingtons of one sort or another. It's odd that the LEDs are wired opposite of each other.
If I was an electrician, I would stick to a good quality old fashion neon type.
Some things are best kept simple.
Electricians don't use neon testers because they are unreliable and can be dangerous. We also don't use these they are only for amateur use.
@@dogwalker666 I have an old Martindale neon voltage indicator they were the only device authorised by the CEGB at one time.
@@letrainavapeur was that the martindale with the cable, The big problem with neon screwdriver types is they require so little current they can actually read through a blown fuse,
I was called one night by one of our customers, I told them to check the fuses before I left and they said they had, I told them it would cost a full service call out and overtime (3AM) it would be quite expensive, They accepted, I arrived checked the fuses with my Avo and the yellow phase was blown, replaced fuse and they were back in production,
2hrs travel for 5 minutes work, They tested the fuses with a neon screwdriver, The owner snapped the driver and banned them from site.
@@dogwalker666seems like ironically only someone who is qualified can use this one safely.
@@dogwalker666 I would guess that the equipment side of the yellow phase may also have various connections to another phase via motors, transformers etc unless they had made sure to fully "switch off" everything that could have resulted in the yellow phase being "back fed" from another phase.
I learned quite quickly when growing up, some of the "interesting differences" between phase and neutral - v - phase and phase, learning the fact a blown (or missing) fuse can be stingy on both sides of the carrier was a memorable one :)
In past days when I used to repair vacuum cleaners I would plug the appliance in and use one of these by running down the outer cable to detect where a break in the wires may be.
I was sweating when you stuck it in the live outlet and touched the opposite metal end of the screwdriver 😮
isn't that how they work? my dad always used one of those and it never shocked him. one side into 240v, other to his hand
Many years ago when I was single digit age I had an original neon screwdriver quality made. Even diagnosed faults in valve circuits with it. There was a little booklet "50(?) Ways to Use a Neon Tester" and I was quick to learn resistance makes things safe to touch. When I got my first multitester (moving coil) I often used it like a neon tester (using one probe only) and I sometimes still do to this day, using a DVM. Set to high AC volts and instead of connecting the other probe to the circuit under test, hold the tip between fingers (or in mouth to prove it's safe). I feel much safer because I won't have both hands near the circuit.
A neon tester only tells you a circuit's live and it won't tell you if it's dead.
The only sure way to know a circuit is dead is connect across it a test lamp which you'd just proved it lights up before and after.
I still own my 1970s neon and resistor screwdriver.
And I'll bet it still works! 👍
I was getting a little worried when you had one screwdriver in the earth hole of the socked and the other in "live". But I knew it couldn't have gone too badly as you've uploaded the video.
Imagine if the video just jump cut to a picture of him with the caption "BigCliveDotCom 19xx-2023"
I bought a neon-style screwdriver when I was a teenager. Even though I bought a reputable brand,researched the theory of these (pre-Internet!) as best I could to date (some 30 years later) I've used it *precisely once* and that was as a test, a fair time after purchasing it.
Nowadays I'd just use a know-working appliance or a non-contact EM device.
I use a neon-style one all the time, after making sure that I am insulated from ground.
Those screwdrivers typically have tips that are softer than brass. Twisted dozens up over the years.
I recall at at some point in Finland one could not have a screwdriver head on those so it just ended in a round head. I think the idea was that they could get damaged when used as a screwdriver.
I had a drill bit bend on me yesterday. Oh lordie!
@@johnpossum556
Thats, because drillbits are mild steel at the shaft to get grip in the chuck.
If you clamp them too short, the thin ones will easily bend there.
@@werner.x
I've never heard that. Really small bits just snap if too much extension is used.
I think a drill bit bending (significantly) would suggest it's made from monkey metal.
@@skylined5534 Yes, i had to realize, that hardly anyone knows, how drillbits are made. That's, why i commented here.
That’s called a Sziklai pair, they’re found in both linear and switching applications as a lower dropout voltage replacement for a Darlington. Mainly linear though, using one instead of putting the load on the collector is usually only done where the output polarity matters.
Also known as a complementary pair, Slizzy pair, or Glizzy pair. At least one of those names isn’t made up.
Also internal pull-ups are like 50k, I doubt they’ve got them on the 100M input at he very least. More likely they’re relying on the pin’s leakage resistance, that and the protection diodes.
Interesting, years ago I had that type of voltage detector but it was just a neon bulb and a series resistor. As you mentioned on reflection it did not seem like a good idea to be in contract with mains voltage with only an unknown resistor for protection. Typically 100k for 120V circuits on this side of the pond. I decided the convenience was not worth the risk. As others have mentioned the steel used for the screwdriver was not the best so it even failed in that regard.
One of the advantages of adding a microcontroller to these mains testers, is that there is the possibility that they can email the next of kin in the event of the inevitable electric shock failure. 😄 This does not look if it has any chance of passing creepage and clearance rules.
I got one of the older versions many years ago when they first came out and the RS Components rep was touting them - in fact I got a bunch for all of us in the office. However, I have never and will never put the tip in direct contact with the mains - I had my one shock as a youth with the Bakelite light switch cover removed and am in no hurry to repeat that experience. Instead I use the method in the instructions - hold it by the tip and place the finger end by the cable to be tested. And, obviously, I'm still careful after that, eg, for preference I want to see both Found and Not-Found states by flicking a switch or 'fuse'. Still, someone's got to test the limits, and I for one am very glad that you know what you're doing - and long may it continue!
I initially wondered why they bothered with the 12k resistor when it is negligible compared to the 2M resistor other than bridging the gap. Presumably a single resistor isn't rated for full mains voltage so the designer split it over 2 resistors. But instead of putting 2x 1M in there someone decided on a single 2M resistor and a (probably cheaper) 12k resistor. Of course, that means that the voltage drop across the 2M resistor exceeds its rated voltage!
I wonder if the same can be said for the 47M and 1.5M resistor ratio in the second device. 2x 22M would have been better and would not change the sensitivity unduly.
I mean, You could also wonder why they would align the resistos in a way that makes the part that sticks to the mains and the part that you touch be just barely 1 solderbridge away...
You beat me to it, it seemed to me that 2 x 1M would have been simpler and safer. (After all, with the existing idea, if you accidentally put two 2M resistors in, instead of a 12K and 2M, it's no biggy, but if then accidentally pop in two 12K resistors its potentially "finger-tingle" time, where the user provides a bonus audiible alert!
My thought is that the 12k resistor doubles as a fuse, quickly burning out while the 2M provides current limitation protection.
@@johanmetreus1268 The only explanation would be, indeed, that the 12k one acts as a fuse in extremis. Otherwise, it makes no sense. The voltage drop on the 12k is negligible compared to the voltage drop on 2M (it's proportional), so @chrishartley1210's hypothesis doesn't hold water.
0Ω resistors were out of stock or expensive that day. Chabuduo (good enough).
Some day in the future, we'll be manually updating the firmware of screwdrivers.
No, they will do it via 5G while showing you adverts for Coca-cola
I've used the old-school ones with the end taped on vacuum tube RF circuits for tank tuning/relative output type stuff.
they're also good leaving them near HV PSUs to see when they're hot
I did liked these 60 years ago, but soon only found use as the cheapest possible terminal screwdriver, bought usually in a local village Elec shop. I usually loaned out rather than my decent screened drivers...
Hi BC! Interesting find! The next version will be cloud based requiring the user to register and have internet service to function. Progress (not) - gimme the analog neon bulb version. Cheers and thanks for the info and video. 🍺
Pinout of the micro matches a Padauk PMS150C SO-8 typical "3 cent microcontroller"
And I think you are right about the big pcb track loop on the 100 Mohm inout, it is likely to be an AC field sensor.
I did an experiment with a 2 inch piece of wire into a MCU ADC input, it was easily detecting 200mV of AC mains waveform so that loop is a pretty decent antenna.
Is it possible the microcontroller is cheaper than the discrete transistors?
@@cheyannei5983 nope, transistors are well under a cent each for this application. They spend the extra couple of cents on a MCU because they can put an extra 50 cents on the product price. Just business as usual. 🙂
The older screwdrivers had a neon bulb where you have to be the capacitor to ground for it to light while the newer one clive was looking at had a battery and a Darlington driving the LED.
A neon lamp encased screwdriver is my choice for poking at line voltages.
Somehow these things (even though this is not the usual one, and your sockets are really not going to have that high of a voltage) always make me think of the video "Killer screwdriver" from Photonicinduction from 10 years ago.
Sweet vid, your breakdowns & subtle curiosity are great.
I kinda want to get one of the old neon style test screwdrivers now.
My old 12v test light melted after checking for current on a chain link fence that was sparking at the latch.
Afterwards we found A leg of 480 volts had shorted to a junction box below grade and our chain link fence circling our Engine house gained about 40 volts DC.
One day I’ll post that video
I know nothing about electrics I just enjoy watching the videos
oh the red and green LED one is interesting. Fancy the last thing you see are 2 flashing LEDs as you try to disconnect your body from the mains supply.
Shocking video 2x👍most amusing.⚡⚡
I love these things. The ones that I have have a KSP13 transistor in it and a 1 Mohm and 10Mohm resistors and they're just kind of stuffed into the handle, there's no circuit board.
Either of these is a few steps beyond my vintage tester that used a small neon lamp with a resistor in series. Drove my mom mad when I would stick the tip into a socket and then touch the opposite end.
I bought a dozen of these when I was in China. There's another function as it can detect the breaking point of a wire, just position the tip of the driver along the length of the wire with the index finger touching the metal part at the top. The green LED would light up when it detect a current inside the wire, and it goes out when reaching the breaking point. Also don't bother to replace the battery, just replace the whole thing as it only cost about 0.5 USD each when you buy 3-5, including shipping.
I bought one of these 25 years ago. It sort of did what it promised, but it did it so poorly I could never be sure if it was checking continuity, an energised terminal, or sensing. It made a reasonable terminal driver after that, but never a tester. i still have it in my toolbox somewhere.
straight away i see an application for this, modified a bit. spark detection for plug leads and systems on cars. could be tweaked to give a good indication of weak or strong spark with distance etc..
I think the 100M and1.5M both form low passes with the input capacity. Due to the phase shift you get a signal on an internal comparator with an applied AC signal
the device with uc - i guess the pin with with 1.5MOhm resistor is configured as an input, the pin with 100MOhm as output and serves as a extremely weak pullup/pulldown. Program probably toggles this output between high/low states and checks if the input "follows". On one hand - using uc for doing this sounds crazy, on the other - clever software can measure interesting things just by checking the delay - like these cheap "component testers" with ZIF socket.
That's an interesting concept.
The NPN and PNP couple used to be called a ( super alpha pair ) but nowadays attributed to a Mr Sziklai ( ! ) they work like a Darlington pair , but have superior properties ( only a 0v6 turn on , Darlingtons have 1v2 ! ) .. with a 33kΩ resistor between +ve and base of NPN then an 8 Ω loudspeaker in the PNP emitter lead , then a 47nF capacitor coupling the loudspeaker back to the NPN base ... using a 1v5 volt cell , you now have a 1st class continuity tester that DOES NOT damage IC's ... for loudest results use a Germanium audio output transistor for the PNP ( from an old 1960's radio ? ) ... tests diodes ( not LED's ) , resistors up to 50 Ω and SMALL coils ( inductors ) .. best to solder the cell as it can last 20 years ! ! ... a very cheap little gizmo and ( tried - n -tested ) ...... DAVE™ 🛑
I have an original that my dad used interesting tool he used in his carry kit. These with a little isolation sure makes the original show it’s age.
An NPN connected to a PNP transistor is a configuration known as a Sziklai pair. It has a couple of advantages over a Darlington. The turn on voltage is only 0.6V and the transconductance is the same as a single transistor, which is double that of a Darlington pair.
I'm surprised they used an 8-pin microcontroller, when a 6-pin chip would have done.
Chinese standard of electronic separation is measured in ms. So 1ms after you buy Chinese electronic, manufacturer separated it self from it.
I have several of the old ones where YOU are the path to ground. Gives a bit of a tingle. LOL!
I was using a 'driver like one of these a couple of months ago whilst I was a bit distracted in a tight space, and I forgot I had hold of an earthed pipe. Wow, that woke me up faster than a chain-brand coffee, I can tell you!
Over-complicated with narrow gaps - I don't trust its reliability and safety; still an interesting design. Why doesn't it have a buzzer for continuity and voltage test? That'd make it a sonic screwdriver...
I like that idea. How small can you get piezo buzzers to fit in the handle?
@@Alacritous not sure, but I think it's something around 6 or 8mm.
There is some continuity probes using a buzzer though not usable as a screwdriver.
Clive is a genius!! Wish i had his knowledge!!
I don't really trust these things, but they did save me once, just moved into a new house and was doing something with the lights upstairs, I thought I had turned the lights off at the fuse box but suddenly saw the neon driver flash. I didn't realise that the upstairs and downstairs lights were on separate breakers!
I don’t mean this as an insult but you had no business doing what you were doing.
Classic old school were self powered with a neon lamp and a resistor. Touching the end would light the neon.
Thanks Big Clive. That microcontroller one is kind of amazing with the quiescent current bit. How does it even do that?
And 100M Ω? Wow.
Also, has anyone thanked you for NOT having a goofy opening video bit? Let me be the first. LOL
Very controlled sleep mode I'd guess, with the internal modules put into their proper sleep mode and a very low frequency oscillator.
Yeah, I don't like intros or outros, so I don't use them.
@@amorphuc Thankfully Clive understands the intelligence of his audience by not telling us to like or subscribe either... Close to 1 million subs so it seems to be working!
Love your channel Big Clive
We installed complete re-wires using these circuit testers during the 70’s, you could even remove faceplates too 😉
I've never felt any confidence in using these screwdrivers for testing live mains, the thought that they could pass full mains voltage through me to earth, no thanks, I tend to just gut the ones I get so it's just a transparent flat-blade screwdriver... :P
My dad has one of those. I used to think it was alien technology when I was a kid 😅
Such a tiny little resistor providing 100M ohm - wow.
The resistor could probably have been omitted entirely. What's the resistance of about 0.03" of G-10?
Probably just a block of ceramic with tinned ends!
@@stepheneyles2198I was thinking the same thing. It probably works more like a slightly leaky coupling capacitor than a resistor. 😊
I know these are frowned upon as electrical tools, but I've found the neon test screwdriver to be very useful in an old Finnish cottage. Some old farmer wired the place up using whatever colour wire he felt like - including green/yellow. The place had no reference to earth whatsoever, and this was the only way I could determine which wires were live.
how can you say that only way you could determine which wire was live when you could use a multimeter, a non contact voltage detector and circuit breaker finder? These options completely remove yourself inadvertently touching anything energized when used properly
😮
@@zeddpilsner4 It wasn't that simple. There were parts of the circuit where two of the three conductors were energised. The multimeter showed no potential between the two parallel lives and it was indeterminate which was live in when measured in reference to the neutral. A non contact voltage detector wouldn't have been accurate enough and a neon test screwdriver happened to be the tool I had on hand that could do the job.
Good video. Lots of technical responses here, but I'd be scared to use one on live 220V lines (even 110V).
I only know the classic one without any electronics, with a little lamp and a resistor.
Greetings from Vienna
The LED position means there is a diode junction between your finger and the circuit , so if the transistors go short you get a half wave shock :)
Your design idea for an all LED tester is excellent ( as an advert says : why did they not think of this before ! ) ... I will stick with your back to back LED's with a 330 K Ω in between each pair .... my idea , using mains bulb filaments might have a flaw ... the reverse voltage on each cycle may damage these long LED strings , and let's face it , 6 green LED's should be enough ( ? ) ....... DAVE™ 🛑
With a microcontroller, but it can't tell you which screw to remove next!
Sir Clive must spend a fortune on ink and printer paper. It must be one cartridge per shot as the image so gorgeous. I can get a couple of pictures of our cat before I run out. Love every video xx
Epson ecotank bulk ink printer.
One of the times that "Unexpected" concerning high voltage is a good thing :)
I've still got a few neon ones floating around the toolboxes. I've also got a wonderfully faulty one where the plastic insulation is longer than the screwdriver shaft and completely covers the blade.
It drives people mad when they grab it without thinking, get up a ladder to do some terminals in a ceiling rose or something only to find it's "a blunt instrument" 😂
Little things that make the day go by...
Some of comments here are great examples of sociological change. Odd isn't it.... How public perception changes, rather like 'cancel culture' tears down statues because we judge past culture through contemporary eyes.
From an era my school caretaker (very popular man) tested current with a finger while smart professional electricians carried a neon screwdriver instead of lugging around a heavy and breakable bakelite Avometer.
The humble neon screwdriver also showed valuable habits to get into to survive such as probing HV with one hand only, learning that insulation was resistance not just an open circuit and many more things...
Instead of being a Darlington pair it is a Sziklai Pair, called the complimentary pair for obvious reasons. Ron W4BIN
There are honestly some things that simply DONT need Microcontrollers. You're not wrong it's ludacris.
Anyone using these on mains level voltages would be wise to use another proven working device for a second opinion ⚡
I usually just stick my fingers in and measure how much of a jolt I get, but to each their own, I guess.
We call these devices "Elektrikers Tod"(electricians death) 😅. In the past it was pretty common to replace the bulb for a fuse to show the apprantice that they are not safe...
my dad had one of those but it was for continuity only, we found that out once when he used to to measure voltage directly and blew it up! LOL
MCU in a tester, impressive. Can one buy only the circuit? I have plenty old german made testers I'd like to upgrade!
Was also wandering why not include a rectifier to replace the batteries?
SMD resistors wont pass safety requirements? What can be used to protect touch even if grounded.
Sensitivity of "Continuity" between one's own hands has any practical use?
I've only seen the module included with the drivers.
Thanks for this Clive. Sooo with these new designs you don't need to lick your finger? That's brilliant!
The one I've got I bought in the 80's, it uses a resistor and a neon indicator bulb.
As a sparkz I only use as a quick continuity test or external live test to find voltage in a cable, otherwise I use a fluke T150 to be safe
“The chinese have an odd definition of electrical separation” - LOL 😂😂😂
Never seen one of these in person before, but they look very handy.
I once said to my chauffeur "I need a screwdriver". Boy was that an embarrassing situation to find myself in?!
Did he oblige?
100 Mega Ohm is huge, I'd expect that to be the sort of impedance between the tracks of the circuit board or via marginally moist air.
china/ebay aside, even the made in the UK supposedly safe versions of these things always made me nervous, here shove this screwdriver in a mains socket, now touch the metal bit on the end, its just so wrong, you have to put aside all your normal notions of Things Not To Do With Electric to even use them as intended
🤗 - and I have an older electrical screwdriver with the neon indicator and still use and test with it
hey clive, 6.35 that looks indeed like a typical zener diode that i use a lot in small projects
Most interesting, I've only seen the neon variety, and yes - electrical safety, what is that
Back in the day, that NPN-PNP combination was known as an "incestuous pair". Kind of stuck in my mind.
Thanks Clive, very interesting.
The resistance between two hands is like several tens of kiloohms. I don't consider that "continuity", certainly not for circuit testing.
always enjoy watching these videos
I have a feeling that allegedly 100M Ohm resistor is functioning more as a few pF coupling capacitor rather than a resistor.
Looking at the way the 2 input resistors are back to back on the first one is that really just 0.5mm mains separation. Aaargh!!!
These are fun curios, but I have never trusted them. I'll always use test lamps or a non-contact volt stick (Fluke make a good one!) to check for mains voltage.
I’ll be the first to admit that the last time I came across a 100M resistor was as the feedback in the ht supply of a colour monitor.
That IC may also be ASIC, I have a PCB out of a fake OBD and it has the SO-8 chip flip-flop with external timing capacitor and resistor._
Around here a test screwdriver is called "dead man's pen".
I don't this as using a microcontroller. A typical microcontroller includes a processor, program memory, RAM, input/output pins, and more on a single chip. The chip look to be some type of logic chip like the LM555.
Modern microcontrollers cost just a few cents.
I have never used one not even the old original type besides using it to clear tubes of glue
John Ward did a video on these years back advising people not to use them for mains testing. They are not fit for purpose.
I wonder how strong the screwdrivers are to actually use as a terminal screwdriver?
Are they "Clive" proof?
KW.
I had an earlier version of these which I used to pry something open. Well, guess what won!!
I prefer the ones with a neon bulb and a resistor.
I don't like those LED-based ones, because they have batteries in it, which are failure points. As are the µC, the transistors and the LEDs. And they're not good for anything. It's a gimmick. For mains, you cannot use them because of unsafe separation between the user and the voltage. For low voltage applications, one rather measures a combination of current carrying capability as well as voltage. And for resistance, what good is that if it cannot differentiate between 1Ohm and 100kOhm?
So, in my opinion, the high-voltage ones with a neon bulb and a resistor, and the low-voltage ones with an incandescent bulb and a ground lead are still miles ahead.
I just love the "Schkemätiks" :)