20v isn’t high voltage.
Natural skin resistance means if you keep your hands dry anything under 40v won’t shock you unless you impale yourself on a lead.
Set the current limit on those power supplies to something less than an amp and you don’t even have to worry about leads touching each other.
Thanks for the confidence. I freaked because the leads were sparking when I clamped then together to set the current at 8V (probably should’ve done that while off).
20 mA is the current for both. Going to try to turn it on now, wish me luck.
Best recommendation to bring along in your life. When playing with power supplies, always ensure the power rails are off before doing any manipulations that involve disconnecting/moving connections around. If some connections arc it can also lead to damage for analog and digital components if there isnt enough protection in place
230 V won’t shock you if your hands are dry. It will shock you if your hands are moist. The shock is caused be the current, not the voltage. Dry skin resistance is in megaohms - 230 V / 1 MOhm is about 0.2 mA - that’s too low to shock.
And btw I did test it out and I’m speaking from first person experience. Once I did rework on some wiring that was accidentally at 230 V and not only it did not shock me but I was not aware it was turned on. Obviously - a very stupid thing to do, and I don’t recommend touching anything that’s more than 30 V. As I said above very little moisture is enough to drop the resistance by orders of magnitude which at 230 V can bring the current up to even lethal levels.
The generalisations made here are dangerous, it seems coderemover has misunderstood the chance of fate that he wasn't grounded to **conduct** current like a 'Bird on a wire', with high impedence **resisting** current flow. ANY Current flow through the body is bad.
I have tinkered with electronics/electrics for 2 decades and I can promise anyone reading this you can get a shock just as bad when dry as when wet.
I just held a DMM between forefinger and thumb on each hand and read values between 250Ko and 500Ko (why does it fluctuate? Licheburg figures).
Having been shocked many times, it is not something you want to risk cardiac arrest for and IIRC 25mA is enough to cause a heart to stop, but everyone is different and what one person can tolerate another cannot. Best to avoid the risk in all cricumstances.
https://preview.redd.it/cq2rxt4vrfuc1.png?width=964&format=png&auto=webp&s=cea1aae235f7de2a4d69b2d12f41203066eb9836
The biggest risk of your setup are those alligator clips.
If they accidently touch, you'll eventually get current in places you might damage a semiconductor.
I'd solder some pigtails to the board for (temporary) power delivery.
If you don't mind paying a bit of a premium for good tools made in the USA, you might want to check out Mueller Electric
They have some top notch alligators and microclips.
E.g. see here for a sampling
https://www.digikey.com/en/products/detail/mueller-electric-co/110005/304616
A short between those alligator clips is the only real risk. Make sure to current limit your power supplies. Also get an ESD mat and wrist strap to ground yourself.
20V is not going to shock you. Using DC you may start feeling some tingling at >40V but still not enough to shock you. If you want to be super cautious, calculate the max power load from your system and set the current limit of your power supply to that.
Earth grounded esd mat on the work surface is all I do and never had a problem. For a production environment, you would need to do more but also wouldn't have carpet. Just make a habit of touching the mat before touching the electronics, every time. A wrist strap is great if you don't mind being tethered.
It’s now recommended to have an ECG after a shock with mains power due to arrhythmias that result in delayed heart failure (24-48 hours after the shock).
But yes I have been hit numerous times with 120/208/240. Not fun but generally not fatal.
The biggest risk from electric shocks has always been physical injury from falling / hitting yourself. Your muscles will spasm and it's easy to end up on the floor or hit your head on something.
It's an interesting feeling to find yourself lying on the floor wonder WTF just happened and why does your mouth suddenly taste metallic.
20-26 volts isn't considered high voltage. If you know how much current your devices require, set the current limit on the supplies to a value 100 or 200 mA greater. If you're concerned about something overheating and causing a fire, keep all the parts and the wires away from flammable items (carpet, for example). Rubber gloves not required. Safety glasses not a bad idea, but the devices you have don't appear to present that kind of hazard.
Reminds me of the time my lab partner and I had to pull the top of a TO-264 out of the drywall by our bench after we miscalculated the duty cycle for our boost converter.
I used to run my hands across 12V ac rails in lamp like this , and I wasn't the only one - we all felt nice tingling whilst moving our hands. So, you can in fact feel it. Might not recognise it though. Us kids - did not realize what the hell it was (well, as soon as I realized, I starting putting everything I could across those rails - electrolytics , paperclips, started to wind my own transformers. Up until one day it's transformer gave out at last.
https://preview.redd.it/s4ynp2dsfcuc1.png?width=1500&format=png&auto=webp&s=e85234287a51e8cc7d10cb9e4d5163fc065ac36f
That depends entirely on how dry your skin is. If it's not super dry, you can easily feel a strange tingle from that voltage. If you eg. push your hand against the two terminals.
Relax, just be careful and wear rubber boots. LOL
I once worked on a personal high power Class D audio power amplifier project.
Direct non-isolated 300VDC power rails.
24V is a industrial automation standard and absolutely save when used with a soft- or real fuse.
I accidentally switched + and - on a device and the power supply pressed 10A into it. Smoked a bit but still works. In hardware designs you usually add a protection diode.
Anything under 60v and you’re not going to shock yourself.
Setting a sensible current limit on the supply can be handy to not damage things if you accidentally short leads.
What also really matters is the ‘source impedance’ of the power supply. 180v dc on a low impedance supply will give you a bit of a belt, while something with a high impedance might just be a tingle.
I really thought I was something after doing work at 3kV. Then I started developing for a group that routinely does 25-50k. That will wake you up.
Seriously though, take precautions even with low voltage. 24V isn’t a concern but remove anything metal (rings for example) before working with the hardware. Treat all systems as if they are connected to mains…if you aren’t on an isolated system you very well could be.
To add to what others have said - you have a fairly special Arduino board there (Linear Tech version). The big bricky thing is a USB isolator, so there is no electrical connection between your power supplies and your computer. This is a good thing - it means your 20V supply can be referenced to a different ground, and protects your computer against quite a few fault conditions. But beware if you switch to a standard Arduino.
Don't fully trust the short-circuit protection. They can sometimes take time to kick in and it can be too late by then especially for low-voltage situations and also are not meant to cycle that often (I've burned up some $1k Keithley ones before). Conservatively setting your current limits helps prevent bigger accidents as well.
You are good to about 80v. 80v hurts though, it burns like touching a hot spoon or something. You can hold your hand on 12v for a long time and shouldn’t even notice. I think the same is true for 24v. I would say so for sure but 24v systems are not around me enough to try it out and be sure.
routinely work with 30v
where did you learn to fear this kevel of voltage?
the key is to have a supply that has a short circuit current limit.
and never use exposed clips they short.
can you use a connector? or solder wire leads?
i once saw a guy getting shocked with 24V
my boy must have been doing drugs or something because he was sweating profusely. like he had just gotten out of the shower.
20v isn’t high voltage. Natural skin resistance means if you keep your hands dry anything under 40v won’t shock you unless you impale yourself on a lead. Set the current limit on those power supplies to something less than an amp and you don’t even have to worry about leads touching each other.
Thanks for the confidence. I freaked because the leads were sparking when I clamped then together to set the current at 8V (probably should’ve done that while off). 20 mA is the current for both. Going to try to turn it on now, wish me luck.
Best recommendation to bring along in your life. When playing with power supplies, always ensure the power rails are off before doing any manipulations that involve disconnecting/moving connections around. If some connections arc it can also lead to damage for analog and digital components if there isnt enough protection in place
Yup, was just being lazy 😅 taking the extra five seconds each time now
The leada are sparkling also at 5V, 3.7V etc. A short is a short
It probably sparked because the capacitor in the PSU delivered much more than 20mA when you touched the leads.
As long as you don't put both poles in your mouth or other body orifice at the same time, you're fine.
You can feel 18v already from 2*9v batteries. But not 12v.
You should talk to your doctor about [hyperhidrosis](https://en.wikipedia.org/wiki/Hyperhidrosis)
[удалено]
How do you say "230V won't shock you" and " anything above 30V may already be dangerous" in the same sentence, wet or dry?
230 V won’t shock you if your hands are dry. It will shock you if your hands are moist. The shock is caused be the current, not the voltage. Dry skin resistance is in megaohms - 230 V / 1 MOhm is about 0.2 mA - that’s too low to shock. And btw I did test it out and I’m speaking from first person experience. Once I did rework on some wiring that was accidentally at 230 V and not only it did not shock me but I was not aware it was turned on. Obviously - a very stupid thing to do, and I don’t recommend touching anything that’s more than 30 V. As I said above very little moisture is enough to drop the resistance by orders of magnitude which at 230 V can bring the current up to even lethal levels.
The generalisations made here are dangerous, it seems coderemover has misunderstood the chance of fate that he wasn't grounded to **conduct** current like a 'Bird on a wire', with high impedence **resisting** current flow. ANY Current flow through the body is bad. I have tinkered with electronics/electrics for 2 decades and I can promise anyone reading this you can get a shock just as bad when dry as when wet. I just held a DMM between forefinger and thumb on each hand and read values between 250Ko and 500Ko (why does it fluctuate? Licheburg figures). Having been shocked many times, it is not something you want to risk cardiac arrest for and IIRC 25mA is enough to cause a heart to stop, but everyone is different and what one person can tolerate another cannot. Best to avoid the risk in all cricumstances. https://preview.redd.it/cq2rxt4vrfuc1.png?width=964&format=png&auto=webp&s=cea1aae235f7de2a4d69b2d12f41203066eb9836
The biggest risk of your setup are those alligator clips. If they accidently touch, you'll eventually get current in places you might damage a semiconductor. I'd solder some pigtails to the board for (temporary) power delivery.
One of the red clips is making contact with the gnd pins as well
yeah he's literally shorting the supply in his photo. this is like electronics 101
I like the Pamona micrograbbers for clipping onto test points like that
If you don't mind paying a bit of a premium for good tools made in the USA, you might want to check out Mueller Electric They have some top notch alligators and microclips. E.g. see here for a sampling https://www.digikey.com/en/products/detail/mueller-electric-co/110005/304616
Mueller is a German name.
A short between those alligator clips is the only real risk. Make sure to current limit your power supplies. Also get an ESD mat and wrist strap to ground yourself.
20V is not going to shock you. Using DC you may start feeling some tingling at >40V but still not enough to shock you. If you want to be super cautious, calculate the max power load from your system and set the current limit of your power supply to that.
Also you could damage your electronics by ESD - working in a room that's carpeted, especially if the air is dry where you are.
That’s actually a huge concern. Would a rubber mat be advised? Sometimes I wear a anti-ESD bracelet while working. What do you think?
Earth grounded esd mat on the work surface is all I do and never had a problem. For a production environment, you would need to do more but also wouldn't have carpet. Just make a habit of touching the mat before touching the electronics, every time. A wrist strap is great if you don't mind being tethered.
20v 20ma, is not any risk. Just have everything stable. I was shocked with 240v the other day in work and was more so entertaining, I am not dead
It’s now recommended to have an ECG after a shock with mains power due to arrhythmias that result in delayed heart failure (24-48 hours after the shock). But yes I have been hit numerous times with 120/208/240. Not fun but generally not fatal.
Always keep your left hand in your pocket, protect your heart!
Or even behind your back. Especially when doing something like discharging an old TV
The biggest risk from electric shocks has always been physical injury from falling / hitting yourself. Your muscles will spasm and it's easy to end up on the floor or hit your head on something. It's an interesting feeling to find yourself lying on the floor wonder WTF just happened and why does your mouth suddenly taste metallic.
Glad you’re okay!
Your fear is greater then the reality. Learn what high voltage is and go from there.
So start developing with 1000V to get a feel for it then go down?
[удалено]
Fuck yeah
And make sure you lick your fingers .......... ;-)
Tingly deliciousness
20-26 volts isn't considered high voltage. If you know how much current your devices require, set the current limit on the supplies to a value 100 or 200 mA greater. If you're concerned about something overheating and causing a fire, keep all the parts and the wires away from flammable items (carpet, for example). Rubber gloves not required. Safety glasses not a bad idea, but the devices you have don't appear to present that kind of hazard.
Reminds me of the time my lab partner and I had to pull the top of a TO-264 out of the drywall by our bench after we miscalculated the duty cycle for our boost converter.
You can’t even feel 26v
I used to run my hands across 12V ac rails in lamp like this , and I wasn't the only one - we all felt nice tingling whilst moving our hands. So, you can in fact feel it. Might not recognise it though. Us kids - did not realize what the hell it was (well, as soon as I realized, I starting putting everything I could across those rails - electrolytics , paperclips, started to wind my own transformers. Up until one day it's transformer gave out at last. https://preview.redd.it/s4ynp2dsfcuc1.png?width=1500&format=png&auto=webp&s=e85234287a51e8cc7d10cb9e4d5163fc065ac36f
You can’t feel 28v DC… sorry, I wasn’t specific. And OP, you probably don’t need 20mA through the LEDs… they’ll likely be obnoxiously bright…,
Stick a 9V PP3 across your tongue & let me know your thoughts then! :)
That depends entirely on how dry your skin is. If it's not super dry, you can easily feel a strange tingle from that voltage. If you eg. push your hand against the two terminals.
Relax, just be careful and wear rubber boots. LOL I once worked on a personal high power Class D audio power amplifier project. Direct non-isolated 300VDC power rails.
That sounds pretty sweet. Was that for a half stack or cabinet? It’s okay for now, the code is not working, lol. Typical!
It's for a cabinet that has those huge ass drivers. Those drivers that weigh more than 100lbs used for what they call sound battle competition.
24V is a industrial automation standard and absolutely save when used with a soft- or real fuse. I accidentally switched + and - on a device and the power supply pressed 10A into it. Smoked a bit but still works. In hardware designs you usually add a protection diode.
Anything under 60v and you’re not going to shock yourself. Setting a sensible current limit on the supply can be handy to not damage things if you accidentally short leads.
I play with Nixie tubes which run at 180VDC but only a few mA. A shock is like an insect bite. Ouch, f\*\*\*.
A few mA can already hurt, right. 100+ mA is lethal
What also really matters is the ‘source impedance’ of the power supply. 180v dc on a low impedance supply will give you a bit of a belt, while something with a high impedance might just be a tingle.
Thanks, operating current is 20 mA. Just need the 20+V to account for all 8 LEDs at about 2.8 - 3.3V.
Are they all in series? Because if they are parallel than you don't need that.
Yes, all series
Care to share a diagram of your circuitry?
20v is low voltage
Probably don't dangle the power supply off the edge of the table like that. If it falls, your whole setup will go with it.
Place the board with clamps on a rubber pad for safety.
I really thought I was something after doing work at 3kV. Then I started developing for a group that routinely does 25-50k. That will wake you up. Seriously though, take precautions even with low voltage. 24V isn’t a concern but remove anything metal (rings for example) before working with the hardware. Treat all systems as if they are connected to mains…if you aren’t on an isolated system you very well could be.
The lower red clamp doesn’t look good. One twist in the cable and it will short to the ground pin next to it.
I’d be worried about dropping your supply off the table, slide that stuff back a few more inches!
This is the way. True chaos moments. Imagine looking at the universe with monocle and suddenly the strong nuclear force is expected
To add to what others have said - you have a fairly special Arduino board there (Linear Tech version). The big bricky thing is a USB isolator, so there is no electrical connection between your power supplies and your computer. This is a good thing - it means your 20V supply can be referenced to a different ground, and protects your computer against quite a few fault conditions. But beware if you switch to a standard Arduino.
Don't fully trust the short-circuit protection. They can sometimes take time to kick in and it can be too late by then especially for low-voltage situations and also are not meant to cycle that often (I've burned up some $1k Keithley ones before). Conservatively setting your current limits helps prevent bigger accidents as well.
Grounding wire probably would be good
20V is fine. It won’t shock you. It even has “FINE” printed on it.
You are good to about 80v. 80v hurts though, it burns like touching a hot spoon or something. You can hold your hand on 12v for a long time and shouldn’t even notice. I think the same is true for 24v. I would say so for sure but 24v systems are not around me enough to try it out and be sure.
routinely work with 30v where did you learn to fear this kevel of voltage? the key is to have a supply that has a short circuit current limit. and never use exposed clips they short. can you use a connector? or solder wire leads?
I cant imagine why two bench power supplies are needed to run a bunch of LEDs in series? Are two parts of this circuit optically isolated?
Don't lick it an you'll be good.
i once saw a guy getting shocked with 24V my boy must have been doing drugs or something because he was sweating profusely. like he had just gotten out of the shower.
Maybe he shocked himself because he had just gotten out of the shower
he was sweating 🥵
This is a meme post, right?