I wish there had been an internet, a TH-cam, and experiments and electronics classes like this when I was a kid 65 years ago. I would have been an EE without the piece of paper by the time I graduated from HS when I was a 17 yo in rural MI, instead of hearing of Ohm's Law for the first time after I'd graduated. All of this knowledge, delivered different ways, from different sources just as fast or slow as one wants, available 24/7 at home, essentially for free. I taught myself from books in the library of a city I moved to to find a job, and in a few months I was working at a CB shop, then at a small electronics company, and I just kept at it in my spare time after work. Everything I needed to know for work I just read another library book in the evening. By the time I retired after 35 years or so I'd been a tech at HP, IBM, and others, and retired as an R&D tech from SONY. So I really can't imagine how different life is now with unlimited knowledge at a child's fingertips. So many questions answered. So many project ideas. So many inexpensive parts, and tools delivered to one's door the next day, or even the same day. $5 multimeters, $35 digital 'scopes, $100 handheld spectrum and network analyzers that gather, store, and analyze data. And they work well up into the GHz range! Wow. I hear that most American kids with our culture and technology these days are pretty lost or disinterested, but I'm sure there are a few who are lapping it all up just as fast as they can. Fundamental physics, math, electronics, programming in multiple languages, young minds integrating it all. They are gorging on a feast of knowledge, and are going to be scary if they ever decide it's time to stop the constant learning and shift gears into the constant doing.
Thank you for sharing! Sadly, despite all the information out there, many students struggle to deeply learn E&M in high school and/or college. Students are rarely given the opportunity to develop real intuition and experience with electronics and the courses end up being a pattern-matching exercise where students feel forced to memorize lots of formulas to survive. We are working on developing lots of low-cost materials to help lower the barrier to a high quality physics education. In 2025 we will be working on a big “understanding the fundamentals of electricity” project (with online course, quick quizzes like this one, boxes of materials needed to implement the quizzes, and a book)! It sounds like your input would be valuable, so please be sure to subscribe and keep an eye out for new content. We are a non-profit, so if you’d like to support us financially, you can at our website www.idealizedscience.org! All the best and happy new year!
A ammeter is a low-impedance device, a dead short in effect. The light bulb goes out, the ammeter goes to fsd and the battery is discharged or dies. Don't try this with a car battery or you will destroy the ammeter too!
You can but provided the voltage source is limited somehow, like it's own internal resistance for instance. However there's no reason to do it because you want to maintain the sources voltage WHILE measuring it's current or it's pretty meaningless
Here is a point to consider: A bulb's resistance depends on how hot the filament is: when the ammeter shorts out the bulb and the filament stops glowing, it's resistance, while still more than that of the ammeter, will be a lot lower, so a decent percentage of the current must also track through the bulb; abeit not enough to heat the filament to glowing.
I like your amp meter.Such a shame analogue is phased out.Bought a few at pawnshop.Still want to connect them to my solar system.So quick and easy to read,especially if you become older.
Plus, they draw no more power than what they have to drop in order to make the meter movement work, and they essentially never break down. I still have some that are in Bakelite cases that are ungodly old, judging by the case style they are probably 80 or 90 years old and still work just like new.
Good problem. I think measuring current can be difficult part for students to understand because they are used to putting probes 'across' things instead of inline.
@@idealizedscience, that's why you start with the old, 'Electricity is like water. Voltage is the pressure. Current is the volume flowing past a point. Resistance is like a constriction to the flow.' Then you get to AC inductive and capacitive phases, and impedance, and resonance, and skin effect, and eddy currents, and saturation, and everything starts getting a little weird. But the guy who taught me the water analogy and Ohm's Law got me started on the road to grasping electronics.
PS further note: try the wire-short experiment using cables bought from Ali Express; they are aluminum and don't conduct as well as copper wires. You might get a long enough cable to match the resistance of the unlit bulb filament. :)
That's why you should use an old alkaline battery like that one. A lithium pack that size is going to pop that current shunt. In the future they will need a series resistor in the circuit for new battery technologies with almost zero internal resistance.
@@johnwest7993 The battery used in the demo might be a carbon-zinc type which would in general have higher internal resistance than an alkaline type. He may have deliberately selected an old battery that was mostly depleted.
Can you list examples of when you can use an Ammeter in Parallel to measure current? Like measuring leakage current and there is no way to disconnect the power from the device under test.
Thank you for your comment! This Quick Quiz is really one in a series designed to help students understand how we measure current and voltage. Both boil down to placing a galvanometer either in series or parallel with other electrical components. The goal of this particular quiz is help students internalize the fact that you should not place ammeters in parallel. You might also find our video on electrical shunts relevant to your line of inquiry: th-cam.com/video/Hl-m7Pya38U/w-d-xo.html. Again, thank you for your comment and let us know if you have further questions!
@idealizedscience but you can place an ammeter in parallel it's called the "shunt method" it was used to biasing amplifiers. I thought you might make a video lesson about this shunt method measurements using an ammeter
Most people have a digital multimeter, which can measure up to 10 amps in series. Even the old analog meter can measure up to 10 amps in series. It is good to understand that the meter setting when on CURRENT or AMP scale has very little resistance, but on the DC VOLTS scale the resistance on a digital meter is about 10 Megaohms. So, if you ask the question to solidify the understanding, if using a Digital multimeter on the DC volts scale in parallel with the bulb, will the bulb go out, or get very dim ? The 12 v incandescent bulb has about 3 to 5 ohms of resistance when cold , but when hot will go to near 50 ohms. Comparing the relatively low bulb resistance to the multimeter 10,000,000 ohms will mean on the Volts scale the voltmeter will have almost no effect on the current going thru the bulb.
@martinploughboy988 lots of DC components are defined in terms of impedance. See for yourself... check out any automotive fuel injector, they all operate as a solenoid coil, and they are identified as low or high impedance.
@@danieljurgill1681 But when you're dealing with newbies, as this is, it's best to keep it simple. At a guess, the reason for using impedance on the fuel injector is related to its need to respond to a steep waveform, the speed at which it switches on.
The light will either dim or go off depending on what the current range of your meter is. Eg. a 10 Amp full scale reading meter will have 10 times lower value of the shunt resistor than that of a 1 Amp one - theoretically that is.
Okay, but not great. Pointing the wire in the ammeter case suggests that the"wire" is all that's in there. Of course, not so. The real answer is that the resistance inside the ammeter is very low, allowing so much current to flow. that the voltage drop across it, and therfore across the bulb to be so low that the bulb goes out. ---Just my $.02.
Where a friend worked, at a steal works, the 'num nuts' sparkies (electricians) had to be supplied with meters with no current scales as their had been two many accidents where the idiots stuck the amps range across a bus bar and blew the absolute crap out of things.
so you are adding a divider that is based on resistance, so you end up with an unbalanced voltage and current divider with the majority of voltage and current going to the lower resistance path.
The voltage will be the same on the lamp and ammeter. Most of the current (nearly all of it) will flow through the ammeter. What exactly will be the voltage depends on the battery internal resistance, resistance of the wires, and resistance of the lamp and ammeter.
Why is it so difficult? An ammeter has negligible resistance, the lamp has a resistance as does a battery. Put an effective short circuit across a resistance & the voltage across the pair drops to zero while the voltage of the battery is dropped entirely across its internal resistance allowing it to pass its highest current. The likelihood is you will damage the battery & the ammeter.
Our educational resources are targeted at teachers and students at the high school level! Many students will not have seen the concept of a short circuit when we introduce utilize this quiz in the classroom.
Take the case of two identical ammeters in parallel, then wired in series with a single bulb and battery. Will the bulb light up? What will each of the ammeters do, what will they display? I know the answer; think about it and respond. 🤔
Blown Fuse (if there is one)... The ammeter should/will be a very low impedance to the current and complete the circuit, if we can call it that :). Confidence level is 8 (1-10) p.s. Don't use my real name for Darwin's sake!!! THANK GOODNESS. I passed. My stepmom was wrong. I'm not worthless!!!
I wish there had been an internet, a TH-cam, and experiments and electronics classes like this when I was a kid 65 years ago. I would have been an EE without the piece of paper by the time I graduated from HS when I was a 17 yo in rural MI, instead of hearing of Ohm's Law for the first time after I'd graduated. All of this knowledge, delivered different ways, from different sources just as fast or slow as one wants, available 24/7 at home, essentially for free. I taught myself from books in the library of a city I moved to to find a job, and in a few months I was working at a CB shop, then at a small electronics company, and I just kept at it in my spare time after work. Everything I needed to know for work I just read another library book in the evening. By the time I retired after 35 years or so I'd been a tech at HP, IBM, and others, and retired as an R&D tech from SONY. So I really can't imagine how different life is now with unlimited knowledge at a child's fingertips. So many questions answered. So many project ideas. So many inexpensive parts, and tools delivered to one's door the next day, or even the same day. $5 multimeters, $35 digital 'scopes, $100 handheld spectrum and network analyzers that gather, store, and analyze data. And they work well up into the GHz range! Wow. I hear that most American kids with our culture and technology these days are pretty lost or disinterested, but I'm sure there are a few who are lapping it all up just as fast as they can. Fundamental physics, math, electronics, programming in multiple languages, young minds integrating it all. They are gorging on a feast of knowledge, and are going to be scary if they ever decide it's time to stop the constant learning and shift gears into the constant doing.
Thank you for sharing! Sadly, despite all the information out there, many students struggle to deeply learn E&M in high school and/or college. Students are rarely given the opportunity to develop real intuition and experience with electronics and the courses end up being a pattern-matching exercise where students feel forced to memorize lots of formulas to survive.
We are working on developing lots of low-cost materials to help lower the barrier to a high quality physics education. In 2025 we will be working on a big “understanding the fundamentals of electricity” project (with online course, quick quizzes like this one, boxes of materials needed to implement the quizzes, and a book)!
It sounds like your input would be valuable, so please be sure to subscribe and keep an eye out for new content. We are a non-profit, so if you’d like to support us financially, you can at our website www.idealizedscience.org! All the best and happy new year!
An amp meter is a voltage drop test across a shunt. The amp scale is actually a recalibrated voltmeter scale
A ammeter is a low-impedance device, a dead short in effect. The light bulb goes out, the ammeter goes to fsd and the battery is discharged or dies. Don't try this with a car battery or you will destroy the ammeter too!
AKA "never attempt to measure the current capacity of a voltage source"
You can but provided the voltage source is limited somehow, like it's own internal resistance for instance.
However there's no reason to do it because you want to maintain the sources voltage WHILE measuring it's current or it's pretty meaningless
@@Dazzwidd Yes, it is a stupid thing to do as it measures nothing and will probably destroy the ammeter and perhaps even the voltage source!
Depends on the ammeter. In many cases it releases the magic smoke, and the ammeter just stops working - permanently.
@@TonyFisher-lo8hh remember that smoke is expensive smoke
Also, don't have your old Heathkit VOM set to Ohms and try to read the house voltage.
One method of meter assassination!
It's amazing what we learn by doing it wrong. 🤣
I once plugged a linking cable in wrong, ever seen a pcb track glow & then turn into a spring?
Bang good 😂
magic smoke
Sometimes this can be done with a LED circuit. Usually there is a resistor in series with the LED to limit the current.
Great info. Always had this as a question in the back of my mind, but never thought it all though. Seems like such an obvious answer now.
That’s great that it feels intuitive now! Thanks for watching
Here is a point to consider: A bulb's resistance depends on how hot the filament is: when the ammeter shorts out the bulb and the filament stops glowing, it's resistance, while still more than that of the ammeter, will be a lot lower, so a decent percentage of the current must also track through the bulb; abeit not enough to heat the filament to glowing.
I like your amp meter.Such a shame analogue is phased out.Bought a few at pawnshop.Still want to connect them to my solar system.So quick and easy to read,especially if you become older.
Plus, they draw no more power than what they have to drop in order to make the meter movement work, and they essentially never break down. I still have some that are in Bakelite cases that are ungodly old, judging by the case style they are probably 80 or 90 years old and still work just like new.
@johnwest7993 If word "bakelite" is used it implies two things: old and quality👍👍👍
Simple LOVE ANALOG meters... nothing else can show "trends" as well. The "digital bar graphs" etc are a FAIL, IMO. Cheers
@@johnwest7993 They were probably built to withstand abuse!
Good problem. I think measuring current can be difficult part for students to understand because they are used to putting probes 'across' things instead of inline.
Definitely!
@@idealizedscience, that's why you start with the old, 'Electricity is like water. Voltage is the pressure. Current is the volume flowing past a point. Resistance is like a constriction to the flow.' Then you get to AC inductive and capacitive phases, and impedance, and resonance, and skin effect, and eddy currents, and saturation, and everything starts getting a little weird. But the guy who taught me the water analogy and Ohm's Law got me started on the road to grasping electronics.
Current can be calculated by the voltage drop across components 😊
PS further note: try the wire-short experiment using cables bought from Ali Express; they are aluminum and don't conduct as well as copper wires. You might get a long enough cable to match the resistance of the unlit bulb filament. :)
I hope your battery and interconnecting wires had enough internal resistance that the ammeter was not damaged.
That's why you should use an old alkaline battery like that one. A lithium pack that size is going to pop that current shunt. In the future they will need a series resistor in the circuit for new battery technologies with almost zero internal resistance.
@@johnwest7993 The battery used in the demo might be a carbon-zinc type which would in general have higher internal resistance than an alkaline type. He may have deliberately selected an old battery that was mostly depleted.
Can you list examples of when you can use an Ammeter in Parallel to measure current? Like measuring leakage current and there is no way to disconnect the power from the device under test.
Thank you for your comment! This Quick Quiz is really one in a series designed to help students understand how we measure current and voltage. Both boil down to placing a galvanometer either in series or parallel with other electrical components. The goal of this particular quiz is help students internalize the fact that you should not place ammeters in parallel. You might also find our video on electrical shunts relevant to your line of inquiry: th-cam.com/video/Hl-m7Pya38U/w-d-xo.html.
Again, thank you for your comment and let us know if you have further questions!
@idealizedscience but you can place an ammeter in parallel it's called the "shunt method" it was used to biasing amplifiers. I thought you might make a video lesson about this shunt method measurements using an ammeter
Most people have a digital multimeter, which can measure up to 10 amps in series. Even the old analog meter can measure up to 10 amps in series. It is good to understand that the meter setting when on CURRENT or AMP scale has very little resistance, but on the DC VOLTS scale the resistance on a digital meter is about 10 Megaohms. So, if you ask the question to solidify the understanding, if using a Digital multimeter on the DC volts scale in parallel with the bulb, will the bulb go out, or get very dim ? The 12 v incandescent bulb has about 3 to 5 ohms of resistance when cold , but when hot will go to near 50 ohms. Comparing the relatively low bulb resistance to the multimeter 10,000,000 ohms will mean on the Volts scale the voltmeter will have almost no effect on the current going thru the bulb.
Thank you for sharing your thought process!
It's a DC circuit, so resistance.
@martinploughboy988 lots of DC components are defined in terms of impedance. See for yourself... check out any automotive fuel injector, they all operate as a solenoid coil, and they are identified as low or high impedance.
@@danieljurgill1681 But when you're dealing with newbies, as this is, it's best to keep it simple. At a guess, the reason for using impedance on the fuel injector is related to its need to respond to a steep waveform, the speed at which it switches on.
The light will either dim or go off depending on what the current range of your meter is.
Eg. a 10 Amp full scale reading meter will have 10 times lower value of the shunt resistor than that of a 1 Amp one - theoretically that is.
Okay, but not great. Pointing the wire in the ammeter case suggests that the"wire" is all that's in there. Of course, not so. The real answer is that the resistance inside the ammeter is very low, allowing so much current to flow. that the voltage drop across it, and therfore across the bulb to be so low that the bulb goes out. ---Just my $.02.
The amp meter will put a dead short across the light so the light will go out and the meter will be PEGGED! Confidence 20
Well done! Keep an eye out for our (slightly trickier) follow-up quizzes!
third grade
Put the meter in series to read current but only in parallel to read voltage.
Where a friend worked, at a steal works, the 'num nuts' sparkies (electricians) had to be supplied with meters with no current scales as their had been two many accidents where the idiots stuck the amps range across a bus bar and blew the absolute crap out of things.
Hilarious story, thanks for the comment😂
The bulb will go out. But that's okay, because the ammeter will provide plenty of light as it catches fire. 100% confidence.
Far too low current and voltage involved, but otherwise quite right! Well done and thanks for the comment!
so you are adding a divider that is based on resistance, so you end up with an unbalanced voltage and current divider with the majority of voltage and current going to the lower resistance path.
The voltage will be the same on the lamp and ammeter. Most of the current (nearly all of it) will flow through the ammeter. What exactly will be the voltage depends on the battery internal resistance, resistance of the wires, and resistance of the lamp and ammeter.
Yeah, don't do this.
Why is it so difficult? An ammeter has negligible resistance, the lamp has a resistance as does a battery. Put an effective short circuit across a resistance & the voltage across the pair drops to zero while the voltage of the battery is dropped entirely across its internal resistance allowing it to pass its highest current. The likelihood is you will damage the battery & the ammeter.
Our educational resources are targeted at teachers and students at the high school level! Many students will not have seen the concept of a short circuit when we introduce utilize this quiz in the classroom.
@@idealizedscience Just seems a strange way to teach, together with inviting damage to equipment.
Dead short on the battery, light goes out.
In the old days, (1940s), we called that a short circuit.
Indeed!
Stop with the over bright HDR. Just cause you can doesn't mean you should.
Noted. Definitely not intentional and we will fix it in the future.
My YT app on my android phone does that as a glitch occasionally on any random YT video. Just a thought that this my be what you're having happen too.
Take the case of two identical ammeters in parallel, then wired in series with a single bulb and battery. Will the bulb light up? What will each of the ammeters do, what will they display?
I know the answer; think about it and respond. 🤔
Why?
It defeats the purpose.
That is how voltage drop is measured.
Current is measured in series 💥⚡⚡⚡
As an educational exercise to help students internalize the fact you just stated!
See if you can measure how many amps is available from the PowerPoint using this method 😂
Think of the flow of electrons, they have no where to go.
You shoulb put a disclaime: do not try this at home. Because under some conditions, it can harm people.
With a 6V power supply it is very safe, but agreed a disclaimer isn’t a bad idea. We will add to the description! Thank you for you comment
@@idealizedscience Good!
Blown Fuse (if there is one)... The ammeter should/will be a very low impedance to the current and complete the circuit, if we can call it that :). Confidence level is 8 (1-10) p.s. Don't use my real name for Darwin's sake!!! THANK GOODNESS. I passed. My stepmom was wrong. I'm not worthless!!!
Yer using it wrong
For educational purposes!
AKA: How to abuse your test instruments.
For educational purposes, of course!
I’m going to guess: Nothing will happen.
Not a good idea. Don't try this at home boys and girls.
Perfectly safe with a 6V battery and the internal resistance of the components. Though, we agree people shouldn’t do this with higher current sources!
@@idealizedscience If using a cheap analogue multimeter to measure the current it could cause damage