I think the simplest answer is that almost everything in electronics has to do with electromagnetic fields that are not contained to the conductor.
Our common-sense, macro-level understanding of water doesn't involve invisible fields that travel outside of pipes.
Further, the charge carriers in electric circuits are actually a part of the "pipe". Things like p-n junctions are not hard to grasp on a basic level, but they just don't make sense if you imagine them as a junction between two hollow tubes.
I've never encountered these analogies. Is this some cultural specific thing in the anglo-saxon world? Or was I just spared these analogies by accident?
You need to register with an email to see it, but it's free. There's a PNP symbol in there, the text talks about n-p-n and p-n-p junctions. And the analogy is described as follows:
"An interesting analogy can be made between a transistor amplifier and a toilet (see the right-hand side of the picture above). The emitter is the flush cistern, while the collector is the toilet bowl. Imagine attaching a small bucket to the flush lever, which represents the base. Pouring a little water into the bucket is like injecting a current into the base of the transistor. The weight of the water poured into the bucket activates the lever and the toilet valve opens, allowing the water contained in the emitter/cistern (the analogue of the charges contained in the voltage source attached to the emitter of the transistor) to flow copiously into the collector/bowl, as if the device were multiplying the water poured into the bucket and letting it flow into the pipe (the analogue of the resistor)."
I think the plumbing analogy is good to get people started, i.e. batteries, lights, switches. but once you get past household electricity level technology, it's best to abandon it and just make people learn/internalize volts, amps, watts.
That said, I frequently use engines as an analogy for "can I use this power supply?". Volts is like RPMs; it always needs to match. too fast and you'll damage the device. too slow, and it doesn't work. Amps is like /available/ torque. It doesn't matter if you hook up a tractor PTO or the motor from a shaver; if it has the specified torque /available/, the device can function. i.e. amps specification is just a floor. But again, the usefulness stops there. I would not try and use it to explain anything more complicated.
Amen!! Should be literally outlawed, IMO the analogy is barely applicable to secondary-school physics, yet I know it’s being taught to university undergraduates because it happened to meeeee. whyyyyy
I have railed against this for years. When I was in charge of tutorial documentation for a technical product, I went so far as to say "all analogies are false." I challenged the authors to come up with better tutorial descriptions. E.g. following the example set by Hewlett Packard consumer products, such as the HP 200 LX
Is there a concise reason why the analogy fails? Is it that there's nothing analogous to magnetism in hydraulics?
I think the simplest answer is that almost everything in electronics has to do with electromagnetic fields that are not contained to the conductor.
Our common-sense, macro-level understanding of water doesn't involve invisible fields that travel outside of pipes.
Further, the charge carriers in electric circuits are actually a part of the "pipe". Things like p-n junctions are not hard to grasp on a basic level, but they just don't make sense if you imagine them as a junction between two hollow tubes.
I've never encountered these analogies. Is this some cultural specific thing in the anglo-saxon world? Or was I just spared these analogies by accident?
Pretty sure the toilet analogy was for a unijunction transistor.
No? I mean, I get what you're saying, but that's not how it was used:
https://medium.com/swlh/how-transistors-work-b63358b95180
You need to register with an email to see it, but it's free. There's a PNP symbol in there, the text talks about n-p-n and p-n-p junctions. And the analogy is described as follows:
"An interesting analogy can be made between a transistor amplifier and a toilet (see the right-hand side of the picture above). The emitter is the flush cistern, while the collector is the toilet bowl. Imagine attaching a small bucket to the flush lever, which represents the base. Pouring a little water into the bucket is like injecting a current into the base of the transistor. The weight of the water poured into the bucket activates the lever and the toilet valve opens, allowing the water contained in the emitter/cistern (the analogue of the charges contained in the voltage source attached to the emitter of the transistor) to flow copiously into the collector/bowl, as if the device were multiplying the water poured into the bucket and letting it flow into the pipe (the analogue of the resistor)."
I think the plumbing analogy is good to get people started, i.e. batteries, lights, switches. but once you get past household electricity level technology, it's best to abandon it and just make people learn/internalize volts, amps, watts.
That said, I frequently use engines as an analogy for "can I use this power supply?". Volts is like RPMs; it always needs to match. too fast and you'll damage the device. too slow, and it doesn't work. Amps is like /available/ torque. It doesn't matter if you hook up a tractor PTO or the motor from a shaver; if it has the specified torque /available/, the device can function. i.e. amps specification is just a floor. But again, the usefulness stops there. I would not try and use it to explain anything more complicated.
Hey, I'm all in favor of tractor analogies!
Amen!! Should be literally outlawed, IMO the analogy is barely applicable to secondary-school physics, yet I know it’s being taught to university undergraduates because it happened to meeeee. whyyyyy
I have railed against this for years. When I was in charge of tutorial documentation for a technical product, I went so far as to say "all analogies are false." I challenged the authors to come up with better tutorial descriptions. E.g. following the example set by Hewlett Packard consumer products, such as the HP 200 LX
But I was so proud of my inductor as paddlewheel analogy....
I think of an inductor as a spinning flywheel. Pretty similar.
And it can remotely spin nearby flywheels, which makes perfect sense
Also, the plumbing analogy is not even that helpful since I am not a plumber! Why the indirection???