One I heard from the early days of electricity use in the house was that you needed to put tape over the unused outlets so the electricity wouldn't leak out.

Isn't that what these are for?
https://cpc.farnell.com/pro-elec/91...vVVPYUeMPNbLqJvZLviybPI7RWE-ky4BoCOmoQAvD_BwE

 

Isn't that what these are for?
https://cpc.farnell.com/pro-elec/9138/safety-cover-uk-plug-pk5/dp/PLSAFEPLUG?gross_price=true&mckv=sshopping_dc|pcrid|224681503328|kword||match||plid||slid||product|PLSAFEPLUG|pgrid|47203068935|ptaid|pla-746545963342|&CMP=KNC-GUK-CPC-SHOPPING-945655906-47203068935-PLSAFEPLUG&s_kwcid=AL!5616!3!224681503328!!!network}!746545963342!&gad_source=1&gad_campaignid=945655906&gclid=CjwKCAjwy5rUBhB5EiwAIoAtCh3zcaXp0cDQXJdU4BQWnnvVVPYUeMPNbLqJvZLviybPI7RWE-ky4BoCOmoQAvD_BwE

Access Denied (Error 403)

 

Access Denied (Error 403)

 

Isn't that what these are for?
https://cpc.farnell.com/pro-elec/9138/safety-cover-uk-plug-pk5/dp/PLSAFEPLUG?gross_price=true&mckv=sshopping_dc|pcrid|224681503328|kword||match||plid||slid||product|PLSAFEPLUG|pgrid|47203068935|ptaid|pla-746545963342|&CMP=KNC-GUK-CPC-SHOPPING-945655906-47203068935-PLSAFEPLUG&s_kwcid=AL!5616!3!224681503328!!!network}!746545963342!&gad_source=1&gad_campaignid=945655906&gclid=CjwKCAjwy5rUBhB5EiwAIoAtCh3zcaXp0cDQXJdU4BQWnnvVVPYUeMPNbLqJvZLviybPI7RWE-ky4BoCOmoQAvD_BwE

Yeah, except it's to protect children from putting a knife in the socket (and touching the knife... barefoot... lethal.)

 

Continuous steady state current.

Thought for a bit longer, and well, you can have alternated steady state current. So there you can also have continuous steady state current. The steady state is independent from AC or DC.

 

I have got scores, a few from the top of my head:

-If a transistor is rated for Vce=100V and Ic=5A, then you can build a 500 watt audio amp with a single transistor (or a pair of transistors if operating class-B).
-If a fuse is rated for, say 2A, it will blow instantaneously with a current of 2.001A.
-If a transformer is rated at 100VA, after rectification you can get 100W.
-All opamps behave ideally under absolutely all operating conditions. Bonus point if those conditions include high frequencies and you are using a 741.
-If in a simulation a 1 ohm resistor withstands 1000V, it should not burn in your prototype.
-That a ground connection ALWAYS has zero impedance, even if it is through a 5 foot long AWG 30 wire.
-AA batteries don’t possess enough energy to damage a circuit.
-You can reliably start a 120VAC, 1HP motor with those little cube relays. And that a 0.1uF snubber capacitor will protect the contacts from becoming welded.
-Digital circuit design is easier than analog circuit design.
-Noise coupling due to ground loops, incorrect layout and poorly placed signal traces can be cured with a 0.1uF capacitor.
-Real men don’t read datasheets, and you shouldn’t either. They are just tables with dozens of numbers anyway.
-If a circuit simulated correctly, an actual breadboard should also work flawlessly.
-Any core you salvaged with a few turns of wire should automatically work as a transformer. Magnetic equations are unnecessary complications.

I could continue all day…………

 

You can use an op-amp as a comparator.

 

@schimitt trigger brought to my mind that a very well paid engineer (ex-boss) used to say the BJT is a current-controlled, current source device. It should be noted that yeah, you can model it like that, but the physics that describes what is really happening involves the Shockley equation for transistors, which is solely dependent on the base-emitter voltage (and other things that don't involve the base current).

 

You can use an op-amp as a comparator.

Fast? no.
Slow speeds? yes.
Will it be very good? Depends on your components' tolerance.

 

Fast? no.
Slow speeds? yes.
Will it be very good? Depends on your components' tolerance.

And those op-amps with back-to-back diodes across the inputs?

 

And those op-amps with back-to-back diodes across the inputs?

With 0.7 V of Vdiff, the slew rate is severely cut, and the open loop gain too.
So depending on speed you want and gain you need, it might not be good.

That's why you should protect with a TVS, or for slow speeds, a zener diode. This grants greater slew rate and open loop gain.

 

There's an electron named Eddy.

 

It's pretty deep, seems the field actually is real, not just apparent

Perhaps you could say that Relativity explains how an electric field creates an apparent magnetic field, but that doesn't mean the magnetic field does not exist.

 

-AA batteries don’t possess enough energy to damage a circuit.

And a 9V (transistor) battery can power a motor for a long period of time.

All opamps behave ideally under absolutely all operating conditions. Bonus point if those conditions include high frequencies and you are using a 741.

And a 741 can operate with a single 5V supply voltage, or down to zero volts in and out with any single supply voltage.

 

a very well paid engineer (ex-boss) used to say the BJT is a current-controlled, current source device. It should be noted that yeah, you can model it like that, but the physics that describes what is really happening involves the Shockley equation for transistors,

Yeah, the solid-state physics equations shows that the BJT is a voltage-controlled device.
But that theoretical info is often not enough for doing circuit design with one.
You need the black-box current-controlled model with the value of Beta or hFE for things like determining the base bias-current needed for a given collector current, or calculating the input impedance of an emitter follower, and also for any switching application.
It may be a voltage-controlled device in theory, but the current-controlled model is often more useful in circuit design.

The voltage controlled model is generally only really useful for calculating things like small-signal AC gain, or working with circuits that are sensitive to the base-emitter voltage such as a current-mirror.

 

Perhaps you could say that Relativity explains how an electric field creates an apparent magnetic field, but that doesn't mean the magnetic field does not exist.

Perhaps, everything seems to point at there being a single tensor field the "electromagnetic" field and it has magnetic and electric components, but those components are not themselves fields, they are observer dependent components of the EM field.

 

Perhaps, everything seems to point at there being a single tensor field the "electromagnetic" field and it has magnetic and electric components, but those components are not themselves fields, they are observer dependent components of the EM field.

Well, I haven't used a tensor, since I studied them 60 years ago, so I'll leave that understanding to you.
But good luck convincing the rest of use that there's no such thing as an electric or magnetic field.

 

Perhaps you could say that Relativity explains how an electric field creates an apparent magnetic field, but that doesn't mean the magnetic field does not exist.

That's a good point. You guys were talking about magnetic fields created by a current. That can be explained by relativity, but what about a magnet? It's a quantum macro effect of the magnetic domains that are aligned, where each atom get its spin aligned once the magnetic field (be it by current or not) is sufficiently high. Then there's remaining B when there's no H.

 

Yeah, the solid-state physics equations shows that the BJT is a voltage-controlled device.
But that theoretical info is often not enough for doing circuit design with one.
You need the black-box current-controlled model with the value of Beta or hFE for things like determining the base bias-current needed for a given collector current, or calculating the input impedance of an emitter follower, and also for any switching application.
It may be a voltage-controlled device in theory, but the current-controlled model is often more useful in circuit design.

The voltage controlled model is generally only really useful for calculating things like small-signal AC gain, or working with circuits that are sensitive to the base-emitter voltage such as a current-mirror.

I agree with you. My point was kind of speaking about how the transistor works, because if you go by Beta/hFE, you have it as a function of the collector current (it's not a known equation). Only with feedback or limiting current you can get a steady hFE/Beta, for a certain range, obviously.

 

Perhaps, everything seems to point at there being a single tensor field the "electromagnetic" field and it has magnetic and electric components, but those components are not themselves fields, they are observer dependent components of the EM field.

I haven't study tensors, but I kinda know how it goes. Are you trying to say that because of position, velocity, and acceleration of the observer, the components change and it's proof they aren't fields?
I think that the more the model describes a phenomenon and persists after tests, the more what the model says is true.
Or I didn't get what you understand by "field".