Questions tagged [conductivity]
Electrical conductivity or specific conductance is the reciprocal of electrical resistivity
134 questions
5
votes
3
answers
725
views
Linear rheostat - where lies a trick of a sliding contact with isolated wire?
This type of linear rheostat consist primarily of an isolated wire (wound around an isolated cylinder) and a sliding contact:
(Source: Linquip - Rheostat Function: The Complete Guide to How Rheostats ...
- 1,325
1
vote
2
answers
156
views
Simple (and non-immersive) way to gauge water level inside my home's plastic water tank
I want to guage the water level inside my home's plastic water tank. The level gauge need not be analogous (continous), indication of water being at or above 10%, 30%, 50%, 70%, or 90% of the total ...
- 155
-4
votes
4
answers
155
views
From the material science perspective, why do some materials and circuits act like (high pass or low pass) filters?
Capacitors, inductors, resistors, wires and transmission lines are fundamentally collection of atoms, and in electronics, usually rocks with fancy names, such as copper or Gallium arsenide.
If you ...
4
votes
2
answers
479
views
NPN Transistor Saturation: "Ib must be at least 10% of Ic", how strict is that rule?
Saturation:
For anyone who doesn't know and is reading this in the future, transistors have an "active region" (its normal hFE rating) where it will ...
- 553
5
votes
2
answers
506
views
Modelling resistance of a complicated "resistor"
This is very similar to a "toaster in a bath" problem, but I've been unable to find any way to go about estimating equivalent resistance.
Suppose I have a 1ft cube (red) in a tub that ...
- 161
1
vote
0
answers
52
views
FEM simulation of a high voltage composite dielectric configuration - interface charge and surface conductivity
I constructed a axisymmetric FEM model of two electrodes, one at 500 kV, held apart by a solid dielectric component immersed in SF6 gas.
I then extracted the information about tangential, normal E ...
- 169
4
votes
1
answer
432
views
What is the difference between resistance and conductance (Ω vs. S)?
I generally understand both concepts and how they influence the movement of charge in a circuit. I've always looked at resistance as being the energy it takes to move through a material; rearranging ...
- 511
0
votes
1
answer
76
views
Capacitor plate surface charge
Imagine a parallel plate capacitor charged to some potential, there is now surface charge on the overlapping plate surfaces, lets say one of the plates has current carrying wires attached to the ...
- 47
2
votes
2
answers
247
views
Drift Velocity of conduction electron in a metal in an alternating electric field
This is a exercise from a book.
Suppose the conduction electrons in a metal are subjected to an
alternating electric field \$E = E_0 \cos(ωt)\$ applied along the x-direction. Let \$V_x\$ represent ...
- 1,325
0
votes
3
answers
118
views
Measuring resistance of conductive carbon parts
I'm trying to set up a resistance measurement of a carbon infused pad. From specification I know the resistance should be around 500 Ohm, however, when pressed against two conductive surfaces using a ...
2
votes
1
answer
152
views
Unexpected measurements results with prototype transformer-type inductive conductivity sensor (TICS)
I have made a prototype transformer-type inductive conductivity sensor (TICS) and I am getting some unexpected results at higher conductivity levels, so I am looking for some ideas for further testing ...
- 79
4
votes
3
answers
1k
views
Minimum Bend Radius of a FR-4 PCB
How much tension from flexure can the standard FR-4 pcb endure?
I know this will be a factor of the number of layers and width of each layer, but I couldn't find anything online on how to calculate or ...
-1
votes
4
answers
177
views
What if negative is less conductive than positive wire in DC circuit? [closed]
In almost all trucks, the chassis and battery's negative are shorted. Say we are to install a vehicle tracker that operates on 12v DC. The positive sides are connected via a copper wire but the ...
- 107
2
votes
3
answers
1k
views
Why does a line-tester glow more when I touch the steel door frame?
I reassembled my line tester, and it was then that I got to know how it actually works. I know that when someone touches the metal part at the top, the neon LED inside glows. However, I have seen that ...
- 107
2
votes
1
answer
115
views
Optimal thin absorber of electromagnetic energy
I am a material engineer and have a question about a formula derivation regarding microwave absorption properties. I really cannot figure it out after days of trying. This should be simple for a ...
- 23