Questions tagged [dielectric]
A dielectric is an insulator that can be polarized by applying an electric field. A common example is the use of a dielectric within a capacitor between the metallic plates to increase the surface charge.
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A basic question about using dielectric material in PCB boards in relation to electric field
I was wondering what the PCB's dielectric material(such as FR-4) do to the electric field.
If I'm not wrong, the dielectric material influences how the electric field lines are distributed. And it ...
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Food for thought: Which person has truth in this discussion on capacity and AC? [closed]
I have stumbled upon interesting discussion in the commentary section regarding safety of electrical engineering in home environment.
person1: AC voltage 'flows' even through insulator, fact.
person2:...
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Should reference plane change its potential value if a track goes to another layer?
Assume you have a four layer board.
Signal
GND
Dielectric
VDD
Signal
And you having a track in the 4:th layer. Suddenly you're using a via to go through the 4:th layer to 1:st layer.
Question
The ...
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Determine dielectric constant of unknown FR4 substrate
I have a piece of single sided FR4 PCB substrate that I need to build a 2.4 GHz patch antenna on using copper tape.
Other than the dimensions and it being FR4 I know nothing about the substrate.
Is ...
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PCB material with high dielectric constant
Typical PCBs have a dielectric with a low constant \$\varepsilon_r\$. I'm studying the effect the electrical fields on dielectrics and as an experiment would like to test PCBs with a very high ...
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Hipot arcing for AC and DC hipot test
I have a substrate with multiple conductor traces (0.5mm gap from each other) with aluminum plate on top used as electrode. The aluminum plate is connected to the hipot "line" and the ...
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How to measure the electrical properties to ensure the performance of a thin electrode/insulator stack-up?
I am a mechanical engineer by trade, and I am looking at some basic electrical properties that I need to measure to ensure the device meets the desired performance.
The device consists of a two-layer ...
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Effective dielectric constant in multilayer PCB design
Top => copper
PP1 => RO4350B
L2 => copper
PP2 => FR4
L3 => copper
PP3 => 185HR
L4 => copper
This is my PCB stackup.
In the top layer, I have a 50 Ω controlled RF trace. The ...
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Hipot results vs surface area
I trying to hipot test a 12"x12" metal with kapton layer. Different sizes of metal (e.g. 1"x1", 4"x4", banana plug) is placed on top of kapton tape. The bigger metal ...
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Arc-shape frequency dependence of phase angle in bioimpedance spectroscopy
I have concerned myself with bioimpedance spectroscopy (BIS) from a medical standpoint for some time now, however there is one concept evading my grasp until now:
When measuring complex impedance of ...
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Trying to make a HASEL actuator
I was told that if I apply high voltage to a zip lock bag filled with baby oil with tin foil paper on the end it'd make it contract and act as a HASEL actuator.
I'm afraid of measuring the exact ...
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Voltage required for a spark plug - dielectric constant of air
The dielectric constant of air is approximately 3 kV/mm. The typical space between car spark plugs is between 0.6 and 1.8 mm. By multiplying those numbers in mm by the dielectric constant of air, we ...
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Dielectric strength test voltage
I am preparing an insulation diagram prior to testing a device against IEC 60601-1.
How do I determine the dielectric strength test voltage? I couldn't find anything in -1.
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Why do material makers call the dielectric constant "Dk" rather than "D.c."?
Why do material makers call the dielectric constant "Dk" rather than "D.c."? Is it kind of German? Something like Dielektrische Konstante? It is actually called a ...
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DC hipot leakage current
I noticed that when testing hipot in DC I always get leakage current, but not during AC hipot testing. Do you have any ideas about this? My hipot tester is Quadtech Sentry 500VA. I’m testing a ...
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Would an inductor work differently under a different dielectric environment?
I am talking about these common rounded inductors with a metal core that you would find on PCBs.
Would the operation be different in, say, mineral oil vs. air? These are two different dielectric ...
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How does selecting a higher permittivity substrate in patch antenna reduce its size?
By selecting a higher permittivity substrate do we reduce the height of the antenna or we reduce the length of the patch antenna? We cannot reduce the length of the antenna as it is dependent on the ...
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Relays: What is High Contact Stability?
This TE RF relay datasheet shows the component coming in three varieties:
High Dielectric
High Contact Stability
High Current
So high-current is obvious (right?), and (correct me if I'm wrong) high ...
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Why do dielectric waveguides support hybrid modes and metallic waveguides do not?
Can anyone explain to me qualitatively why dielectric waveguides (core and infinite cladding) support hybrid modes (E_z and H_z components in the guided wave), while metallic waveguides cannot?
I am ...
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The field in a waveguide at exactly the cut-off frequency
Can anyone explain to me qualitatively, what kind of field exists inside a waveguide at EXACTLY the cut-off frequency?
I would be grateful if an explanation was given about waveguides with metalic ...
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How to increase efficiency of antenna without moving antenna far from tree?
I have designed a monopole antenna at 868MHz frequency. Now I would like to attach that antenna to the tree (wood). But, due to Why does placing an antenna far from the wood increase the efficiency of ...
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Why does placing an antenna far from the wood increase the efficiency of the antenna?
I designed a monopole antenna at 868MHz frequency. I placed wood as the surrounding material. I noticed that placing the antenna far from the wood increases the efficiency of the antenna. Can anyone ...
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Dielectric withstand test of DC powered product
I am trying to figure if our test set-up for dielectric withstand test is correct. There are two versions of the DUT (device under test), an AC powered (typical 85-264 Vrms) and DC powered type (12-...
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Ampere's Law with dielectric
I am asked to calculate the magnetic-field-strength and magnetic-flux-density for different regions inside a coaxial-cable. I found Ampere's Law for that, but it uses \$\mu_0\$ , and the coaxial-cable ...
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Following is an excerpt from a power electronics textbook. Is the statement true?
As far as I know ESR primarily depends on the type of dielectric.
eg: Al electrolytic (higher capacitance value) would have much higher ESR than ceramic (usually lower capacitance value).
Say for ...
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Capacitors: voltage-dependent capacitance?
While playing around with a capacitive power supplies, I observed some very weird behavior when passing a 60Hz sinusoidal current through a 1000V disk ceramic capacitor. The voltage curve was very ...
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How do I calculate the capacitance of a capacitive touch or water sensor?
Sensors like capacitive touch or moisture sensors are simply two traces drawn on a PCB. For example, you may check the Grove soil moisture sensor. In these types of sensors, the capacitance increases ...
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Why it can be asserted that the bottom plate takes the highest potential and the top plates takes the lowest of the capacitor?
The ideal parallel capacitor has been filled with 2 dielectrics as shown in the above diagram.
$$ V_{1} :=\text{potential at the top plate} $$
$$ V_{2} :=\text{potential at the bottom plate} $$
$$...
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When is PCB thermal destruction desirable?
In the Wikipedia page for FR-4, it contains this excerpt:
FR-4 epoxy resin systems typically employ bromine, a halogen, to
facilitate flame-resistant properties in FR-4 glass epoxy laminates.
Some ...
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Why the euclid distance between the plates of the capacitor has been doubled to find out the capacitance?
I may have been asking of an easy problem.
The problem requires to find out the capacitance.
The ideal capacitor with area of \$S\$ exists and the euclid distance between the plates is \$d\$.
The ...