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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.

19 votes
4 answers
65k views

How does the tester screwdriver work?

How does the tester screwdriver work? If I put the tester screwdriver inside the "hot wire" of an electrical socket, it lits up if I press my finger against the metal cap on top of the screwdriver. ...
John Donn's user avatar
  • 293
2 votes
2 answers
2k views

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 ...
FrancoVS's user avatar
  • 1,563
-2 votes
1 answer
1k views

I want to build a portable railgun and I'm a complete rookie [closed]

I'd like to enter the world of electronic hobbies by making a railgun, and so far I know that I understand the basics of the device and that I need high amounts of direct current. However, I am ...
lychnus's user avatar
  • 75
6 votes
1 answer
1k views

What impact, if any, does the solder mask color have on the electrical and mechanical properties of a PCB

At my place of work, we use soldermask colors as a sort of poke-yoke for manufacturing purposes E.g. Technicians know that green pcb goes with green, blue pcb with blue, etc. This has lead to some ... ...
crasic's user avatar
  • 5,838
3 votes
1 answer
606 views

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 ...
Mrunal Shinde's user avatar
3 votes
2 answers
3k views

What dielectric liquids can be used as coolants?

I've seen some interesting videos of people putting their computers in containers with sunflower oil, where they continue to work normal. Are there any other dielectric liquids that can be used to ...
user1306322's user avatar
  • 1,238
2 votes
1 answer
4k views

How do internal capacitor stud finders work?

I don't understand how a non-magnetic object like wood can be detected using a stud finder. For instance, stud finders find wood from the dielectric constant, but I don't understand the principle. The ...
Napster's user avatar
  • 507
1 vote
1 answer
179 views

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 ...
Sai's user avatar
  • 27