Name: resistivity in conductors and insulators
Uploaded: 2023-04-30T12:38:52.000Z
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Resistivity

Elektriksel direnç, bir malzemenin yük akışına ne kadar etkili bir şekilde direndiğini tanımlayan içsel bir özelliktir.
Dirençlilik, elektriksel iletkenliğin tersidir ve elektrik alanı ve akım yoğunluğu cinsinden tanımlanabilir. SI özdirenç birimi ohm-metredir.
İyi iletkenler yüksek iletkenliğe ancak düşük bir dirence sahipken, iyi yalıtkanlar düşük iletkenliğe ancak yüksek bir dirence sahiptir.
Sıcaklık, bazı malzemelerin direncini etkiler. Birçok malzemede, bağımlılık yaklaşık olarak doğrusaldır ve ρ'nin malzemenin bir sıcaklıktaki direnci, α'in malzemenin sıcaklık katsayısı ve ρ0'ın oda sıcaklığındaki özdirenç olduğu doğrusal bir denklem kullanılarak modellenebilir.
Bakır gibi bazı malzemelerin direnci sıcaklık arttıkça artar; karbon gibi diğerlerinde sıcaklık arttıkça özdirenç azalır.
Yarı iletkenlerde sıcaklık katsayısı negatiftir, bu da sıcaklık arttıkça direncin azaldığı anlamına gelir.

<ol>
	<li>Stax'ı açın. (2019). Üniversite Fiziği Cilt 2. [Web versiyonu], Sayfa 396 - 398. <a href="https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance" adresinden alındı>https://openstax.org/books/university-physics-volume-2/pages/9-3-resistivity-and-resistance</a></li>
</ol>

direncin hesaplanması

Bir iletken üzerine bir gerilim uygulandığında, bir elektrik alanı oluşur ve iletken içindeki yükler elektrik alanı nedeniyle kuvvet hisseder. Sonuç olarak oluşan akım yoğunluğu, elektrik alanına ve malzemenin özelliklerine bağlıdır. Bazı malzemelerde, özellikle belirli bir sıcaklıkta metallerde, akım yoğunluğu yaklaşık olarak elektrik alanına orantılıdır. Bu durumlarda akım yoğunluğu aşağıdaki gibi modellenebilir:

<img alt="Equation1" src="/files/ftp_upload/13746/13746_Equation_1.svg" style="text-align: center; height: 16px;" />

Burada em>σ, elektrik iletkenliğini temsil eden (Ω·m)−1 olarak gösterilir. Elektrik iletkenliği, bir malzemenin elektrik akımını iletme veya taşıma yeteneğinin bir ölçüsü olan termal iletkenlikle benzerdir. İletkenler, yalıtkanlardan daha yüksek bir elektrik iletkenliğine sahiptir. İletkenlik, bir malzemenin içsel bir özelliğidir. Bir malzemenin bir başka içsel özelliği ise direnci veya elektrik direncidir. Bir malzemenin direnci, elektrik akımının akışına ne kadar güçlü bir şekilde karşı koyduğunun bir ölçüsüdür. Direnç, elektrik iletkenliğinin tersidir ve Yunan harfi rho ρ ile temsil edilir. SI birimlerinde direnç birimi ohm-metredir. Direnç aynı zamanda elektrik alanı ile akım yoğunluğunun oranı olarak da tanımlanabilir. Direnç ne kadar büyükse, belirli bir akım yoğunluğu üretmek için gereken alan o kadar büyük olur. Direnç ne kadar düşükse, belirli bir elektrik alan tarafından üretilen akım yoğunluğu o kadar büyük olur. Tablo 1'de listelenen iyi iletkenler yüksek iletkenliğe ve düşük dirence sahipken, iyi yalıtkanlar düşük iletkanlığa ve yüksek dirence sahiptir.

Tablo 1: Çeşitli malzemelerin direnç ve iletkenlik değerlerini listeleyin.

<table style="border-collapse: collapse; width: 45%; margin: 20px auto; text-align: center; font-size: 13px;">
	<thead>
		<tr>
			<th style="border: 1px solid #000; padding: 5px;">Malzemeler</th>
			<th style="border: 1px solid #000; padding: 5px;">İletkenlik, σ 
			(Ω·m)−1</th>
			<th style="border: 1px solid #000; padding: 5px;">Direnç, ρ 
			(Ω·m)</th>
			<th style="border: 1px solid #000; padding: 5px;">Isı Derecesi 
			Katsayısı, α (°C)−1</th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Gümüş</td>
			<td style="border: 1px solid #000; padding: 5px;">6.29 × 107</td>
			<td style="border: 1px solid #000; padding: 5px;">1.59 × 10−8</td>
			<td style="border: 1px solid #000; padding: 5px;">0.0038</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Bakır</td>
			<td style="border: 1px solid #000; padding: 5px;">5.95 × 107</td>
			<td style="border: 1px solid #000; padding: 5px;">1.68 × 10−8</td>
			<td style="border: 1px solid #000; padding: 5px;">0.0039</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Altın</td>
			<td style="border: 1px solid #000; padding: 5px;">4.10 × 107</td>
			<td style="border: 1px solid #000; padding: 5px;">2.44 × 10−8</td>
			<td style="border: 1px solid #000; padding: 5px;">0.0034</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Alüminyum</td>
			<td style="border: 1px solid #000; padding: 5px;">3.77 × 107</td>
			<td style="border: 1px solid #000; padding: 5px;">2.65 × 10−8</td>
			<td style="border: 1px solid #000; padding: 5px;">0.0039</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Tungsten</td>
			<td style="border: 1px solid #000; padding: 5px;">1.79 × 107</td>
			<td style="border: 1px solid #000; padding: 5px;">5.60 × 10−8</td>
			<td style="border: 1px solid #000; padding: 5px;">0.0045</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Karbon (saf)</td>
			<td style="border: 1px solid #000; padding: 5px;">2.86 × 10−6</td>
			<td style="border: 1px solid #000; padding: 5px;">3.50 × 10−5</td>
			<td style="border: 1px solid #000; padding: 5px;">−0.0005</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Silikon</td>
			<td style="border: 1px solid #000; padding: 5px;"></td>
			<td style="border: 1px solid #000; padding: 5px;">0.1 − 2300</td>
			<td style="border: 1px solid #000; padding: 5px;">−0.07</td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Kehribar</td>
			<td style="border: 1px solid #000; padding: 5px;">2.00 × 10−15</td>
			<td style="border: 1px solid #000; padding: 5px;">5 × 1014</td>
			<td style="border: 1px solid #000; padding: 5px;"></td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Cam</td>
			<td style="border: 1px solid #000; padding: 5px;">10−9 − 10−14</td>
			<td style="border: 1px solid #000; padding: 5px;">109 − 1014</td>
			<td style="border: 1px solid #000; padding: 5px;"></td>
		</tr>
		<tr>
			<td style="border: 1px solid #000; padding: 5px;">Lüsit</td>
			<td style="border: 1px solid #000; padding: 5px;"><10−13</td>
			<td style="border: 1px solid #000; padding: 5px;">>1013</td>
			<td style="border: 1px solid #000; padding: 5px;"></td>
		</tr>
	</tbody>
</table>

Direncin hesaplanması

Bir iletkene bir voltaj uygulandığında, bir elektrik alanı üretilir ve iletkendeki yükler elektrik alanından kaynaklanan kuvveti hisseder. Bu ...

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resistivity in conductors and insulators

Resistivity describes how much a material opposes electric current. When a voltage is applied to a conductor, an electric field forms. The charges in the conductor feel that force, and a current density develops. In some materials, including metals at a given temperature, the current density is approximately proportional to the electric field.

In those cases, current density can be modeled with conductivity, written as sigma. Electrical conductivity is measured in (ohm·m)^−1. It tells how well a material can conduct electricity. This idea is similar to thermal conductivity, which describes how well a material carries heat. Conductors have higher electrical conductivity than insulators, and conductivity is an intrinsic property of the material.

Resistivity, written as rho, is another intrinsic property. It is the reciprocal of electrical conductivity. In SI units, resistivity is measured in ohm-meter. It can also be defined as the ratio of electric field to current density. A higher resistivity means a larger electric field is needed to produce a given current density. A lower resistivity means the same electric field produces a larger current density.

The transcript also compares common materials. Good conductors have high conductivity and low resistivity. Good insulators have low conductivity and high resistivity. Examples of good conductors include silver, copper, gold, aluminum, and tungsten. Pure carbon has much lower conductivity than these metals. Silicon falls between conductor and insulator values, while amber, glass, and Lucite show very high resistivity and very low conductivity.

Resistivity in Conductors and Insulators

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resistivity

Resistivity describes how much a material opposes electric current. When a voltage is applied to a conductor, an electric field forms. The charges in the conductor feel that force, and a current density develops. In some materials, including metals at a given temperature, the current density is approximately proportional to the electric field. In those cases, current density can be modeled with conductivity, written as sigma. Electrical conductivity is measured in (ohm·m)^−1. It tells how well...

resistance

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key terms and concepts

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Resistivity in Conductors and Insulators | JoVE K12

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Use models to explain magnetism in terms of domains, interactions of poles, and magnetic fields.

PS.PSc.6.4

Analyze motion in terms of speed, velocity, acceleration, and momentum.

Resistivity in Conductors and Insulators

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