Resistor Temperature Coefficient Calculator

TCR Equation:

\[ TCR = \frac{R_2 - R_1}{R_1 \times (T_2 - T_1)} \]

Resistance at T1 (R1):

ohms

Resistance at T2 (R2):

ohms

Temperature 1 (T1):

°C

Temperature 2 (T2):

°C

Temperature Coefficient of Resistance (TCR):

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1. What is Temperature Coefficient of Resistance?

The Temperature Coefficient of Resistance (TCR) describes how much a resistor's value changes with temperature. It's expressed in parts per million per degree Celsius (ppm/°C) and indicates the stability of a resistor's value across temperature variations.

2. How Does the Calculator Work?

The calculator uses the TCR equation:

\[ TCR = \frac{R_2 - R_1}{R_1 \times (T_2 - T_1)} \]

Where:

\( R_1 \) — Resistance at temperature T1 (ohms)
\( R_2 \) — Resistance at temperature T2 (ohms)
\( T_1 \) — Initial temperature (°C)
\( T_2 \) — Final temperature (°C)

Explanation: The equation calculates the relative change in resistance per degree of temperature change. Positive TCR means resistance increases with temperature (common in metals), negative means it decreases (common in semiconductors).

3. Importance of TCR Calculation

Details: TCR is crucial for precision circuits, temperature sensors, and applications where resistance stability across temperature ranges is important. Different materials have characteristic TCR values.

4. Using the Calculator

Tips: Measure resistance at two different temperatures. Enter values in ohms and °C. Ensure T2 ≠ T1 to avoid division by zero. Typical TCR values range from ±100 ppm/°C for precision resistors to ±5000 ppm/°C for thermistors.

5. Frequently Asked Questions (FAQ)

Q1: What's a good TCR value?
A: For precision applications, look for resistors with TCR < ±100 ppm/°C. Standard resistors might have TCR up to ±500 ppm/°C.

Q2: How does TCR vary with material?
A: Copper ≈ +3900 ppm/°C, Nichrome ≈ +100 ppm/°C, Carbon ≈ -500 ppm/°C, Silicon ≈ -70,000 ppm/°C.

Q3: Can TCR be non-linear?
A: Yes, especially over wide temperature ranges. This calculator assumes linear behavior between T1 and T2.

Q4: How to minimize TCR effects?
A: Use low-TCR materials, temperature-compensated designs, or operate in temperature-controlled environments.

Q5: What's the difference between TCR and alpha (α)?
A: TCR is typically expressed in ppm/°C, while alpha (α) is the same concept expressed as a fraction per °C (α = TCR × 10^-6).