T = 25☌, we have to find the material's thermal coefficient (TCR).
Taking into account metals, their resistance increases with the temperature rise, so to define the resistance at some standardized temperature, e.g. Even worse, these dependencies differ for metals, semiconductors, or insulators. Well, in general, there should be no significant difference between these methods, but we must be aware that the resistance of the vast majority of materials is temperature-dependent. Some of you may be wondering why people measure an unknown resistance with a voltage divider when they can simply read the value of amperage that flows through the resistor when an external voltage is applied - just a simple Ohm's law. You can always transform the general voltage divider equation to find R ₂ R₂ R ₂ as an unknown parameter: Afterward, just insert all these values into the voltage divider calculator, and that's it - the mystery is revealed. For exceptionally high voltages (let's say above 100 kV), it is better to use capacitive instead of resistive ones.įinding unknown resistance - Is it possible to find some unknown resistance if you only have a voltage source and another resistor with known resistance? You're lucky if you can read its color code, but what if there isn't one? Well, you can just create a simple circuit with both resistors arranged in series, set an input voltage, and measure the voltage over the desired resistor. In that case, it's convenient to use the voltage divider to lower the voltage to a safe region. High voltage measurement devices - It turns out that it is possible to measure high voltages even if the direct measurement can be destructive for the device. The critical element is a sliding contact, adjusting the output resistance possible. Some of the most popular types of potentiometers are slide pots, trimpots, or thumb pots, which vary by size and structure. We can distinguish between analog and digital ones, but, in any case, we can set the resistance with high precision. They are usually made out of only resistive components. Another word describing this element is a rheostat. One of the most commonly used devices which works thanks to the voltage divider concept is a potentiometer.
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