Crossing Wheatstone Bridges

The Wheatstone bridge is a way of measuring resistance with great accuracy and despite having been invented over 150 years ago, it still finds plenty of use today. Even searching for it on Hackaday brings up its use in a number of hacks. It’s a fundamental experimental device, and you should know about it.

How It Works

Here’s an easy way to understand how the Wheatstone bridge works. In the schematic are two voltage dividers (pairs of resistors in series): R1 with R2 and R3 with R4. If you do the math, you’ll notice that the voltages across R1 and …read more

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Automatic Resistance: Resistors Controlled by the Environment

Resistors are one of the fundamental components used in electronic circuits. They do one thing: resist the flow of electrical current. There is more than one way to skin a cat, and there is more than one way for a resistor to work. In previous articles I talked about fixed value resistors as well as variable resistors.

There is one other major group of variable resistors which I didn’t get into: resistors which change value without human intervention. These change by environmental means: temperature, voltage, light, magnetic fields and physical strain. They’re commonly used for automation and without them our …read more

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