Do You Trust Your Cheap Fuses?

Discovering that the fuses you’ve been relying on may not meet the expected specifications can be unsettling. Andreas Speiss found himself in this situation with the cheap, unbranded fuses commonly found in online kits. To address this concern, he embarked on a journey to test these fuses and determine their performance.

Understanding how fuses work is crucial in this investigation, as their labeled current rating indicates the maximum they can handle, not the precise current at which they blow. To test the fuses, Andreas devised a circuit using an 18650 cell and three one-ohm resistors in parallel to create a 1/3 ohm resistor. This setup would pass approximately 10 A when connected to the 18650, allowing him to assess the performance of the fuses.

Using this circuit and a storage oscilloscope, Andreas conducted tests on both the cheap fuses and a Bosch fuse for comparison. While the results showed that the cheap fuses were slower to blow than the Bosch fuse, they didn’t raise as much concern as initially anticipated. Nevertheless, this experiment highlights the importance of verifying the reliability of components, especially those critical for circuit protection. If you have similar fuses in your inventory, it might be worth conducting your own tests to ensure they meet your requirements.

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