Measuring Small Signals

Question: Recently I’ve been trying to measure a small signal.  But, my results aren’t really repeatable. Any suggestions?

Answer: I would start by looking at the probe. Most oscilloscopes come with standard passive probes. These probes work well for many applications, but tend to have high input capacitance, which can load the circuit under test. This loading can increase rise- and fall-times and decrease bandwidth. Probably the best solution would be to use an active probe instead. An active probe puts an amplifier out at the probe tip, reducing the input capacitance by an order of magnitude or more, while increasing the measurement system bandwidth.  One helpful resource might be this primer, the ABCs of Probes, which outlines key considerations when probing.

Explore posts in the same categories: Ask Scope Guru Q/A, Probes

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