nScope displays phantom sine wave

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nScope displays phantom sine wave #11

Closed josenj closed 8 years ago

josenj commented 8 years ago

Turn on A1
Set frequency to 10kHz.
Hook up a wire from A1 to Ch1. No other wires are [connected.]
Turn off Ch1 in the app
Set 'Run control' to 'Continuous' (or 'Single')
Turn on Ch2 and you will see a sine wave
Turning on Ch3 displays a smaller wave, Ch4 displays even a smaller wave.

Running:

nscope version

Example Screenshot:

nscope phantom sine wave

davidjmeyer commented 8 years ago

This is actually not a phantom sine wave. It's capacitive coupling between the connections on the breadboard, and is a very real phenomenon. If you were to measure the voltage on those pins with a professional oscilloscope, it would also report the presence of a sine wave. If you want the pins to be ground, then you should connect them to ground with a wire.