PicoScope 7 Automotive
Available for Windows, Mac, and Linux, the next evolution of our diagnostic scope software is now available.
When to ground probes?
When to ground probes?
I'm new to Picoscope and can't seem to wrap my head around why I sometimes need to ground a probe other times not. I have a Diagnostic tool, which outputs a serial data stream. I plugged the tool into mains, my 2204A into my laptop, and then put the probe onto the data out pin. It showed a weird graph from roughly -12v to +12v even though the pin shouldn't have been live, with no data stream. The same thing happens if I probe the positive of say, a 12v power supply. I would expect to see a flat 0v line from the tool, and a straight 12v line from the power supply.
Yet when I probe the output of a synthesizer, outputting a +-1v sawtooth wave, the scope works as expected.
What's going on here? Why is it I am able to probe my synthesizer and get a waveform, yet probing even just a simple power supply or diagnostic tool gives the same weird waveform of -12v to +12v. When do I need to attach the ground on the probe to the ground of the thing I'm measuring?
Yet when I probe the output of a synthesizer, outputting a +-1v sawtooth wave, the scope works as expected.
What's going on here? Why is it I am able to probe my synthesizer and get a waveform, yet probing even just a simple power supply or diagnostic tool gives the same weird waveform of -12v to +12v. When do I need to attach the ground on the probe to the ground of the thing I'm measuring?