Why is isolation important for a PC oscilloscope ?
When you connect a measuring device to a PC, generally the ground of the instrument is wired to the ground of the PC. If your PC is earthed, and you accidentally touch the ground clip on the instrument to an earth referred voltage, like the output of a power supply, or mains voltage for example, you will short circuit that voltage via the instrument and the PC. This can lead to damaged equipment, damaged PC, dangerous currents flowing and so on. An even more hazardous situation arrises when the PC isn’t earthed. You connect your instrument and connect the ground clip to a high potential (perhaps by mistake). Then the whole PC is at that elevated potential. This is very dangerous as it presents a shock hazard for you when you touch the PC. The USBscope50 avoids this hazard by isolating the ground clip from the PC’s ground. If you measure with a DMM between the USBscope50’s ground (on the BNC) and the ground on the USB shell, there is no direct current path (there is a small AC path caus
