How can I increase the isolation of an oscilloscope?

Question

The isolation between the channels is not infinite. Are there possibilities to increase it?

Answer

Please check if the following points are helpful:

• The isolation which is specified in the datasheet relates to the neighbor channel, i.e. CH1 to CH2. If your oscilloscope has more channels use a combination with the highest distance. Usually this is CH1 <--> CH4

But also "outside" of the oscilloscope the isolation can be increased:

• Use shielded cables with high quality. Some coaxial cables have only few wires as shielding, which reduces the isolation.
• The connection of the screen of the cable to the connector might be damaged caused by bending.
• Put some ferrit cores on the cable to prevent surface current on the screen.