Hi @dbotich, there’s some discussion of a circuit for measuring high voltages in the thread linked below, including schematics and sims. A lot off folks think that a just a cap will block the DC, and it will after a few seconds. But when you initially connect the 600V, the cap will appear as a short and pass the full voltage through. So, you need a clamp after the cap. And you probably should have input/output bleed down resistors, etc. All very dangerous stuff!