Convert a high-voltage output to 0-5V for Arduino ADC

[Wawa]

@marie2808

• The risk of HV reaching the Arduino if there’s a fault
• Possibly insufficient isolation between HV and low-voltage sections
• Long-term stability and reliability of the HV resistor divider

That all depends on the type of HV resistor used, and your build.
A circuit board is likely not good enough for 15KV, because of creep.
Only current can damage an Arduino pin, and 100Megohm alone (if the 10k resistor to ground fails) can't produce enough current to damage a pin. But flashover voltage or creep still can.
The resistor shown in post#9 is a 5KV type. 15KV types are much longer.
Leo..