19-02-2017, 03:01 PM
Forget about power ratings in this application - it is the voltage rating which is important.
Although voltage and current govern the ratings of resistors in most normal applications, there will be a maximum voltage for any resistor type regardless of current.
The maximum voltage for a 0.125W resistor might be as low as 150V and will increase slightly for every doubling of power rating. The actual figure will vary depending on resistor type and manufacturer so, if you have some suitable high value resistors you would like to use, it would be wise to seek out the manufacturer's data.
Alternatively, use the chart below but derate the figures shown by 50V to be on the safe side.
For example, if you have a 100 1M 0.5W resistors kicking around you could build a 100M chain with a maximum voltage rating
of around 300kV - but I wouldn't really recommend it!
Although voltage and current govern the ratings of resistors in most normal applications, there will be a maximum voltage for any resistor type regardless of current.
The maximum voltage for a 0.125W resistor might be as low as 150V and will increase slightly for every doubling of power rating. The actual figure will vary depending on resistor type and manufacturer so, if you have some suitable high value resistors you would like to use, it would be wise to seek out the manufacturer's data.
Alternatively, use the chart below but derate the figures shown by 50V to be on the safe side.
For example, if you have a 100 1M 0.5W resistors kicking around you could build a 100M chain with a maximum voltage rating
of around 300kV - but I wouldn't really recommend it!
