throbscottle
Well-Known Member
Ok thanks for that both of you - my plan was to ensure the fixed and higher voltage rated capacitor was always the smaller value one, however it looks like this approach is inadequate. As to bandwidth, it doesn't need to be a particularly precise compensation, if I can get it up to 1MHz I'll be very happy. I did consider breaking up the top resistor into sections with a cap on each section but decided the ratio tolerance and t/c of the 1776 series Caddock divider I originally planned to use is more important as this is /mainly/ for DC, so the value can't be broken up. I may end up finding the right value with a trimmer and then making it up out of fixed capacitors in parallel. The alternative is using a fixed upper cap and trimming the larger capacitors on the smaller resistors.
The pcb option is a bit chunky - 4sq cm of fr4 gives about 1pF apparently, not to mention the additionnal leakage current so I don't think I'll be doing that!
The pcb option is a bit chunky - 4sq cm of fr4 gives about 1pF apparently, not to mention the additionnal leakage current so I don't think I'll be doing that!
