From 05dd07ce83028fce18d5f6993c230cbd3245331e Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Fri, 4 Jun 2010 12:23:14 +0100 Subject: [PATCH] clarify three stage pot div --- pt100/pt100.tex | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/pt100/pt100.tex b/pt100/pt100.tex index 3df29a5..6c67fe4 100644 --- a/pt100/pt100.tex +++ b/pt100/pt100.tex @@ -52,7 +52,9 @@ look-up tables or a suitable polynomial expression. \end{figure} -The voltage ranges we expect from this three stage potential divider +The voltage ranges we expect from this three stage potential divider\footnote{ +two stages are required for validation, a third stage is used to measure the current flowing +through the circuit to obtain accurate temperature readings} are shown in figure \ref{fig:pt100vrange}. Note that there is an expected range for each reading, for a given temperature span. Note that the low reading goes down as temperature increases, and the higher reading goes up.