At 11:14 AM 5/12/99 , you wrote:
>Friends,
>I have a project where I need to read an analog voltage of
>+7V-+18V. It is an internal power monitor of a RF amplifier.
>I am using it in a test fixture and was hoping of some way
>to read the voltage to know how many watts are at the
>output of the amp, without using a power meter.
>Does anybody know of an A/D converter that
>goes that high? Does the PICs internal A/D go that high?
>Any ideas?? Thanks in advance.............................

The PIC A/D converter won't go that high.  (I don't think any input
can go beyond the voltage rails).

However, a simple resistor ladder should do it.  If you want to get 256
levels between 7 and 18 volts, use an opamp to shift and scale the 7-18
volts to 0 to 5.

Matt

--
Matt Bennett
mjb@arlut.utexas.edu