At 06:39 20/05/97 +0200, Tjaart van der Walt wrote:
>Gerhard Fiedler wrote:
>>
>> At 20:03 19/05/97 +0300, Jussi Vainionp wrote:
>> >Microchip application note AN513 describes a method for ADC.
>> >I'm not that great at analog electronics, and I don't quite understand the
>> >schematics. It has this chip that is supposed to be voltage to current
>> >converter 4066, but according to my data it is a quad bilateral analog
>> >switch. How could it convert anything?
>
>Why not charge a cap and measure time-to-trip on an input? You only
>need a cap and two resistors.

I've never tried this approach, but I saw a Philips app note doing some
analysis of a similar method to measure resistance, and they came up with
around 5 bit for the most simple version (one port, one C, and one R),
about 8 bit for a version using two ports and two HC buffers, and around 14
bit using two comparators.

Since what you suggest seems to be similar, I think the results might be
similar, too. Do you have any experience with the precision and
repeatability (also over temp range) with this simple circuit?