Hello Everybody,
I am trying to use my PC to measure resistance, capacitance and inductance
of the
respective components.
I would like to use the parallel or serial port to do it.
Do I need to have a ADC circuit to do it ?
I would appreciate any advice on this.
Thank you,
Indroneel
Yes, you need an ADC circuit, but it doesn't need to
be a "conventional" one using a commercial ADC chip.
If you are handy with programming low-level real-mode
DOS, you can do all sorts of tricks based upon timing
of printer port interrupt requests. You would need to
convert your input variables to an appropriate period or
frequency.
You can make a simple 8-bit R-2R ladder DAC that
the proper software can use to make a successive
approximation ADC. The LPTX driver for my Daqarta
software <
www.daqarta.com/download> includes
complete tutorial information on how to build this,
which you can read on-line before you download.
In many cases the whole works can be completely
passive; nothing but resistors, while the PC does
all the active stuff. If you use this circuit with the
LPTX driver, Daqarta can read it as a waveform
for a scope display, spectrum, or spectrogram in real-time.
Finally, the simplest way to do many measurement
tasks is to use the joystick port on a sound card.
There have been many articles written on how to
do this. The PC essentially measures resistance
based upon how long it takes to charge up a
capacitance as the resistance varies. You can
thus measure capacitance by the reverse approach.
Hope this helps!
Bob Masta
dqatechATdaqartaDOTcom
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com