Resistor Ohm Meter

[TheMadMan]

Hi All
Way back I seem to remember seeing a circuit in some book or other that acts like a resistor but can be changed using only electronic means. Was supposed to replace the volume pot in a amplifier I think.
Question 1 : Is it possible to "emulate" a resistor in this way?
Question 2 : Is it possible to "emulate" a capacitor as well?

Now the big question : If both the above are possible, does anyone have a circuit for each that is nice and simple (and stable).

Reason: I still like the 555 timer idea but dont want to have a whole bunch if resistors and caps to get it working. If there is a way to "create" the values I need, lets get the PIC to do the hard work. I'll worry about the display later.

Best

[T.Jackson]

Emulating a resistor? - grab yourself a BJT (bipolar junction transistor) - and there's your emulator. As for a capacitor? - just find other parts that exhibit good quantities of capacitive like characteristics and model a circuit around them.

[khetanikrunal]

hello friends,

I already obtain the range of 1mohm to 1 tera ohm but i need to go upto 1000 teraohm as per my specification.

so I need Schematic for this solution.

Thanking you,
khetani krunal

[Gusse]

Second time Wow!!

Your application must be something really extreme or not!
1000 Tera = 1000 * 10^12 = 1 Peta

So, you really want to measure up to 1 Peta ohm and with some self-made equipment
Before any hints for schematics. Could you tell a little bit more about you application?

Sorry, but this question make me smile

BR,
-Gusse-

[Dave]

I am also interested in the test voltage used for measuring the resistor?

Dave Purola,
N8NTA

[khetanikrunal]

hello,

These type of measuring devices are used to mesure Transformer oil conductivity.You will find other site too.

Once again i am asking for the schematic related to this topic.

thanking you,

krunal khetani

[Gusse]

I am also interested in the test voltage used for measuring the resistor?

I would be also very curious to know that, because it must be very high. Also how low currents you can measure? Depends on that quite much.

hello,

These type of measuring devices are used to mesure Transformer oil conductivity.You will find other site too.

Once again i am asking for the schematic related to this topic.

thanking you,

krunal khetani

I though that it must be something to do with insulators, obviously. Is there any way that you could boost your existing equipment? I know, 1000x times more is pretty tough requirement (=1000x times high test voltage).

BR,
-Gusse-