Resistor Capacitor circuit

[maximade]

http://www.mediafire.com/?dqjlrfbu0m63l67
Hey I've been trying to recreate this circuit on a breadboard for a while and it never works...
Then I try to make it in a circuit simulator and it still doesn't work. Anyone know if the circuit actually works?
Also I believe this circuit can be used for measuring capacitance of capacitors, but is there any other useful applications in using this circuit? (like someone told me it could be use to find harmful things in blood)

[DarioC]

Pass on downloading unknown files from unknow site. Put the circuit here, then you will get comments, maybe answers.
DC

[berkeman]

http://www.mediafire.com/?dqjlrfbu0m63l67
Hey I've been trying to recreate this circuit on a breadboard for a while and it never works...
Then I try to make it in a circuit simulator and it still doesn't work. Anyone know if the circuit actually works?
Also I believe this circuit can be used for measuring capacitance of capacitors, but is there any other useful applications in using this circuit? (like someone told me it could be use to find harmful things in blood)

I agree with DarioC. I clicked on the link, and only got a bunch of popups. Please upload it as a PDF.

[maximade]

http://www.mediafire.com/?dqjlrfbu0m63l67
Hey I've been trying to recreate this circuit on a breadboard for a while and it never works...
Then I try to make it in a circuit simulator and it still doesn't work. Anyone know if the circuit actually works?
Also I believe this circuit can be used for measuring capacitance of capacitors, but is there any other useful applications in using this circuit? (like someone told me it could be use to find harmful things in blood)

Sorry about that, anyways I uploaded the PDF.

[berkeman]

Sorry about that, anyways I uploaded the PDF.

What do you mean it doesn't work in a circuit simulator? Do you have models for the parts used in the schematic? What does the simulation do that is not right? Do you get offset pulses at the final AND gate and nothing out? What about at the outputs of the two delays?

It will be hard to build this on a breadboard, unless you are building it onto a ground plane soldered breadboard. This is probably too fast of a circuit to prototype on a plastic plug-board.

As for applications, they mention very fast sampling as one. It could also be used for generating pulses for cable testing (TDR = time delay reflectometer). I don't see a direct application for capacitance testing.

[maximade]

What do you mean it doesn't work in a circuit simulator? Do you have models for the parts used in the schematic? What does the simulation do that is not right? Do you get offset pulses at the final AND gate and nothing out? What about at the outputs of the two delays?

It will be hard to build this on a breadboard, unless you are building it onto a ground plane soldered breadboard. This is probably too fast of a circuit to prototype on a plastic plug-board.

As for applications, they mention very fast sampling as one. It could also be used for generating pulses for cable testing (TDR = time delay reflectometer). I don't see a direct application for capacitance testing.

The picture of the similator is attached, anyways I think I am using wrong comparators, and I am also using a function generator in the similator as opposed to a pulse generator. Anyways hopefully that isn't the probelm I hope. Also at the top left part of the schematic, the thing above the "variable delay" is that a potentiometer?

Can you supply me pictures on what the plastic plug and the ground plane soldered breadboard looks like? Plus what do you mean by too fast? Once again thanks in advance.

[berkeman]

The picture of the similator is attached, anyways I think I am using wrong comparators, and I am also using a function generator in the similator as opposed to a pulse generator. Anyways hopefully that isn't the probelm I hope. Also at the top left part of the schematic, the thing above the "variable delay" is that a potentiometer?

Can you supply me pictures on what the plastic plug and the ground plane soldered breadboard looks like? Plus what do you mean by too fast? Once again thanks in advance.

Look farther back into the circuit with your observation oscilloscope in the simulation. What is coming out of the first comparator? And yes, I'd use pulse inputs instead of sine wave input.

The plated-through, pad per hole, 0.1" spacing, ground plane prototype board that I like to use is this:

Twin Industries 8200-4565 http://www.twinind.com/catalog_detail.php?id=116

There is interstitial ground plane on both sides (not connected to each other, though, unless you make the connection yourself). To ground a pin, you just short it to the interstitial ground with a solder bridge. You can make some nice low-impedance circuits using this prototype board, so it's good for high-speed digital circuits or low-level analog circuits.

[DarioC]

Questions: Do you have a scope? How fast is it? Make yourself a little pulse generator with a 555 or some better chip. As a matter of fact, you might want to build some slower pulse generators using chips like the 555 before you jump into the high speed stuff. Kinda work your way up to the faster and more complicated stuff.

The circuit looks workable to me as far as the general principle goes.

The board suggested appears to be very similar to those available at your local Radio Shack. That is if they are still available. Radio Shack seems to be turning into another consumer products Walmart, from what I have seen.