Recent content by riie

Forgot to mention that the dual dc supply is a variable supply used in lab. So just to confirm, I need a 7805 and a 7905 voltage regulator for +5v and -5v respectively?

Hi all, I have - 2 ICs that requires -10v and +10v - 1 IC that requires -5v and +5v How can I power them using one dual dc supply? Thanks!

anyone?

Hi all, Does anyone know how do I connect an OTA if I want to use it as a voltage-controlled current source, meaning that it will ouput an AC current when i supplied an AC voltage? Any guide I can refer to? And how do I adjust the gain or transconductance, gm? For example, OPA860 with...

The circuit from the thread you have given me, is the same mine with R2 removed. I'm not sure how to carry this out using my circuit, or another other method. For my circuit, - The left side circuit need to the 2 points to be connected for current to flow - But right side circuit has only one...

Any suggestions?

If I use a resistor to convert to current, wouldn't the transimpedance amplifier become an inverting amplifier as the resistor will be in series at the input? Is there a way to connect up the left hand side current output the the input at the right hand side?

Hi all, I need to have an AC current source for testing but i do not have any equipment that can generate an AC current source. I have a function generator to produce an AC sine voltage and thinking to convert V to I using the transconductance op amp. The first stage of my test circuit...

This is the datasheet of the instrumentation amplifier, INA116. www.ti.com/lit/ds/symlink/ina116.pdf You can see that the gain is set by the value of Rg.I am still learning by the day, so I'm not really sure will this method work. Or configuring a transimpedance amplifer (using electrometer...

IA is a instrumentation amplifier. So the last two steps are not required? The gain of the instrumentation amplifier can be set by an external resistor, apologizes for not showing. I am referring to the INA116 instrumentation amplifier as it's input bias current is 3fA(typ) so as not to affect...

The vibrating kelvin capacitor is made of a piezo-vibrated kelvin probe and sample plate. The AC current induced will be of same frequency with the frequency used to vibrate the probe. The attached image is a quick sketch of the method I am talking about. Other methods were using opamp or...

The 1x10^7 gain is from the 10Mega ohm resistor Not sure whether the induced AC current can be converted to voltage that way.

I am still exploring for solutions. Would it work if 1) A high precision resistor(0.02%) 10Mohm is used to convert I(nA to pA range) to V with a gain of 10^7 2) Then passed on to an instrumentation amplifier to remove any noise that is present and provide further gain. Am I oversimplifiying...

Sorry for not providing more info. Jim hardy is right, I am doing something similar to what he has stated. Have been reading about circuits that are used to measure the induced AC current that is produced by the vibrating kelvin probe which can be represented by the kelvin capacitor. This...

Anybody? :confused: