Recent content by SanDiegan

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    AC Current Source: Build an Op-Amp Circuit for µA RMS

    Hi All, Thank you for all your contribution. I am going to try few circuits based on op-amp, and also with only resistors in series first before trying anything more complicated. We want an AC current just to be able to modulate it and filter the signal with the lockIn in order to cancel the...
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    AC Current Source: Build an Op-Amp Circuit for µA RMS

    Okay now I understand how it could generate an AC current. Does the attached picture correspond to your circuit / can it be used in my case? And last question how do you choose the power supply for the op-amp and the resistors? I know how to choose R3,R4,R5 (cf. the circuit) since they set the...
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    AC Current Source: Build an Op-Amp Circuit for µA RMS

    We can have a sine wave source, but I cannot find any information anywhere clearly stating the Howland circuit can be used to generate an AC current. And actually, we would like to avoid using a resistor, but yes that would have been an easy solution!
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    AC Current Source: Build an Op-Amp Circuit for µA RMS

    Hi everybody, As part of my research at UCSD, we are trying to measure Hall resistance of some materials. And to do that we need to send an AC current. So I wondered how we could easily build an ac current source, probably based on op-amp. I know there is the Howland circuit (current pump), but...