• Re: AD8221 Problem

    Hi Matt, ^_^~

    I also want to ask questions about AD8221 here. Actually I built a very simple circuit with it, just as Figure 47 in AD8221 Datasheet (rev.C). I use 500ohm as Rg, +-15V as Power Supply, with 0.1uF capacitor on each power supply pin to REF…

  • 关于AD8221问题

    我用的是AD8221对信号进行放大,其中+V接的是+5V电压,-V接的地,Rg两端的电阻接的51欧姆(相当于放大了900倍左右),当输入端的电压为3.5mV的时候,输出电压为1.578V,当输入端变为3.9mV的时候,输出电压还是1.578V。
    当在AD8221输入端加(电阻为1K,电容为2.2UF)低通滤波器时,滤波器之前的电压由1.1mV变化到1.6mV,经过滤波后的电压为2.7mV变化到2.8mV(即AD8221两端的输入电压),而输出电压(放大900倍左右)一直都是2.51V保持不变,一直找不出原因来…

  • Offset null with AD8221

    Hello,

    I am working on some transducer application and need to measure very low voltage 0~800mV DC to convert it into 0~5VDC. I use AD8221 here with gain of 6.25 to achieve this. AD8221 is supplied with +/- 6VDC.

    Problem is, there remains about 2mV…

  • AD8221, Vin+=Vss Input

    Hi,

    I'm planning to use the AD8221 to measure current on the low-side of an AC Load. Before the current is measured, however, I plan to apply a 2.5V DC signal to the Neutral lead of the load to determine Neutral->Ground Isolation. When this occurs…

  • AD8221 gain of <1

    I am evaluating a circuit that uses an AD8221. The circuit is from a product I have bought recently and I am trying to establish what it does so I can develop using an alternative approach.

    Circuit below:

    R6+R3 (or R4+R5) form a potential divider on the…

  • using buffer with AD8221

    Hi,

    i would like to use AD8221 in one of my application, where idea is to amplify the differential potential recieved from 2 electrodes. To remove high frequency noise i use an RC filter just before the instrumentation amplifier input. do you think it…

  • AD8221 Rg Parasitics Cause Oscillation

    Hello,

    I have 2 AD8221 layouts, one which works well, and one identical schematic, different layout which has oscillations on the output.

    I have probed the inputs and they look good. If I remove my two resistors and open switches between RG terminals…

  • Orcad Capture simulation error using AD8221

    Hi..This is Anirban..I am trying to design an bridge amplification circuit using AD8221 in orcad capture. But while running I am getting an error msg as "ERROR --Subcircuit AD8221 used by X_U10 is undefined"...I am not understanding how to rectify this…

  • AD8221 vs. AD8421 for EMG signals

    Hi all,

    I need an instrumentation amplifier which will be used in an EMG signal processing project. I found the AD8221 and the AD8421. Which one is the best for this application? Are there any other specified IAs for Electromyography?

    Thanks in advance…

  • AD8221 gain smaller than 1

    Good morning, 

    I am using AD8221 in series (so one after the other) and I want to have a gain of 1, which is supposed to be the smallest possible when leaving the resistance pins in open circuit. However, for some reason, I am having gains between 0.8…