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Pls simulate this active electrode using Ltspice or other simulators
loop123:
Hi can you pls simulate this active electrode circuit in Ltspice or other simulators? I dont know how and cant risk experiment with output that is unknown.
https://www.olimex.com/Products/EEG/Electrodes/EEG-AE/open-source-hardware
see clearer schematic above
The output plug is GndA, Chx_in and 5V. It is supposed to plug to their EEG-SMT but if the purpose is to get 5V to power it then get the Chx-in data to further amplify in the SMT amp. Then we can easily build adapter to power it with 5V and acquire the data to input any amplifier?
I just want to confirm. It has gain of 1 and no further amplification? Its only purpose is impedance converter to create high impedance input and low impedance output? So if I input 10microVolt or 1 milliVolt. It will also output same 10uV and 1 mV?
Thank you.
ataradov:
This is a very basic opamp amplifier in a unity gain configuration. It is just a buffer, there is no need to simulate it.
But if you are afraid that it will fry some sensitive equipment if gain is higher, then you absolutely need to do measurements on the real hardware before you plug it into anything. Just one poorly soldered pin and it will output full 5V.
loop123:
--- Quote from: ataradov on March 03, 2024, 06:06:43 am ---This is a very basic opamp amplifier in a unity gain configuration. It is just a buffer, there is no need to simulate it.
But if you are afraid that it will fry some sensitive equipment if gain is higher, then you absolutely need to do measurements on the real hardware before you plug it into anything. Just one poorly soldered pin and it will output full 5V.
--- End quote ---
What do you mean in second paragraph it can fry some sensitive equipment if gain is higher. I thought you said it is a buffer which means it has gain of 1. Also the output is always 5V? If gain is higher. It cant increase voltage since its powered by maximum 5V already so how can it fry other equipments?
Someone:
Posters might want to check the OP's topic history, its all pretty much on the evolution of one (questionable) project.
ataradov:
The schematic and practical implementation are two different things. The schematic is a unity gain buffer. But if in practice you forget to solder pin 2 or route something incorrectly, then it will output whatever voltage (up to 5V, of course). This is why you test stuff after assembly with test equipment before using in a real system.
I don't know how sensitive your equipment is. A lot of stuff can be damaged by 5V, especially if it only expects 10 mV.
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