Hello everyone, I've been trying to build an EEG circuit found on one of the instructibles:
https://www.instructables.com/id/DIY-EEG-and-ECG-Circuit/Here they used 220nf ceramic capacitors which are non-polorised, would it be okay to use 220nf electrolic capacitors instead?

Thank you in advance!

 

It would be better to use ceramic, and also for the 10uf and 1uf cap as well.
Another problem would be that a 220nF electrolytic will be very hard to find, because very few manufacturers make electrolytics below 1uF.

 

You definitely do not want to do that. Ceramic capacitors have tighter tolerances and temperature coefficients than Electrolytics. The tolerance on capacitance for an Electrolytic is typically +20%, -80%

 

Electrolytics are polarized and have poorer characteristics compared to ceramics, so they are usually only used for coupling and filtering,
Why do you want to use electrolytics instead of ceramics?

 

Ok thank you for the replies

 

Electrolytics are polarized and have poorer characteristics compared to ceramics, so they are usually only used for coupling and filtering,
Why do you want to use electrolytics instead of ceramics?

I ordered the wrong ones

 

It looks like a typical Instructables circuit . If the opamps are LM358 (the text is too small to read clearly), does the circuit designer explain why only half of each IC is used, why unused opamps have floating inputs, or why the non-inverting inputs of some opamps are grounded via a resistor whereas others are grounded directly?