Hi Kai,
Thanks a lot for your helpfull response.

I would use TLC274, or even TLC279, if it is available in your region. It's a LinCMOS quad operational amplifier and has become a standard type. You should be able to get it.
It's not a rail to rail type, but delivers slightly higher output voltage than TL084. Advantageously is also its rather low current consumption of about 0.95mA typically per Opamp.

TLC274 excellent one! least Ib [biase current] I have ever come across. I have sent a quotation enquiry to RS India let's see if it fits in my budget.

Also, do use 1N4148 or even Schottkys instead of 1N4004 arround ICL7660.
With ICL7660 I used 1N4007.


Thanks & Regards,
Prahlad Purohit

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