Hi, Me and my group are working on an ECG circuit. The one where the doctor in hospitals stick the electrodes and measure your electrical pulses. Anyways our lab tutor wants us to use only 1 opamp, he wants an LM341 only and it has to provide a gain of Av = 1000. The input frequencies will only be between 1-40Hz sine wave. The datasheet says the typical gain as 200, not even 1000. I designed a 2-stage amplifier with the LM341, the first stage amplies to 100 and the 2nd stage amplifies by 10 giving an overall gain of 1000. However the tutor said he wont accept it since he only wants 1 LM341 to be used. So my group member proposes we use this circuit a few days later when we met up (another group used a similar one - they 'googled' it and the tutor accepted):
With R3 at 100k, and R1 at 100Ohm so Av = 1000. Our power sources are 2x 9V batteries, V+ has +9V. and V- has -9V. The problem looks somewhat like this (I know lame drawing), it simply does not seem to amplify.
I've included as an attachment my original design in multisim of the 2-stage amplifier using 2 LM341s that I did.
Any ideas? Thanks guys!
With R3 at 100k, and R1 at 100Ohm so Av = 1000. Our power sources are 2x 9V batteries, V+ has +9V. and V- has -9V. The problem looks somewhat like this (I know lame drawing), it simply does not seem to amplify.
I've included as an attachment my original design in multisim of the 2-stage amplifier using 2 LM341s that I did.
Any ideas? Thanks guys!
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