are the input impedances for both inverting and non-inverting amplifiers infinity?
What's the full part number of the opamp? The transistors that I'm referring to are inside the opamp -- that's how an opamp is made. Take a look at the datasheet for your opamp, or the one for a simple LM741, for example. In addition to listing the input characteristics of the opamp, they will usually show you a simplified equivalent circuit. That will show you approximately how they have built the opamp out of transistors, resistors and capacitors on the monolithic opamp IC.math&science said:but i was using a 411 amplifier and not transistors
Well, the LF411 has JFET input transistors, and its DC input resistance is listed as 10^12 Ohms typical. That's pretty high, but not infinite. The datasheet doesn't list input capacitance, unfortunately, but guess it's around 10pF and that gives about -j160kOhms of impedance, definitely not infinite.math&science said:Oh, I see what you're saying. I used an LF411. I guess my question was more of a theoretical one. Would it be infinity theoretically for both types?