Seeing tutorials about amplifiers

[Pellefant]

Hi i am looking after some good tutorial for amplifiers, and with amplifiers i mean Inverting amplifier, noe-inverting amplifier and diffrential amplifier. I should point out that i am a new about amplifiers atm.

Kindly Pellefant ...

[berkeman]

Thread moved to EE forum (the Tutorials forum is for posting tutorials, not for asking for pointers to tutorials).

I googled amplifier tutorial, and got lots of good hits. Here's the hit list:

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4SUNA_en___US232&q=amplifier+tutorial

[Pellefant]

Thread moved to EE forum (the Tutorials forum is for posting tutorials, not for asking for pointers to tutorials).

I googled amplifier tutorial, and got lots of good hits. Here's the hit list:

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4SUNA_en___US232&q=amplifier+tutorial

In more detail i need tutorials here i calculate on some simpel amp ... I haven't found any pedagogic tutorial for that yet :( ...

[edmondng]

what you're looking for are some 'general rules/laws' for op amp.
Then you can derive the output from the input.

For example amplifiers have high input impedance and low output impedance (so they can drive current). Also V- = V+. Then there is a need for some KCL, KVL, ohm's law.

http://www.google.com/search?hl=en&rlz=1T4SUNA_en___US232&q=inverting+amplifier&btnG=Search

[chroot]

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar.html

- Warren

[Pellefant]

http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar.html

- Warren

I am not sure but i think that was exactly what i wanted, thank you a bunch, Warren!

Kindly Paul

[TheAnalogKid83]

does v+ = v- under all conditions or just when the output is fedback into the + or - terminal??

[chroot]

does v+ = v- under all conditions or just when the output is fedback into the + or - terminal??

An op-amp will drive its inputs to the same voltage when it is physically possible. The amplifier cannot produce higher voltages than those of its supplies. Also, it cannot it source more power than it is designed to source, or more than the power supplies can deliver.

If you wire up an op-amp without any feedback, it will generally just rail one way or another. An op-amp circuit without any feedback would be entirely pointless.

- Warren

[TheAnalogKid83]

An op-amp will drive its inputs to the same voltage when it is physically possible. The amplifier cannot produce higher voltages than those of its supplies. Also, it cannot it source more power than it is designed to source, or more than the power supplies can deliver.

If you wire up an op-amp without any feedback, it will generally just rail one way or another. An op-amp circuit without any feedback would be entirely pointless.

- Warren

is this because it ideally has infinite gain and its unstable with such high gain, so the feedback stabilizes it? I haven't studied opamps in a couple years, but what about a differential operation of just subtracting v- from v+, where neither one is at ground level, does this still require feedback? I think almost all of the examples I've worked on and have read in my text book have always had one terminal grounded and it has given me a very limited idea of how to use and design circuits using opamps.

[chroot]

is this because it ideally has infinite gain and its unstable with such high gain, so the feedback stabilizes it? I haven't studied opamps in a couple years, but what about a differential operation of just subtracting v- from v+, where neither one is at ground level, does this still require feedback? I think almost all of the examples I've worked on and have read in my text book have always had one terminal grounded and it has given me a very limited idea of how to use and design circuits using opamps.

Yep, difference amps still require feedback. See, e.g. http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar6.html#c1

- Warren