gain of LM3900?

I have just completed the first stage of my project and have a question regarding the LM3900 chip, on the input i have such a small sinewave it is barely visible with the scope, meanwhile i have a thumping great sinewave on the output pin, it's beautiful!!!

So what is the gain of the LM3900? it must be huge?

Neil.

I guess you didn't look at its datasheet. It is a very odd quad amplifier.
Its voltage gain is typically only 2800, minimum of 1200.
Most ordinary opamps have a voltage gain of 200,000 up to millions. They use lots of negative feedback to reduce the gain, reduce the distortion and reduce the output impedance.

Thanks AudioGuru....no i didn't look at the datasheet, simply because that kind of stuff is way beyond my ability to understand and comprehend, i'm not an engineer, just a backstreet kid enjoying building circuits and learning stuff along the way, would you believe my interest in electronics stemmed from looking inside a radio many years ago and wondering what all the pretty coloured bits were for lol

Opamps are a mystery i want to unravel once i get my projects i am currently working on finished, i am keen to get the hang of some of the maths behind negative and positive gain.

Neil.

Neil,
Here are 2 Op Amp amplifier configurations.

If you want to know how the formulae are derived, just let me know & I'll write out the maths for you.

Len

Thanks Len, i can't wait till i get my current projects finished so i can build these 2 circuits for real, stick a waveform in and have a scope around to see whats going on. i may then contact you for the math, so i can get a better understanding of what is going on.

Neil.