Jul 15, 2015 #1 C casemod Member level 1 Joined Sep 21, 2013 Messages 34 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Activity points 1,618 Is there a way to have a constant output when an opamp is used as an amplifier for an input signal with variable amplitude? If so, how could this be achieved? Basically how to change the opamp gain depending on the output voltage
Is there a way to have a constant output when an opamp is used as an amplifier for an input signal with variable amplitude? If so, how could this be achieved? Basically how to change the opamp gain depending on the output voltage
Jul 16, 2015 #2 W Warpspeed Advanced Member level 5 Joined May 23, 2015 Messages 2,366 Helped 773 Reputation 1,548 Reaction score 789 Trophy points 1,393 Location Melbourne, Australia Activity points 20,317 Usual way to do this is either with a variable transconductance amplifier, or an analog multiplier.
Jul 16, 2015 #3 crutschow Advanced Member level 6 Joined Feb 22, 2012 Messages 4,504 Helped 1,002 Reputation 2,002 Reaction score 1,145 Trophy points 1,393 Location Colorado USA Zulu -7 Activity points 25,591 Look up AGC (Automatic Gain Control) circuits. Below is the LTspice simulation of an example circuit. As you can see, the output remains fairly constant for a varying amplitude input.
Look up AGC (Automatic Gain Control) circuits. Below is the LTspice simulation of an example circuit. As you can see, the output remains fairly constant for a varying amplitude input.
Jul 16, 2015 #4 Audioguru Advanced Member level 7 Joined Jan 19, 2008 Messages 9,461 Helped 2,152 Reputation 4,304 Reaction score 2,009 Trophy points 1,393 Location Toronto area of Canada Activity points 59,764 The AGC circuit is used on Wien Bridge oscillators and on radio stations (and for TV audio).