bluesteel Posted May 4, 2010 Report Share Posted May 4, 2010 Hi Allive had a look around but cant seem to find any answers for what im trying to doi have a signal that basically goes from 5v to 0v and i need to invert it to 0v to 5vi have used a simple inverting op amp circuit based on an lm741the actual input voltages are 4.8v to 0.9v and i cant quite get the output to reflect that properly.i have changed the input resistor to change the high output side, and that is now up to 4.5v and that is good.i cannot however get the low output side to drop under 1vattatched is a diagram with what i haveany help would be awesomecheers Quote Link to comment Share on other sites More sharing options...
indulis Posted May 4, 2010 Report Share Posted May 4, 2010 The 741 can't swing to GND, you need a negative supply of a few volts. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 4, 2010 Report Share Posted May 4, 2010 The inputs of a 741 opamp must be at least 3V more positive of pin 4.Your input pin 3 is the same voltage as pin 4 so its input transistors are completely turned off all the time.Bias pin 3 at +3V with two resistors then the opamp will have an output high voltage of +10.8V and an output low voltage of +1.2V.Why not use a Cmos logic inverter? There are 6 in one package and they can be paralleled for more output current if you want. Quote Link to comment Share on other sites More sharing options...
login
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.